Merge branch 'master' of https://github.com/OpenSkywalking/skywalking-netcore

appveyor.yml

@@ -23,3 +23,11 @@ deploy:
   artifact: /artifacts\/packages\/.+\.nupkg/
   on:
     branch: master
+- provider: NuGet
+  server: https://api.nuget.org/v3/index.json
+  api_key:
+    secure: 6N8pLjIHa7SK3l+Lj7b1qKk7CvKdZdQyj9ZNTaUjfPSd+/SL8PuSHq+ysNKaMHAF
+  skip_symbols: true
+  artifact: /artifacts\/packages\/.+\.nupkg/
+  on:
+    appveyor_repo_tag: true

build/version.cake

@@ -76,9 +76,17 @@ public class BuildParameters
 
 		var suffix = versionQuality;
 		if (!IsTagged)
+		{
+			var buildSystem = Context.BuildSystem();
+			if (buildSystem.IsRunningOnAppVeyor && buildSystem.AppVeyor.Environment.Repository.Branch == "master")
+			{
+				suffix += "prerelease-" + Util.CreateStamp();
+			} 
+			else
 			{
 				suffix += (IsCI ? "preview-" : "dev-") + Util.CreateStamp();
 			}
+		}
 		suffix = string.IsNullOrWhiteSpace(suffix) ? null : suffix;
 
 		Version =

build/version.props

 <Project>
 	<PropertyGroup>
 		<VersionMajor>0</VersionMajor>
-		<VersionMinor>3</VersionMinor>
+		<VersionMinor>6</VersionMinor>
 		<VersionPatch>0</VersionPatch>
 		<VersionQuality></VersionQuality>
 		<VersionPrefix>$(VersionMajor).$(VersionMinor).$(VersionPatch)</VersionPrefix>

sample/SkyWalking.Sample.AspNet/SkyWalking.Sample.AspNet.csproj

@@ -10,7 +10,7 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>SkyWalking.Sample.AspNet</RootNamespace>
     <AssemblyName>SkyWalking.Sample.AspNet</AssemblyName>
-    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v4.6.1</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">

sample/SkyWalking.Sample.Backend/SkyWalking.Sample.Backend.csproj

@@ -12,4 +12,17 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />
   </ItemGroup>
+  <ItemGroup>
+    <Content Update="appsettings.json">
+      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </Content>
+    <Content Update="appsettings.Development.json">
+      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+  <ItemGroup>
+    <Folder Include="logs" />
+  </ItemGroup>
 </Project>
\ No newline at end of file

sample/SkyWalking.Sample.Backend/Startup.cs

@@ -25,13 +25,6 @@ namespace SkyWalking.Sample.Backend
         {
             services.AddMvc();
             
-            services.AddSkyWalking(option =>
-            {
-                option.DirectServers = "localhost:11800";
-                option.ApplicationCode = "asp-net-core-backend";
-            }).
-            AddEntityFrameworkCore(c => { c.AddSqlite(); });
-
             var sqliteConnection = new SqliteConnection("DataSource=:memory:");
             sqliteConnection.Open();
             

sample/SkyWalking.Sample.Backend/appsettings.json

@@ -11,5 +11,8 @@
         "Default": "Warning"
       }
     }
+  },
+  "SkyWalking": {
+    "ApplicationCode": "asp-net-core-backend"
   }
 }

sample/SkyWalking.Sample.Frontend/Controllers/ValuesController.cs

@@ -9,7 +9,7 @@ namespace SkyWalking.Sample.Frontend.Controllers
     public class ValuesController : Controller
     {
         // GET api/values
-        [HttpGet]
+        [HttpGet("/values")]
         public async Task<IEnumerable<string>> Get()
         {
             await new HttpClient().GetAsync("http://localhost:5002/api/values");

sample/SkyWalking.Sample.Frontend/SkyWalking.Sample.Frontend.csproj

@@ -11,4 +11,10 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />
   </ItemGroup>
+  <ItemGroup>
+    <Content Update="appsettings.json">
+      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
 </Project>
\ No newline at end of file

sample/SkyWalking.Sample.Frontend/Startup.cs

@@ -19,12 +19,6 @@ namespace SkyWalking.Sample.Frontend
         public void ConfigureServices(IServiceCollection services)
         {
             services.AddMvc();
-             
-            services.AddSkyWalking(option =>
-            {
-                option.DirectServers = "localhost:11800";
-                option.ApplicationCode = "asp-net-core-frontend";
-            }); 
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.

sample/SkyWalking.Sample.Frontend/appsettings.json

@@ -11,6 +11,9 @@
         "Default": "Warning"
       }
     }
+  },
+  "SkyWalking": {
+    "ApplicationCode": "asp-net-core-frontend"
   }
 }
 

src/SkyWalking.Abstractions/Components/ComponentsDefine.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+using System.Collections.Generic;
+
+namespace SkyWalking.Components
+{
+    public class ComponentsDefine
+    {
+        public static readonly IComponent HttpClient = new OfficialComponent(2, "HttpClient");
+        
+        public static readonly IComponent AspNetCore = new OfficialComponent(3001, "AspNetCore");
+
+        public static readonly IComponent EntityFrameworkCore = new OfficialComponent(3002, "EntityFrameworkCore");
+
+        public static readonly IComponent SqlClient = new OfficialComponent(3003, "SqlClient");
+        
+        public static readonly IComponent CAP = new OfficialComponent(3004, "CAP");
+        
+        public static readonly IComponent StackExchange_Redis = new OfficialComponent(3005, "StackExchange.Redis");
+        
+        public static readonly IComponent SqlServer = new OfficialComponent(3006, "SqlServer");
+        
+        public static readonly IComponent Npgsql = new OfficialComponent(3007, "Npgsql");
+        
+        public static readonly IComponent MySqlConnector = new OfficialComponent(3008, "MySqlConnector");
+        
+        public static readonly IComponent EntityFrameworkCore_InMemory = new OfficialComponent(3009, "EntityFrameworkCore.InMemory");
+        
+        public static readonly IComponent EntityFrameworkCore_SqlServer = new OfficialComponent(3010, "EntityFrameworkCore.SqlServer");
+        
+        public static readonly IComponent EntityFrameworkCore_Sqlite = new OfficialComponent(3011, "EntityFrameworkCore.Sqlite");
+        
+        public static readonly IComponent Pomelo_EntityFrameworkCore_MySql = new OfficialComponent(3012, "Pomelo.EntityFrameworkCore.MySql");
+        
+        public static readonly IComponent Npgsql_EntityFrameworkCore_PostgreSQL = new OfficialComponent(3013, "Npgsql.EntityFrameworkCore.PostgreSQL");
+        
+        public static readonly IComponent InMemoryDatabase = new OfficialComponent(3014, "InMemoryDatabase");
+        
+        public static readonly IComponent AspNet = new OfficialComponent(3015, "AspNet");
+    }
+}

src/SkyWalking.NetworkProtocol.Trace/IComponent.cs → src/SkyWalking.Abstractions/Components/IComponent.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -16,7 +16,7 @@
  *
  */
 
-namespace SkyWalking.NetworkProtocol.Trace
+namespace SkyWalking.Components
 {
     /// <summary>
     /// The <code>Component</code> represents component library , which has been supported by skywalking
@@ -24,6 +24,7 @@ namespace SkyWalking.NetworkProtocol.Trace
     public interface IComponent
     {
         int Id { get; }
+        
         string Name { get; }
     }
 }
\ No newline at end of file

src/SkyWalking.NetworkProtocol.Trace/OfficialComponent.cs → src/SkyWalking.Abstractions/Components/OfficialComponent.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -16,7 +16,7 @@
  *
  */
 
-namespace SkyWalking.NetworkProtocol.Trace
+namespace SkyWalking.Components
 {
     public class OfficialComponent : IComponent
     {

src/SkyWalking.Abstractions/Config/AgentConfig.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-namespace SkyWalking.Config
-{
-    public static class AgentConfig
-    {
-        /// <summary>
-        /// Namespace isolates headers in cross propagation. The HEADER name will be 'HeaderName:Namespace'.
-        /// </summary>
-        public static string Namespace { get; set; }
-
-        /// <summary>
-        /// Application code is showed in sky-walking-ui
-        /// </summary>
-        public static string ApplicationCode { get; set; }
-
-        /// <summary>
-        /// The number of sampled traces per 3 seconds
-        /// Negative number means sample traces as many as possible, most likely 100% , by default
-        /// 
-        /// </summary>
-        public static int SamplePer3Secs = -1;
-
-        /// <summary>
-        /// If the operation name of the first span is included in this set, this segment should be ignored.
-        /// </summary>
-        public static string IgnoreSuffix = ".jpg,.jpeg,.js,.css,.png,.bmp,.gif,.ico,.mp3,.mp4,.html,.svg";
-
-        /// <summary>
-        /// The max number of spans in a single segment. Through this config item, skywalking keep your application memory cost estimated.
-        /// </summary>
-        public static int SpanLimitPerSegment = 300;
-
-        /// <summary>
-        /// The max number of segments in the memory queue waiting to be sent to collector.
-        /// It means that when the number of queued segments reachs this limit,
-        /// any more segments enqueued into the sending queue, will leads the same number of oldest queued segments dequeued and droped.
-        /// Zero or minus value means no limit.
-        /// </summary>
-        public static int PendingSegmentsLimit = 300000;
-        
-    }
-}
\ No newline at end of file

src/SkyWalking.Abstractions/Config/CollectorConfig.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-namespace SkyWalking.Config
-{
-    public class CollectorConfig
-    {
-        /// <summary>
-        /// service registry check interval
-        /// </summary>
-        public static long ServiceRegisterCheckInterval { get; set; } = 3;
-        
-        /// <summary>
-        /// Collector agent_gRPC/grpc service addresses.
-        /// By using this, no discovery mechanism provided. The agent only uses these addresses to uplink data.
-        /// Recommend to use this only when collector cluster IPs are unreachable from agent side. Such as:
-        /// 1. Agent and collector cluster are in different VPC in Cloud.
-        /// 2. Agent uplinks data to collector cluster through Internet.
-        /// Single collector：DirectServers="127.0.0.1:11800"
-        /// Collector cluster：DirectServers="10.2.45.126:11800,10.2.45.127:11800"
-        /// </summary>
-        public static string DirectServers { get; set; }
-        
-        public static string Authentication { get; set; }
-        
-        public static string CertificatePath { get; set; }
-    }
-}
\ No newline at end of file

src/SkyWalking.Core/Dictionary/NotFound.cs → src/SkyWalking.Abstractions/Config/ConfigAttribute.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
@@ -16,17 +16,17 @@
  *
  */
 
-using SkyWalking.Dictionarys;
+using System;
 
-namespace SkyWalking.Dictionarys
+namespace SkyWalking.Config
 {
-    public class NotFound : PossibleFound
+    public class ConfigAttribute : Attribute
     {
-        public NotFound()
-            : base()
+        public string[] Sections { get; }
+
+        public ConfigAttribute(params string[] sections)
         {
+            Sections = sections;
         }
-
-        public static readonly PossibleFound Instance = new NotFound();
     }
 }
\ No newline at end of file

src/SkyWalking.Abstractions/Config/DictionaryConfig.cs → src/SkyWalking.Abstractions/Config/IConfigAccessor.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
@@ -18,10 +18,10 @@
 
 namespace SkyWalking.Config
 {
-    public static class DictionaryConfig
+    public interface IConfigAccessor
     {
-        public static int ApplicationCodeBufferSize { get; set; } = 10 * 10000;
+        T Get<T>() where T : class, new();
 
-        public static int OperationNameBufferSize { get; set; } = 1000 * 10000;
+        T Value<T>(string key, params string[] sections);
     }
 }
\ No newline at end of file

src/SkyWalking.Abstractions/Config/InstrumentationConfig.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+namespace SkyWalking.Config
+{
+    [Config("SkyWalking")]
+    public class InstrumentationConfig
+    {
+        public string Namespace { get; set; }
+
+        public string ApplicationCode { get; set; }
+
+        public int SpanLimitPerSegment { get; set; } = 300;
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/Config/RuntimeConfig.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+namespace SkyWalking.Config
+{
+    public class RuntimeConfig
+    {
+        public NullableValue ApplicationId { get; set; }
+
+        public NullableValue ApplicationInstance { get; set; }
+    }
+}
\ No newline at end of file

src/SkyWalking.Core/Dictionary/Found.cs → src/SkyWalking.Abstractions/Config/SamplingConfig.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
@@ -16,15 +16,11 @@
  *
  */
 
-using SkyWalking.Dictionarys;
-
-namespace SkyWalking.Dictionarys
+namespace SkyWalking.Config
 {
-    public class Found : PossibleFound
-    {
-        public Found(int value)
-            : base(value)
+    [Config("SkyWalking", "Sampling")]
+    public class SamplingConfig
     {
-        }
+        public int SamplePer3Secs { get; set; } = -1;
     }
 }
\ No newline at end of file

src/SkyWalking.Abstractions/Config/TransportConfig.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+namespace SkyWalking.Config
+{
+    [Config("SkyWalking", "Transport")]
+    public class TransportConfig
+    {
+        public int PendingSegmentLimit { get; set; } = 30000;
+        
+        /// <summary>
+        /// Flush Interval Millisecond
+        /// </summary>
+        public int Interval { get; set; } = 3000;
+
+        /// <summary>
+        /// Data queued beyond this time will be discarded.
+        /// </summary>
+        public int PendingSegmentTimeout { get; set; } = 1000;
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/Context/CarrierItem.cs

@@ -16,56 +16,33 @@
  *
  */
 
-using System;
 using System.Collections;
 using System.Collections.Generic;
-using SkyWalking.Config;
 
 namespace SkyWalking.Context
 {
     public class CarrierItem : IEnumerable<CarrierItem>
     {
-        private string _headKey;
+        private readonly string _headKey;
         private string _headValue;
-        private CarrierItem _next;
+        private readonly CarrierItem _next;
 
-        public virtual string HeadKey
-        {
-            get
-            {
-                return _headKey;
-            }
-        }
+        public virtual string HeadKey => _headKey;
 
         public virtual string HeadValue
         {
-            get
-            {
-                return _headValue;
-            }
-            set
-            {
-                _headValue = value;
-            }
+            get => _headValue;
+            set => _headValue = value;
         }
 
-        public CarrierItem(String headKey, String headValue)
+        protected CarrierItem(string headKey, string headValue, string @namespace)
+            : this(headKey, headValue, null, @namespace)
         {
-            _headKey = headKey;
-            _headValue = headValue;
-            _next = null;
         }
 
-        public CarrierItem(String headKey, String headValue, CarrierItem next)
+        protected CarrierItem(string headKey, string headValue, CarrierItem next, string @namespace)
         {
-            if (string.IsNullOrEmpty(AgentConfig.Namespace))
-            {
-                _headKey = headKey;
-            }
-            else
-            {
-                _headKey = $"{AgentConfig.Namespace}-{headKey}";
-            }
+            _headKey = string.IsNullOrEmpty(@namespace) ? headKey : $"{@namespace}-{headKey}";
             _headValue = headValue;
             _next = next;
         }
@@ -82,17 +59,16 @@ namespace SkyWalking.Context
 
         private class Enumerator : IEnumerator<CarrierItem>
         {
-            private CarrierItem _head;
-            private CarrierItem _current;
+            private readonly CarrierItem _head;
 
-            public CarrierItem Current => _current;
+            public CarrierItem Current { get; private set; }
 
-            object IEnumerator.Current => _current;
+            object IEnumerator.Current => Current;
 
             public Enumerator(CarrierItem head)
             {
                 _head = head;
-                _current = head;
+                Current = head;
             }
 
             public void Dispose()
@@ -101,18 +77,19 @@ namespace SkyWalking.Context
 
             public bool MoveNext()
             {
-                var next = _current._next;
+                var next = Current._next;
                 if (next == null)
                 {
                     return false;
                 }
-                _current = next;
+
+                Current = next;
                 return true;
             }
 
             public void Reset()
             {
-                _current = _head;
+                Current = _head;
             }
         }
     }

src/SkyWalking.Core/Utils/TaskUtils.cs → src/SkyWalking.Abstractions/Context/IContextCarrierFactory.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -16,12 +16,10 @@
  *
  */
 
-using System.Threading.Tasks;
-
-namespace SkyWalking.Utils
+namespace SkyWalking.Context
 {
-    internal static class TaskUtils
+    public interface IContextCarrierFactory
     {
-        public static readonly Task CompletedTask = Task.FromResult(0);
+        IContextCarrier Create();
     }
 }
\ No newline at end of file

src/SkyWalking.Abstractions/Context/Ids/DistributedTraceId.cs

@@ -18,11 +18,12 @@
 
 
 using System;
-using SkyWalking.NetworkProtocol;
+using SkyWalking.Transport;
 
 namespace SkyWalking.Context.Ids
 {
 
+    /// <inheritdoc />
     /// <summary>
     /// The <code>DistributedTraceId</code> presents a distributed call chain.
     /// This call chain has an unique (service) entrance,
@@ -34,50 +35,35 @@ namespace SkyWalking.Context.Ids
     {
         private readonly ID _id;
 
-        public DistributedTraceId(ID id)
+        protected DistributedTraceId(ID id)
         {
             _id = id;
         }
 
-        public DistributedTraceId(string id)
+        protected DistributedTraceId(string id)
         {
             _id = new ID(id);
         }
 
-        public string Encode
-        {
-            get
-            {
-                return _id?.Encode;
-            }
-        }
+        public string Encode => _id?.Encode;
 
