Kafka, mail # user - Re: High Level Consumer error handling and clean exit - 2013-07-09, 18:23
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Re: High Level Consumer error handling and clean exit
Hi Philip,

Correct, I don't want to explicitly control the offset committing. The
ConsumerConnector handles that well enough except for when I want to
shutdown and NOT have Kafka think I consumed that last message for a
stream. This isn't the crash case, it is a case where the logic consuming
the message detects and error and wants to cleanly exit until that issue
can be resolved, but not lose the message it was trying to process when the
problem is resolved.

My understanding is that the commitOffsets() call is across all threads,
not just for the stream my thread is reading from. So knowing it is okay to
call this requires coordination across all my threads, which makes a High
Level Consumer a lot harder to write correctly.

Thinking about what I'd like to happen is: my code hands the message back
to the KafkaStream (or whatever level knows about the consumed offsets) and
- set the next start offset for this topic/partition to this message in
- cleanly shutdown the stream from the broker(s)
- don't force a rebalance on the consumer since something is wrong with
processing of the data in the message, not the message.
- If I try to use the stream again I should get an exception
- I don't think I would want this to cause a complete shutdown of the
ConsumerConnector, in case other threads are still processing. If all
threads have the same issue they will all fail soon enough and do the same
logic. But if only one thread fails, our Operations teams will need to
resolve the issue then do a clean restart to recover.

I think this logic would only happen when the down stream system was having
issues since the iterator would be drained correctly when the 'shutdown'
call to ConsumerConnector is made.



On Tue, Jul 9, 2013 at 11:21 AM, Philip O'Toole <[EMAIL PROTECTED]> wrote:
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