Hello Walker, Thanks for proposing the KIP! I have a couple more comments:
1. ShutdownRequestedException: my understanding is that this exception is only used if the application-shutdown was initiated by by the user triggered "shutdownApplication()", otherwise e.g. if it is due to source topic not found and Streams library decides to close the whole application automatically, we would still throw the original exception a.k.a. MissingSourceTopicException to the uncaught exception handling. Is that the case? Also for this exception, which package are you proposing to add to? 2. ShutdownRequestedException: for its constructor, I'm wondering what Throwable "root cause" could it ever be? Since I'm guessing here that we would just use a single error code in the protocol still to tell other instances to shutdown, and that error code would not allow us to encode any more information like root causes at all, it seems that parameter would always be null. 3. shutdownApplication: again I'd like to clarify, would this function block on the local instance to complete shutting down all its threads like `close()` as well, or would it just to initiate the shutdown and not wait for local threads at all? Also a nit suggestion regarding the name, if it is only for initiating the shutdown, maybe naming as "initiateCloseAll" would be more specific? Guozhang On Mon, Sep 14, 2020 at 10:13 AM Walker Carlson <wcarl...@confluent.io> wrote: > Hello Matthias and Sophie, > > You both make good points. I will respond to the separately below. > > > Matthias: > That is a fair point. KIP-662 > < > https://cwiki.apache.org/confluence/display/KAFKA/KIP-662%3A+Throw+Exception+when+Source+Topics+of+a+Streams+App+are+Deleted > >, > which > is accepted, will make it so Source topic deletion will make it to the > uncaught exception handler. Shutdown can be initiated from there. However > this would mean that the stream thread is already dead. So I would have to > rethink the exception for this use case, perhaps it would be needed in the > KakfaStreams object. But this still leaves the case where there is only one > stream thread. I will think about it. > > Maybe the source topics are a bad example as it makes this kip dependent on > Kip-662 getting implemented in a certain way. However this is not the only > reason this could be useful here > <https://issues.apache.org/jira/browse/KAFKA-4748> is a jira ticket asking > for the same functionality. I have added a few other use cases to the kip. > Although I will still be rethinking where I want to add this functionality > and whether it should be an exception or not. > > Sophie: > I agree that shutting down an instance could also be useful. There was some > discussion about this on KIP-663. It seems that we came to the conclusion > that close(Duration.ZERO) would be sufficient. link > < > https://mail-archives.apache.org/mod_mbox/kafka-dev/202008.mbox/%3c95f95168-2811-e57e-96e2-fb5e71d92...@confluent.io%3e > > > to > thread > > Also I am not set on the name ShutdownRequested. If we decide to keep at as > an exception your idea is probably a better name. > > > Thanks for the feedback, > Walker > > > On Fri, Sep 11, 2020 at 11:08 AM Matthias J. Sax <mj...@apache.org> wrote: > > > Thanks for the KIP. > > > > It seem that the new exception would need to be thrown by user code? > > However, in the motivation you mention the scenario of a missing source > > topic that a user cannot detect, but KafkaStreams runtime would be > > responsible to handle. > > > > How do both things go together? > > > > > > -Matthias > > > > On 9/11/20 10:31 AM, Walker Carlson wrote: > > > Hello all, > > > > > > I have created KIP-671 to give the option to shutdown a streams > > > application in response to an error. > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-671%3A+Shutdown+Streams+Application+when+appropriate+exception+is+thrown > > > > > > This is because of the Jira ticket > > > <https://issues.apache.org/jira/browse/KAFKA-9331> > > > > > > Please give it a look and let me know if you have any feedback. > > > > > > Thanks, > > > Walker > > > > > > > > -- -- Guozhang
