CODEWITHSUNDEEP
springspring-integrationspring-cloud-stream
Nikem
Nikem

Reputation: 5784

How to test delivery in PublishSubscribeChannel?

I have a PublishSubscribeChannel in my application, which should deliver messages to different MessageHandlers inside the same JVM. Handlers are subscribed to the channel using @StreamListener annotation. Channel uses Executors so delivery is asynchronous.

Now, I want to test that senders and handlers agree on the specific object type which send through channel (the type of Message body). AFAIU I have two ways to test this:

  1. Find all subscribers of the given channel and verify their signature.
  2. Send a message to a channel and verify that no handlers have thrown an exception.

I have no idea how to do (1). And I think I could do (2) by listening to errorChannel (there should be no messages there), but I don't quite understand how long should I wait for error messages.

Any suggestions?

Upvotes: 0

Views: 69

Answers (1)

Gary Russell
Gary Russell

Reputation: 174729

For 1, you can use reflection to look at the collection of handlers in the channel's dispatcher; then use reflection again to look at the hander's Method.

However, your design is flawed, unless you don't mind losing messages; the incoming message will be ack'd as soon as you hand off to the executor; if the server then crashes, the message will be lost.

If you get rid of the executor, it would be simpler to add an interceptor to the channel, which will be notified of any exceptions in its afterSendCompletion() method (satisfying your 2).

Upvotes: 2

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