-        public UniqueId ToUniqueId()
-        {
-            return _id?.Transform();
-        }
+        public UniqueIdRequest ToUniqueId() => _id?.Transform();
 
         public bool Equals(DistributedTraceId other)
         {
             if (other == null)
                 return false;
-            return _id != null ? _id.Equals(other._id) : other._id == null;
+            return _id?.Equals(other._id) ?? other._id == null;
         }
 
         public override bool Equals(object obj)
         {
-            DistributedTraceId id = obj as DistributedTraceId;
+            var id = obj as DistributedTraceId;
             return Equals(id);
         }
 
-        public override int GetHashCode()
-        {
-            return _id != null ? _id.GetHashCode() : 0;
-        }
+        public override int GetHashCode() => _id != null ? _id.GetHashCode() : 0;
 
-        public override string ToString()
-        {
-            return _id?.ToString();
-        }
+        public override string ToString() => _id?.ToString();
     }
 }

src/SkyWalking.Abstractions/Context/Ids/ID.cs

@@ -17,7 +17,7 @@
  */
 
 using System;
-using SkyWalking.NetworkProtocol;
+using SkyWalking.Transport;
 
 namespace SkyWalking.Context.Ids
 {
@@ -26,35 +26,18 @@ namespace SkyWalking.Context.Ids
         private readonly long _part1;
         private readonly long _part2;
         private readonly long _part3;
-        private readonly bool _isValid;
         private string _encoding;
 
-        public bool IsValid
-        {
-            get
-            {
-                return _isValid;
-            }
-        }
+        public bool IsValid { get; }
 
-        public string Encode
-        {
-            get
-            {
-                if (_encoding == null)
-                {
-                    _encoding = ToString();
-                }
-                return _encoding;
-            }
-        }
+        public string Encode => _encoding ?? (_encoding = ToString());
 
         public ID(long part1, long part2, long part3)
         {
             _part1 = part1;
             _part2 = part2;
             _part3 = part3;
-            _isValid = true;
+            IsValid = true;
         }
 
         public ID(string encodingString)
@@ -68,17 +51,17 @@ namespace SkyWalking.Context.Ids
             {
                 if (part == 0)
                 {
-                    _isValid = long.TryParse(idParts[part], out _part1);
+                    IsValid = long.TryParse(idParts[part], out _part1);
                 }
                 else if (part == 1)
                 {
-                    _isValid = long.TryParse(idParts[part], out _part2);
+                    IsValid = long.TryParse(idParts[part], out _part2);
                 }
                 else
                 {
-                    _isValid = long.TryParse(idParts[part], out _part3);
+                    IsValid = long.TryParse(idParts[part], out _part3);
                 }
-                if (!_isValid)
+                if (!IsValid)
                 {
                     break;
                 }
@@ -92,7 +75,7 @@ namespace SkyWalking.Context.Ids
 
         public override int GetHashCode()
         {
-            int result = (int)(_part1 ^ (_part1 >> 32));
+            var result = (int)(_part1 ^ (_part1 >> 32));
             result = 31 * result + (int)(_part2 ^ (_part2 >> 32));
             result = 31 * result + (int)(_part3 ^ (_part3 >> 32));
             return result;
@@ -100,7 +83,7 @@ namespace SkyWalking.Context.Ids
 
         public override bool Equals(object obj)
         {
-            ID id = obj as ID;
+            var id = obj as ID;
             return Equals(id);
         }
 
@@ -117,12 +100,9 @@ namespace SkyWalking.Context.Ids
             return _part3 == other._part3;
         }
 
-        public UniqueId Transform()
+        public UniqueIdRequest Transform()
         {
-            UniqueId uniqueId = new UniqueId();
-            uniqueId.IdParts.Add(_part1);
-            uniqueId.IdParts.Add(_part2);
-            uniqueId.IdParts.Add(_part3);
+            var uniqueId = new UniqueIdRequest {Part1 = _part1, Part2 = _part2, Part3 = _part3};
             return uniqueId;
         }
     }

src/SkyWalking.Abstractions/Context/Trace/AbstractTracingSpan.cs

@@ -18,11 +18,8 @@
 
 using System;
 using System.Collections.Generic;
-using SkyWalking.Dictionarys;
-using SkyWalking.NetworkProtocol;
-using SkyWalking.NetworkProtocol.Trace;
-using System.Linq;
-using SkyWalking.Utils;
+using SkyWalking.Transport;
+using SkyWalking.Components;
 
 namespace SkyWalking.Context.Trace
 {
@@ -31,8 +28,8 @@ namespace SkyWalking.Context.Trace
     /// </summary>
     public abstract class AbstractTracingSpan : ISpan
     {
-        protected int _spanId;
-        protected int _parnetSpanId;
+        protected readonly int _spanId;
+        protected readonly int _parnetSpanId;
         protected Dictionary<string, string> _tags;
         protected string _operationName;
         protected int _operationId;
@@ -69,7 +66,6 @@ namespace SkyWalking.Context.Trace
         protected AbstractTracingSpan(int spanId, int parentSpanId, string operationName)
         {
             _operationName = operationName;
-            _operationId = DictionaryUtil.NullValue;
             _spanId = spanId;
             _parnetSpanId = parentSpanId;
         }
@@ -90,23 +86,17 @@ namespace SkyWalking.Context.Trace
 
         public virtual string OperationName
         {
-            get
-            {
-                return _operationName;
-            }
+            get => _operationName;
             set
             {
                 _operationName = value;
-                _operationId = DictionaryUtil.NullValue;
+                _operationId = 0;
             }
         }
 
         public virtual int OperationId
         {
-            get
-            {
-                return _operationId;
-            }
+            get => _operationId;
             set
             {
                 _operationId = value;
@@ -132,6 +122,7 @@ namespace SkyWalking.Context.Trace
             {
                 _tags = new Dictionary<string, string>();
             }
+
             _tags.Add(key, value);
             return this;
         }
@@ -166,11 +157,12 @@ namespace SkyWalking.Context.Trace
         public virtual ISpan Log(long timestamp, IDictionary<string, object> events)
         {
             EnsureLogs();
-            LogDataEntity.Builder builder = new LogDataEntity.Builder();
+            var builder = new LogDataEntity.Builder();
             foreach (var @event in events)
             {
                 builder.Add(@event.Key, @event.Value.ToString());
             }
+
             _logs.Add(builder.Build(timestamp));
             return this;
         }
@@ -193,6 +185,7 @@ namespace SkyWalking.Context.Trace
             {
                 _refs = new List<ITraceSegmentRef>();
             }
+
             if (!_refs.Contains(traceSegmentRef))
             {
                 _refs.Add(traceSegmentRef);
@@ -211,69 +204,58 @@ namespace SkyWalking.Context.Trace
             return true;
         }
 
-        public virtual SpanObject Transform()
+        public virtual SpanRequest Transform()
         {
-            SpanObject spanObject = new SpanObject();
-
-            spanObject.SpanId = _spanId;
-            spanObject.ParentSpanId = _parnetSpanId;
-            spanObject.StartTime = _startTime;
-            spanObject.EndTime = _endTime;
-
-            if (_operationId != DictionaryUtil.NullValue)
+            var spanRequest = new SpanRequest
             {
-                spanObject.OperationNameId = _operationId;
-            }
-            else
-            {
-                spanObject.OperationName = _operationName;
-            }
+                SpanId = _spanId,
+                ParentSpanId = _parnetSpanId,
+                StartTime = _startTime,
+                EndTime = _endTime,
+                OperationName = new StringOrIntValue(_operationId, _operationName),
+                Component = new StringOrIntValue(_componentId, _componentName),
+                IsError = _errorOccurred
+            };
 
             if (IsEntry)
             {
-                spanObject.SpanType = SpanType.Entry;
+                spanRequest.SpanType = 0;
             }
             else if (IsExit)
             {
-                spanObject.SpanType = SpanType.Exit;
+                spanRequest.SpanType = 1;
             }
             else
             {
-                spanObject.SpanType = SpanType.Local;
+                spanRequest.SpanType = 2;
             }
 
             if (_layer.HasValue)
             {
-                spanObject.SpanLayer = (NetworkProtocol.SpanLayer)((int)_layer.Value);
-            }
-
-            if (_componentId != DictionaryUtil.NullValue)
-            {
-                spanObject.ComponentId = _componentId;
-            }
-            else
-            {
-                spanObject.Component = _componentName;
+                spanRequest.SpanLayer = (int) _layer.Value;
             }
 
-            spanObject.IsError = _errorOccurred;
 
-            if (_tags != null)
+            foreach (var tag in _tags)
             {
-                spanObject.Tags.Add(_tags.Select(x => new KeyWithStringValue { Key = x.Key, Value = x.Value }));
+                spanRequest.Tags.Add(new KeyValuePair<string, string>(tag.Key, tag.Value));
             }
 
             if (_logs != null)
             {
-                spanObject.Logs.Add(_logs.Select(x => x.Transform()));
+                foreach (var logDataEntity in _logs)
+                {
+                    spanRequest.Logs.Add(logDataEntity.Transform());
+                }
             }
 
-            if (_refs != null)
+            if (_refs == null) return spanRequest;
+            foreach (var traceSegmentRef in _refs)
             {
-                spanObject.Refs.Add(_refs.Select(x => x.Transform()));
+                spanRequest.References.Add(traceSegmentRef.Transform());
             }
 
-            return spanObject;
+            return spanRequest;
         }
 
         private void EnsureLogs()

src/SkyWalking.Abstractions/Context/Trace/ISpan.cs

@@ -18,8 +18,7 @@
 
 using System;
 using System.Collections.Generic;
-using System.Text;
-using SkyWalking.NetworkProtocol.Trace;
+using SkyWalking.Components;
 
 namespace SkyWalking.Context.Trace
 {
@@ -36,7 +35,7 @@ namespace SkyWalking.Context.Trace
         ISpan SetComponent(IComponent component);
 
         /// <summary>
-        /// Only use this method in explicit instrumentation, like opentracing-skywalking-bridge. It it higher recommend
+        /// Only use this method in explicit skyWalking, like opentracing-skywalking-bridge. It it higher recommend
         /// don't use this for performance consideration.
         /// </summary>
         /// <param name="componentName"></param>

src/SkyWalking.Abstractions/Context/Trace/ITraceSegment.cs

@@ -17,8 +17,8 @@
  */
 
 using System.Collections.Generic;
+using SkyWalking.Transport;
 using SkyWalking.Context.Ids;
-using SkyWalking.NetworkProtocol;
 
 namespace SkyWalking.Context.Trace
 {
@@ -48,6 +48,6 @@ namespace SkyWalking.Context.Trace
 
         void RelatedGlobalTrace(DistributedTraceId distributedTraceId);
 
-        UpstreamSegment Transform();
+        TraceSegmentRequest Transform();
     }
 }

src/SkyWalking.Abstractions/Context/Trace/ITraceSegmentRef.cs

@@ -17,7 +17,7 @@
  */
 
 using System;
-using SkyWalking.NetworkProtocol;
+using SkyWalking.Transport;
 
 namespace SkyWalking.Context.Trace
 {
@@ -29,6 +29,6 @@ namespace SkyWalking.Context.Trace
         
         int EntryApplicationInstanceId { get; }
 
-        TraceSegmentReference Transform();
+        TraceSegmentReferenceRequest Transform();
     }
 }
\ No newline at end of file

src/SkyWalking.Abstractions/Context/Trace/LogDataEntity.cs

@@ -18,14 +18,14 @@
 
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using SkyWalking.NetworkProtocol;
+using SkyWalking.Transport;
 
 namespace SkyWalking.Context.Trace
 {
     public class LogDataEntity
     {
-        private long _timestamp = 0;
-        private Dictionary<string, string> _logs;
+        private readonly long _timestamp;
+        private readonly Dictionary<string, string> _logs;
 
         private LogDataEntity(long timestamp, Dictionary<string, string> logs)
         {
@@ -33,14 +33,11 @@ namespace SkyWalking.Context.Trace
             _logs = logs;
         }
 
-        public IReadOnlyDictionary<string, string> Logs
-        {
-            get { return new ReadOnlyDictionary<string, string>(_logs); }
-        }
+        public IReadOnlyDictionary<string, string> Logs => new ReadOnlyDictionary<string, string>(_logs);
 
         public class Builder
         {
-            private Dictionary<string, string> _logs;
+            private readonly Dictionary<string, string> _logs;
 
             public Builder()
             {
@@ -66,13 +63,13 @@ namespace SkyWalking.Context.Trace
             }
         }
 
-        public LogMessage Transform()
+        public LogDataRequest Transform()
         {
-            LogMessage logMessage = new LogMessage();
-            logMessage.Time = _timestamp;
+            var logMessage = new LogDataRequest();
+            logMessage.Timestamp = _timestamp;
             foreach (var log in _logs)
             {
-                logMessage.Data.Add(new KeyWithStringValue {Key = log.Key, Value = log.Value});
+                logMessage.Data.Add(new KeyValuePair<string, string>(log.Key, log.Value));
             }
 
             return logMessage;

src/SkyWalking.Abstractions/Context/Trace/SegmentRefType.cs

@@ -20,7 +20,7 @@ namespace SkyWalking.Context.Trace
 {
     public enum SegmentRefType
     {
-        CrossProcess,
-        CrossThread
+        CrossProcess = 0,
+        CrossThread = 1
     }
 }
\ No newline at end of file

src/SkyWalking.AspNet/SkyWalkingStartup.cs → src/SkyWalking.Abstractions/ExecutionService.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -17,66 +17,65 @@
  */
 
 using System;
-using System.Reflection;
+using System.Threading;
 using System.Threading.Tasks;
-using System.Web.Configuration;
-using SkyWalking.AspNet.Logging;
-using SkyWalking.Boot;
-using SkyWalking.Config;
 using SkyWalking.Logging;
-using SkyWalking.Remote;
 
-namespace SkyWalking.AspNet
+namespace SkyWalking
 {
-    public class SkyWalkingStartup : IDisposable
+    public abstract class ExecutionService : IExecutionService, IDisposable
     {
-        public void Start()
+        private Timer _timer;
+        private CancellationTokenSource _cancellationTokenSource;
+
+        protected readonly ILogger Logger;
+        protected readonly IRuntimeEnvironment RuntimeEnvironment;
+        protected readonly ISkyWalkingClient SkyWalking;
+
+        protected ExecutionService(ISkyWalkingClient skyWalking, IRuntimeEnvironment runtimeEnvironment, ILoggerFactory loggerFactory)
         {
-            LoadConfigurationSetting();
-            LogManager.SetLoggerFactory(new DebugLoggerFactoryAdapter());
-            AsyncContext.Run(async () => await StartAsync());
+            SkyWalking = skyWalking;
+            RuntimeEnvironment = runtimeEnvironment;
+            Logger = loggerFactory.CreateLogger(GetType());
         }
 
-        private async Task StartAsync()
+        public Task StartAsync(CancellationToken cancellationToken = default(CancellationToken))
         {
-            await GrpcConnectionManager.Instance.ConnectAsync(TimeSpan.FromSeconds(3));
-            await ServiceManager.Instance.Initialize();
+            _cancellationTokenSource = new CancellationTokenSource();
+            var source = CancellationTokenSource.CreateLinkedTokenSource(_cancellationTokenSource.Token, cancellationToken);
+            _timer = new Timer(Callback, source, DueTime, Period);
+            Logger.Information($"Loaded instrument service [{GetType().FullName}].");
+            return Task.CompletedTask;
         }
 
-        private void LoadConfigurationSetting()
+        public async Task StopAsync(CancellationToken cancellationToken = default(CancellationToken))
         { 
-            CollectorConfig.DirectServers = GetAppSetting(nameof(CollectorConfig.DirectServers), true);
-            AgentConfig.ApplicationCode = GetAppSetting(nameof(AgentConfig.ApplicationCode), true);
-            AgentConfig.Namespace = GetAppSetting(nameof(AgentConfig.Namespace), false);
-            CollectorConfig.CertificatePath = GetAppSetting(nameof(CollectorConfig.CertificatePath), false);
-            CollectorConfig.Authentication = GetAppSetting(nameof(CollectorConfig.Authentication), false);
-            var samplePer3Secs = GetAppSetting(nameof(AgentConfig.SamplePer3Secs), false);
-            if (int.TryParse(samplePer3Secs, out var v))
-            {
-                AgentConfig.SamplePer3Secs = v;
+            _cancellationTokenSource?.Cancel();
+            await Stopping(cancellationToken);
+            Logger.Information($"Stopped instrument service {GetType().Name}.");
         }
-            var pendingSegmentsLimit = GetAppSetting(nameof(AgentConfig.PendingSegmentsLimit), false);
-            if(int.TryParse(pendingSegmentsLimit, out v))
+
+        public void Dispose()
         {
-                AgentConfig.PendingSegmentsLimit = v;
-            }
+            _timer?.Dispose();
         }
 
-        private string GetAppSetting(string key, bool @throw)
+        private async void Callback(object state)
         {
-            var value = WebConfigurationManager.AppSettings[key];
-            if (@throw && string.IsNullOrEmpty(value))
+            if (state is CancellationTokenSource token && !token.IsCancellationRequested && CanExecute())
             {
-                throw new InvalidOperationException($"Cannot read valid '{key}' in AppSettings.");
+                await ExecuteAsync(token.Token);
             }
-
-            return value;
         }
 
