Added shovel command to Tapeti.cmd [ci skip]

Tapeti.Cmd/Commands/ExportCommand.cs

@@ -5,7 +5,6 @@ namespace Tapeti.Cmd.Commands
 {
     public class ExportCommand
     {
-        public ConnectionFactory ConnectionFactory { get; set; }
         public IMessageSerializer MessageSerializer { get; set; }
 
         public string QueueName { get; set; }
@@ -13,19 +12,7 @@ namespace Tapeti.Cmd.Commands
         public int? MaxCount { get; set; }
 
 
-        public int Execute()
-        {
-            using (var connection = ConnectionFactory.CreateConnection())
-            {
-                using (var channel = connection.CreateModel())
-                {
-                    return GetMessages(channel);
-                }
-            }
-        }
-
-
-        private int GetMessages(IModel channel)
+        public int Execute(IModel channel)
         {
             var messageCount = 0;
 

Tapeti.Cmd/Commands/ImportCommand.cs

@@ -5,25 +5,12 @@ namespace Tapeti.Cmd.Commands
 {
     public class ImportCommand
     {
-        public ConnectionFactory ConnectionFactory { get; set; }
         public IMessageSerializer MessageSerializer { get; set; }
 
         public bool DirectToQueue { get; set; }
 
 
-        public int Execute()
-        {
-            using (var connection = ConnectionFactory.CreateConnection())
-            {
-                using (var channel = connection.CreateModel())
-                {
-                    return PublishMessages(channel);
-                }
-            }
-        }
-
-
-        private int PublishMessages(IModel channel)
+        public int Execute(IModel channel)
         {
             var messageCount = 0;
 

Tapeti.Cmd/Commands/ShovelCommand.cs

@@ -0,0 +1,37 @@
+using RabbitMQ.Client;
+ 
+namespace Tapeti.Cmd.Commands
+{
+    public class ShovelCommand
+    {
+        public string QueueName { get; set; }
+        public string TargetQueueName { get; set; }
+        public bool RemoveMessages { get; set; }
+        public int? MaxCount { get; set; }
+
+
+        public int Execute(IModel sourceChannel, IModel targetChannel)
+        {
+            var messageCount = 0;
+
+            while (!MaxCount.HasValue || messageCount < MaxCount.Value)
+            {
+                var result = sourceChannel.BasicGet(QueueName, false);
+                if (result == null)
+                    // No more messages on the queue
+                    break;
+
+
+                targetChannel.BasicPublish("", TargetQueueName, result.BasicProperties, result.Body);
+
+
+                messageCount++;
+
+                if (RemoveMessages)
+                    sourceChannel.BasicAck(result.DeliveryTag, false);
+            }
+
+            return messageCount;
+        }
+    }
+}

Tapeti.Cmd/Program.cs

@@ -71,13 +71,47 @@ namespace Tapeti.Cmd
         }
 
 
+        [Verb("shovel", HelpText = "Reads messages from a queue and publishes them to another queue, optionally to another RabbitMQ server.")]
+        public class ShovelOptions : CommonOptions
+        {
+            [Option('q', "queue", Required = true, HelpText = "The queue to read the messages from.")]
+            public string QueueName { get; set; }
+
+            [Option('t', "targetqueue", HelpText = "The target queue to publish the messages to. Defaults to the source queue if a different target host, port or virtualhost is specified. Otherwise it must be different from the source queue.")]
+            public string TargetQueueName { get; set; }
+
+            [Option('r', "remove", HelpText = "If specified messages are acknowledged and removed from the source queue. If not messages are kept.")]
+            public bool RemoveMessages { get; set; }
+
+            [Option('n', "maxcount", HelpText = "(Default: all) Maximum number of messages to retrieve from the queue.")]
+            public int? MaxCount { get; set; }
+
+            [Option("targethost", HelpText = "Hostname of the target RabbitMQ server. Defaults to the source host. Note that you may still specify a different targetusername for example.")]
+            public string TargetHost { get; set; }
+
+            [Option("targetport", HelpText = "AMQP port of the target RabbitMQ server. Defaults to the source port.")]
+            public int? TargetPort { get; set; }
+
+            [Option("targetvirtualhost", HelpText = "Virtual host used for the target RabbitMQ connection. Defaults to the source virtualhost.")]
+            public string TargetVirtualHost { get; set; }
+
+            [Option("targetusername", HelpText = "Username used to connect to the target RabbitMQ server. Defaults to the source username.")]
+            public string TargetUsername { get; set; }
+
+            [Option("targetpassword", HelpText = "Password used to connect to the target RabbitMQ server. Defaults to the source password.")]
+            public string TargetPassword { get; set; }
+        }
+
+
+
 
         public static int Main(string[] args)
         {
-            return Parser.Default.ParseArguments<ExportOptions, ImportOptions>(args)
+            return Parser.Default.ParseArguments<ExportOptions, ImportOptions, ShovelOptions>(args)
                 .MapResult(
                     (ExportOptions o) => ExecuteVerb(o, RunExport),
                     (ImportOptions o) => ExecuteVerb(o, RunImport),
+                    (ShovelOptions o) => ExecuteVerb(o, RunShovel),
                     errs =>
                     {
                         if (!Debugger.IsAttached) 
@@ -106,9 +140,9 @@ namespace Tapeti.Cmd
         }
 
