/// <summary>
/// Implements RPC over an asynchronous message bus. While the publisher does not block
/// and can complete other unrelated work, the publisher is synchronous in terms that they
/// can't complete their entire work until the response is received.
/// </summary>
/// <param name="queueName">The name of the queue on which the subscriber will receive commands.</param>
/// <param name="actionNamespace">For a given RPC command, identifies to the consumer the associated action.</param>
/// <param name="busName">The bus name key used to lookup connection.</param>
/// <param name="settings">Optional delegate called allowing caller to set
/// additional exchange properties.</param>
/// <typeparam name="TMessage">The command type associated with the queue.</typeparam>
protected void DefineRpcQueue <TMessage>(string queueName, string actionNamespace, string busName,
Action <ExchangeMeta <TMessage> > settings = null)
where TMessage : ICommand
{
if (string.IsNullOrWhiteSpace(actionNamespace))
{
throw new ArgumentException("RPC Action Namespace not Specified.", nameof(actionNamespace));
}
var publisherStrategy = new RpcPublisherStrategy();
var exchange = ExchangeMeta.DefineDefault <TMessage>(busName, queueName,
config =>
{
config.IsAutoDelete = true;
config.IsDurable = false;
config.IsPassive = false;
config.IsExclusive = false;
});
exchange.IsAutoDelete = true;
exchange.IsRpcExchange = true;
exchange.ActionNamespace = actionNamespace;
exchange.SetPublisherStrategy(publisherStrategy);
_exchanges.Add(exchange);
settings?.Invoke(exchange);
}
public override async Task PublishMessageAsync(IMessage message, CancellationToken cancellationToken)
{
if (message == null)
{
throw new ArgumentNullException(nameof(message));
}
// Only process messages for which there are defined exchanges.
Type messageType = message.GetType();
if (!PublisherModule.IsExchangeMessage(messageType))
{
return;
}
// Lookup the exchange associated with the message and the bus
// on which it should be created.
ExchangeMeta definition = PublisherModule.GetDefinition(messageType);
IBus bus = BusModule.GetBus(definition.BusName);
// Create the exchange/queue:
CreatedExchange createdExchange = await CreateExchange(bus, definition).ConfigureAwait(false);
LogPublishedMessage(createdExchange, message);
// Publish the message to the created exchange/queue.
await definition.PublisherStrategy.Publish(this, createdExchange,
message,
cancellationToken);
}
protected virtual IRpcClient CreateRpcClient(ExchangeMeta definition)
{
IBus bus = BusModule.GetBus(definition.BusName);
var rpcClient = new RpcClient(definition.BusName, definition.QueueMeta.QueueName, bus);
var logger = Context.LoggerFactory.CreateLogger <RpcClient>();
rpcClient.SetLogger(logger);
return(rpcClient);
}
public CreatedExchange(
IBus bus,
IExchange exchange,
ExchangeMeta definition)
{
Bus = bus ?? throw new System.ArgumentNullException(nameof(bus));
Exchange = exchange ?? throw new System.ArgumentNullException(nameof(exchange));
Definition = definition ?? throw new System.ArgumentNullException(nameof(definition));
}
private static async Task <bool> Satisfies(IPublisherContext context, CreatedExchange createdExchange, IMessage message)
{
ExchangeMeta definition = createdExchange.Definition;
bool applies = definition.Applies(message);
if (applies && definition.ScriptPredicate != null)
{
return(await context.Scripting.SatisfiesPredicateAsync(message, definition.ScriptPredicate));
}
return(applies);
}
public QueueMeta CreateQueueMeta(SubscriberQueueAttribute attribute)
{
var exchange = ExchangeMeta.DefineDefault(attribute.BusName, attribute.QueueName,
config =>
{
config.IsAutoDelete = false;
config.IsDurable = true;
config.IsPassive = false;
config.IsExclusive = false;
});
return(exchange.QueueMeta);
}
/// <summary>
/// Defines a fanout exchange that will broadcast messages to all bound message queues.
/// This should be used for notification type messages where the subscriber only cares
/// about current occurring messages and not about prior missed messages that happened
/// when they were offline.
///
/// https://www.rabbitmq.com/tutorials/amqp-concepts.html#exchange-fanout
/// </summary>
/// <param name="name">The name of the exchange.</param>
/// <param name="busName">The bus name key used to lookup connection.</param>
/// <param name="settings">Optional delegate called allowing caller to set
/// additional exchange properties.</param>
/// <typeparam name="TMessage">The domain-event type associated with the exchange.</typeparam>
protected void DefineFanoutExchange <TMessage>(string name, string busName,
Action <ExchangeMeta <TMessage> > settings = null)
where TMessage : IDomainEvent
{
var exchange = ExchangeMeta.Define <TMessage>(busName, name, ExchangeType.Fanout,
config =>
{
config.IsAutoDelete = true;
config.IsDurable = false;
config.IsPersistent = false;
config.IsPassive = false;
});
_exchanges.Add(exchange);
settings?.Invoke(exchange);
}
public QueueMeta CreateQueueMeta(SubscriberQueueAttribute attribute)
{
var rpcAttribute = (RpcQueueAttribute)attribute;
var exchange = ExchangeMeta.DefineDefault(rpcAttribute.BusName, rpcAttribute.QueueName,
config =>
{
config.IsAutoDelete = true;
config.IsDurable = false;
config.IsPassive = false;
config.IsExclusive = false;
});
exchange.IsRpcExchange = true;
exchange.ActionNamespace = rpcAttribute.ActionNamespace;
return(exchange.QueueMeta);
}
/// <summary>
/// Defines a work queue. For the other type of exchanges, the publisher does not know
/// the consumers subscribing to the queues defined on the exchange. A work queue is used
/// to make a request of another service by sending a command to the queue for processing.