-        public void Dispose()
-        {
-            AsyncContext.Run(async () => await GrpcConnectionManager.Instance.ShutdownAsync());
-            ServiceManager.Instance.Dispose();
-        }
+        protected virtual bool CanExecute() => RuntimeEnvironment.Initialized;
+        
+        protected virtual Task Stopping(CancellationToken cancellationToke) => Task.CompletedTask;
+
+        protected abstract TimeSpan DueTime { get; }
+
+        protected abstract TimeSpan Period { get; }
+
+        protected abstract Task ExecuteAsync(CancellationToken cancellationToken);
     }
 }
\ No newline at end of file

src/SkyWalking.Abstractions/IEnvironmentProvider.cs

+namespace SkyWalking
+{
+    public interface IEnvironmentProvider
+    {
+        string EnvironmentName { get; }
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/IExecutionService.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace SkyWalking
+{
+    public interface IExecutionService
+    {
+        Task StartAsync(CancellationToken cancellationToken = default(CancellationToken));
+
+        Task StopAsync(CancellationToken cancellationToken = default(CancellationToken));
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/IRuntimeEnvironment.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+using System;
+using SkyWalking.Config;
+
+namespace SkyWalking
+{
+    public interface IRuntimeEnvironment
+    {
+        NullableValue ApplicationId { get; }
+
+        NullableValue ApplicationInstanceId { get; }
+
+        bool Initialized { get; }
+
+        Guid AgentUUID { get; }
+
+        IEnvironmentProvider Environment { get; }
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/Sampling/ISampler.cs → src/SkyWalking.Abstractions/ISampler.cs

@@ -16,13 +16,11 @@
  *
  */
 
-using SkyWalking.Boot;
-
-namespace SkyWalking.Sampling
+namespace SkyWalking
 {
-    public interface ISampler : IBootService
+    public interface ISampler
     {
-        bool TrySampling();
+        bool Sampled();
 
         void ForceSampled();
     }

src/SkyWalking.Abstractions/ISkyWalkingAgentStartup.cs

+using System.Threading;
+using System.Threading.Tasks;
+
+namespace SkyWalking
+{
+    public interface ISkyWalkingAgentStartup
+    {
+        Task StartAsync(CancellationToken cancellationToken = default(CancellationToken));
+
+        Task StopAsync(CancellationToken cancellationToken = default(CancellationToken));
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/ISkyWalkingClient.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using SkyWalking.Transport;
+
+namespace SkyWalking
+{
+    public interface ISkyWalkingClient
+    {
+        Task<NullableValue> RegisterApplicationAsync(string applicationCode, CancellationToken cancellationToken = default(CancellationToken));
+
+        Task<NullableValue> RegisterApplicationInstanceAsync(int applicationId, Guid agentUUID, long registerTime, AgentOsInfoRequest osInfoRequest,
+            CancellationToken cancellationToken = default(CancellationToken));
+
+        Task HeartbeatAsync(int applicationInstance, long heartbeatTime, CancellationToken cancellationToken = default(CancellationToken));
+
+        Task CollectAsync(IEnumerable<TraceSegmentRequest> request, CancellationToken cancellationToken = default(CancellationToken));
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/Diagnostics/ITracingDiagnosticProcessor.cs → src/SkyWalking.Abstractions/ITracingDiagnosticProcessor.cs

@@ -16,7 +16,7 @@
  *
  */
 
-namespace SkyWalking.Diagnostics
+namespace SkyWalking
 {
     public interface ITracingDiagnosticProcessor
     {

src/SkyWalking.Abstractions/Logging/ILogger.cs

@@ -24,7 +24,7 @@ namespace SkyWalking.Logging
     {
         void Debug(string message);
 
-        void Info(string message);
+        void Information(string message);
 
         void Warning(string message);
 

src/SkyWalking.Abstractions/NullableValue.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+namespace SkyWalking
+{
+    public struct NullableValue
+    {
+        public static readonly NullableValue Null = new NullableValue(0);
+            
+        private const int NULL_VALUE = 0;
+        
+        public int Value { get; }
+
+        public NullableValue(int value)
+        {
+            Value = value;
+        }
+
+        public bool HasValue => Value != NULL_VALUE;
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/SkyWalking.Abstractions.csproj

@@ -3,16 +3,12 @@
   <PropertyGroup>
     <Description>SkyWalking Core abstractions and interfaces for apm agent.</Description>
     <AssemblyTitle>SkyWalking.Abstractions</AssemblyTitle>
-    <TargetFrameworks>netstandard2.0;net45;net451</TargetFrameworks>
     <AssemblyName>SkyWalking.Abstractions</AssemblyName>
     <PackageId>SkyWalking.Abstractions</PackageId>
     <PackageTags>SkyWalking;APM</PackageTags>
     <PackageReleaseNotes>
     </PackageReleaseNotes>
     <RootNamespace>SkyWalking</RootNamespace>
+    <TargetFramework>netstandard2.0</TargetFramework>
   </PropertyGroup>
-  <ItemGroup>
-    <ProjectReference Include="..\SkyWalking.NetworkProtocol.Trace\SkyWalking.NetworkProtocol.Trace.csproj" />
-    <ProjectReference Include="..\SkyWalking.NetworkProtocol\SkyWalking.NetworkProtocol.csproj" />
-  </ItemGroup>
 </Project>
\ No newline at end of file

src/SkyWalking.Abstractions/StringOrIntValue.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+namespace SkyWalking
+{
+    public struct StringOrIntValue
+    {
+        private readonly int _intValue;
+        private readonly string _stringValue;
+
+        public StringOrIntValue(int value)
+        {
+            _intValue = value;
+            _stringValue = null;
+        }
+
+        public bool HasIntValue => _intValue != 0;
+        
+        public bool HasStringValue => _stringValue != null;
+
+        public StringOrIntValue(string value)
+        {
+            _intValue = 0;
+            _stringValue = value;
+        }
+
+        public StringOrIntValue(int intValue, string stringValue)
+        {
+            _intValue = intValue;
+            _stringValue = stringValue;
+        }
+
+        public int GetIntValue() => _intValue;
+        
+        public string GetStringValue() => _stringValue;
+        
+        public (string, int) GetValue()
+        {
+            return (_stringValue, _intValue);
+        }
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/Transport/AgentOsInfoRequest.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+namespace SkyWalking.Transport
+{
+    public class AgentOsInfoRequest
+    {
+        public string OsName { get; set; }
+
+        public string HostName { get; set; }
+
+        public int ProcessNo { get; set; }
+
+        public string[] IpAddress { get; set; }
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/Transport/ITraceDispatcher.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace SkyWalking.Transport
+{
+    public interface ITraceDispatcher
+    {
+        bool Dispatch(TraceSegmentRequest segment);
+
+        Task Flush(CancellationToken token = default(CancellationToken));
+
+        void Close();
+    }
+}

src/SkyWalking.Abstractions/Transport/TraceSegmentRequest.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenSkywalking licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+using System.Collections.Generic;
+
+namespace SkyWalking.Transport
+{
+    public class TraceSegmentRequest
+    {
+        public IEnumerable<UniqueIdRequest> UniqueIds { get; set; }
+
+        public TraceSegmentObjectRequest Segment { get; set; }
+    }
+
+    public class UniqueIdRequest
+    {
+        public long Part1 { get; set; }
+
+        public long Part2 { get; set; }
+
+        public long Part3 { get; set; }
+
+        public override string ToString()
+        {
+            return $"{Part1}.{Part2}.{Part3}";
+        }
+    }
+
+    public class TraceSegmentObjectRequest
+    {
+        public UniqueIdRequest SegmentId { get; set; }
+
+        public int ApplicationId { get; set; }
+
+        public int ApplicationInstanceId { get; set; }
+
+        public IList<SpanRequest> Spans { get; set; } = new List<SpanRequest>();
+    }
+
+    public class SpanRequest
+    {
+        public int SpanId { get; set; }
+
+        public int SpanType { get; set; }
+
+        public int SpanLayer { get; set; }
+
+        public int ParentSpanId { get; set; }
+
+        public long StartTime { get; set; }
+
+        public long EndTime { get; set; }
+
+        public StringOrIntValue Component { get; set; }
+
+        public StringOrIntValue OperationName { get; set; }
+
+        public StringOrIntValue Peer { get; set; }
+
+        public bool IsError { get; set; }
+
+        public IList<TraceSegmentReferenceRequest> References { get; } = new List<TraceSegmentReferenceRequest>();
+
+        public IList<KeyValuePair<string, string>> Tags { get; } = new List<KeyValuePair<string, string>>();
+
+        public IList<LogDataRequest> Logs { get; } = new List<LogDataRequest>();
+    }
+
+    public class TraceSegmentReferenceRequest
+    {
+        public UniqueIdRequest ParentTraceSegmentId { get; set; }
+
+        public int ParentApplicationInstanceId { get; set; }
+
+        public int ParentSpanId { get; set; }
+
+        public int EntryApplicationInstanceId { get; set; }
+
+        public int RefType { get; set; }
+
+        public StringOrIntValue ParentServiceName { get; set; }
+
+        public StringOrIntValue EntryServiceName { get; set; }
+
+        public StringOrIntValue NetworkAddress { get; set; }
+    }
+
+    public class LogDataRequest
+    {
+        public long Timestamp { get; set; }
+
+        public IList<KeyValuePair<string, string>> Data { get; } = new List<KeyValuePair<string, string>>();
+    }
+}
\ No newline at end of file

src/SkyWalking.AspNet/AsyncContext.cs

@@ -22,7 +22,7 @@ using System.Threading.Tasks;
 
 namespace SkyWalking.AspNet
 {
-    internal class AsyncContext
+    internal static class AsyncContext
     {
         public static void Run(Func<Task> task)
         {

src/SkyWalking.AspNet/Extensions/ServiceCollectionExtensions.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+using Microsoft.Extensions.DependencyInjection;
+using SkyWalking.Config;
+using SkyWalking.Context;
+using SkyWalking.Diagnostics;
+using SkyWalking.Logging;
+using SkyWalking.Service;
+using SkyWalking.Transport;
+using SkyWalking.Transport.Grpc;
+using SkyWalking.Utilities.Configuration;
+using SkyWalking.Utilities.Logging;
+
+namespace SkyWalking.AspNet.Extensions
+{
+    internal static class ServiceCollectionExtensions
+    {
+        public static IServiceCollection AddSkyWalkingCore(this IServiceCollection services)
+        {
+            services.AddSingleton<SkyWalkingApplicationRequestCallback>();
+            services.AddSingleton<IContextCarrierFactory, ContextCarrierFactory>();
+            services.AddSingleton<ITraceDispatcher, AsyncQueueTraceDispatcher>();
+            services.AddSingleton<IExecutionService, TraceSegmentTransportService>();
+            services.AddSingleton<IExecutionService, ServiceDiscoveryService>();
+            services.AddSingleton<IExecutionService, SamplingRefreshService>();
+            services.AddSingleton<ISkyWalkingAgentStartup, SkyWalkingAgentStartup>();
+            services.AddSingleton<TracingDiagnosticProcessorObserver>();
+            services.AddSingleton<IConfigAccessor, ConfigAccessor>();
+            services.AddSingleton<IEnvironmentProvider, HostingEnvironmentProvider>();
+            services.AddSingleton<ILoggerFactory, DefaultLoggerFactory>();
+            services.AddSingleton<ISkyWalkingClient, GrpcClient>();
+            services.AddSingleton<ConnectionManager>();
+            services.AddSingleton<IExecutionService, GrpcStateCheckService>();
+            services.AddSingleton<ISampler>(DefaultSampler.Instance);
+            services.AddSingleton(RuntimeEnvironment.Instance);
+            return services;
+        }
+    }
+}
\ No newline at end of file

src/SkyWalking.Abstractions/Utils/DateTimeOffsetExtensions.cs → src/SkyWalking.AspNet/HostingEnvironmentProvider.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -18,15 +18,17 @@
 
 using System;
 
-namespace SkyWalking.Utils
+namespace SkyWalking.AspNet
 {
-#if NET45 || NET451
-    public static class DateTimeOffsetExtensions
+    internal class HostingEnvironmentProvider : IEnvironmentProvider
     {
-        public static long ToUnixTimeMilliseconds(this DateTimeOffset dateTimeOffset)
+        private const string ENVIRONMENT_KEY = "ASPNET__ENVIRONMENT";
+        
+        public string EnvironmentName { get; }
+
+        public HostingEnvironmentProvider()
         {
-            return dateTimeOffset.UtcDateTime.Ticks / 10000L - 62135596800000L;
+            EnvironmentName = Environment.GetEnvironmentVariable(ENVIRONMENT_KEY) ?? "Production";
         }
     }
-#endif
 }
\ No newline at end of file

src/SkyWalking.AspNet/HttpTracingHandler.cs

@@ -20,30 +20,38 @@ using System;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
+using SkyWalking.Components;
 using SkyWalking.Context;
 using SkyWalking.Context.Tag;
 using SkyWalking.Context.Trace;
-using SkyWalking.NetworkProtocol.Trace;
 
 namespace SkyWalking.AspNet
 {
     public class HttpTracingHandler : DelegatingHandler
     {
+        private readonly IContextCarrierFactory _contextCarrierFactory;
+
         public HttpTracingHandler()
             : this(new HttpClientHandler())
         {
         }
 
         public HttpTracingHandler(HttpMessageHandler innerHandler)
+            : this(innerHandler, CommonServiceLocator.ServiceLocator.Current.GetInstance<IContextCarrierFactory>())
+        {
+        }
+
+        private HttpTracingHandler(HttpMessageHandler innerHandler, IContextCarrierFactory contextCarrierFactory)
         {
             InnerHandler = innerHandler;
+            _contextCarrierFactory = contextCarrierFactory;
         }
 
         protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
             CancellationToken cancellationToken)
         {
             var peer = $"{request.RequestUri.Host}:{request.RequestUri.Port}";
-            var contextCarrier = new ContextCarrier();
+            var contextCarrier = _contextCarrierFactory.Create();
             var span = ContextManager.CreateExitSpan(request.RequestUri.ToString(), contextCarrier, peer);
             try
             {

src/SkyWalking.AspNetCore/Extensions/SkyWalkingBuilderExtensions.cs → src/SkyWalking.AspNet/ServiceProviderLocator.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -16,30 +16,34 @@
  *
  */
 
+using CommonServiceLocator;
+using System;
+using System.Collections.Generic;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Hosting;
-using SkyWalking.AspNetCore.Diagnostics;
-using SkyWalking.AspNetCore.Logging;
-using SkyWalking.Diagnostics;
-using SkyWalking.Extensions.DependencyInjection;
-using SkyWalking.Logging;
-
-namespace SkyWalking.AspNetCore
+
+namespace SkyWalking.AspNet
 {
-    internal static class SkyWalkingBuilderExtensions
-    {
-        public static SkyWalkingBuilder AddHosting(this SkyWalkingBuilder builder)
+    internal class ServiceProviderLocator : IServiceLocator
     {
-            builder.Services.AddSingleton<IHostedService, SkyWalkingHostedService>();
-            builder.Services.AddSingleton<ITracingDiagnosticProcessor, HostingDiagnosticProcessor>();
-            builder.Services.AddSingleton<ILoggerFactory, LoggerFactoryAdapter>();
-            return builder;
-        }
+        private readonly IServiceProvider _serviceProvider;
 
