Merge pull request #379 from deepakverma/clientname

Default ClientName to Roleinstance ID for a web/worker role 

StackExchange.Redis.Tests/Config.cs

@@ -124,6 +124,28 @@ public void ClientName()
             }
         }
 
+        [Test]
+        public void DefaultClientName()
+        {
+            using (var muxer = Create(allowAdmin: true))
+            {
+                Assert.AreEqual(Environment.MachineName, muxer.ClientName);
+                var conn = muxer.GetDatabase();
+                conn.Ping();
+#if DEBUG
+                var name = GetServer(muxer).ClientGetName();
+                Assert.AreEqual(Environment.MachineName, name);
+#endif
+            }
+        }
+
+        [Test]
+        public void TryGetAzureRoleInstanceIdNoThrow()
+        {
+            ConfigurationOptions config = new ConfigurationOptions();
+            Assert.IsNull(config.TryGetAzureRoleInstanceIdNoThrow());
+        }
+
         [Test]
         public void ReadConfigWithConfigDisabled()
         {

StackExchange.Redis/StackExchange/Redis/ConnectionMultiplexer.cs

@@ -8,6 +8,7 @@
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using System.Reflection;
 #if NET40
 using Microsoft.Runtime.CompilerServices;
 #else
@@ -91,7 +92,53 @@ public ServerCounters GetCounters()
         /// <summary>
         /// Gets the client-name that will be used on all new connections
         /// </summary>
-        public string ClientName => configuration.ClientName ?? Environment.GetEnvironmentVariable("ComputerName");
+        public string ClientName => configuration.ClientName ?? ConnectionMultiplexer.GetDefaultClientName();
+
+        private static string defaultClientName;
+        private static string GetDefaultClientName()
+        {
+            if (defaultClientName == null)
+            {
+                defaultClientName =  TryGetAzureRoleInstanceIdNoThrow() ?? Environment.GetEnvironmentVariable("ComputerName");
+            }
+            return defaultClientName;
+        }
+
+        /// Tries to get the Roleinstance Id if Microsoft.WindowsAzure.ServiceRuntime is loaded.
+        /// In case of any failure, swallows the exception and returns null
+        internal static string TryGetAzureRoleInstanceIdNoThrow()
+        {
+            string roleInstanceId = null;
+            try
+            {
+                Assembly asm = null;
+                foreach (var asmb in AppDomain.CurrentDomain.GetAssemblies())
+                {
+                    if (asmb.GetName().Name.Equals("Microsoft.WindowsAzure.ServiceRuntime"))
+                    {
+                        asm = asmb;
+                        break;
+                    }
+                }
+                if (asm == null)
+                    return null;
+
+                var currentRoleInstanceProp = asm.GetType("Microsoft.WindowsAzure.ServiceRuntime.RoleEnvironment").GetProperty("CurrentRoleInstance");
+                var currentRoleInstanceId = currentRoleInstanceProp.GetValue(null, null);
+                roleInstanceId = currentRoleInstanceId.GetType().GetProperty("Id").GetValue(currentRoleInstanceId, null).ToString();
+
+                if (String.IsNullOrEmpty(roleInstanceId))
+                {
+                    roleInstanceId = null;
+                }
+            }
+            catch (Exception)
+            {
+                //silently ignores the exception
+                roleInstanceId = null;
+            }
+            return roleInstanceId;
+        }
 
         /// <summary>
         /// Gets the configuration of the connection