/// The processing is asynchronous and the publisher does not wait for a response. This
/// should be used by a publisher to submit a time consuming task to a specific service
/// for processing.
/// </summary>
/// <param name="queueName">The name of the queue on which the consuming service will receive commands.</param>
/// <param name="busName">The bus name key used to lookup connection.</param>
/// <param name="settings">Optional delegate called allowing caller to set
/// additional exchange properties.</param>
/// <typeparam name="TMessage">The command type associated with the queue.</typeparam>
protected void DefineWorkQueue <TMessage>(string queueName, string busName,
Action <ExchangeMeta <TMessage> > settings = null)
where TMessage : ICommand
{
var exchange = ExchangeMeta.DefineDefault <TMessage>(busName, queueName,
config =>
{
config.IsAutoDelete = false;
config.IsDurable = true;
config.IsPassive = false;
config.IsExclusive = false;
});
exchange.RouteKey = queueName;
_exchanges.Add(exchange);
settings?.Invoke(exchange);
}
private void ApplyExchangeSettingsInternal(ExchangeMeta meta, bool applyQueueSettings = true)
{
if (meta == null)
{
throw new ArgumentNullException(nameof(meta));
}
if (!meta.IsDefaultExchange)
{
var exchangeSettings = GetExchangeSettings(meta.BusName, meta.ExchangeName);
if (exchangeSettings != null)
{
meta.ApplyOverrides(exchangeSettings);
}
}
if (applyQueueSettings && meta.QueueMeta != null)
{
ApplyQueueSettings(meta.QueueMeta);
}
}
public void CanSpecifyExchangeSettings_InConfiguration()
{
ContainerFixture.Test(fixture => {
fixture.Arrange
.Configuration(TestSetup.AddValidBusConfigWithExchangeSettings)
.Container(c =>
{
c.WithRabbitMqHost();
})
.Assert.PluginModule <MockBusModule>(m =>
{
var exchangeMeta = ExchangeMeta.Define("TestBus1", "TestExchangeName", ExchangeType.Direct);
m.ApplyExchangeSettings(exchangeMeta);
Assert.True(exchangeMeta.IsPassive);
Assert.Equal("TestAltExchangeName", exchangeMeta.AlternateExchangeName);
Assert.Equal("TestContentType", exchangeMeta.ContentType);
Assert.Equal(10000, exchangeMeta.CancelRpcRequestAfterMs);
});
});
}
public QueueMeta CreateQueueMeta(SubscriberQueueAttribute attribute)
{
var exchange = ExchangeMeta.Define(attribute.BusName, attribute.ExchangeName, ExchangeType.Fanout,
config =>
{
config.IsAutoDelete = true;
config.IsDurable = false;
config.IsPassive = false;
config.IsPersistent = false;
});
var queue = QueueMeta.Define(attribute.QueueName, exchange,
config =>
{
config.IsAutoDelete = true;
config.IsDurable = false;
config.IsPassive = false;
config.IsExclusive = true;
config.AppendUniqueId = true;
});
return(queue);
}
public void CanSpecifyQueueSettings_InConfiguration()
{
ContainerFixture.Test(fixture => {
fixture.Arrange
.Configuration(TestSetup.AddValidBusConfigWithQueueSettings)
.Container(c =>
{
c.WithRabbitMqHost();
})
.Assert.PluginModule <MockBusModule>(m =>
{
var queueMeta = ExchangeMeta.DefineDefault("TestBus1", "TestQueueName").QueueMeta;
m.ApplyQueueSettings(queueMeta);
Assert.True(queueMeta.IsPassive);
Assert.Equal(20000, queueMeta.PerQueueMessageTtl);
Assert.Equal("TestDeadLetterExchange", queueMeta.DeadLetterExchange);
Assert.Equal("TestDeadLetterRoutingKey", queueMeta.DeadLetterRoutingKey);
Assert.Equal((byte)10, queueMeta.MaxPriority);
Assert.Equal(5, queueMeta.PrefetchCount);
Assert.Equal(2, queueMeta.Priority);
});
});
}
public void ApplyExchangeSettings(ExchangeMeta meta)
{
ApplyExchangeSettingsInternal(meta);
}
protected override IRpcClient CreateRpcClient(ExchangeMeta definition)
{
Mock <IRpcClient> mockRpcClient = new Mock <IRpcClient>();
return(mockRpcClient.Object);
}
private static async Task <CreatedExchange> CreateExchange(IBus bus, ExchangeMeta meta)
{
IExchange exchange = await bus.Advanced.ExchangeDeclareAsync(meta);
return(new CreatedExchange(bus, exchange, meta));
}