-        public static SkyWalkingBuilder AddDiagnostics(this SkyWalkingBuilder builder)
+        public ServiceProviderLocator(IServiceProvider serviceProvider)
         {
-            builder.Services.AddSingleton<TracingDiagnosticProcessorObserver>();
-            return builder;
+            _serviceProvider = serviceProvider;
         }
+
+        public object GetService(Type serviceType) => _serviceProvider.GetService(serviceType);
+
+        public object GetInstance(Type serviceType) => _serviceProvider.GetService(serviceType);
+
+        public object GetInstance(Type serviceType, string key) => GetInstance(serviceType);
+
+        public IEnumerable<object> GetAllInstances(Type serviceType) => _serviceProvider.GetServices(serviceType);
+
+        public TService GetInstance<TService>() => (TService) GetInstance(typeof(TService));
+
+        public TService GetInstance<TService>(string key) => (TService) GetInstance(typeof(TService));
+
+        public IEnumerable<TService> GetAllInstances<TService>() => _serviceProvider.GetServices<TService>();
     }
 }
\ No newline at end of file

src/SkyWalking.AspNet/SkyWalking.AspNet.csproj

 <Project Sdk="Microsoft.NET.Sdk">
   <Import Project="..\..\build\common.props" />
   <PropertyGroup>
-    <TargetFrameworks>net45;net451;net452;net46;net461;net462;net47;net471</TargetFrameworks>
+    <TargetFrameworks>net461;net462;net47;net471</TargetFrameworks>
   </PropertyGroup>
   <PropertyGroup>
     <AssemblyName>SkyWalking.AspNet</AssemblyName>
@@ -13,13 +13,20 @@
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\SkyWalking.Core\SkyWalking.Core.csproj" />
+    <ProjectReference Include="..\SkyWalking.Transport.Grpc\SkyWalking.Transport.Grpc.csproj" />
+    <ProjectReference Include="..\SkyWalking.Utilities.Configuration\SkyWalking.Utilities.Configuration.csproj" />
+    <ProjectReference Include="..\SkyWalking.Utilities.DependencyInjection\SkyWalking.Utilities.DependencyInjection.csproj" />
+    <ProjectReference Include="..\SkyWalking.Utilities.Logging\SkyWalking.Utilities.Logging.csproj" />
   </ItemGroup>
   <ItemGroup>
     <Reference Include="System.Configuration" />
     <Reference Include="System.Web" />
-    <Reference Include="System.Net.Http"/>
+    <Reference Include="System.Net.Http" />
   </ItemGroup>
   <ItemGroup>
+    <PackageReference Include="CommonServiceLocator" Version="2.0.4" />
+    <PackageReference Include="Microsoft.Extensions.Configuration" Version="2.2.0-preview2-35157" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="2.1.0" />
     <PackageReference Include="Microsoft.Web.Infrastructure" Version="1.0.0" />
   </ItemGroup>
 </Project>
\ No newline at end of file

src/SkyWalking.AspNet/SkyWalkingApplicationRequestCallback.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Web;
+using SkyWalking.Components;
+using SkyWalking.Config;
+using SkyWalking.Context;
+using SkyWalking.Context.Tag;
+using SkyWalking.Context.Trace;
+
+namespace SkyWalking.AspNet
+{
+    internal class SkyWalkingApplicationRequestCallback
+    {
+        private readonly IContextCarrierFactory _contextCarrierFactory;
+        private readonly InstrumentationConfig _config;
+
+        public SkyWalkingApplicationRequestCallback(IConfigAccessor configAccessor, IContextCarrierFactory carrierFactory)
+        {
+            _config = configAccessor.Get<InstrumentationConfig>();
+            _contextCarrierFactory = carrierFactory;
+        }
+
+        public void ApplicationOnBeginRequest(object sender, EventArgs e)
+        {
+            var httpApplication = sender as HttpApplication;
+            var httpContext = httpApplication.Context;
+            var carrier = _contextCarrierFactory.Create();
+            foreach (var item in carrier.Items)
+                item.HeadValue = httpContext.Request.Headers[item.HeadKey];
+            var httpRequestSpan = ContextManager.CreateEntrySpan($"{_config.ApplicationCode} {httpContext.Request.Path}", carrier);
+            httpRequestSpan.AsHttp();
+            httpRequestSpan.SetComponent(ComponentsDefine.AspNet);
+            Tags.Url.Set(httpRequestSpan, httpContext.Request.Path);
+            Tags.HTTP.Method.Set(httpRequestSpan, httpContext.Request.HttpMethod);
+            httpRequestSpan.Log(DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(),
+                new Dictionary<string, object>
+                {
+                    {"event", "AspNet BeginRequest"},
+                    {"message", $"Request starting {httpContext.Request.Url.Scheme} {httpContext.Request.HttpMethod} {httpContext.Request.Url.OriginalString}"}
+                });
+        }
+
+        public void ApplicationOnEndRequest(object sender, EventArgs e)
+        {
+            var httpRequestSpan = ContextManager.ActiveSpan;
+            if (httpRequestSpan == null)
+            {
+                return;
+            }
+
+            var httpApplication = sender as HttpApplication;
+            var httpContext = httpApplication.Context;
+
+            var statusCode = httpContext.Response.StatusCode;
+            if (statusCode >= 400)
+            {
+                httpRequestSpan.ErrorOccurred();
+            }
+
+            Tags.StatusCode.Set(httpRequestSpan, statusCode.ToString());
+
+            var exception = httpContext.Error;
+            if (exception != null)
+            {
+                httpRequestSpan.ErrorOccurred().Log(exception);
+            }
+
+            httpRequestSpan.Log(DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(),
+                new Dictionary<string, object>
+                {
+                    {"event", "AspNet EndRequest"},
+                    {"message", $"Request finished {httpContext.Response.StatusCode} {httpContext.Response.ContentType}"}
+                });
+            ContextManager.StopSpan(httpRequestSpan);
+        }
+    }
+}
\ No newline at end of file

src/SkyWalking.AspNet/SkyWalkingModule.cs

@@ -16,87 +16,33 @@
  *
  */
 
-using System;
-using System.Collections.Generic;
+using CommonServiceLocator;
+using Microsoft.Extensions.DependencyInjection;
 using System.Web;
-using SkyWalking.Boot;
-using SkyWalking.Context;
-using SkyWalking.Context.Tag;
-using SkyWalking.Context.Trace;
-using SkyWalking.NetworkProtocol.Trace;
-using SkyWalking.Remote;
-using SkyWalking.Utils;
+using SkyWalking.AspNet.Extensions;
 
 namespace SkyWalking.AspNet
 {
     public class SkyWalkingModule : IHttpModule
     {
-        private readonly SkyWalkingStartup _skyWalkingStartup = new SkyWalkingStartup();
-        
-        public void Dispose()
+        public SkyWalkingModule()
         {
-            _skyWalkingStartup.Dispose();
+            var serviceProvider = new ServiceCollection().AddSkyWalkingCore().BuildServiceProvider();
+            var serviceLocatorProvider = new ServiceProviderLocator(serviceProvider);
+            ServiceLocator.SetLocatorProvider(() => serviceLocatorProvider);
         }
 
         public void Init(HttpApplication application)
         {
-            _skyWalkingStartup.Start();
-            application.BeginRequest += ApplicationOnBeginRequest;
-            application.EndRequest += ApplicationOnEndRequest;
-        }
-
-        private void ApplicationOnBeginRequest(object sender, EventArgs e)
-        {
-            var httpApplication = sender as HttpApplication;
-            var httpContext = httpApplication.Context;
-            var carrier = new ContextCarrier();
-            foreach (var item in carrier.Items)
-                item.HeadValue = httpContext.Request.Headers[item.HeadKey];
-            var httpRequestSpan = ContextManager.CreateEntrySpan($"{Config.AgentConfig.ApplicationCode} {httpContext.Request.Path}", carrier);
-            httpRequestSpan.AsHttp();
-            httpRequestSpan.SetComponent(ComponentsDefine.AspNet);
-            Tags.Url.Set(httpRequestSpan, httpContext.Request.Path);
-            Tags.HTTP.Method.Set(httpRequestSpan, httpContext.Request.HttpMethod);
-            httpRequestSpan.Log(DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(),
-                new Dictionary<string, object>
-                {
-                    {"event", "AspNet BeginRequest"},
-                    {"message", $"Request starting {httpContext.Request.Url.Scheme} {httpContext.Request.HttpMethod} {httpContext.Request.Url.OriginalString}"}
-                });
-        }
-        
-        private void ApplicationOnEndRequest(object sender, EventArgs e)
-        {
-            var httpRequestSpan = ContextManager.ActiveSpan;
-            if (httpRequestSpan == null)
-            {
-                return;
+            var startup = ServiceLocator.Current.GetInstance<ISkyWalkingAgentStartup>();
+            AsyncContext.Run(() => startup.StartAsync());
+            var requestCallback = ServiceLocator.Current.GetInstance<SkyWalkingApplicationRequestCallback>();
+            application.BeginRequest += requestCallback.ApplicationOnBeginRequest;
+            application.EndRequest += requestCallback.ApplicationOnEndRequest;
         }
 
-            var httpApplication = sender as HttpApplication;
-            var httpContext = httpApplication.Context;
-            
-            var statusCode = httpContext.Response.StatusCode;
-            if (statusCode >= 400)
-            {
-                httpRequestSpan.ErrorOccurred();
-            }
-
-            Tags.StatusCode.Set(httpRequestSpan, statusCode.ToString());
-
-            var exception = httpContext.Error;
-            if (exception != null)
-            {
-                httpRequestSpan.ErrorOccurred().Log(exception);
-            }
-            
-            httpRequestSpan.Log(DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(),
-                new Dictionary<string, object>
+        public void Dispose()
         {
-                    {"event", "AspNetCore Hosting EndRequest"},
-                    {"message", $"Request finished {httpContext.Response.StatusCode} {httpContext.Response.ContentType}"}
-                });
-            ContextManager.StopSpan(httpRequestSpan);
         }
     }
 }
\ No newline at end of file

src/SkyWalking.AspNet/SkyWalkingOptions.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-namespace SkyWalking.AspNet
-{
-    public class SkyWalkingOptions
-    {
-        /// <summary>
-        /// Application code is showed in sky-walking-ui
-        /// </summary>
-        public string ApplicationCode { get; set; }
-
-        /// <summary>
-        /// Collector agent_gRPC/grpc service addresses.
-        /// By using this, no discovery mechanism provided. The agent only uses these addresses to uplink data.
-        /// Recommend to use this only when collector cluster IPs are unreachable from agent side. Such as:
-        /// 1. Agent and collector cluster are in different VPC in Cloud.
-        /// 2. Agent uplinks data to collector cluster through Internet.
-        /// Single collector：DirectServers="127.0.0.1:11800"
-        /// Collector cluster：DirectServers="10.2.45.126:11800,10.2.45.127:11800"
-        /// </summary>
-        public string DirectServers { get; set; }
-
-        /// <summary>
-        /// The number of sampled traces per 3 seconds
-        /// Negative number means sample traces as many as possible, most likely 100% , by default
-        /// 
-        /// </summary>
-        public int SamplePer3Secs { get; set; } = -1;
-
-        /// <summary>
-        /// Namespace isolates headers in cross propagation. The HEADER name will be 'HeaderName:Namespace'.
-        /// </summary>
-        public string Namespace { get; set; }
-
-        /// <summary>
-        /// The max number of segments in the memory queue waiting to be sent to collector.
-        /// It means that when the number of queued segments reachs this limit,
-        /// any more segments enqueued into the sending queue, will leads the same number of oldest queued segments dequeued and droped.
-        /// Zero or minus value means no limit.
-        /// </summary>
-        public int PendingSegmentsLimit { get; set; } = 300000;
-        
-        /// <summary>
-        /// Set your own token to active auth
-        /// </summary>
-        public string Authentication
-        {
-            get;
-            set;
-        }
-
-        /// <summary>
-        /// Set certificate path to open ssl/tls
-        /// </summary>
-        public string CertificatePath
-        {
-            get;
-            set;
-        }
-    }
-}
\ No newline at end of file

src/SkyWalking.AspNetCore/Extensions/ServiceCollectionExtensions.cs

@@ -17,45 +17,63 @@
  */
 
 using System;
-using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using SkyWalking.AspNetCore.Diagnostics;
+using SkyWalking.Config;
+using SkyWalking.Context;
+using SkyWalking.Diagnostics;
+using SkyWalking.Diagnostics.EntityFrameworkCore;
 using SkyWalking.Diagnostics.HttpClient;
 using SkyWalking.Diagnostics.SqlClient;
-using SkyWalking.Extensions.DependencyInjection;
+using SkyWalking.Utilities.Configuration;
+using SkyWalking.Utilities.DependencyInjection;
+using SkyWalking.Utilities.Logging;
+using SkyWalking.Logging;
+using SkyWalking.Service;
+using SkyWalking.Transport;
+using SkyWalking.Transport.Grpc;
 
 namespace SkyWalking.AspNetCore
 {
-    public static class ServiceCollectionExtensions
+    internal static class ServiceCollectionExtensions
     {
-        public static SkyWalkingBuilder AddSkyWalking(this IServiceCollection services,
-            Action<SkyWalkingOptions> options)
+        public static IServiceCollection AddSkyWalkingCore(this IServiceCollection services)
         {
-            if (options == null)
+            if (services == null)
             {
-                throw new ArgumentNullException(nameof(options));
+                throw new ArgumentNullException(nameof(services));
             }
 
-            return services.Configure(options).AddSkyWalkingCore();
+            services.AddSingleton<IContextCarrierFactory, ContextCarrierFactory>();
+            services.AddSingleton<ITraceDispatcher, AsyncQueueTraceDispatcher>();
+            services.AddSingleton<IExecutionService, TraceSegmentTransportService>();
+            services.AddSingleton<IExecutionService, ServiceDiscoveryService>();
+            services.AddSingleton<IExecutionService, SamplingRefreshService>();
+            services.AddSingleton<ISkyWalkingAgentStartup, SkyWalkingAgentStartup>();
+            services.AddSingleton<ISampler>(DefaultSampler.Instance);
+            services.AddSingleton(RuntimeEnvironment.Instance);
+            services.AddSingleton<TracingDiagnosticProcessorObserver>();
+            services.AddSingleton<IConfigAccessor, ConfigAccessor>();
+            services.AddSingleton<IHostedService, InstrumentationHostedService>();
+            services.AddSingleton<IEnvironmentProvider, HostingEnvironmentProvider>();
+            services.AddGrpcTransport().AddLogging();
+            services.AddSkyWalkingExtensions().AddAspNetCoreHosting().AddHttpClient().AddSqlClient().AddEntityFrameworkCore(c => c.AddSqlite().AddPomeloMysql().AddNpgsql());
+            return services;
         }
 
-        public static SkyWalkingBuilder AddSkyWalking(this IServiceCollection services,
-            IConfiguration configuration)
+        private static IServiceCollection AddGrpcTransport(this IServiceCollection services)
         {
-            return services.Configure<SkyWalkingOptions>(configuration).AddSkyWalkingCore();
+            services.AddSingleton<ISkyWalkingClient, GrpcClient>();
+            services.AddSingleton<ConnectionManager>();
+            services.AddSingleton<IExecutionService, GrpcStateCheckService>();
+            return services;
         }
         
-        private static SkyWalkingBuilder AddSkyWalkingCore(this IServiceCollection services)
+        private static IServiceCollection AddLogging(this IServiceCollection services)
         {
-            if (services == null)
-            {
-                throw new ArgumentNullException(nameof(services));
-            }
-
-            var builder = new SkyWalkingBuilder(services);
-
-            builder.AddHosting().AddDiagnostics().AddHttpClient().AddSqlClient();
-
-            return builder;
+            services.AddSingleton<ILoggerFactory, DefaultLoggerFactory>();
+            return services;
         }
     }
 }
\ No newline at end of file

src/SkyWalking.AspNetCore/HostingEnvironmentProvider.cs

+using Microsoft.AspNetCore.Hosting;
+
+namespace SkyWalking.AspNetCore
+{
+    internal class HostingEnvironmentProvider : IEnvironmentProvider
+    {
+        public string EnvironmentName { get; }
+
+        public HostingEnvironmentProvider(IHostingEnvironment hostingEnvironment)
+        {
+            EnvironmentName = hostingEnvironment.EnvironmentName;
+        }
+    }
+}
\ No newline at end of file

src/SkyWalking.Core/Logging/LogManager.cs → src/SkyWalking.AspNetCore/InstrumentationHostedService.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -16,29 +16,29 @@
  *
  */
 
-using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Hosting;
 
-namespace SkyWalking.Logging
+namespace SkyWalking.AspNetCore
 {
-    public static class LogManager
+    public class InstrumentationHostedService : IHostedService
     {
-        private static readonly ILoggerFactory defaultLoggerFactory = new NullLoggerFactory();
-        private static ILoggerFactory _loggerFactory;
+        private readonly ISkyWalkingAgentStartup _startup;
 
-        public static ILogger GetLogger(Type type)
+        public InstrumentationHostedService(ISkyWalkingAgentStartup startup)
         {
-            var loggerFactory = _loggerFactory ?? defaultLoggerFactory;
-            return loggerFactory.CreateLogger(type);
+            _startup = startup;
         }
 
-        public static ILogger GetLogger<T>()
+        public Task StartAsync(CancellationToken cancellationToken)
         {
-            return GetLogger(typeof(T));
+            return _startup.StartAsync(cancellationToken);
         }
 
-        public static void SetLoggerFactory(ILoggerFactory loggerFactory)
+        public Task StopAsync(CancellationToken cancellationToken)
         {
-            _loggerFactory = loggerFactory;
+            return _startup.StopAsync(cancellationToken);
         }
     }
 }
\ No newline at end of file

src/SkyWalking.AspNetCore/SkyWalking.AspNetCore.csproj

@@ -4,7 +4,7 @@
     <Description>SkyWalking ASP.NET Core Agent.</Description>
     <AssemblyTitle>SkyWalking.AspNetCore</AssemblyTitle>
     <TargetFramework>netstandard2.0</TargetFramework>
-    <AssemblyName>SkyWalking.AspNetCore</AssemblyName>
+    <AssemblyName>SkyWalking_AspNetCore</AssemblyName>
     <PackageId>SkyWalking.AspNetCore</PackageId>
     <PackageTags>SkyWalking;APM</PackageTags>
     <PackageReleaseNotes>
@@ -12,18 +12,22 @@
     <RootNamespace>SkyWalking.AspNetCore</RootNamespace>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.AspNetCore.Hosting" Version="2.0.0" />
-    <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.0.0" />
-    <PackageReference Include="Microsoft.AspNetCore.Mvc.Abstractions" Version="2.0.0" />
-    <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="2.0.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Hosting.Abstractions" Version="2.1.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.1.0" />
   </ItemGroup>
   <ItemGroup>
+    <ProjectReference Include="..\SkyWalking.Abstractions\SkyWalking.Abstractions.csproj" />
     <ProjectReference Include="..\SkyWalking.Core\SkyWalking.Core.csproj" />
+    <ProjectReference Include="..\SkyWalking.Diagnostics.AspNetCore\SkyWalking.Diagnostics.AspNetCore.csproj" />
+    <ProjectReference Include="..\SkyWalking.Diagnostics.EntityFrameworkCore.Npgsql\SkyWalking.Diagnostics.EntityFrameworkCore.Npgsql.csproj" />
+    <ProjectReference Include="..\SkyWalking.Diagnostics.EntityFrameworkCore.Pomelo.MySql\SkyWalking.Diagnostics.EntityFrameworkCore.Pomelo.MySql.csproj" />
+    <ProjectReference Include="..\SkyWalking.Diagnostics.EntityFrameworkCore.Sqlite\SkyWalking.Diagnostics.EntityFrameworkCore.Sqlite.csproj" />
+    <ProjectReference Include="..\SkyWalking.Diagnostics.EntityFrameworkCore\SkyWalking.Diagnostics.EntityFrameworkCore.csproj" />
     <ProjectReference Include="..\SkyWalking.Diagnostics.HttpClient\SkyWalking.Diagnostics.HttpClient.csproj" />
     <ProjectReference Include="..\SkyWalking.Diagnostics.SqlClient\SkyWalking.Diagnostics.SqlClient.csproj" />
-    <ProjectReference Include="..\SkyWalking.Extensions.DependencyInjection\SkyWalking.Extensions.DependencyInjection.csproj">
-      <Project>{BF5579ED-113C-4EE6-AE03-9A9CA590C924}</Project>
-      <Name>SkyWalking.Extensions.DependencyInjection</Name>
-    </ProjectReference>
+    <ProjectReference Include="..\SkyWalking.Utilities.Configuration\SkyWalking.Utilities.Configuration.csproj" />
+    <ProjectReference Include="..\SkyWalking.Utilities.DependencyInjection\SkyWalking.Utilities.DependencyInjection.csproj" />
+    <ProjectReference Include="..\SkyWalking.Utilities.Logging\SkyWalking.Utilities.Logging.csproj" />
+    <ProjectReference Include="..\SkyWalking.Transport.Grpc\SkyWalking.Transport.Grpc.csproj" />
   </ItemGroup>
 </Project>
\ No newline at end of file

