MINOR:Refactor the metric names into constants in ReplicaManager

[hudeqi]

Inspired by #13623, the code of the metric in ReplicaManager is optimized (to improve the commit of #13471).

[hudeqi]

and this, thanks! @divijvaidya @dajac

[kirktrue]

Mostly reviewing this to learn more about the broker side of things. Seems like a straightforward clean up.

[machi1990]

lgtm

[divijvaidya]

@hudeqi you requested the review today but I think there are some existing comments above that have not yet been addressed

[hudeqi]

Hi, @divijvaidya, it has been updated according to your comment, thank you!

[divijvaidya]

Looks good to me. One minor thing is to update the PR name (since we use the same for commit messages). As I understand, we are not really optimizing anything here. We are refactoring the metric names into constants.

Can you please change the PR description to reflect the same?

[hudeqi]

Looks good to me. One minor thing is to update the PR name (since we use the same for commit messages). As I understand, we are not really optimizing anything here. We are refactoring the metric names into constants.

Can you please change the PR description to reflect the same?

ok, I see, updated the pr name. @divijvaidya

[divijvaidya]

I triggered the CI tests again since last run wasn't complete. Will merge this in after they are successful.

[hudeqi]

I triggered the CI tests again since last run wasn't complete. Will merge this in after they are successful.

It seems that the failure of CI check has nothing to do with this pr. @divijvaidya

[divijvaidya]

It seems that the failure of CI check has nothing to do with this pr. @divijvaidya

Hmm...not sure about that. There are 99 tests failing and I am not comfortable saying that they are not because of this PR. Let's wait a day or 2 for CI to stabilize, after that we can merge from trunk again and try the CI for this PR.

[hudeqi]

It seems that the failure of CI check has nothing to do with this pr. @divijvaidya

Hmm...not sure about that. There are 99 tests failing and I am not comfortable saying that they are not because of this PR. Let's wait a day or 2 for CI to stabilize, after that we can merge from trunk again and try the CI for this PR.

Is this CI test often unstable? I've hardly ever seen anything that can be completely checked successfully. 😂

[divijvaidya]

Failing tests are unrelated. These are frequently failing tests in trunk.

[Build / JDK 17 and Scala 2.13 / org.apache.kafka.connect.mirror.integration.MirrorConnectorsIntegrationBaseTest.testReplicateSourceDefault()](https://ci-builds.apache.org/job/Kafka/job/kafka-pr/job/PR-13705/11/testReport/junit/org.apache.kafka.connect.mirror.integration/MirrorConnectorsIntegrationBaseTest/Build___JDK_17_and_Scala_2_13___testReplicateSourceDefault__/)
[Build / JDK 17 and Scala 2.13 / kafka.api.ConsumerBounceTest.testClose()](https://ci-builds.apache.org/job/Kafka/job/kafka-pr/job/PR-13705/11/testReport/junit/kafka.api/ConsumerBounceTest/Build___JDK_17_and_Scala_2_13___testClose__/)
[Build / JDK 17 and Scala 2.13 / kafka.api.TransactionsTest.testBumpTransactionalEpoch(String).quorum=kraft](https://ci-builds.apache.org/job/Kafka/job/kafka-pr/job/PR-13705/11/testReport/junit/kafka.api/TransactionsTest/Build___JDK_17_and_Scala_2_13___testBumpTransactionalEpoch_String__quorum_kraft/)
[Build / JDK 17 and Scala 2.13 / kafka.zk.ZkMigrationIntegrationTest.[1] Type=ZK, Name=testNewAndChangedTopicsInDualWrite, MetadataVersion=3.4-IV0, Security=PLAINTEXT](https://ci-builds.apache.org/job/Kafka/job/kafka-pr/job/PR-13705/11/testReport/junit/kafka.zk/ZkMigrationIntegrationTest/Build___JDK_17_and_Scala_2_13____1__Type_ZK__Name_testNewAndChangedTopicsInDualWrite__MetadataVersion_3_4_IV0__Security_PLAINTEXT/)
[Build / JDK 11 and Scala 2.13 / org.apache.kafka.connect.mirror.integration.IdentityReplicationIntegrationTest.testReplicateSourceDefault()](https://ci-builds.apache.org/job/Kafka/job/kafka-pr/job/PR-13705/11/testReport/junit/org.apache.kafka.connect.mirror.integration/IdentityReplicationIntegrationTest/Build___JDK_11_and_Scala_2_13___testReplicateSourceDefault__/)
[Build / JDK 11 and Scala 2.13 / kafka.zk.ZkMigrationIntegrationTest.[1] Type=ZK, Name=testNewAndChangedTopicsInDualWrite, MetadataVersion=3.4-IV0, Security=PLAINTEXT](https://ci-builds.apache.org/job/Kafka/job/kafka-pr/job/PR-13705/11/testReport/junit/kafka.zk/ZkMigrationIntegrationTest/Build___JDK_11_and_Scala_2_13____1__Type_ZK__Name_testNewAndChangedTopicsInDualWrite__MetadataVersion_3_4_IV0__Security_PLAINTEXT/)
[Build / JDK 11 and Scala 2.13 / org.apache.kafka.controller.QuorumControllerTest.testBalancePartitionLeaders()](https://ci-builds.apache.org/job/Kafka/job/kafka-pr/job/PR-13705/11/testReport/junit/org.apache.kafka.controller/QuorumControllerTest/Build___JDK_11_and_Scala_2_13___testBalancePartitionLeaders__/)
[Build / JDK 8 and Scala 2.12 / kafka.api.ConsumerBounceTest.testClose()](https://ci-builds.apache.org/job/Kafka/job/kafka-pr/job/PR-13705/11/testReport/junit/kafka.api/ConsumerBounceTest/Build___JDK_8_and_Scala_2_12___testClose__/)