[improvement] Add support for tracing-aware Guava FutureCallbacks. #77
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| /** | ||
| * Like {@link #wrapWithNewTrace(String, Callable)}, but for Guava's FutureCallback. | ||
| */ | ||
| public static <V> FutureCallback<V> wrapWithNewTrace(String operation, FutureCallback<V> delegate) { |
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I don't think we ever want to create a new trace around just the callback
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@ellisjoe is putting some thought into support for tracing asynchronous operations as well.
| ListenableFuture<Void> success = listeningExecutorService.submit(() -> null); | ||
| ListenableFuture<Void> failure = listeningExecutorService.submit(() -> { | ||
| throw new IllegalStateException(); | ||
| }); |
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should use separate test cases for the successful/failed futures. Otherwise when tests fail, it. takes additional debugging to figure out what the problem is.
| ListenableFuture<Void> success = listeningExecutorService.submit(() -> null); | ||
| ListenableFuture<Void> failure = listeningExecutorService.submit(() -> { | ||
| throw new IllegalStateException(); | ||
| }); |
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Should use separate test cases for these
| @@ -104,6 +106,11 @@ public static Runnable wrap(Runnable delegate) { | |||
| return new TracingAwareRunnable(delegate); | |||
| } | |||
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| /** Like {@link #wrap(Callable)}, but for Guava's FutureCallback. */ | |||
| public static <V> FutureCallback<V> wrap(FutureCallback<V> delegate) { | |||
| return new TracingAwareFutureCallback<>(delegate); | |||
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Should this take an operation name? Once #71 merges DeferredTracer can take an operation name. I'd prefer we we required an operation name for new methods, and did not provide a method using a default.
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Sure. Can wait until #71 merges and then rebase to use the DeferredTracer with the operation name.
| Tracer.startSpan("before-construction"); | ||
| FutureCallback<Void> successCallback = Tracers.wrap(futureCallback); | ||
| Tracer.startSpan("after-construction"); | ||
| Futures.addCallback(success, successCallback, MoreExecutors.directExecutor()); |
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We should have a test that runs on an executor using a different thread, since tracing-java heavily uses thread state. The direct executor just invokes run() on the current thread.
Before this PR
Functionality defined as part of a Guava FutureCallback may not be correctly traced as the thread it runs on may not be the thread adding the callback.
After this PR
FutureCallbacks can be wrapped such that their traces are parented to the thread adding the callback or wrapped in a new trace if desired.