src/SkyWalking.AspNetCore/SkyWalkingHostingStartup.cs

+using Microsoft.AspNetCore.Hosting;
+using SkyWalking.AspNetCore;
+
+[assembly: HostingStartup(typeof(SkyWalkingHostingStartup))]
+
+namespace SkyWalking.AspNetCore
+{
+    public class SkyWalkingHostingStartup : IHostingStartup
+    {
+        public void Configure(IWebHostBuilder builder)
+        {
+            builder.ConfigureServices(services => services.AddSkyWalkingCore());
+        }
+    }
+}
\ No newline at end of file

src/SkyWalking.AspNetCore/SkyWalkingOptions.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-using System.Runtime.CompilerServices;
-using Microsoft.Extensions.Options;
-
-namespace SkyWalking.AspNetCore
-{
-    public class SkyWalkingOptions : IOptions<SkyWalkingOptions>
-    {
-        public SkyWalkingOptions Value => this;
-    
-        /// <summary>
-        /// Application code is showed in sky-walking-ui
-        /// </summary>
-        public string ApplicationCode
-        {
-            get;
-            set;
-        }
-
-        /// <summary>
-        /// Collector agent_gRPC/grpc service addresses.
-        /// By using this, no discovery mechanism provided. The agent only uses these addresses to uplink data.
-        /// Recommend to use this only when collector cluster IPs are unreachable from agent side. Such as:
-        /// 1. Agent and collector cluster are in different VPC in Cloud.
-        /// 2. Agent uplinks data to collector cluster through Internet.
-        /// Single collector：DirectServers="127.0.0.1:11800"
-        /// Collector cluster：DirectServers="10.2.45.126:11800,10.2.45.127:11800"
-        /// </summary>
-        public string DirectServers
-        {
-            get;
-            set;
-        }
-
-        /// <summary>
-        /// The number of sampled traces per 3 seconds
-        /// Negative number means sample traces as many as possible, most likely 100% , by default
-        /// 
-        /// </summary>
-        public int SamplePer3Secs
-        {
-            get; 
-            set;
-        } = -1;
-
-        /// <summary>
-        /// The max number of segments in the memory queue waiting to be sent to collector.
-        /// It means that when the number of queued segments reachs this limit,
-        /// any more segments enqueued into the sending queue, will leads the same number of oldest queued segments dequeued and droped.
-        /// Zero or minus value means no limit.
-        /// </summary>
-        public int PendingSegmentsLimit
-        {
-            get;
-            set;
-        } = 300000;
-
-        /// <summary>
-        /// Set your own token to active auth
-        /// </summary>
-        public string Authentication
-        {
-            get;
-            set;
-        }
-
-        /// <summary>
-        /// Set certificate path to open ssl/tls
-        /// </summary>
-        public string CertificatePath
-        {
-            get;
-            set;
-        }
-    }
-}

src/SkyWalking.Core/Context/CarrierItemHead.cs

@@ -21,7 +21,7 @@ namespace SkyWalking.Context
 {
     public class CarrierItemHead : CarrierItem
     {
-        public CarrierItemHead(CarrierItem next) : base(string.Empty, string.Empty, next)
+        public CarrierItemHead(CarrierItem next, string @namespace) : base(string.Empty, string.Empty, next, @namespace)
         {
         }
     }

src/SkyWalking.Core/Context/ContextCarrier.cs

@@ -19,7 +19,6 @@
 using System.Collections.Generic;
 using System.Linq;
 using SkyWalking.Context.Ids;
-using SkyWalking.Dictionarys;
 
 namespace SkyWalking.Context
 {
@@ -35,12 +34,12 @@ namespace SkyWalking.Context
         /// <summary>
         /// id of parent application instance
         /// </summary>
-        private int _parentApplicationInstanceId = DictionaryUtil.NullValue;
+        private int _parentApplicationInstanceId = 0;
 
         /// <summary>
         /// id of first application instance in this distributed trace
         /// </summary>
-        private int _entryApplicationInstanceId = DictionaryUtil.NullValue;
+        private int _entryApplicationInstanceId = 0;
 
         /// <summary>
         /// peer(ipv4/ipv6/hostname + port) of the server , from client side .
@@ -65,6 +64,12 @@ namespace SkyWalking.Context
 
         private DistributedTraceId _primaryDistributedTraceId;
 
+        private readonly string _namespace;
+
+        public ContextCarrier(string @namespace)
+        {
+            _namespace = @namespace;
+        }
 
         public DistributedTraceId DistributedTraceId => _primaryDistributedTraceId;
 
@@ -135,8 +140,8 @@ namespace SkyWalking.Context
                 return _traceSegmentId != null
                        && _traceSegmentId.IsValid
                        && _spanId > -1
-                       && _parentApplicationInstanceId != DictionaryUtil.NullValue
-                       && _entryApplicationInstanceId != DictionaryUtil.NullValue
+                       && _parentApplicationInstanceId != 0
+                       && _entryApplicationInstanceId != 0
                        && !string.IsNullOrEmpty(_peerHost)
                        && !string.IsNullOrEmpty(_parentOperationName)
                        && !string.IsNullOrEmpty(_entryOperationName)
@@ -180,17 +185,14 @@ namespace SkyWalking.Context
                 PrimaryDistributedTraceId.Encode);
         }
 
-        public DistributedTraceId PrimaryDistributedTraceId
-        {
-            get { return _primaryDistributedTraceId; }
-        }
+        public DistributedTraceId PrimaryDistributedTraceId => _primaryDistributedTraceId;
 
         public CarrierItem Items
         {
             get
             {
-                SW3CarrierItem carrierItem = new SW3CarrierItem(this, null);
-                CarrierItemHead head = new CarrierItemHead(carrierItem);
+                var carrierItem = new SW3CarrierItem(this, null, _namespace);
+                var head = new CarrierItemHead(carrierItem, _namespace);
                 return head;
             }
         }

src/SkyWalking.AspNet/Logging/DebugLoggerFactoryAdapter.cs → src/SkyWalking.Core/Context/ContextCarrierFactory.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -16,22 +16,22 @@
  *
  */
 
-using System;
-using System.Diagnostics;
-using SkyWalking.Logging;
+using SkyWalking.Config;
 
-namespace SkyWalking.AspNet.Logging
+namespace SkyWalking.Context
 {
-    internal class DebugLoggerFactoryAdapter : ILoggerFactory
+    public class ContextCarrierFactory : IContextCarrierFactory
     {
-        public DebugLoggerFactoryAdapter()
+        private readonly InstrumentationConfig _config;
+
+        public ContextCarrierFactory(IConfigAccessor configAccessor)
         {
-            Debug.Listeners.Add(new TextWriterTraceListener(Console.Out));
+            _config = configAccessor.Get<InstrumentationConfig>();
         }
 
-        public ILogger CreateLogger(Type type)
+        public IContextCarrier Create()
         {
-            return new DebugLoggerAdapter(type);
+            return new ContextCarrier(_config.Namespace);
         }
     }
 }
\ No newline at end of file

src/SkyWalking.Core/Context/ContextManager.cs

@@ -16,16 +16,9 @@
  *
  */
 
-using System;
 using System.Collections.Generic;
 using System.Threading;
-using System.Threading.Tasks;
-using SkyWalking.Boot;
-using SkyWalking.Config;
 using SkyWalking.Context.Trace;
-using SkyWalking.Dictionarys;
-using SkyWalking.Sampling;
-using SkyWalking.Utils;
 
 namespace SkyWalking.Context
 {
@@ -34,8 +27,15 @@ namespace SkyWalking.Context
     /// We also provide the CONTEXT propagation based on ThreadLocal mechanism.
     /// Meaning, each segment also related to singe thread.
     /// </summary>
-    public class ContextManager : ITracingContextListener, IBootService, IIgnoreTracerContextListener
+    public class ContextManager : ITracingContextListener, IIgnoreTracerContextListener
     {
+        static ContextManager()
+        {
+            var manager = new ContextManager();
+            TracingContext.ListenerManager.Add(manager);
+            IgnoredTracerContext.ListenerManager.Add(manager);
+        }
+
         private static readonly AsyncLocal<ITracerContext> _context = new AsyncLocal<ITracerContext>();
 
         private static ITracerContext GetOrCreateContext(string operationName, bool forceSampling)
@@ -50,18 +50,17 @@ namespace SkyWalking.Context
                 }
                 else
                 {
-                    if (!DictionaryUtil.IsNull(RemoteDownstreamConfig.Agent.ApplicationId) &&
-                        !DictionaryUtil.IsNull(RemoteDownstreamConfig.Agent.ApplicationInstanceId))
+                    if (RuntimeEnvironment.Instance.Initialized)
                     {
-                        var suffixIdx = operationName.LastIndexOf('.');
-                        if (suffixIdx > -1 && AgentConfig.IgnoreSuffix.Contains(operationName.Substring(suffixIdx)))
-                        {
-                            _context.Value = new IgnoredTracerContext();
-                        }
-                        else
-                        {
-                            var sampler = ServiceManager.Instance.GetService<SamplingService>();
-                            if (forceSampling || sampler.TrySampling())
+//                        var suffixIdx = operationName.LastIndexOf('.');
+//                        if (suffixIdx > -1 && AgentConfig.IgnoreSuffix.Contains(operationName.Substring(suffixIdx)))
+//                        {
+//                            _context.Value = new IgnoredTracerContext();
+//                        }
+//                        else
+//                        {
+                            var sampler = DefaultSampler.Instance;
+                            if (forceSampling || sampler.Sampled())
                             {
                                 _context.Value = new TracingContext();
                             }
@@ -69,14 +68,13 @@ namespace SkyWalking.Context
                             {
                                 _context.Value = new IgnoredTracerContext();
                             }
-                        }
+//                        }
                     }
                     else
                     {
                         _context.Value = new IgnoredTracerContext();
                     }
                 }
-
             }
 
             return _context.Value;
@@ -103,7 +101,7 @@ namespace SkyWalking.Context
 
         public static ISpan CreateEntrySpan(string operationName, IContextCarrier carrier)
         {
-            var samplingService = ServiceManager.Instance.GetService<SamplingService>();
+            var samplingService = DefaultSampler.Instance;
             if (carrier != null && carrier.IsValid)
             {
                 samplingService.ForceSampled();
@@ -179,19 +177,6 @@ namespace SkyWalking.Context
             _context.Value = null;
         }
 
-        public void Dispose()
-        {
-        }
-
-        public int Order { get; } = 1;
-
-        public Task Initialize(CancellationToken token)
-        {
-            TracingContext.ListenerManager.Add(this);
-            IgnoredTracerContext.ListenerManager.Add(this);
-            return TaskUtils.CompletedTask;
-        }
-
         public void AfterFinish(ITracerContext tracerContext)
         {
             _context.Value = null;

src/SkyWalking.Core/Context/ContextSnapshot.cs

@@ -19,7 +19,6 @@
 using System.Collections.Generic;
 using System.Linq;
 using SkyWalking.Context.Ids;
-using SkyWalking.Dictionarys;
 
 namespace SkyWalking.Context
 {
@@ -39,7 +38,7 @@ namespace SkyWalking.Context
         private string _parentOperationName;
 
         private readonly DistributedTraceId _primaryDistributedTraceId;
-        private int _entryApplicationInstanceId = DictionaryUtil.NullValue;
+        private NullableValue _entryApplicationInstanceId = NullableValue.Null;
 
         public ContextSnapshot(ID traceSegmentId, int spanId, IEnumerable<DistributedTraceId> distributedTraceIds)
         {
@@ -48,7 +47,6 @@ namespace SkyWalking.Context
             _primaryDistributedTraceId = distributedTraceIds?.FirstOrDefault();
         }
 
-
         public string EntryOperationName
         {
             get => _entryOperationName;
@@ -65,8 +63,8 @@ namespace SkyWalking.Context
 
         public int EntryApplicationInstanceId
         {
-            get => _entryApplicationInstanceId;
-            set => _entryApplicationInstanceId = value;
+            get => _entryApplicationInstanceId.Value;
+            set => _entryApplicationInstanceId = new NullableValue(value);
         }
 
         public int SpanId => _spanId;
@@ -75,7 +73,7 @@ namespace SkyWalking.Context
 
         public bool IsValid => _traceSegmentId != null
                                && _spanId > -1
-                               && _entryApplicationInstanceId != DictionaryUtil.NullValue
+                               && _entryApplicationInstanceId.HasValue
                                && _primaryDistributedTraceId != null
                                && string.IsNullOrEmpty(_entryOperationName)
                                && string.IsNullOrEmpty(_parentOperationName);

src/SkyWalking.Core/Context/Ids/GlobalIdGenerator.cs

@@ -18,9 +18,6 @@
 
 using System;
 using System.Threading;
-using SkyWalking.Config;
-using SkyWalking.Dictionarys;
-using  SkyWalking.Utils;
 
 namespace SkyWalking.Context.Ids
 {
@@ -30,7 +27,7 @@ namespace SkyWalking.Context.Ids
 
         public static ID Generate()
         {
-            if (RemoteDownstreamConfig.Agent.ApplicationId == DictionaryUtil.NullValue)
+            if (!RuntimeEnvironment.Instance.ApplicationInstanceId.HasValue)
             {
                 throw new InvalidOperationException();
             }
@@ -38,7 +35,7 @@ namespace SkyWalking.Context.Ids
             IDContext context = threadIdSequence.Value;
 
             return new ID(
-                RemoteDownstreamConfig.Agent.ApplicationInstanceId,
+                RuntimeEnvironment.Instance.ApplicationInstanceId.Value,
                 Thread.CurrentThread.ManagedThreadId,
                 context.NextSeq()
             );

src/SkyWalking.Core/Context/SW3CarrierItem.cs

@@ -22,15 +22,19 @@ namespace SkyWalking.Context
 {
     public class SW3CarrierItem : CarrierItem
     {
-        public const String HEADER_NAME = "sw3";
+        private const string HEADER_NAME = "sw3";
         private readonly IContextCarrier _carrier;
 
-        public SW3CarrierItem(IContextCarrier carrier, CarrierItem next)
-            : base(HEADER_NAME, carrier.Serialize(), next)
+        public SW3CarrierItem(IContextCarrier carrier, CarrierItem next, string @namespace)
+            : base(HEADER_NAME, carrier.Serialize(), next, @namespace)
         {
             _carrier = carrier;
         }
 
-        public override string HeadValue { get => base.HeadValue; set => _carrier.Deserialize(value); }
+        public override string HeadValue
+        {
+            get => base.HeadValue;
+            set => _carrier.Deserialize(value);
+        }
     }
 }
\ No newline at end of file

src/SkyWalking.Core/Context/Trace/EntrySpan.cs

@@ -16,8 +16,7 @@
  *
  */
 
-using SkyWalking.Dictionarys;
-using SkyWalking.NetworkProtocol.Trace;
+using SkyWalking.Components;
 
 namespace SkyWalking.Context.Trace
 {
@@ -119,7 +118,7 @@ namespace SkyWalking.Context.Trace
 
         private void ClearWhenRestart()
         {
-            _componentId = DictionaryUtil.NullValue;
+            _componentId = 0;
             _componentName = null;
             _layer = null;
             _logs = null;

src/SkyWalking.Core/Context/Trace/ExitSpan.cs

@@ -17,11 +17,8 @@
  */
 
 using System;
-using System.Collections.Generic;
-using System.Text;
-using SkyWalking.Dictionarys;
-using SkyWalking.NetworkProtocol;
-using SkyWalking.NetworkProtocol.Trace;
+using SkyWalking.Transport;
+using SkyWalking.Components;
 
 namespace SkyWalking.Context.Trace
 {
@@ -34,7 +31,7 @@ namespace SkyWalking.Context.Trace
             : base(spanId, parentSpanId, operationName)
         {
             _peer = peer;
-            _peerId = DictionaryUtil.NullValue;
+            _peerId = 0;
         }
 
         public ExitSpan(int spanId, int parentSpanId, int operationId, int peerId)
@@ -48,7 +45,7 @@ namespace SkyWalking.Context.Trace
             : base(spanId, parentSpanId, operationId)
         {
             _peer = peer;
-            _peerId = DictionaryUtil.NullValue;
+            _peerId = 0;
         }
 
         public ExitSpan(int spanId, int parentSpanId, String operationName, int peerId)
@@ -108,17 +105,12 @@ namespace SkyWalking.Context.Trace
 
         public override ISpan SetComponent(string componentName)
         {
-            if (_stackDepth == 1)
-            {
-                return base.SetComponent(componentName);
-            }
-
-            return this;
+            return _stackDepth == 1 ? base.SetComponent(componentName) : this;
         }
 
         public override string OperationName
         {
-            get { return base.OperationName; }
+            get => base.OperationName;
             set
             {
                 if (_stackDepth == 1)
@@ -130,7 +122,7 @@ namespace SkyWalking.Context.Trace
 
         public override int OperationId
         {
-            get { return base.OperationId; }
+            get => base.OperationId;
             set
             {
                 if (_stackDepth == 1)
@@ -140,18 +132,11 @@ namespace SkyWalking.Context.Trace
             }
         }
 
