I have a question regarding the shutdown semantics of Logstash's Kafka Input Plugin:
When I run it with default settings, send a batch of 10.000 message into kafka and restart* logstash while it is processing the message, I end up with more than 10.000 (e.g. 10.212) messages in ES.
So at a first glance it looks like it just continues at the last commit done via the auto_commit_interval_ms (which may be up to 5seconds old). But I would assume that the plugin properly closes the consumer and sends a last offset commit to avoid double processing of messages.
Now I wonder how this is supposed to work?
Thank you in advance!
*) I restart logstash with a SIGTERM first, wait until it is properly shut down and then wait a minute to start it again.