I have Java code similar to this in a class called "MyService" to receive messages, process the object passed and return a response, with the intention to have the returned response using the configured exchange and routing key, as specified using the #SendTo annotation:
#RabbitListener(containerFactory = "myContainerFactory", queues = RabbitConfig.MY_QUEUE_NAME)
#SendTo("#{T(com.acme.config.RabbitOutboundConfig).OUTBOUND_EXCHANGE_NAME + '/' + myService.getRoutingKey()}")
public OrderResponse handlePaidOrder(Order order) {
// do processing on the input Order object here...
OrderResponse orderResponse = new OrderResponse();
// fill up response object here
return orderResponse;
}
public String getRoutingKey() {
String routingKey;
// .. custom logic to build a routing key
return routingKey;
}
This makes sense and works fine. The problem I am having is I can't figure out how to stop the "reply_to" property from coming in the message. I know if my sender configures a RabbitTemplate by calling setReplyAddress, that will result in a reply_to property and a correlation_id in the message.
However, if I simply do not call setReplyAddress, I still get a reply_to property, one that looks like this:
reply_to: amq.rabbitmq.reply-to.g2dkAAxyYWJiaXRAd3NK and so forth
and with that reply_to in the message, #SendTo has no effect. The Spring AMQP docs and this post: Dynamic SendTo annotation state:
The #SendTo is only used if there's no replyTo in the message.
Furthermore, when I don't call setReplyAddress on the RabbitTemplate, I don't get a correlation-id either. I pretty sure I am going to need that. So, my question is, how do I get my sender to generate a correlation-id but to not generate a reply-to so that my receiver can use the #SendTo annotation?
Thanks much in advance.
The correlationId is for the sender; it's not needed with direct reply-to since the channel is reserved; you could add a MessagePostProcessor on the sending side to add a correlationId.
The #SendTo is a fallback in case there is no reply_to header.
If you want to change that behavior you can add an afterReceivePostProcessor to the listener container to remove the replyTo property on the MessageProperties.
container.setAfterReceivePostProcessor(m -> {
m.getMessageProperties().setReplyTo(null);
return m;
}
Bear in mind, though, that if the sender set a replyTo, he is likely expecting a reply, so sending the reply someplace else is going to disappoint him and likely will cause some delay there until the reply times out.
If you mean you want to send an initial reply someplace else that does some more work and then finally replies to the originator, then you should save off the replyTo in another header, and reinstate it (or use an expression that references the saved-off header).
Related
I have a test for an actor that might respond with some unexpected messages but eventually it must respond with a particular known message.
So in essence I want an assertion that will within in some timespan ignore other messages but expect a known message, like so:
[TestMethod]
[TestCategory("Integration")]
public async Task Should_fetch_fund_shareclass_and_details_from_test_service()
{
var testIsins = new HashSet<string> {"isin1", "isin2", "isin3"};
var props = Props.Create(() => new DataFetchSupervisor());
var actor = Sys.ActorOf(props, "fetchSupervisor");
Within(TimeSpan.FromSeconds(30), () =>
{
actor.Tell(new StartDataFetch(testIsins));
//ignore unexpected messages here
var fetchComplteMsg = ExpectMsg<DataFetchComplete>();
});
}
So now this will fail because I get some other messages before DataFetchComplete message.
As always, thanks in advance for any help.
Akka.TestKit class has a number of different versions of ExcpectMsg or equivalent checkers. The one you're looking for is probably a FishForMessage. It takes a predicate and will ignore all incoming messages as long as they will fail to pass predicate's condition. Once a passing message is found this check will complete and your code may be continued.
You can also use the TestKit.IgnoreMessages method, which will accept a delegate function specifying which types of messages you wish to ignore while waiting for your target message.
I am trying to write sender receiver program which will send request and wait for the reply until receiver process the request. But getting a "null" response when I call this method -convertSendAndReceive().
Well, which reply are you going to get if your "receiver is not running"?
Anyway RabbitTemplate has replyTimeout option which is:
private static final long DEFAULT_REPLY_TIMEOUT = 5000;
yeah... by default.
I am implementing a MassTransit middleware in my receive end point to record the performance of handling the message, i want to get the message type from the PipeContext, how can i get it?
public async Task Send(T context, IPipe<T> next)
{
// I want to know the message type from here so that i can log it
using (_logger.BeginTimedOperation("Time for handling message", null, LogEventLevel.Debug))
{
await next.Send(context);
}
}
You would need to intercept at the ConsumeContext, which has a property for the message types from the serialization envelope.
Then, you can get the supported message types using:
IEnumerable<string> SupportedMessageTypes {get;}
That should get you what you need to log the message type with the duration.