-        public override SpanObject Transform()
+        public override SpanRequest Transform()
         {
             var spanObject = base.Transform();
 
-            if (_peerId != DictionaryUtil.NullValue)
-            {
-                spanObject.PeerId = _peerId;
-            }
-            else
-            {
-                spanObject.Peer = _peer;
-            }
+            spanObject.Peer = new StringOrIntValue(_peerId, _peer);
 
             return spanObject;
         }

src/SkyWalking.Core/Context/Trace/NoopSpan.cs

@@ -18,8 +18,7 @@
 
 using System;
 using System.Collections.Generic;
-using System.Text;
-using SkyWalking.NetworkProtocol.Trace;
+using SkyWalking.Components;
 
 namespace SkyWalking.Context.Trace
 {

src/SkyWalking.Core/Context/Trace/TraceSegment.cs

@@ -18,10 +18,8 @@
 
 using System.Collections.Generic;
 using System.Linq;
-using Google.Protobuf;
-using SkyWalking.Config;
+using SkyWalking.Transport;
 using SkyWalking.Context.Ids;
-using SkyWalking.NetworkProtocol;
 
 namespace SkyWalking.Context.Trace
 {
@@ -30,12 +28,11 @@ namespace SkyWalking.Context.Trace
         private readonly IList<ITraceSegmentRef> _refs;
         private readonly IList<AbstractTracingSpan> _spans;
         private readonly DistributedTraceIdCollection _relatedGlobalTraces;
-        private bool _isSizeLimited = false;
+        private bool _isSizeLimited;
 
+        public int ApplicationId => RuntimeEnvironment.Instance.ApplicationId.Value;
 
-        public int ApplicationId => RemoteDownstreamConfig.Agent.ApplicationId;
-
-        public int ApplicationInstanceId => RemoteDownstreamConfig.Agent.ApplicationInstanceId;
+        public int ApplicationInstanceId => RuntimeEnvironment.Instance.ApplicationInstanceId.Value;
 
         public IEnumerable<ITraceSegmentRef> Refs => _refs;
 
@@ -85,21 +82,21 @@ namespace SkyWalking.Context.Trace
             _relatedGlobalTraces.Append(distributedTraceId);
         }
 
-        public UpstreamSegment Transform()
+        public TraceSegmentRequest Transform()
         {
-            var upstreamSegment = new UpstreamSegment();
-            upstreamSegment.GlobalTraceIds.AddRange(_relatedGlobalTraces.GetRelatedGlobalTraces()
-                .Select(x => x.ToUniqueId()));
-
-            var traceSegment = new TraceSegmentObject {TraceSegmentId = TraceSegmentId.Transform()};
-
-            traceSegment.Spans.AddRange(_spans.Select(x => x.Transform()));
-
-            traceSegment.ApplicationId = ApplicationId;
-            traceSegment.ApplicationInstanceId = ApplicationInstanceId;
-            traceSegment.IsSizeLimited = _isSizeLimited;
+            var upstreamSegment = new TraceSegmentRequest
+            {
+                UniqueIds = _relatedGlobalTraces.GetRelatedGlobalTraces()
+                    .Select(x => x.ToUniqueId()).ToArray()
+            };
 
-            upstreamSegment.Segment = traceSegment.ToByteString();
+            upstreamSegment.Segment = new TraceSegmentObjectRequest
+            {
+                SegmentId = TraceSegmentId.Transform(),
+                Spans = _spans.Select(x => x.Transform()).ToArray(),
+                ApplicationId = ApplicationId,
+                ApplicationInstanceId = ApplicationInstanceId
+            };
             
             return upstreamSegment;
         }

src/SkyWalking.Core/Context/Trace/TraceSegmentRef.cs

@@ -17,26 +17,25 @@
  */
 
 using System.Linq;
+using SkyWalking.Transport;
 using SkyWalking.Config;
 using SkyWalking.Context.Ids;
-using SkyWalking.Dictionarys;
-using SkyWalking.NetworkProtocol;
 
 namespace SkyWalking.Context.Trace
 {
     public class TraceSegmentRef : ITraceSegmentRef
     {
-        private SegmentRefType _type;
-        private ID _traceSegmentId;
-        private int _spanId = -1;
-        private int _peerId = DictionaryUtil.NullValue;
-        private string _peerHost;
-        private int _entryApplicationInstanceId = DictionaryUtil.NullValue;
-        private int _parentApplicationInstanceId = DictionaryUtil.NullValue;
-        private string _entryOperationName;
-        private int _entryOperationId = DictionaryUtil.NullValue;
-        private string _parentOperationName;
-        private int _parentOperationId = DictionaryUtil.NullValue;
+        private readonly SegmentRefType _type;
+        private readonly ID _traceSegmentId;
+        private readonly int _spanId = -1;
+        private readonly int _peerId = 0;
+        private readonly string _peerHost;
+        private readonly int _entryApplicationInstanceId = 0;
+        private readonly int _parentApplicationInstanceId = 0;
+        private readonly string _entryOperationName;
+        private readonly int _entryOperationId = 0;
+        private readonly string _parentOperationName;
+        private readonly int _parentOperationId = 0;
 
         public TraceSegmentRef(IContextCarrier carrier)
         {
@@ -81,7 +80,7 @@ namespace SkyWalking.Context.Trace
             _type = SegmentRefType.CrossThread;
             _traceSegmentId = contextSnapshot.TraceSegmentId;
             _spanId = contextSnapshot.SpanId;
-            _parentApplicationInstanceId = RemoteDownstreamConfig.Agent.ApplicationInstanceId;
+            _parentApplicationInstanceId = RuntimeEnvironment.Instance.ApplicationInstanceId.Value;
             _entryApplicationInstanceId = contextSnapshot.EntryApplicationInstanceId;
             string entryOperationName = contextSnapshot.EntryOperationName;
             if (entryOperationName.First() == '#')
@@ -148,45 +147,29 @@ namespace SkyWalking.Context.Trace
 
         public int EntryApplicationInstanceId => _entryApplicationInstanceId;
 
-        public TraceSegmentReference Transform()
+        public TraceSegmentReferenceRequest Transform()
         {
-            TraceSegmentReference traceSegmentReference = new TraceSegmentReference();
+            TraceSegmentReferenceRequest traceSegmentReference = new TraceSegmentReferenceRequest();
             if (_type == SegmentRefType.CrossProcess)
             {
-                traceSegmentReference.RefType = RefType.CrossProcess;
-                if (_peerId == DictionaryUtil.NullValue)
-                {
-                    traceSegmentReference.NetworkAddress = _peerHost;
-                }
-                else
-                {
-                    traceSegmentReference.NetworkAddressId = _peerId;
-                }
+                traceSegmentReference.RefType = (int) SegmentRefType.CrossProcess;
+                traceSegmentReference.NetworkAddress = new StringOrIntValue(_peerId, _peerHost);
             }
             else
             {
-                traceSegmentReference.RefType = RefType.CrossThread;
+                traceSegmentReference.RefType = (int) SegmentRefType.CrossThread;
+                traceSegmentReference.NetworkAddress = new StringOrIntValue();
             }
+
             traceSegmentReference.ParentApplicationInstanceId = _parentApplicationInstanceId;
             traceSegmentReference.EntryApplicationInstanceId = _entryApplicationInstanceId;
             traceSegmentReference.ParentTraceSegmentId = _traceSegmentId.Transform();
             traceSegmentReference.ParentSpanId = _spanId;
-            if (_entryOperationId == DictionaryUtil.NullValue)
-            {
-                traceSegmentReference.EntryServiceName = _entryOperationName;
-            }
-            else
-            {
-                traceSegmentReference.EntryServiceId = _entryOperationId;
-            }
-            if (_parentOperationId == DictionaryUtil.NullValue)
-            {
-                traceSegmentReference.ParentServiceName = _parentOperationName;
-            }
-            else
-            {
-                traceSegmentReference.ParentServiceId = _parentOperationId;
-            }
+
+            traceSegmentReference.EntryServiceName = new StringOrIntValue(_entryOperationId, _entryOperationName);
+
+            traceSegmentReference.ParentServiceName = new StringOrIntValue(_parentOperationId, _parentOperationName);
+
             return traceSegmentReference;
         }
     }

src/SkyWalking.Core/Context/TraceContextCarrierItem.cs

@@ -16,16 +16,14 @@
  *
  */
 
-using System;
-
 namespace SkyWalking.Context
 {
     public class TraceContextCarrierItem : CarrierItem
     {
         private const string HEAD_NAME = "Trace-Context";
 
-        public TraceContextCarrierItem(String headValue, CarrierItem next)
-        : base(HEAD_NAME, headValue, next)
+        public TraceContextCarrierItem(string headValue, CarrierItem next, string @namespace)
+            : base(HEAD_NAME, headValue, next, @namespace)
         {
         }
     }

src/SkyWalking.Core/Context/TracingContext.cs

@@ -20,10 +20,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Runtime.CompilerServices;
-using SkyWalking.Boot;
 using SkyWalking.Context.Trace;
-using SkyWalking.Dictionarys;
-using SkyWalking.Sampling;
 using SkyWalking.Utils;
 
 namespace SkyWalking.Context
@@ -38,7 +35,7 @@ namespace SkyWalking.Context
 
         public TracingContext()
         {
-            _sampler = ServiceManager.Instance.GetService<SamplingService>();
+            _sampler = DefaultSampler.Instance;
             _segment = new TraceSegment();
             _activeSpanStacks = new Stack<ISpan>();
         }
@@ -62,7 +59,7 @@ namespace SkyWalking.Context
             carrier.SpanId = span.SpanId;
             carrier.ParentApplicationInstanceId = _segment.ApplicationInstanceId;
 
-            if (DictionaryUtil.IsNull(peerId))
+            if (peerId == 0)
             {
                 carrier.PeerHost = peer;
             }
@@ -78,7 +75,7 @@ namespace SkyWalking.Context
 
             carrier.EntryApplicationInstanceId = metaValue.entryApplicationInstanceId;
 
-            if (DictionaryUtil.IsNull(metaValue.operationId))
+            if (metaValue.operationId == 0)
             {
                 carrier.EntryOperationName = metaValue.operationName;
             }
@@ -88,7 +85,7 @@ namespace SkyWalking.Context
             }
 
             var parentOperationId = firstSpan.OperationId;
-            if (DictionaryUtil.IsNull(parentOperationId))
+            if (parentOperationId == 0)
             {
                 carrier.ParentOperationName = firstSpan.OperationName;
             }
@@ -151,24 +148,13 @@ namespace SkyWalking.Context
             var parentSpanId = parentSpan?.SpanId ?? -1;
 
             if (parentSpan != null && parentSpan.IsEntry)
-            {
-                var entrySpan = (ISpan) DictionaryManager.OperationName.FindOnly(_segment.ApplicationId, operationName)
-                    .InCondition(id =>
-                    {
-                        parentSpan.OperationId = id;
-                        return parentSpan;
-                    }, () =>
             {
                 parentSpan.OperationName = operationName;
-                        return parentSpan;
-                    });
-                return entrySpan.Start();
+                return parentSpan.Start();
             }
             else
             {
-                var entrySpan = (ISpan) DictionaryManager.OperationName.FindOnly(_segment.ApplicationId, operationName)
-                    .InCondition(id => new EntrySpan(_spanIdGenerator++, parentSpanId, id),
-                        () => new EntrySpan(_spanIdGenerator++, parentSpanId, operationName));
+                var entrySpan = new EntrySpan(_spanIdGenerator++, parentSpanId, operationName);
 
                 entrySpan.Start();
 
@@ -192,10 +178,7 @@ namespace SkyWalking.Context
 
             var parentSpanId = parentSpan?.SpanId ?? -1;
 
-            var span = (ISpan) DictionaryManager.OperationName
-                .FindOrPrepareForRegister(_segment.ApplicationId, operationName, false, false)
-                .InCondition(id => new LocalSpan(_spanIdGenerator++, parentSpanId, operationName),
-                    () => new LocalSpan(_spanIdGenerator++, parentSpanId, operationName));
+            var span = new LocalSpan(_spanIdGenerator++, parentSpanId, operationName);
             span.Start();
             _activeSpanStacks.Push(span);
             return span;
@@ -214,30 +197,7 @@ namespace SkyWalking.Context
             else
             {
                 var parentSpanId = parentSpan?.SpanId ?? -1;
-                var exitSpan = (ISpan) DictionaryManager.NetworkAddress.Find(remotePeer)
-                    .InCondition(peerId =>
-                        {
-                            if (IsLimitMechanismWorking())
-                            {
-                                return new NoopExitSpan(peerId);
-                            }
-
-                            return DictionaryManager.OperationName.FindOnly(_segment.ApplicationId, operationName)
-                                .InCondition(id => new ExitSpan(_spanIdGenerator++, parentSpanId, id, peerId),
-                                    () => new ExitSpan(_spanIdGenerator++, parentSpanId, operationName, peerId));
-                        },
-                        () =>
-                        {
-                            if (IsLimitMechanismWorking())
-                            {
-                                return new NoopExitSpan(remotePeer);
-                            }
-
-                            return DictionaryManager.OperationName.FindOnly(_segment.ApplicationId, operationName)
-                                .InCondition(id => new ExitSpan(_spanIdGenerator++, parentSpanId, id, remotePeer),
-                                    () => new ExitSpan(_spanIdGenerator++, parentSpanId, operationName,
-                                        remotePeer));
-                        });
+                var exitSpan = IsLimitMechanismWorking() ? (ISpan)new NoopExitSpan(remotePeer) : new ExitSpan(_spanIdGenerator++, parentSpanId, operationName, remotePeer);
                 _activeSpanStacks.Push(exitSpan);
                 return exitSpan.Start();
             }
@@ -263,7 +223,6 @@ namespace SkyWalking.Context
                 {
                     _activeSpanStacks.Pop();
                 }
-                
             }
             else
             {
@@ -283,7 +242,7 @@ namespace SkyWalking.Context
 
             if (!_segment.HasRef && _segment.IsSingleSpanSegment)
             {
-                if (!_sampler.TrySampling())
+                if (!_sampler.Sampled())
                 {
                     finishedSegment.IsIgnore = true;
                 }
@@ -321,7 +280,7 @@ namespace SkyWalking.Context
 
             snapshot.EntryApplicationInstanceId = metaValue.entryApplicationInstanceId;
 
-            if (DictionaryUtil.IsNull(metaValue.operationId))
+            if (metaValue.operationId == 0)
             {
                 snapshot.EntryOperationName = metaValue.operationName;
             }
@@ -332,7 +291,7 @@ namespace SkyWalking.Context
 
             var parentSpan = _activeSpanStacks.Last();
 
-            if (DictionaryUtil.IsNull(parentSpan.OperationId))
+            if (parentSpan.OperationId == 0)
             {
                 snapshot.ParentOperationName = parentSpan.OperationName;
             }
@@ -362,7 +321,7 @@ namespace SkyWalking.Context
 
         private bool IsLimitMechanismWorking()
         {
-            if (_spanIdGenerator < Config.AgentConfig.SpanLimitPerSegment)
+            if (_spanIdGenerator < 300)
             {
                 return false;
             }

src/SkyWalking.Core/Sampling/SamplingService.cs → src/SkyWalking.Core/DefaultSampler.cs

-/*
+/*
  * Licensed to the OpenSkywalking under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
@@ -16,50 +16,48 @@
  *
  */
 
-using System;
-using System.Threading;
-using System.Threading.Tasks;
-using SkyWalking.Boot;
-using SkyWalking.Config;
+using System.Runtime.CompilerServices;
 using SkyWalking.Utils;
 
-namespace SkyWalking.Sampling
+namespace SkyWalking
 {
-    // ReSharper disable once ClassNeverInstantiated.Global
-    public class SamplingService :TimerService, ISampler
+    public class DefaultSampler : ISampler
     {
-        private readonly AtomicInteger _atomicInteger = new AtomicInteger();
-        private readonly int _sample_N_Per_3_Secs = AgentConfig.SamplePer3Secs;
-        private readonly bool _sample_on = AgentConfig.SamplePer3Secs > 0;
+        public static DefaultSampler Instance { get; } = new DefaultSampler();
         
-        public bool TrySampling()
+        private readonly AtomicInteger _idx = new AtomicInteger();
+        
+        private int _samplePer3Secs;
+        private bool _sample_on;
+
+        public bool Sampled()
         {
             if (!_sample_on)
             {
                 return true;
             }
 
-            return _atomicInteger.Increment() < _sample_N_Per_3_Secs;
+            return _idx.Increment() < _samplePer3Secs;
         }
 
         public void ForceSampled()
         {
             if (_sample_on)
             {
-                _atomicInteger.Increment();
+                _idx.Increment();
             }
         }
 
-        protected override TimeSpan Interval { get; } = TimeSpan.FromSeconds(3);
-        
-        protected override Task Execute(CancellationToken token)
+        [MethodImpl(MethodImplOptions.Synchronized)]
+        internal void SetSamplePer3Secs(int samplePer3Secs)
         {
-            if (_sample_on)
-            {
-                _atomicInteger.Value = 0;
+            _samplePer3Secs = samplePer3Secs;
+            _sample_on = samplePer3Secs > -1;
         }
 
