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https://issues.apache.org/jira/browse/KAFKA-6520?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16554817#comment-16554817
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Guozhang Wang commented on KAFKA-6520:
--------------------------------------
Just want to re-emphasize that, it is not only a Streams feature request: if
you start a Java consumer today talking to a broker, and the broker is not
available, that consumer client would not throw an exception either. This was
by-design of the consumer at that time:
{code}
When KafkaConsumer.poll is called, in which updateAssignmentMetadataIfNeeded is
called and coordinator.poll() is called. If the broker(s) are not available
then the last call will always return false after timeout, and hence
KafkaConsumer.poll will return empty set without any indicator that brokers are
disconnect. In fact, if the brokers are unavailable at the very beginning when
streams application starts, we will hit the same issue as the instance will
also be in the RUNNING state since the onPartitionRevoked would not be called
ever.
...
On the other hand, it is by-design of the consumer to not let users worry about
the connectivity of the broker, or to handle any disconnect issues. Here is my
proposed options:
{code}
> When a Kafka Stream can't communicate with the server, it's Status stays
> RUNNING
> --------------------------------------------------------------------------------
>
> Key: KAFKA-6520
> URL: https://issues.apache.org/jira/browse/KAFKA-6520
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: Michael Kohout
> Assignee: Milind Jain
> Priority: Major
> Labels: newbie, user-experience
>
> When you execute the following scenario the application is always in RUNNING
> state
>
> 1)start kafka
> 2)start app, app connects to kafka and starts processing
> 3)kill kafka(stop docker container)
> 4)the application doesn't give any indication that it's no longer
> connected(Stream State is still RUNNING, and the uncaught exception handler
> isn't invoked)
>
>
> It would be useful if the Stream State had a DISCONNECTED status.
>
> See
> [this|https://groups.google.com/forum/#!topic/confluent-platform/nQh2ohgdrIQ]
> for a discussion from the google user forum.
> [This|https://issues.apache.org/jira/browse/KAFKA-4564] is a link to a
> related issue.
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