add default group name configuartion to CapOptions.

src/DotNetCore.CAP/Abstractions/TopicAttribute.cs

@@ -20,9 +20,10 @@ namespace DotNetCore.CAP.Abstractions
         public string Name { get; }
 
         /// <summary>
+        /// Default group name is CapOptions setting.(Assembly name)
         /// kafka --> groups.id
         /// rabbit MQ --> queue.name
         /// </summary>
-        public string Group { get; set; } = "cap.default.group";
+        public string Group { get; set; }
     }
 }
\ No newline at end of file

src/DotNetCore.CAP/CAP.Options.cs

 using System;
 using System.Collections.Generic;
+using System.Reflection;
 using DotNetCore.CAP.Models;
 
 namespace DotNetCore.CAP
@@ -34,6 +35,7 @@ namespace DotNetCore.CAP
         /// </summary>
         public const int DefaultFailedRetryCount = 100;
 
+
         public CapOptions()
         {
             PollingDelay = DefaultPollingDelay;
@@ -42,10 +44,16 @@ namespace DotNetCore.CAP
             FailedRetryInterval = DefaultFailedMessageWaitingInterval;
             FailedRetryCount = DefaultFailedRetryCount;
             Extensions = new List<ICapOptionsExtension>();
+            DefaultGroup = "cap.queue." + Assembly.GetEntryAssembly().GetName().Name.ToLower();
         }
 
         internal IList<ICapOptionsExtension> Extensions { get; }
 
+        /// <summary>
+        /// Subscriber default group name. kafka-->group name. rabbitmq --> queue name.
+        /// </summary>
+        public string DefaultGroup { get; set; }
+
         /// <summary>
         /// Producer job polling delay time.
         /// Default is 15 sec.

src/DotNetCore.CAP/Internal/IConsumerServiceSelector.Default.cs

@@ -10,23 +10,26 @@ namespace DotNetCore.CAP.Internal
 {
     /// <inheritdoc />
     /// <summary>
-    /// A default <see cref="T:DotNetCore.CAP.Abstractions.IConsumerServiceSelector" /> implementation.
+    ///     A default <see cref="T:DotNetCore.CAP.Abstractions.IConsumerServiceSelector" /> implementation.
     /// </summary>
     internal class DefaultConsumerServiceSelector : IConsumerServiceSelector
     {
+        private readonly CapOptions _capOptions;
         private readonly IServiceProvider _serviceProvider;
 
         /// <summary>
-        /// Creates a new <see cref="DefaultConsumerServiceSelector" />.
+        ///     Creates a new <see cref="DefaultConsumerServiceSelector" />.
         /// </summary>
-        public DefaultConsumerServiceSelector(IServiceProvider serviceProvider)
+        public DefaultConsumerServiceSelector(IServiceProvider serviceProvider, CapOptions capOptions)
         {
             _serviceProvider = serviceProvider;
+            _capOptions = capOptions;
         }
 
         /// <summary>
-        /// Selects the best <see cref="ConsumerExecutorDescriptor" /> candidate from <paramref name="executeDescriptor" /> for the
-        /// current message associated.
+        ///     Selects the best <see cref="ConsumerExecutorDescriptor" /> candidate from <paramref name="executeDescriptor" /> for
+        ///     the
+        ///     current message associated.
         /// </summary>
         public ConsumerExecutorDescriptor SelectBestCandidate(string key,
             IReadOnlyList<ConsumerExecutorDescriptor> executeDescriptor)
@@ -45,7 +48,7 @@ namespace DotNetCore.CAP.Internal
             return executorDescriptorList;
         }
 
-        private static IEnumerable<ConsumerExecutorDescriptor> FindConsumersFromInterfaceTypes(
+        private IEnumerable<ConsumerExecutorDescriptor> FindConsumersFromInterfaceTypes(
             IServiceProvider provider)
         {
             var executorDescriptorList = new List<ConsumerExecutorDescriptor>();
@@ -66,7 +69,7 @@ namespace DotNetCore.CAP.Internal
             }
         }
 
-        private static IEnumerable<ConsumerExecutorDescriptor> FindConsumersFromControllerTypes()
+        private IEnumerable<ConsumerExecutorDescriptor> FindConsumersFromControllerTypes()
         {
             var executorDescriptorList = new List<ConsumerExecutorDescriptor>();
 
@@ -81,18 +84,21 @@ namespace DotNetCore.CAP.Internal
             return executorDescriptorList;
         }
 
-        private static IEnumerable<ConsumerExecutorDescriptor> GetTopicAttributesDescription(TypeInfo typeInfo)
+        private IEnumerable<ConsumerExecutorDescriptor> GetTopicAttributesDescription(TypeInfo typeInfo)
         {
             foreach (var method in typeInfo.DeclaredMethods)
             {
                 var topicAttr = method.GetCustomAttributes<TopicAttribute>(true);
-
                 var topicAttributes = topicAttr as IList<TopicAttribute> ?? topicAttr.ToList();
 
                 if (!topicAttributes.Any()) continue;
 
                 foreach (var attr in topicAttributes)
+                {
+                    if (attr.Group == null)
+                        attr.Group = _capOptions.DefaultGroup;
                     yield return InitDescriptor(attr, method, typeInfo);
+                }
             }
         }