-            return TaskUtils.CompletedTask;
+        internal void Reset()
+        {
+            _idx.Value = 0;
         }
     }
 }
\ No newline at end of file

src/SkyWalking.Core/Diagnostics/TracingDiagnosticMethod.cs

@@ -25,14 +25,14 @@ namespace SkyWalking.Diagnostics
     internal class TracingDiagnosticMethod
     {
         private readonly MethodInfo _method;
-        private readonly ITracingDiagnosticProcessor _diagnosticProcessor;
+        private readonly ITracingDiagnosticProcessor _tracingDiagnosticProcessor;
         private readonly string _diagnosticName;
         private readonly IParameterResolver[] _parameterResolvers;
 
-        public TracingDiagnosticMethod(ITracingDiagnosticProcessor diagnosticProcessor, MethodInfo method,
+        public TracingDiagnosticMethod(ITracingDiagnosticProcessor tracingDiagnosticProcessor, MethodInfo method,
             string diagnosticName)
         {
-            _diagnosticProcessor = diagnosticProcessor;
+            _tracingDiagnosticProcessor = tracingDiagnosticProcessor;
             _method = method;
             _diagnosticName = diagnosticName;
             _parameterResolvers = GetParameterResolvers(method).ToArray();
@@ -51,7 +51,7 @@ namespace SkyWalking.Diagnostics
                 args[i] = _parameterResolvers[i].Resolve(value);
             }
 
-            _method.Invoke(_diagnosticProcessor, args);
+            _method.Invoke(_tracingDiagnosticProcessor, args);
         }
 
         private static IEnumerable<IParameterResolver> GetParameterResolvers(MethodInfo methodInfo)

src/SkyWalking.Core/Diagnostics/TracingDiagnosticMethodCollection.cs

@@ -26,15 +26,15 @@ namespace SkyWalking.Diagnostics
     {
         private readonly List<TracingDiagnosticMethod> _methods;
 
-        public TracingDiagnosticMethodCollection(ITracingDiagnosticProcessor diagnosticProcessor)
+        public TracingDiagnosticMethodCollection(ITracingDiagnosticProcessor tracingDiagnosticProcessor)
         {
             _methods = new List<TracingDiagnosticMethod>();
-            foreach (var method in diagnosticProcessor.GetType().GetMethods())
+            foreach (var method in tracingDiagnosticProcessor.GetType().GetMethods())
             {
                 var diagnosticName = method.GetCustomAttribute<DiagnosticName>();
                 if(diagnosticName==null)
                     continue;
-                _methods.Add(new TracingDiagnosticMethod(diagnosticProcessor, method, diagnosticName.Name));
+                _methods.Add(new TracingDiagnosticMethod(tracingDiagnosticProcessor, method, diagnosticName.Name));
             }
         }
         

src/SkyWalking.Core/Diagnostics/TracingDiagnosticProcessorObserver.cs

@@ -26,12 +26,12 @@ namespace SkyWalking.Diagnostics
 {
     public class TracingDiagnosticProcessorObserver : IObserver<DiagnosticListener>
     {
-        private static readonly ILogger _logger = LogManager.GetLogger<TracingDiagnosticProcessorObserver>();
-
+        private readonly ILogger _logger;
         private readonly IEnumerable<ITracingDiagnosticProcessor> _tracingDiagnosticProcessors;
 
-        public TracingDiagnosticProcessorObserver(IEnumerable<ITracingDiagnosticProcessor> tracingDiagnosticProcessors)
+        public TracingDiagnosticProcessorObserver(IEnumerable<ITracingDiagnosticProcessor> tracingDiagnosticProcessors, ILoggerFactory loggerFactory)
         {
+            _logger = loggerFactory.CreateLogger(typeof(TracingDiagnosticProcessorObserver));
             _tracingDiagnosticProcessors = tracingDiagnosticProcessors ??
                                            throw new ArgumentNullException(nameof(tracingDiagnosticProcessors));
         }
@@ -51,16 +51,16 @@ namespace SkyWalking.Diagnostics
                 if (listener.Name == diagnosticProcessor.ListenerName)
                 {
                     Subscribe(listener, diagnosticProcessor);
-                    _logger.Debug(
-                        $"TracingDiagnosticObserver subscribe diagnosticListener named [{diagnosticProcessor.ListenerName}].");
+                    _logger.Information(
+                        $"Loaded diagnostic listener [{diagnosticProcessor.ListenerName}].");
                 }
             }
         }
 
         protected virtual void Subscribe(DiagnosticListener listener,
-            ITracingDiagnosticProcessor diagnosticProcessor)
+            ITracingDiagnosticProcessor tracingDiagnosticProcessor)
         {
-            listener.Subscribe(new TracingDiagnosticObserver(diagnosticProcessor));
+            listener.Subscribe(new TracingDiagnosticObserver(tracingDiagnosticProcessor));
         }
     }
 }
\ No newline at end of file

src/SkyWalking.Core/Dictionary/DictionaryManager.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-namespace SkyWalking.Dictionarys
-{
-    public class DictionaryManager
-    {
-        public static NetworkAddressDictionary NetworkAddress => NetworkAddressDictionary.Instance;
-
-        public static OperationNameDictionary OperationName => OperationNameDictionary.Instance;
-    }
-}
\ No newline at end of file

src/SkyWalking.Core/Dictionary/OperationNameDictionary.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-using System;
-using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Net.NetworkInformation;
-using System.Xml.Schema;
-using SkyWalking.Config;
-using SkyWalking.Dictionarys;
-using SkyWalking.NetworkProtocol;
-
-namespace SkyWalking.Dictionarys
-{
-    public class OperationNameDictionary
-    {
-        private static readonly OperationNameDictionary _instance=new OperationNameDictionary();
-        public static OperationNameDictionary Instance => _instance;
-
-        private OperationNameDictionary()
-        {
-        }
-
-        private readonly ConcurrentDictionary<OperationNameKey,int> _operationNameDic=new ConcurrentDictionary<OperationNameKey, int>();
-        private readonly ConcurrentDictionary<OperationNameKey,object> _unRegisterOpNames=new ConcurrentDictionary<OperationNameKey, object>();
-
-        public PossibleFound FindOrPrepareForRegister(int applicationId, string operationName, bool isEntry,
-            bool isExit)
-        {
-            return internalFind(applicationId, operationName, isEntry, isExit, true);
-        }
-        
-        public PossibleFound FindOnly(int applicationId, string operationName)
-        {
-            return internalFind(applicationId, operationName, false, false, false);
-        }
-        
-        private PossibleFound internalFind(int applicationId, string operationName, bool isEntry, bool isExit,
-            bool registerWhenNotFound)
-        {
-            if (string.IsNullOrEmpty(operationName))
-            {
-                return NotFound.Instance;
-            }
-
-            var operationNameKey = new OperationNameKey(applicationId, operationName, isEntry, isExit);
-            if (_operationNameDic.TryGetValue(operationNameKey, out var id))
-            {
-                return new Found(id);
-            }
-            else
-            {
-                if (registerWhenNotFound && _operationNameDic.Count + _unRegisterOpNames.Count <
-                    DictionaryConfig.OperationNameBufferSize)
-                {
-                    _unRegisterOpNames.TryAdd(operationNameKey, null);
-                }
-
-                return NotFound.Instance;
-            }
-        }
-
-        public void SyncRemote(ServiceNameDiscoveryService.ServiceNameDiscoveryServiceClient serviceClient)
-        {
-            if (_unRegisterOpNames.Count > 0)
-            {
-                var serviceNameCollection = new ServiceNameCollection();
-                foreach (var opName in _unRegisterOpNames)
-                {
-                    var serviceName = new ServiceNameElement();
-                    serviceName.ApplicationId = opName.Key.ApplicationId;
-                    serviceName.ServiceName = opName.Key.OperationName;
-                    serviceName.SrcSpanType = opName.Key.SpanType;
-                    serviceNameCollection.Elements.Add(serviceName);
-                }
-
-                var mapping = serviceClient.discovery(serviceNameCollection);
-
-                foreach (var item in mapping.Elements)
-                {
-                    var element = item.Element;
-                    var key = new OperationNameKey(element.ApplicationId, element.ServiceName,
-                        SpanType.Entry == element.SrcSpanType, SpanType.Exit == element.SrcSpanType);
-                    _unRegisterOpNames.TryRemove(key, out _);
-                    _operationNameDic.TryAdd(key, item.ServiceId);
-                }
-
-            }
-        }
-    }
-
-    public class OperationNameKey : IEquatable<OperationNameKey>
-    {
-        private readonly int _applicationId;
-        private readonly string _operationName;
-        private readonly bool _isEntry;
-        private readonly bool _isExit;
-
-        public OperationNameKey(int applicationId, string operationName, bool isEntry, bool isExit)
-        {
-            _applicationId = applicationId;
-            _operationName = operationName;
-            _isEntry = isEntry;
-            _isExit = isExit;
-        }
-
-        public int ApplicationId => _applicationId;
-
-        public string OperationName => _operationName;
-
-        public bool Equals(OperationNameKey other)
-        {
-            if (other == null)
-            {
-                return false;
-            }
-            var isMatch = _applicationId == other._applicationId || _operationName == other._operationName;
-            return isMatch && _isEntry == other._isEntry && _isExit == other._isExit;
-        }
-
-        public override bool Equals(object obj)
-        {
-            var other = obj as OperationNameKey;
-            return Equals(other);
-        }
-
-        public override int GetHashCode()
-        {
-            var result = _applicationId;
-            result = 31 * result + _operationName.GetHashCode();
-            return result;
-        }
-
-        public SpanType SpanType
-        {
-            get
-            {
-                if (_isEntry)
-                {
-                    return SpanType.Entry;
-                }
-                else if(_isExit)
-                {
-                    return SpanType.Exit;
-                }
-                else
-                {
-                    return SpanType.Local;
-                }
-            }
-        }
-    }
-}
\ No newline at end of file

src/SkyWalking.Core/Logging/NullLogger.cs

@@ -26,7 +26,7 @@ namespace SkyWalking.Logging
         {
         }
 
-        public void Info(string message)
+        public void Information(string message)
         {
         }
 

src/SkyWalking.Core/Logging/NullLoggerFactory.cs

@@ -20,7 +20,7 @@ using System;
 
 namespace SkyWalking.Logging
 {
-    internal class NullLoggerFactory : ILoggerFactory
+    public class NullLoggerFactory : ILoggerFactory
     {
         public ILogger CreateLogger(Type type)
         {

src/SkyWalking.Core/Remote/Authentication/AuthenticationInterceptors.cs

@@ -16,31 +16,31 @@
  *
  */
 
-using Grpc.Core;
-using SkyWalking.Utils;
-
-namespace SkyWalking.Remote.Authentication
-{
-    internal static class AuthenticationInterceptors
-    {
-        private const string header = "authentication";
-        
-        public static AsyncAuthInterceptor CreateAuthInterceptor(string token)
-        {
-            return (context, metadata) =>
-            {
-                var entry = CreateTokenHeader(token);
-                if (entry != null)
-                {
-                    metadata.Add(entry);
-                }    
-                return TaskUtils.CompletedTask;
-            };
-        }
-
-        private static Metadata.Entry CreateTokenHeader(string token)
-        {
-            return string.IsNullOrEmpty(token) ? null : new Metadata.Entry(header, token);
-        }
-    }
-}
+//using Grpc.Core;
+//using SkyWalking.Utils;
+//
+//namespace SkyWalking.Remote.Authentication
+//{
+//    internal static class AuthenticationInterceptors
+//    {
+//        private const string header = "authentication";
+//        
+//        public static AsyncAuthInterceptor CreateAuthInterceptor(string token)
+//        {
+//            return (context, metadata) =>
+//            {
+//                var entry = CreateTokenHeader(token);
+//                if (entry != null)
+//                {
+//                    metadata.Add(entry);
+//                }    
+//                return TaskUtils.CompletedTask;
+//            };
+//        }
+//
+//        private static Metadata.Entry CreateTokenHeader(string token)
+//        {
+//            return string.IsNullOrEmpty(token) ? null : new Metadata.Entry(header, token);
+//        }
+//    }
+//}

src/SkyWalking.Core/Remote/GrpcChannelBuilder.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-using Grpc.Core;
-using SkyWalking.Remote.Authentication;
-
-namespace SkyWalking.Remote
-{
-    internal class GrpcChannelBuilder
-    {
-        private string _token;
-
-        private string _server;
-
-        private string _rootCertificatePath;
-
-        public GrpcChannelBuilder WithAuthenticationToken(string token)
-        {
-            _token = token;
-            return this;
-        }
-
-        public GrpcChannelBuilder WithServer(string server)
-        {
-            _server = server;
-            return this;
-        }
-
-        public GrpcChannelBuilder WithCredential(string rootCertificatePath)
-        {
-            _rootCertificatePath = rootCertificatePath;
-            return this;
-        }
-
-        public Channel Build()
-        {
-            return new Channel(_server, GetCredentials());
-        }
-
-        private ChannelCredentials GetCredentials()
-        {
-            if (_rootCertificatePath != null)
-            {
-                var authInterceptor = AuthenticationInterceptors.CreateAuthInterceptor(_token);
-                return ChannelCredentials.Create(new SslCredentials(), CallCredentials.FromInterceptor(authInterceptor));
-            }
-            return ChannelCredentials.Insecure;
-        }
-    }
-}
+///*
+// * Licensed to the OpenSkywalking under one or more
+// * contributor license agreements.  See the NOTICE file distributed with
+// * this work for additional information regarding copyright ownership.
+// * The ASF licenses this file to You under the Apache License, Version 2.0
+// * (the "License"); you may not use this file except in compliance with
+// * the License.  You may obtain a copy of the License at
+// *
+// *     http://www.apache.org/licenses/LICENSE-2.0
+// *
+// * Unless required by applicable law or agreed to in writing, software
+// * distributed under the License is distributed on an "AS IS" BASIS,
+// * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// * See the License for the specific language governing permissions and
+// * limitations under the License.
+// *
+// */
+//
+//using Grpc.Core;
+//using SkyWalking.Remote.Authentication;
+//
+//namespace SkyWalking.Remote
+//{
+//    internal class GrpcChannelBuilder
+//    {
+//        private string _token;
+//
+//        private string _server;
+//
+//        private string _rootCertificatePath;
+//
+//        public GrpcChannelBuilder WithAuthenticationToken(string token)
+//        {
+//            _token = token;
+//            return this;
+//        }
+//
+//        public GrpcChannelBuilder WithServer(string server)
+//        {
+//            _server = server;
+//            return this;
+//        }
+//
+//        public GrpcChannelBuilder WithCredential(string rootCertificatePath)
+//        {
+//            _rootCertificatePath = rootCertificatePath;
+//            return this;
+//        }
+//
+//        public Channel Build()
+//        {
+//            return new Channel(_server, GetCredentials());
+//        }
+//
+//        private ChannelCredentials GetCredentials()
+//        {
+//            if (_rootCertificatePath != null)
+//            {
+//                var authInterceptor = AuthenticationInterceptors.CreateAuthInterceptor(_token);
+//                return ChannelCredentials.Create(new SslCredentials(), CallCredentials.FromInterceptor(authInterceptor));
+//            }
+//
+//            return ChannelCredentials.Insecure;
+//        }
+//    }
+//}