 
-        private static ConnectionFactory GetConnectionFactory(CommonOptions options)
+        private static IConnection GetConnection(CommonOptions options)
         {
-            return new ConnectionFactory
+            var factory = new ConnectionFactory
             {
                 HostName = options.Host,
                 Port = options.Port,
@@ -116,6 +150,8 @@ namespace Tapeti.Cmd
                 UserName = options.Username,
                 Password = options.Password
             };
+
+            return factory.CreateConnection();
         }
 
 
@@ -140,16 +176,17 @@ namespace Tapeti.Cmd
             int messageCount;
 
             using (var messageSerializer = GetMessageSerializer(options, options.OutputPath))
+            using (var connection = GetConnection(options))
+            using (var channel = connection.CreateModel())
             {
                 messageCount = new ExportCommand
                 {
-                    ConnectionFactory = GetConnectionFactory(options),
                     MessageSerializer = messageSerializer,
 
                     QueueName = options.QueueName,
                     RemoveMessages = options.RemoveMessages,
                     MaxCount = options.MaxCount
-                }.Execute();
+                }.Execute(channel);
             }
 
             Console.WriteLine($"{messageCount} message{(messageCount != 1 ? "s" : "")} exported.");
@@ -161,17 +198,96 @@ namespace Tapeti.Cmd
             int messageCount;
 
             using (var messageSerializer = GetMessageSerializer(options, options.Input))
+            using (var connection = GetConnection(options))
+            using (var channel = connection.CreateModel())
             {
                 messageCount = new ImportCommand
                 {
-                    ConnectionFactory = GetConnectionFactory(options),
                     MessageSerializer = messageSerializer,
 
                     DirectToQueue = !options.PublishToExchange
-                }.Execute();
+                }.Execute(channel);
             }
 
             Console.WriteLine($"{messageCount} message{(messageCount != 1 ? "s" : "")} published.");
         }
+
+
+        private static void RunShovel(ShovelOptions options)
+        {
+            int messageCount;
+
+            using (var sourceConnection = GetConnection(options))
+            using (var sourceChannel = sourceConnection.CreateModel())
+            {
+                var shovelCommand = new ShovelCommand
+                {
+                    QueueName = options.QueueName,
+                    TargetQueueName = !string.IsNullOrEmpty(options.TargetQueueName) ? options.TargetQueueName : options.QueueName,
+                    RemoveMessages = options.RemoveMessages,
+                    MaxCount = options.MaxCount
+                };
+
+
+                if (RequiresSecondConnection(options))
+                {
+                    using (var targetConnection = GetTargetConnection(options))
+                    using (var targetChannel = targetConnection.CreateModel())
+                    {
+                        messageCount = shovelCommand.Execute(sourceChannel, targetChannel);
+                    }
+                }
+                else
+                    messageCount = shovelCommand.Execute(sourceChannel, sourceChannel);
+            }
+
+            Console.WriteLine($"{messageCount} message{(messageCount != 1 ? "s" : "")} shoveled.");
+        }
+
+
+        private static bool RequiresSecondConnection(ShovelOptions options)
+        {
+            if (!string.IsNullOrEmpty(options.TargetHost) && options.TargetHost != options.Host)
+                return true;
+
+            if (options.TargetPort.HasValue && options.TargetPort.Value != options.Port)
+                return true;
+
+            if (!string.IsNullOrEmpty(options.TargetVirtualHost) && options.TargetVirtualHost != options.VirtualHost)
+                return true;
+
+
+            // All relevant target host parameters are either omitted or the same. This means the queue must be different
+            // to prevent an infinite loop.
+            if (string.IsNullOrEmpty(options.TargetQueueName) || options.TargetQueueName == options.QueueName)
+                throw new ArgumentException("Target queue must be different from the source queue when shoveling within the same (virtual) host");
+
+
+            if (!string.IsNullOrEmpty(options.TargetUsername) && options.TargetUsername != options.Username)
+                return true;
+
+            // ReSharper disable once ConvertIfStatementToReturnStatement
+            if (!string.IsNullOrEmpty(options.TargetPassword) && options.TargetPassword != options.Password)
+                return true;
+
+            
+            // Everything's the same, we can use the same channel
+            return false;
+        }
+
+
+        private static IConnection GetTargetConnection(ShovelOptions options)
+        {
+            var factory = new ConnectionFactory
+            {
+                HostName = !string.IsNullOrEmpty(options.TargetHost) ? options.TargetHost : options.Host,
+                Port = options.TargetPort ?? options.Port,
+                VirtualHost = !string.IsNullOrEmpty(options.TargetVirtualHost) ? options.TargetVirtualHost : options.VirtualHost,
+                UserName = !string.IsNullOrEmpty(options.TargetUsername) ? options.TargetUsername : options.Username,
+                Password = !string.IsNullOrEmpty(options.TargetPassword) ? options.TargetPassword : options.Password,
+            };
+
+            return factory.CreateConnection();
+        }
     }
 }