vvcephei commented on a change in pull request #9487: URL: https://github.com/apache/kafka/pull/9487#discussion_r523089743
########## File path: streams/src/main/java/org/apache/kafka/streams/KafkaStreams.java ########## @@ -366,6 +375,93 @@ public void setUncaughtExceptionHandler(final Thread.UncaughtExceptionHandler eh } } + /** + * Set the handler invoked when an {@link StreamsConfig#NUM_STREAM_THREADS_CONFIG internal thread} + * throws an unexpected exception. + * These might be exceptions indicating rare bugs in Kafka Streams, or they + * might be exceptions thrown by your code, for example a NullPointerException thrown from your processor + * logic. + * The handler will execute on the thread that produced the exception. + * So inorder to get the thread as the java handler type uses use Thread.currentThread() + * <p> + * Note, this handler must be threadsafe, since it will be shared among all threads, and invoked from any + * thread that encounters such an exception. + * + * @param streamsUncaughtExceptionHandler the uncaught exception handler of type {@link StreamsUncaughtExceptionHandler} for all internal threads + * @throws IllegalStateException if this {@code KafkaStreams} instance is not in state {@link State#CREATED CREATED}. + * @throws NullPointerException if streamsUncaughtExceptionHandler is null. + */ + public void setUncaughtExceptionHandler(final StreamsUncaughtExceptionHandler streamsUncaughtExceptionHandler) { + final Consumer<Throwable> handler = exception -> handleStreamsUncaughtException(exception, streamsUncaughtExceptionHandler); + synchronized (stateLock) { + if (state == State.CREATED) { + Objects.requireNonNull(streamsUncaughtExceptionHandler); + for (final StreamThread thread : threads) { + thread.setStreamsUncaughtExceptionHandler(handler); + } + if (globalStreamThread != null) { + globalStreamThread.setUncaughtExceptionHandler(handler); + } + } else { + throw new IllegalStateException("Can only set UncaughtExceptionHandler in CREATED state. " + + "Current state is: " + state); + } + } + } + + private void handleStreamsUncaughtExceptionDefaultWrapper(final Throwable throwable) { + if (Thread.getDefaultUncaughtExceptionHandler() != null) { + if (throwable instanceof RuntimeException) { + throw (RuntimeException) throwable; + } else if (throwable instanceof Error) { + throw (Error) throwable; + } else { + throw new RuntimeException("Unexpected checked exception caught in the uncaught exception handler", throwable); + } + } else { + handleStreamsUncaughtException(throwable, t -> SHUTDOWN_CLIENT); + } + } + + private void handleStreamsUncaughtException(final Throwable e, + final StreamsUncaughtExceptionHandler streamsUncaughtExceptionHandler) { + final StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse action = streamsUncaughtExceptionHandler.handle(e); + if (Thread.getDefaultUncaughtExceptionHandler() != null) { Review comment: If that's the case, then we really should just set a flag on KafkaStreams to indicate whether that handler has been set. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org