Merge pull request #92 from rabbitmq/rabbitmq-dotnet-client-81

Introduce ConnectionFactory#CreateConnection with a list of hostnames

Author: michaelklishin

projects/client/RabbitMQ.Client/RabbitMQ.Client.csproj

@@ -139,6 +139,7 @@
     <Compile Include="src\client\api\IConnection.cs" />
     <Compile Include="src\client\api\IConnectionFactory.cs" />
     <Compile Include="src\client\api\IContentHeader.cs" />
+    <Compile Include="src\client\api\IHostnameSelector.cs" />
     <Compile Include="src\client\api\IMethod.cs" />
     <Compile Include="src\client\api\IModel.cs" />
     <Compile Include="src\client\api\IProtocol.cs" />
@@ -216,6 +217,7 @@
     <Compile Include="src\client\impl\ContentHeaderBase.cs" />
     <Compile Include="src\client\impl\ContentHeaderPropertyReader.cs" />
     <Compile Include="src\client\impl\ContentHeaderPropertyWriter.cs" />
+    <Compile Include="src\client\impl\ExtensionMethods.cs" />
     <Compile Include="src\client\impl\Frame.cs" />
     <Compile Include="src\client\impl\HardProtocolException.cs" />
     <Compile Include="src\client\impl\IConsumerDispatcher.cs" />
@@ -232,6 +234,7 @@
     <Compile Include="src\client\impl\ProtocolBase.cs" />
     <Compile Include="src\client\impl\ProtocolException.cs" />
     <Compile Include="src\client\impl\QuiescingSession.cs" />
+    <Compile Include="src\client\impl\RandomHostnameSelector.cs" />
     <Compile Include="src\client\impl\RecordedBinding.cs" />
     <Compile Include="src\client\impl\RecordedConsumer.cs" />
     <Compile Include="src\client\impl\RecordedEntity.cs" />

projects/client/RabbitMQ.Client/src/client/api/AmqpTcpEndpoint.cs

@@ -55,7 +55,7 @@ namespace RabbitMQ.Client
     /// the Uri "Scheme" property is ignored: only the "Host" and
     /// "Port" properties are extracted.
     /// </para>
-    public class AmqpTcpEndpoint
+    public class AmqpTcpEndpoint : ICloneable
     {
         /// <summary>
         /// Default Amqp ssl port.
@@ -119,6 +119,25 @@ public AmqpTcpEndpoint(Uri uri) : this(uri.Host, uri.Port)
         {
         }
 
+        /// <summary>
+        /// Clones the endpoint.
+        /// </summary>
+        /// <returns>A copy with the same hostname, port, and TLS settings</returns>
+        public object Clone()
+        {
+            return new AmqpTcpEndpoint(HostName, _port, Ssl);
+        }
+
+        /// <summary>
+        /// Clones the endpoint using the provided hostname.
+        /// </summary>
+        /// <param name="hostname">Hostname to use</param>
+        /// <returns>A copy with the provided hostname and port/TLS settings of this endpoint</returns>
+        public AmqpTcpEndpoint CloneWithHostname(string hostname)
+        {
+            return new AmqpTcpEndpoint(hostname, _port, Ssl);
+        }
+
         /// <summary>
         /// Retrieve or set the hostname of this <see cref="AmqpTcpEndpoint"/>.
         /// </summary>

projects/client/RabbitMQ.Client/src/client/api/ConnectionFactory.cs

@@ -44,6 +44,7 @@
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using System.Linq;
 
 #if !NETFX_CORE
 
@@ -143,18 +144,26 @@ public class ConnectionFactory : ConnectionFactoryBase, IConnectionFactory
         /// <summary>
         ///  Default SASL auth mechanisms to use.
         /// </summary>
-        public static readonly AuthMechanismFactory[] DefaultAuthMechanisms = { new PlainMechanismFactory() };
+        public static readonly IList<AuthMechanismFactory> DefaultAuthMechanisms =
+            new List<AuthMechanismFactory>(){ new PlainMechanismFactory() };
 
         /// <summary>
         ///  SASL auth mechanisms to use.
         /// </summary>
-        public AuthMechanismFactory[] AuthMechanisms = DefaultAuthMechanisms;
+        public IList<AuthMechanismFactory> AuthMechanisms = DefaultAuthMechanisms;
 
         /// <summary>
         /// Set to true to enable automatic connection recovery.
         /// </summary>
         public bool AutomaticRecoveryEnabled;
 
+        /// <summary>
+        /// Used to select next hostname to try when performing
+        /// connection recovery (re-connecting). Is not used for
+        /// non-recovering connections.
+        /// </summary>
+        public IHostnameSelector HostnameSelector = new RandomHostnameSelector();
+
         /// <summary>The host to connect to.</summary>
         public String HostName = "localhost";
 