src/SkyWalking.Core/Remote/GrpcConnection.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-using System;
-using System.Threading.Tasks;
-using Grpc.Core;
-using SkyWalking.Logging;
-
-namespace SkyWalking.Remote
-{
-    public class GrpcConnection
-    {
-        private static readonly ILogger _logger = LogManager.GetLogger<GrpcConnection>();
-
-        public Channel GrpcChannel { get; }
-
-        public GrpcConnectionState State { get; private set; } = GrpcConnectionState.Idle;
-
-        public string Server { get; }
-
-        public GrpcConnection(string server, string rootCertificatePath = null, string token = null)
-        {
-            Server = server;
-            GrpcChannel = new GrpcChannelBuilder()
-                .WithServer(server)
-                .WithCredential(rootCertificatePath)
-                .WithAuthenticationToken(token)
-                .Build();
-        }
-
-        public async Task<bool> ConnectAsync(TimeSpan timeout)
-        {
-            if (State == GrpcConnectionState.Ready)
-            {
-                return true;
-            }
-            State = GrpcConnectionState.Connecting;
-            try
-            {
-                var deadLine = DateTime.UtcNow.AddSeconds(timeout.TotalSeconds);
-                await GrpcChannel.ConnectAsync(deadLine);
-                State = GrpcConnectionState.Ready;
-                _logger.Info($"Grpc channel connect success. [Server] = {GrpcChannel.Target}");
-            }
-            catch (TaskCanceledException ex)
-            {
-                State = GrpcConnectionState.Failure;
-                _logger.Warning($"Grpc channel connect timeout. {ex.Message}");
-            }
-            catch (Exception ex)
-            {
-                State = GrpcConnectionState.Failure;
-                _logger.Warning($"Grpc channel connect fail. {ex.Message}");
-            }
-
-            return State == GrpcConnectionState.Ready;
-        }
-
-        public async Task ShutdowmAsync()
-        {
-            try
-            {
-                await GrpcChannel.ShutdownAsync();
-            }
-            catch (Exception e)
-            {
-                _logger.Debug($"Grpc channel shutdown fail. {e.Message}");
-            }
-            finally
-            { 
-                State = GrpcConnectionState.Shutdown;
-            }
-        }
-
-        public bool CheckState()
-        {
-            return State == GrpcConnectionState.Ready && GrpcChannel.State == ChannelState.Ready;
-        }
-
-        public void Failure()
-        {
-            var currentState = State;
-            
-            if (GrpcConnectionState.Ready == currentState)
-            {
-                _logger.Debug($"Grpc channel state changed. {State} -> {GrpcChannel.State}");
-            }
-
-            State = GrpcConnectionState.Failure;
-        }
-    }
-}
+///*
+// * Licensed to the OpenSkywalking under one or more
+// * contributor license agreements.  See the NOTICE file distributed with
+// * this work for additional information regarding copyright ownership.
+// * The ASF licenses this file to You under the Apache License, Version 2.0
+// * (the "License"); you may not use this file except in compliance with
+// * the License.  You may obtain a copy of the License at
+// *
+// *     http://www.apache.org/licenses/LICENSE-2.0
+// *
+// * Unless required by applicable law or agreed to in writing, software
+// * distributed under the License is distributed on an "AS IS" BASIS,
+// * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// * See the License for the specific language governing permissions and
+// * limitations under the License.
+// *
+// */
+//
+//using System;
+//using System.Threading.Tasks;
+//using Grpc.Core;
+//using SkyWalking.Logging;
+//
+//namespace SkyWalking.Remote
+//{
+//    public class GrpcConnection
+//    {
+//        private static readonly ILogger Logger = LogManager.GetLogger<GrpcConnection>();
+//
+//        public Channel GrpcChannel { get; }
+//
+//        public GrpcConnectionState State { get; private set; } = GrpcConnectionState.Idle;
+//
+//        public string Server { get; }
+//
+//        public GrpcConnection(string server, string rootCertificatePath = null, string token = null)
+//        {
+//            Server = server;
+//            GrpcChannel = new GrpcChannelBuilder()
+//                .WithServer(server)
+//                .WithCredential(rootCertificatePath)
+//                .WithAuthenticationToken(token)
+//                .Build();
+//        }
+//
+//        public async Task<bool> ConnectAsync(TimeSpan timeout)
+//        {
+//            if (State == GrpcConnectionState.Ready)
+//            {
+//                return true;
+//            }
+//            State = GrpcConnectionState.Connecting;
+//            try
+//            {
+//                var deadLine = DateTime.UtcNow.AddSeconds(timeout.TotalSeconds);
+//                await GrpcChannel.ConnectAsync(deadLine);
+//                State = GrpcConnectionState.Ready;
+//                Logger.Information($"Grpc channel connect success. [Server] = {GrpcChannel.Target}");
+//            }
+//            catch (TaskCanceledException ex)
+//            {
+//                State = GrpcConnectionState.Failure;
+//                Logger.Warning($"Grpc channel connect timeout. {ex.Message}");
+//            }
+//            catch (Exception ex)
+//            {
+//                State = GrpcConnectionState.Failure;
+//                Logger.Warning($"Grpc channel connect fail. {ex.Message}");
+//            }
+//
+//            return State == GrpcConnectionState.Ready;
+//        }
+//
+//        public async Task ShutdowmAsync()
+//        {
+//            try
+//            {
+//                await GrpcChannel.ShutdownAsync();
+//            }
+//            catch (Exception e)
+//            {
+//                Logger.Debug($"Grpc channel shutdown fail. {e.Message}");
+//            }
+//            finally
+//            { 
+//                State = GrpcConnectionState.Shutdown;
+//            }
+//        }
+//
+//        public bool CheckState()
+//        {
+//            return State == GrpcConnectionState.Ready && GrpcChannel.State == ChannelState.Ready;
+//        }
+//
+//        public void Failure()
+//        {
+//            var currentState = State;
+//            
+//            if (GrpcConnectionState.Ready == currentState)
+//            {
+//                Logger.Debug($"Grpc channel state changed. {State} -> {GrpcChannel.State}");
+//            }
+//
+//            State = GrpcConnectionState.Failure;
+//        }
+//    }
+//}
\ No newline at end of file

src/SkyWalking.Core/Remote/GrpcConnectionManager.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-using System;
-using System.Linq;
-using System.Threading.Tasks;
-using SkyWalking.Config;
-using SkyWalking.Logging;
-using SkyWalking.Utils;
-
-namespace SkyWalking.Remote
-{
-    public class GrpcConnectionManager
-    {
-        private static readonly ILogger _logger = LogManager.GetLogger<GrpcConnectionManager>();
-
-        public const string NotFoundErrorMessage = "Not found available connection.";
-
-        public static GrpcConnectionManager Instance { get; } = new GrpcConnectionManager();
-
-        private readonly Random _random = new Random();
-        private readonly AsyncLock _lock = new AsyncLock();
-        private GrpcConnection _connection;
-
-        public bool Available => _connection != null && _connection.CheckState();
-
-        private GrpcConnectionManager()
-        {
-        }
-
-        public async Task ConnectAsync(TimeSpan timeout)
-        {
-            // using async lock
-            using (await _lock.LockAsync())
-            {
-                if (_connection != null && _connection.CheckState())
-                {
-                    return;
-                }
-
-                if (_connection != null && !_connection.CheckState())
-                {
-                    await _connection.ShutdowmAsync();
-                }
-
-                var metadata = GetServerMetadata(_connection?.Server);
-                _connection = new GrpcConnection(metadata.Address, metadata.CertificatePath, metadata.Token);
-                await _connection.ConnectAsync(timeout);
-            }
-        }
-
-        public async Task ShutdownAsync()
-        {
-            await _connection?.ShutdowmAsync();
-        }
-
-        public GrpcConnection GetAvailableConnection()
-        {
-            var connection = _connection;
-            if (connection == null || connection.State != GrpcConnectionState.Ready)
-            {
-                _logger.Debug(NotFoundErrorMessage);
-                return null;
-            }
-
-            return connection;
-        }
-
-        private ServerMetadata GetServerMetadata(string currentServer)
-        {
-            return new ServerMetadata(GetServerAddress(currentServer),
-                CollectorConfig.CertificatePath, CollectorConfig.Authentication);
-        }
-
-        private string GetServerAddress(string currentServer)
-        {
-            var servers = RemoteDownstreamConfig.Collector.gRPCServers.Distinct().ToArray();
-            if (servers.Length == 1)
-            {
-                return servers[0];
-            }
-
-            if (currentServer != null)
-            {
-                servers = servers.Where(x => x != currentServer).ToArray();
-            }
-
-            var index = _random.Next() % servers.Length;
-            return servers[index];
-        }
-
-        public struct ServerMetadata
-        {
-            public string Address { get; }
-            
-            public string Token { get;  }
-            
-            public string CertificatePath { get; }
-
-            public ServerMetadata(string address, string certificate, string token)
-            {
-                Address = address;
-                CertificatePath = certificate;
-                Token = token;
-            }
-        } 
-    }
-}
+///*
+// * Licensed to the OpenSkywalking under one or more
+// * contributor license agreements.  See the NOTICE file distributed with
+// * this work for additional information regarding copyright ownership.
+// * The ASF licenses this file to You under the Apache License, Version 2.0
+// * (the "License"); you may not use this file except in compliance with
+// * the License.  You may obtain a copy of the License at
+// *
+// *     http://www.apache.org/licenses/LICENSE-2.0
+// *
+// * Unless required by applicable law or agreed to in writing, software
+// * distributed under the License is distributed on an "AS IS" BASIS,
+// * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// * See the License for the specific language governing permissions and
+// * limitations under the License.
+// *
+// */
+//
+//using System;
+//using System.Linq;
+//using System.Threading.Tasks;
+//using SkyWalking.Config;
+//using SkyWalking.Logging;
+//using SkyWalking.Utils;
+//
+//namespace SkyWalking.Remote
+//{
+//    public class GrpcConnectionManager
+//    {
+//        private static readonly ILogger Logger = LogManager.GetLogger<GrpcConnectionManager>();
+//
+//        public const string NotFoundErrorMessage = "Not found available connection.";
+//
+//        public static GrpcConnectionManager Instance { get; } = new GrpcConnectionManager();
+//
+//        private readonly Random _random = new Random();
+//        private readonly AsyncLock _lock = new AsyncLock();
+//        private GrpcConnection _connection;
+//
+//        public bool Available => _connection != null && _connection.CheckState();
+//
+//        private GrpcConnectionManager()
+//        {
+//        }
+//
+//        public async Task ConnectAsync(TimeSpan timeout)
+//        {
+//            // using async lock
+//            using (await _lock.LockAsync())
+//            {
+//                if (_connection != null && _connection.CheckState())
+//                {
+//                    return;
+//                }
+//
+//                if (_connection != null && !_connection.CheckState())
+//                {
+//                    await _connection.ShutdowmAsync();
+//                }
+//
+//                var metadata = GetServerMetadata(_connection?.Server);
+//                _connection = new GrpcConnection(metadata.Address, metadata.CertificatePath, metadata.Token);
+//                await _connection.ConnectAsync(timeout);
+//            }
+//        }
+//
+//        public async Task ShutdownAsync()
+//        {
+//            await _connection?.ShutdowmAsync();
+//        }
+//
+//        public GrpcConnection GetAvailableConnection()
+//        {
+//            var connection = _connection;
+//            if (connection == null || connection.State != GrpcConnectionState.Ready)
+//            {
+//                Logger.Debug(NotFoundErrorMessage);
+//                return null;
+//            }
+//
+//            return connection;
+//        }
+//
+//        private ServerMetadata GetServerMetadata(string currentServer)
+//        {
+//            return new ServerMetadata(GetServerAddress(currentServer),
+//                CollectorConfig.CertificatePath, CollectorConfig.Authentication);
+//        }
+//
+//        private string GetServerAddress(string currentServer)
+//        {
+//            var servers = RemoteDownstreamConfig.Collector.gRPCServers.Distinct().ToArray();
+//            if (servers.Length == 1)
+//            {
+//                return servers[0];
+//            }
+//
+//            if (currentServer != null)
+//            {
+//                servers = servers.Where(x => x != currentServer).ToArray();
+//            }
+//
+//            var index = _random.Next() % servers.Length;
+//            return servers[index];
+//        }
+//
+//        public struct ServerMetadata
+//        {
+//            public string Address { get; }
+//            
+//            public string Token { get;  }
+//            
+//            public string CertificatePath { get; }
+//
+//            public ServerMetadata(string address, string certificate, string token)
+//            {
+//                Address = address;
+//                CertificatePath = certificate;
+//                Token = token;
+//            }
+//        } 
+//    }
+//}
\ No newline at end of file

src/SkyWalking.Core/Remote/GrpcConnectionService.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-using System;
-using System.Threading;
-using System.Threading.Tasks;
-using SkyWalking.Boot;
-
-namespace SkyWalking.Remote
-{
-    public class GrpcConnectionService : TimerService
-    {
-        protected override TimeSpan Interval { get; } = TimeSpan.FromSeconds(15);
-
-        protected override async Task Execute(CancellationToken token)
-        {
-            if (!GrpcConnectionManager.Instance.Available)
-            {
-                // default timeout = 5s
-                await GrpcConnectionManager.Instance.ConnectAsync(TimeSpan.FromSeconds(5));
-            }
-        }
-    }
-}
+///*
+// * Licensed to the OpenSkywalking under one or more
+// * contributor license agreements.  See the NOTICE file distributed with
+// * this work for additional information regarding copyright ownership.
+// * The ASF licenses this file to You under the Apache License, Version 2.0
+// * (the "License"); you may not use this file except in compliance with
+// * the License.  You may obtain a copy of the License at
+// *
+// *     http://www.apache.org/licenses/LICENSE-2.0
+// *
+// * Unless required by applicable law or agreed to in writing, software
+// * distributed under the License is distributed on an "AS IS" BASIS,
+// * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// * See the License for the specific language governing permissions and
+// * limitations under the License.
+// *
+// */
+//
+//using System;
+//using System.Threading;
+//using System.Threading.Tasks;
+//using SkyWalking.Boot;
+//
+//namespace SkyWalking.Remote
+//{
+//    public class GrpcConnectionService : TimerService
+//    {
+//        protected override TimeSpan Interval { get; } = TimeSpan.FromSeconds(15);
+//
+//        protected override async Task Execute(CancellationToken token)
+//        {
+//            if (!GrpcConnectionManager.Instance.Available)
+//            {
+//                // default timeout = 5s
+//                await GrpcConnectionManager.Instance.ConnectAsync(TimeSpan.FromSeconds(5));
+//            }
+//        }
+//    }
+//}
\ No newline at end of file

src/SkyWalking.Core/Remote/GrpcConnectionState.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-namespace SkyWalking.Remote
-{
-    public enum GrpcConnectionState
-    {
-        Idle,
-        Connecting,
-        Ready,
-        Failure,
-        Shutdown
-    }
-}
+///*
+// * Licensed to the OpenSkywalking under one or more
+// * contributor license agreements.  See the NOTICE file distributed with
+// * this work for additional information regarding copyright ownership.
+// * The ASF licenses this file to You under the Apache License, Version 2.0
+// * (the "License"); you may not use this file except in compliance with
+// * the License.  You may obtain a copy of the License at
+// *
+// *     http://www.apache.org/licenses/LICENSE-2.0
+// *
+// * Unless required by applicable law or agreed to in writing, software
+// * distributed under the License is distributed on an "AS IS" BASIS,
+// * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// * See the License for the specific language governing permissions and
+// * limitations under the License.
+// *
+// */
+//
+//namespace SkyWalking.Remote
+//{
+//    public enum GrpcConnectionState
+//    {
+//        Idle,
+//        Connecting,
+//        Ready,
+//        Failure,
+//        Shutdown
+//    }
+//}

src/SkyWalking.Core/Remote/GrpcRuntimeService.cs

-/*
- * Licensed to the OpenSkywalking under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-using System;
-using System.Threading;
-using System.Threading.Tasks;
-using SkyWalking.Boot;
-using SkyWalking.Utils;
-
-namespace SkyWalking.Remote
-{
-    public class GrpcRuntimeService : TimerService
-    {
-        protected override TimeSpan Interval { get; } = TimeSpan.FromSeconds(120);
-        
-        protected override Task Execute(CancellationToken token)
-        {
-            // todo 
-            return TaskUtils.CompletedTask;
-        }
-    }
-}
+///*
+// * Licensed to the OpenSkywalking under one or more
+// * contributor license agreements.  See the NOTICE file distributed with
+// * this work for additional information regarding copyright ownership.
+// * The ASF licenses this file to You under the Apache License, Version 2.0
+// * (the "License"); you may not use this file except in compliance with
+// * the License.  You may obtain a copy of the License at
+// *
+// *     http://www.apache.org/licenses/LICENSE-2.0
+// *
+// * Unless required by applicable law or agreed to in writing, software
+// * distributed under the License is distributed on an "AS IS" BASIS,
+// * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// * See the License for the specific language governing permissions and
+// * limitations under the License.
+// *
+// */
+//
+//using System;
+//using System.Threading;
+//using System.Threading.Tasks;
+//using SkyWalking.Boot;
+//using SkyWalking.Utils;
+//
+//namespace SkyWalking.Remote
+//{
+//    public class GrpcRuntimeService : TimerService
+//    {
+//        protected override TimeSpan Interval { get; } = TimeSpan.FromSeconds(120);
+//        
+//        protected override Task Execute(CancellationToken token)
+//        {
+//            // todo 
+//            return TaskUtils.CompletedTask;
+//        }
+//    }
+//}
\ No newline at end of file

src/SkyWalking.Core/RuntimeEnvironment.cs

+/*
+ * Licensed to the OpenSkywalking under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+using System;
+
+namespace SkyWalking
+{
+    public class RuntimeEnvironment : IRuntimeEnvironment
+    {
+        public static IRuntimeEnvironment Instance { get; } = new RuntimeEnvironment();
+
+        public NullableValue ApplicationId { get; internal set; }
+
+        public NullableValue ApplicationInstanceId { get; internal set; }
+
+        public bool Initialized => ApplicationId.HasValue && ApplicationInstanceId.HasValue;
+
+        public Guid AgentUUID { get; } = Guid.NewGuid();
+        
+        public IEnvironmentProvider Environment { get; set; }
+    }
+}
\ No newline at end of file

src/SkyWalking.Core/SkyWalking.Core.csproj

@@ -3,22 +3,19 @@
   <PropertyGroup>
     <Description>SkyWalking core components.</Description>
     <AssemblyTitle>SkyWalking.Core</AssemblyTitle>
-    <TargetFrameworks>netstandard2.0;net45;net451</TargetFrameworks>
     <AssemblyName>SkyWalking.Core</AssemblyName>
     <PackageId>SkyWalking.Core</PackageId>
     <PackageTags>SkyWalking;APM</PackageTags>
     <PackageReleaseNotes>
     </PackageReleaseNotes>
     <RootNamespace>SkyWalking</RootNamespace>
+    <TargetFramework>netstandard2.0</TargetFramework>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\SkyWalking.Abstractions\SkyWalking.Abstractions.csproj" />
-    <ProjectReference Include="..\SkyWalking.NetworkProtocol.Trace\SkyWalking.NetworkProtocol.Trace.csproj" />
-    <ProjectReference Include="..\SkyWalking.NetworkProtocol\SkyWalking.NetworkProtocol.csproj" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="4.4.1" />
-    <PackageReference Include="System.Runtime.InteropServices.RuntimeInformation" Version="4.3.0" />
+    <PackageReference Include="System.Diagnostics.DiagnosticSource" Version="4.5.0" />
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />
   </ItemGroup>
 </Project>
\ No newline at end of file