[FLINK-13764][task, metrics] Pass the counter of numRecordsIn into the constructor of StreamInputProcessor

[zhijiangW]

What is the purpose of the change

Currently the counter of numRecordsIn is setup while processing input in processor. In order to integrate the processing logic based on StreamTaskInput#emitNext(Output) later, we need to pass the counter into output functions then. So there are three reasons to do this:

• It is the precondition of following integration work.
• We could make the counter as final fields in StreamInputProcessor and StreamTwoInputSelectableProcessor.
• We could reuse the counter setup logic for all the input processors.

There should be no side effects if we make the counter setup a bit earlier than the previous way.

Brief change log

• Introduce the method of setup numRecordsIn counter in StreamTask
• Pass the counter into the constructors of StreamOne/TwoInputProcessors
• Remove the logic of initializing counter in StreamOne/TwoInputProcessors

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[flinkbot]

Thanks a lot for your contribution to the Apache Flink project. I'm the @flinkbot. I help the community
to review your pull request. We will use this comment to track the progress of the review.

Automated Checks

Last check on commit 8effe87 (Tue Aug 27 09:13:45 UTC 2019)

Warnings:

• No documentation files were touched! Remember to keep the Flink docs up to date!

_{Mention the bot in a comment to re-run the automated checks.}

Review Progress

• ❓ 1. The [description] looks good.
• ❓ 2. There is [consensus] that the contribution should go into to Flink.
• ❓ 3. Needs [attention] from.
• ❓ 4. The change fits into the overall [architecture].
• ❓ 5. Overall code [quality] is good.

Please see the Pull Request Review Guide for a full explanation of the review process.

The Bot is tracking the review progress through labels. Labels are applied according to the order of the review items. For consensus, approval by a Flink committer of PMC member is required

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot approve description to approve one or more aspects (aspects: description, consensus, architecture and quality)
• @flinkbot approve all to approve all aspects
• @flinkbot approve-until architecture to approve everything until architecture
• @flinkbot attention @username1 [@username2 ..] to require somebody's attention
• @flinkbot disapprove architecture to remove an approval you gave earlier

[flinkbot]

CI report:

• df58cd5 : FAILURE Build
• 870e919 : FAILURE Build
• 8effe87 : SUCCESS Build

[zhijiangW]

@flinkbot run travis

[pnowojski]

LGTM

+1 for the commits split :)

I think the test failure is unrelated (https://issues.apache.org/jira/browse/FLINK-13772), so you can merge this as you wish (or try to rebase and re-run the travis to be sure). Also you can ignore my nitty nit comment if you choose so.

[zhijiangW]

Thanks for the review @pnowojski ! I would rebase to merge after travis green. :)

[zhijiangW]

@flinkbot run travis