@@ -212,7 +221,7 @@ public ConnectionFactory()
         }
 
         /// <summary>
-        /// The AMQP connection target.
+        /// Connection endpoint.
         /// </summary>
         public AmqpTcpEndpoint Endpoint
         {
@@ -285,12 +294,12 @@ public Uri uri
         /// Given a list of mechanism names supported by the server, select a preferred mechanism,
         ///  or null if we have none in common.
         /// </summary>
-        public AuthMechanismFactory AuthMechanismFactory(string[] mechanismNames)
+        public AuthMechanismFactory AuthMechanismFactory(IList<string> mechanismNames)
         {
             // Our list is in order of preference, the server one is not.
             foreach (AuthMechanismFactory factory in AuthMechanisms)
             {
-                if (Array.Exists(mechanismNames, x => string.Equals(x, factory.Name, StringComparison.OrdinalIgnoreCase)))
+                if (mechanismNames.Any<string>(x => string.Equals(x, factory.Name, StringComparison.OrdinalIgnoreCase)))
                 {
                     return factory;
                 }
@@ -301,35 +310,59 @@ public AuthMechanismFactory AuthMechanismFactory(string[] mechanismNames)
         /// <summary>
         /// Create a connection to the specified endpoint.
         /// </summary>
+        /// <exception cref="BrokerUnreachableException">
+        /// When the configured hostname was not reachable.
+        /// </exception>
         public virtual IConnection CreateConnection()
         {
-            IConnection connection;
+            return CreateConnection(new List<string>() { HostName });
+        }
+
+        /// <summary>
+        /// Create a connection using a list of hostnames. The first reachable
+        /// hostname will be used initially. Subsequent hostname picks are determined
+        /// by the <see cref="IHostnameSelector" /> configured.
+        /// </summary>
+        /// <param name="hostnames">
+        /// List of hostnames to use for the initial
+        /// connection and recovery.
+        /// </param>
+        /// <returns>Open connection</returns>
+        /// <exception cref="BrokerUnreachableException">
+        /// When no hostname was reachable.
+        /// </exception>
+        public IConnection CreateConnection(IList<string> hostnames)
+        {
+            IConnection conn;
             try
             {
                 if (AutomaticRecoveryEnabled)
                 {
                     var autorecoveringConnection = new AutorecoveringConnection(this);
-                    autorecoveringConnection.init();
-                    connection = autorecoveringConnection;
+                    autorecoveringConnection.Init(hostnames);
+                    conn = autorecoveringConnection;
                 }
                 else
                 {
                     IProtocol protocol = Protocols.DefaultProtocol;
-                    connection = protocol.CreateConnection(this, false, CreateFrameHandler());
+                    conn = protocol.CreateConnection(this, false, CreateFrameHandler());
                 }
             }
             catch (Exception e)
             {
                 throw new BrokerUnreachableException(e);
             }
-
-            return connection;
+            return conn;
         }
 
         public IFrameHandler CreateFrameHandler()
         {
-            IProtocol protocol = Protocols.DefaultProtocol;
-            return protocol.CreateFrameHandler(Endpoint, SocketFactory, RequestedConnectionTimeout);
+            return Protocols.DefaultProtocol.CreateFrameHandler(Endpoint, SocketFactory, RequestedConnectionTimeout);
+        }
+
+        public IFrameHandler CreateFrameHandler(AmqpTcpEndpoint endpoint)
+        {
+            return Protocols.DefaultProtocol.CreateFrameHandler(endpoint, SocketFactory, RequestedConnectionTimeout);
         }
 
         private void SetUri(Uri uri)

projects/client/RabbitMQ.Client/src/client/api/IConnectionFactory.cs

@@ -90,13 +90,20 @@ public interface IConnectionFactory
         /// Given a list of mechanism names supported by the server, select a preferred mechanism,
         /// or null if we have none in common.
         /// </summary>
-        AuthMechanismFactory AuthMechanismFactory(string[] mechanismNames);
+        AuthMechanismFactory AuthMechanismFactory(IList<string> mechanismNames);
 
         /// <summary>
         /// Create a connection to the specified endpoint.
         /// </summary>
         IConnection CreateConnection();
 
+        /// <summary>
+        /// Connects to the first reachable hostname from the list.
+        /// </summary>
+        /// <param name="hostnames">List of host names to use</param>
+        /// <returns></returns>
+        IConnection CreateConnection(IList<string> hostnames);
+
         /// <summary>
         /// Advanced option.
         /// 

projects/client/RabbitMQ.Client/src/client/api/IHostnameSelector.cs

@@ -0,0 +1,56 @@
+// This source code is dual-licensed under the Apache License, version
+// 2.0, and the Mozilla Public License, version 1.1.
+//
+// The APL v2.0:
+//
+//---------------------------------------------------------------------------
+//   Copyright (C) 2007-2014 GoPivotal, Inc.
+//
+//   Licensed 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.
+//---------------------------------------------------------------------------
+//
+// The MPL v1.1:
+//
+//---------------------------------------------------------------------------
+//  The contents of this file are subject to the Mozilla Public License
+//  Version 1.1 (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.mozilla.org/MPL/
+//
+//  Software distributed under the License is distributed on an "AS IS"
+//  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+//  the License for the specific language governing rights and
+//  limitations under the License.
+//
+//  The Original Code is RabbitMQ.
+//
+//  The Initial Developer of the Original Code is GoPivotal, Inc.
+//  Copyright (c) 2007-2014 GoPivotal, Inc.  All rights reserved.
+//---------------------------------------------------------------------------
+
+using System;
+using System.Collections.Generic;
+
+namespace RabbitMQ.Client
+{
+    public interface IHostnameSelector
+    {
+        /// <summary>
+        /// Picks a hostname from a list of options that should be used
+        /// by <see cref="IConnectionFactory"/>.
+        /// </summary>
+        /// <param name="options"></param>
+        /// <returns></returns>
+        string NextFrom(IList<string> options);
+    }
+}

projects/client/RabbitMQ.Client/src/client/api/NetworkConnection.cs

@@ -47,25 +47,11 @@ namespace RabbitMQ.Client
     /// </summary>
     public interface NetworkConnection
     {
-#if !NETFX_CORE
-        /// <summary>
-        /// Identifies local network address.
-        /// </summary>
-        EndPoint LocalEndPoint { get; }
-#endif
-
         /// <summary>
         /// Local port.
         /// </summary>
         int LocalPort { get; }
 
-#if !NETFX_CORE
-        /// <summary>
-        /// Identifies remote network address.
-        /// </summary>
-        EndPoint RemoteEndPoint { get; }
-#endif
-
         /// <summary>
         /// Remote port.
         /// </summary>