So a filter along the lines of:
public class LogMessageTypeFilter :
IFilter<ConsumeContext>
{
}
Implement the send method, call next within the method, and then take action after the next pipe completes.
In my test application I can see messages that were processed with an exception being automatically inserted into the default EasyNetQ_Default_Error_Queue, which is great. I can then successfully dump or requeue these messages using the Hosepipe, which also works fine, but requires dropping down to the command line and calling against both Hosepipe and the RabbitMQ API to purge the queue of retried messages.
So I'm thinking the easiest approach for my application is to simply subscribe to the error queue, so I can re-process them using the same infrastructure. But in EastNetQ, the error queue seems to be special. We need to subscribe using a proper type and routing ID, so I'm not sure what these values should be for the error queue:
bus.Subscribe<WhatShouldThisBe>("and-this", ReprocessErrorMessage);
Can I use the simple API to subscribe to the error queue, or do I need to dig into the advanced API?
If the type of my original message was TestMessage, then I'd like to be able to do something like this:
bus.Subscribe<ErrorMessage<TestMessage>>("???", ReprocessErrorMessage);
where ErrorMessage is a class provided by EasyNetQ to wrap all errors. Is this possible?
You can't use the simple API to subscribe to the error queue because it doesn't follow EasyNetQ queue type naming conventions - maybe that's something that should be fixed ;)
But the Advanced API works fine. You won't get the original message back, but it's easy to get the JSON representation which you could de-serialize yourself quite easily (using Newtonsoft.JSON). Here's an example of what your subscription code should look like:
[Test]
[Explicit("Requires a RabbitMQ server on localhost")]
public void Should_be_able_to_subscribe_to_error_messages()
{
var errorQueueName = new Conventions().ErrorQueueNamingConvention();
var queue = Queue.DeclareDurable(errorQueueName);
var autoResetEvent = new AutoResetEvent(false);
bus.Advanced.Subscribe<SystemMessages.Error>(queue, (message, info) =>
{
var error = message.Body;
Console.Out.WriteLine("error.DateTime = {0}", error.DateTime);
Console.Out.WriteLine("error.Exception = {0}", error.Exception);
Console.Out.WriteLine("error.Message = {0}", error.Message);
Console.Out.WriteLine("error.RoutingKey = {0}", error.RoutingKey);
autoResetEvent.Set();
return Task.Factory.StartNew(() => { });
});
autoResetEvent.WaitOne(1000);
}
I had to fix a small bug in the error message writing code in EasyNetQ before this worked, so please get a version >= 0.9.2.73 before trying it out. You can see the code example here
Code that works:
(I took a guess)
The screwyness with the 'foo' is because if I just pass that function HandleErrorMessage2 into the Consume call, it can't figure out that it returns a void and not a Task, so can't figure out which overload to use. (VS 2012)
Assigning to a var makes it happy.
You will want to catch the return value of the call to be able to unsubscribe by disposing the object.
Also note that Someone used a System Object name (Queue) instead of making it a EasyNetQueue or something, so you have to add the using clarification for the compiler, or fully specify it.
using Queue = EasyNetQ.Topology.Queue;
private const string QueueName = "EasyNetQ_Default_Error_Queue";
public static void Should_be_able_to_subscribe_to_error_messages(IBus bus)
{
Action <IMessage<Error>, MessageReceivedInfo> foo = HandleErrorMessage2;
IQueue queue = new Queue(QueueName,false);
bus.Advanced.Consume<Error>(queue, foo);
}
private static void HandleErrorMessage2(IMessage<Error> msg, MessageReceivedInfo info)
{
}
If I have a saga that consists of two message types, say started by message1 and completed by message2, can I return a callback if a message2 comes in without a message1 already existing? I know it will dump it in the error queue, but I want to be able to return a status to the sending client to say there is an error state due to the first message not being there.
So I figured it out, I just needed to implement IFindSagas for the message type:
public class MySagaFinder : IFindSagas<MySagaData>.Using<Message2>
{
public ISagaPersister Persister { get; set; }
public IBus Bus { get; set; }
public MySagaFinder FindBy(Message2 message)
{
var data = Persister.Get<MySagaData>("MessageIdProperty", message.MessageIdProperty);
if (data == null)
{
Bus.Return(0);
}
return data;
}
}
I don't know if this is the right way to do it, but it works!
If you have a saga that can receive two messages, but messages can be received in any order, make sure the saga can be started by both messages. Then verify if both message have arrived by setting some state in the saga itself. If both messages have arrived, mark it as complete.
Default NServicebBus behavior is to ignore any message that has no corresponding saga. This is because you can set a timeout, for example. If nothing happens within 24 hours, the saga can send a Timeout message to itself. But if something did happen and you marked your saga as being completed, what should happen to the Timeout message? Therefor NServiceBus ignores it.