Default ClientName to Roleinstance ID for a web/worker role to help identify...

Default ClientName to Roleinstance ID for a web/worker role to help identify where a client connection is coming from, further helps to identify connectivity problems.

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/ConfigurationOptions.cs

@@ -5,6 +5,7 @@
 using System.Linq;
 using System.Net;
 using System.Net.Security;
+using System.Reflection;
 using System.Text;
 using System.Threading.Tasks;
 
@@ -161,7 +162,7 @@ public static string TryNormalize(string value)
         /// <summary>
         /// The client name to use for all connections
         /// </summary>
-        public string ClientName { get { return clientName; } set { clientName = value; } }
+        public string ClientName { get { return clientName ?? (clientName = AzureRoleInstanceId); } set { clientName = value; } }
 
         /// <summary>
         /// The number of times to repeat the initial connect cycle if no servers respond promptly
@@ -665,6 +666,46 @@ private bool IsAzureEndpoint()
             return result; 
         }
 
+        internal static string AzureRoleInstanceId = TryGetAzureRoleInstanceIdNoThrow();
+
+        /// <summary>
+        /// Tries to get the Roleinstance Id if Microsoft.WindowsAzure.ServiceRuntime is loaded.
+        /// In case of any failure, swallows the exception and returns null
+        /// </summary>
+        private 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;
+        }
+
         private string InferSslHostFromEndpoints() {
             var dnsEndpoints = endpoints.Select(endpoint => endpoint as DnsEndPoint);
             string dnsHost = dnsEndpoints.FirstOrDefault()?.Host;