Listeners not working?

[failsafe-lib]

Listeners not working?

[jhalterman]

@BenRomberg Thanks for filing this. This was indeed a bug where the failed attempt listener would not always be called the final time. For example, with 3 retries as in your example, it might only be called 3 times, not 4 as expected.

onRetry is a little different though since it only gets called before a retry happens. So with 3 retries it would only be called 3 times, whereas onFailedAttempt should be called 4 times (since the initial execution failed, plus the 3 retry attempts).

Let me know if that doesn't describe the problem you were having. Also, let me know if you can try the current code in master and if that resolves your issue.

[BenRomberg]

The problem I had was that the listener was not called at all in the 2 scenarios I described above, even though there were 3 failing retries. Using v0.8.3 btw.

I'll try out master once I get to it, probably by the end of next week (it's for a side project I only work on Fridays). If it still doesn't work, I'll provide a failing test that highlights the issue. Thanks for the prompt response!

[jhalterman]

@BenRomberg I just updated a test case for this issue, and I think it matches the failing scenario you describe:

https://github.com/jhalterman/failsafe/blob/55bc48d2a106405f7f796a259ecfc4297c93340c/src/test/java/net/jodah/failsafe/issues/Issue36.java

Right now the test passes. If you do get a chance to come up with a failing test for what you're seeing, that would be great.

[BenRomberg]

@jhalterman: Finally had the time to try it out. Either it still doesn't work or I'm doing something wrong.

Below are 4 tests that I would expect to pass:

    @Test
    public void failedAttemptListener_WithFailedResponses_ShouldBeCalled() throws Exception {
        @SuppressWarnings("unchecked")
        RetryPolicy policy = new RetryPolicy().retryIf((Boolean response) -> response != null && response)
                .retryOn(Exception.class).withDelay(1, TimeUnit.SECONDS).withMaxRetries(3);
        AtomicInteger listenerCallbacks = new AtomicInteger();
        Failsafe.<Response> with(policy)
                .onFailedAttempt((failedResponse, exception, context) -> listenerCallbacks.incrementAndGet())
                .get(() -> false);
        assertThat(listenerCallbacks.get()).isEqualTo(4);
    }

    @Test
    public void retryListener_WithFailedResponses_ShouldBeCalled() throws Exception {
        @SuppressWarnings("unchecked")
        RetryPolicy policy = new RetryPolicy().retryIf((Boolean response) -> response != null && response)
                .retryOn(Exception.class).withDelay(1, TimeUnit.SECONDS).withMaxRetries(3);
        AtomicInteger listenerCallbacks = new AtomicInteger();
        Failsafe.<Response> with(policy)
                .onRetry((failedResponse, exception, context) -> listenerCallbacks.incrementAndGet()).get(() -> false);
        assertThat(listenerCallbacks.get()).isEqualTo(3);
    }

    @Test
    public void failedAttemptListener_WithExceptions_ShouldBeCalled() throws Exception {
        @SuppressWarnings("unchecked")
        RetryPolicy policy = new RetryPolicy().retryIf((Boolean response) -> response != null && response)
                .retryOn(Exception.class).withDelay(1, TimeUnit.SECONDS).withMaxRetries(3);
        AtomicInteger listenerCallbacks = new AtomicInteger();
        try {
            Failsafe.<Response> with(policy)
                    .onFailedAttempt((failedResponse, exception, context) -> listenerCallbacks.incrementAndGet())
                    .get(() -> {
                        throw new RuntimeException();
                    });
        } catch (RuntimeException e) {
        }
        assertThat(listenerCallbacks.get()).isEqualTo(4);
    }

    @Test
    public void retryListener_WithExceptions_ShouldBeCalled() throws Exception {
        @SuppressWarnings("unchecked")
        RetryPolicy policy = new RetryPolicy().retryIf((Boolean response) -> response != null && response)
                .retryOn(Exception.class).withDelay(1, TimeUnit.SECONDS).withMaxRetries(3);
        AtomicInteger listenerCallbacks = new AtomicInteger();
        try {
            Failsafe.<Response> with(policy)
                    .onRetry((failedResponse, exception, context) -> listenerCallbacks.incrementAndGet()).get(() -> {
                        throw new RuntimeException();
                    });
        } catch (RuntimeException e) {
        }
        assertThat(listenerCallbacks.get()).isEqualTo(3);
    }

Only the last 2 pass (using either 0.8.3, 0.9.1 or 0.9.2-SNAPSHOT from master) when the retry is triggered by an exception, but not if it's triggered by an unsatisfying result from the callback (from the retryIf condition in the policy). As you've used only the retry-on-exception case in your test, it passes, but what I'm talking about is the retryIf condition not triggering the listener correctly.

[jhalterman]

@BenRomberg Thanks for posting this. I think it might just be a problem with the retryIf statement. Should it be .retryIf((Boolean response) -> response != null && !response) ? We want to retry when response is false.

[BenRomberg]

@jhalterman: You're right, I mixed that up. I want it to retry 3 times in the test. But even after changing it, the tests still fail.

[jhalterman]

@BenRomberg Do you have any more details on the failure you're seeing? I just added your test cases (without the delay), and they're passing. See ef79e25.

[BenRomberg]

@jhalterman: I finally figured it out. It was because of the wrong generic type <Response> I was calling the Failsafe.<Response> with method with. I changed the types during development and forgot to adjust that one. I think it was necessary in one of the earlier versions of Failsafe, nowadays it's not needed at all and I can just call Failsafe.with(...) without having to bind an explicit type.

Thanks for your support!

[BenRomberg]

Actually I just realized that the generic type in Failsafe.with(...) is still necessary if you need the correct type in the listener callback.