fix(consumer): follow preferred broker #1936
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Historically (before protocol version 11) if we attempted to consume from a follower, we would get a NotLeaderForPartition response and move our consumer to the new leader. However, since v11 the Kafka broker treats us just like any other follower and permits us to consume from any replica and it is up to us to monitor metadata to determine when the leadership has changed. Modifying the handleResponse func to check the topic partition leadership against the current broker (in the absence of a preferredReadReplica) and trigger a re-create of the consumer for that partition Contributes-to: #1927
gofumpt is a stricter but compatible gofmt: https://github.com/mvdan/gofumpt Run it across the repo just to tidy things up a little more.
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TestConsumeMessagesTrackLeader ensures that in the event that leadership of a topicPartition changes and no preferredReadReplica is specified, the consumer connects back to the new leader to resume consumption and doesn't continue consuming from the follower. See #1927
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FetchResponse from a follower will _not_ contain a PreferredReadReplica. It seems like the partitionConsumer would overwrite the previously assigned value from the leader with -1 which would then trigger the "reconnect to the current leader" changes from #1936 causing a flip-flop effect. Contributes-to: #2071 Signed-off-by: Dominic Evans <dominic.evans@uk.ibm.com>
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Historically (before protocol version 11) if we attempted to consume
from a follower, we would get a NotLeaderForPartition response and move
our consumer to the new leader. However, since v11 the Kafka broker
treats us just like any other follower and permits us to consume from
any replica and it is up to us to monitor metadata to determine when the
leadership has changed.
Modifying the handleResponse func to check the topic partition
leadership against the current broker (in the absence of a
preferredReadReplica) and trigger a re-create of the consumer for that
partition
Contributes-to: #1927