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https://issues.apache.org/jira/browse/KAFKA-7678?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16845824#comment-16845824
]
Sebastiaan commented on KAFKA-7678:
-----------------------------------
Hi guys! I think this fix is not complete yet. In version 2.1.1 we are getting
a very similar exception, but in the 'flush' method that is called pre-close.
This is the full stacktrace:
{code:java}
message: stream-thread
[webhook-poster-7034dbb0-7423-476b-98f3-d18db675d6d6-StreamThread-1] Failed
while closing StreamTask 1_26 due to the following error:
logger_name: org.apache.kafka.streams.processor.internals.AssignedStreamsTasks
java.lang.NullPointerException: null
at
org.apache.kafka.streams.processor.internals.RecordCollectorImpl.flush(RecordCollectorImpl.java:245)
at
org.apache.kafka.streams.processor.internals.StreamTask.flushState(StreamTask.java:493)
at
org.apache.kafka.streams.processor.internals.StreamTask.commit(StreamTask.java:443)
at
org.apache.kafka.streams.processor.internals.StreamTask.suspend(StreamTask.java:568)
at
org.apache.kafka.streams.processor.internals.StreamTask.close(StreamTask.java:691)
at
org.apache.kafka.streams.processor.internals.AssignedTasks.close(AssignedTasks.java:397)
at
org.apache.kafka.streams.processor.internals.TaskManager.shutdown(TaskManager.java:260)
at
org.apache.kafka.streams.processor.internals.StreamThread.completeShutdown(StreamThread.java:1181)
at
org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:758)
{code}
Followed by:
{code:java}
message: task [1_26] Could not close task due to the following error:
logger_name: org.apache.kafka.streams.processor.internals.StreamTask
java.lang.NullPointerException: null
at
org.apache.kafka.streams.processor.internals.RecordCollectorImpl.flush(RecordCollectorImpl.java:245)
at
org.apache.kafka.streams.processor.internals.StreamTask.flushState(StreamTask.java:493)
at
org.apache.kafka.streams.processor.internals.StreamTask.commit(StreamTask.java:443)
at
org.apache.kafka.streams.processor.internals.StreamTask.suspend(StreamTask.java:568)
at
org.apache.kafka.streams.processor.internals.StreamTask.close(StreamTask.java:691)
at
org.apache.kafka.streams.processor.internals.AssignedTasks.close(AssignedTasks.java:397)
at
org.apache.kafka.streams.processor.internals.TaskManager.shutdown(TaskManager.java:260)
at
org.apache.kafka.streams.processor.internals.StreamThread.completeShutdown(StreamThread.java:1181)
at
org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:758){code}
If I look at the source code at this point, I see a nice null check in the
close method, but not in the flush method that is called just before that:
{code:java}
public void flush() {
this.log.debug("Flushing producer");
this.producer.flush();
this.checkForException();
}
public void close() {
this.log.debug("Closing producer");
if (this.producer != null) {
this.producer.close();
this.producer = null;
}
this.checkForException();
}{code}
{color:#000080} {color}
Seems to my (ignorant) eye that the flush method should also be wrapped in a
null check.
> Failed to close producer due to java.lang.NullPointerException
> --------------------------------------------------------------
>
> Key: KAFKA-7678
> URL: https://issues.apache.org/jira/browse/KAFKA-7678
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 1.1.1, 2.0.1, 2.1.0
> Reporter: Jonathan Santilli
> Assignee: Jonathan Santilli
> Priority: Minor
> Fix For: 1.1.2, 2.2.0, 2.1.1, 2.0.2
>
>
> This occurs when the group is rebalancing in a Kafka Stream application and
> the process (the Kafka Stream application) receives a *SIGTERM* to stop it
> gracefully.
>
>
> {noformat}
> ERROR org.apache.kafka.streams.processor.internals.StreamTask - task [1_46]
> Failed to close producer due to the following error:
> java.lang.NullPointerException
> at
> org.apache.kafka.streams.processor.internals.RecordCollectorImpl.close(RecordCollectorImpl.java:252)
> at
> org.apache.kafka.streams.processor.internals.StreamTask.maybeAbortTransactionAndCloseRecordCollector(StreamTask.java:607)
> at
> org.apache.kafka.streams.processor.internals.StreamTask.suspend(StreamTask.java:584)
> at
> org.apache.kafka.streams.processor.internals.StreamTask.close(StreamTask.java:691)
> at
> org.apache.kafka.streams.processor.internals.AssignedTasks.closeUnclean(AssignedTasks.java:428)
> at
> org.apache.kafka.streams.processor.internals.AssignedTasks.close(AssignedTasks.java:408)
> at
> org.apache.kafka.streams.processor.internals.TaskManager.shutdown(TaskManager.java:260)
> at
> org.apache.kafka.streams.processor.internals.StreamThread.completeShutdown(StreamThread.java:1181)
> at
> org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:758){noformat}
>
>
> Although I have checked the code and the method
> `*maybeAbortTransactionAndCloseRecordCollector*` in the `*StreamTask*.*java*`
> class is expecting any kind of error to happen since is catching
> `*Throwable*`.
>
>
>
> {noformat}
> try {
> recordCollector.close();
> } catch (final Throwable e) {
> log.error("Failed to close producer due to the following error:", e);
> } finally {
> producer = null;
> }{noformat}
>
> Should we consider this a bug?
> In my opinion, we could check for the `*null*` possibility at
> `*RecordCollectorImpl*.*java*` class:
> {noformat}
> @Override
> public void close() {
> log.debug("Closing producer");
> producer.close();
> producer = null;
> checkForException();
> }{noformat}
>
> Change it for:
>
> {noformat}
> @Override
> public void close() {
> log.debug("Closing producer");
> if ( Objects.nonNull(producer) ) {
> producer.close();
> producer = null;
> }
> checkForException();
> }{noformat}
>
> How does that sound?
>
> Kafka Brokers running 2.0.0
> Kafka Stream and client 2.1.0
> OpenJDK 8
>
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