KAFKA-10505: Fix parsing of generation log string.

[nizhikov]

Two tests fails with the same reason:

  File "/opt/kafka-dev/tests/kafkatest/tests/streams/streams_upgrade_test.py", line 533, in extract_highest_generation
    return int(found_generations[-1])
ValueError: invalid literal for int() with base 10: "Generation{generationId=6,memberId='StreamsUpgradeTest-8a6ac110-1c65-40eb-af05-8bee270f1701-StreamThread-1-consumer-207de872-6588-407a-8485-101a19ba2bf0',protocol='stream'}\n"

  File "/opt/kafka-dev/tests/kafkatest/tests/streams/streams_static_membership_test.py", line 86, in test_rolling_bounces_will_not_trigger_rebalance_under_static_membership
    generation = int(generation)
ValueError: invalid literal for int() with base 10: "Generation{generationId=5,memberId='consumer-A-2-3e9cc50c-9835-4772-b282-29e07b2f9ad6',protocol='stream'}\n"

This PR fix the above errors by extracting the correct number from the log string.

Committer Checklist (excluded from commit message)

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation (including upgrade notes)

[nizhikov]

Hello, @mjsax @ableegoldman

2 system tests for streams are fails because of an unexpected string format.
I fixed it.

Please, take a look at my PR.

[mjsax]

@nizhikov @ableegoldman Do we know when this broke? What was the old log line and what is the new one?

Triggered system test run: https://jenkins.confluent.io/job/system-test-kafka-branch-builder/4181/

[nizhikov]

@mjsax These tests are broken with the 7e7bb18

Line logging only generationId - 7e7bb18#diff-30048900127c988a69027b70b0ce4eacL504

New line with the whole Generation object logging - 7e7bb18#diff-30048900127c988a69027b70b0ce4eacR590

[ableegoldman]

Original system test run was aborted for some reason. Kicked off a new set: https://jenkins.confluent.io/job/system-test-kafka-branch-builder/4182/

[guozhangwang]

https://jenkins.confluent.io/job/system-test-kafka-branch-builder/4182/ passed now. I'm going to merge this one.

[nizhikov]

Thanks for the review and merge!

[ableegoldman]

@guozhangwang I think this needs to be cherrypicked back to 2.6

[guozhangwang]

Yup, cherry-picked to 2.6 as well.