minor: MongoServerInstance is now persisting certain server information between disconnections. MultipleInstanceMongoServerProxy reuses addresses specified with a different hostname than the replica recognizes. Primary disconnect no longers causes invalid extra instance.

Author: craiggwilson

Driver/Core/MongoServerInstance.cs

@@ -72,6 +72,7 @@ public sealed class MongoServerInstance
         private bool _inStateVerification;
         private ServerInformation _serverInfo;
         private IPEndPoint _ipEndPoint;
+        private bool _permanentlyDisconnected;
         private int _sequentialId;
         private MongoServerState _state;
         private Timer _stateVerificationTimer;
@@ -96,6 +97,7 @@ internal MongoServerInstance(MongoServer server, MongoServerAddress address)
             };
             _connectionPool = new MongoConnectionPool(this);
             _pingTimeAggregator = new PingTimeAggregator(5);
+            _permanentlyDisconnected = false;
             // Console.WriteLine("MongoServerInstance[{0}]: {1}", sequentialId, address);
         }
 
@@ -425,7 +427,7 @@ internal void Connect()
             // Console.WriteLine("MongoServerInstance[{0}]: Connect() called.", sequentialId);
             lock (_serverInstanceLock)
             {
-                if (_state == MongoServerState.Connecting || _state == MongoServerState.Connected)
+                if (_permanentlyDisconnected || _state == MongoServerState.Connecting || _state == MongoServerState.Connected)
                 {
                     return;
                 }
@@ -513,6 +515,19 @@ internal void Disconnect()
             }
         }
 
+        /// <summary>
+        /// Disconnects this instance permanently.
+        /// </summary>
+        internal void DisconnectPermanently()
+        {
+            lock (_serverInstanceLock)
+            {
+                _permanentlyDisconnected = true;
+            }
+
+            Disconnect();
+        }
+
         /// <summary>
         /// Releases the connection.
         /// </summary>
@@ -618,18 +633,20 @@ private void LookupServerInformation(MongoConnection connection)
                         currentServerInfo = _serverInfo;
                     }
 
+                    // keep the current instance type, build info, and replica set info
+                    // as these aren't relevent to state and are likely still correct.
                     var newServerInfo = new ServerInformation
                     {
-                        BuildInfo = null,
+                        BuildInfo = currentServerInfo.BuildInfo,
                         InstanceType = currentServerInfo.InstanceType,
                         IsArbiter = false,
                         IsMasterResult = isMasterResult,
                         IsPassive = false,
                         IsPrimary = false,
                         IsSecondary = false,
-                        MaxDocumentSize = MongoDefaults.MaxDocumentSize,
-                        MaxMessageLength = MongoDefaults.MaxMessageLength,
-                        ReplicaSetInformation = null
+                        MaxDocumentSize = currentServerInfo.MaxDocumentSize,
+                        MaxMessageLength = currentServerInfo.MaxMessageLength,
+                        ReplicaSetInformation = currentServerInfo.ReplicaSetInformation
                     };
 
                     SetState(MongoServerState.Disconnected, newServerInfo);

Driver/Internal/MultipleInstanceMongoServerProxy.cs

@@ -323,6 +323,11 @@ public void VerifyState()
         /// <param name="address">The address.</param>
         protected void EnsureInstanceWithAddress(MongoServerAddress address)
         {
+            if (address == null)
+            {
+                throw new ArgumentNullException("address");
+            }
+
             lock (_lock)
             {
                 if (!_instances.Any(x => x.Address == address))
@@ -365,7 +370,10 @@ protected void MakeInstancesMatchAddresses(IEnumerable<MongoServerAddress> addre
 
                 foreach (var address in addresses)
                 {
-                    EnsureInstanceWithAddress(address);
+                    if (address != null)
+                    {
+                        EnsureInstanceWithAddress(address);
+                    }
                 }
             }
         }
@@ -427,6 +435,20 @@ private void ProcessInstanceStateChange(MongoServerInstance instance)
                             return;
                         }
 
+                        if (instance.Address != instance.IsMasterResult.MyAddress)
+                        {
+                            if (!_instances.Any(x => x.Address == instance.IsMasterResult.MyAddress))
+                            {
+                                instance.Address = instance.IsMasterResult.MyAddress;
+                            }
+                            else
+                            {
+                                // we need to get rid of the duplicate.
+                                RemoveInstance(instance);
+                                return;
+                            }
+                        }
+
                         if (_state != MongoServerState.Disconnecting && _state != MongoServerState.Disconnected)
                         {
                             _connectedInstances.EnsureContains(instance);
@@ -450,7 +472,7 @@ private void RemoveInstance(MongoServerInstance instance)
             {
                 _instances.Remove(instance);
                 instance.StateChanged -= InstanceStateChanged;
-                instance.Disconnect();
+                instance.DisconnectPermanently();
                 ProcessInstanceStateChange(instance);
             }
         }

Driver/Internal/ReplicaSetMongoServerProxy.cs

@@ -175,8 +175,12 @@ private void ProcessConnectedPrimaryStateChange(MongoServerInstance instance)
 
         private void ProcessConnectedSecondaryStateChange(MongoServerInstance instance)
         {
-            // make sure the primary exists in the instance list
-            EnsureInstanceWithAddress(instance.ReplicaSetInformation.Primary);
+            var address = instance.ReplicaSetInformation.Primary;
+            if (address != null)
+            {
+                // make sure the primary exists in the instance list
+                EnsureInstanceWithAddress(address);
+            }
         }
     }
 }