[FLINK-7697][connectors] Add metrics for ElasticSearchSink

[piygoyal]

What is the purpose of the change

This pull request add metrics to the Elasticsearch connectors, to make it easier to operate and monitor in a production environment.

Brief change log

The following metrics have been added:

• ItemRequest success count (counter)
• ItemRequest failure count (counter) grouped by error type.
• BulkRequest failure count (counter) grouped by error type.
• BulkRequest latency (gauge)

Note: Gauge doesn't feel like the right metric type for measuring bulkRequest latency, as it will only capture the last requestLatency before the gauge gets polled. Flink metric system currently lacks a timer type that can be used to capture event latencies in a richer way. I opened FLINK-12680 to track addition of a timer type.
Another metric-related thing we noticed during internal reviews is that the SimpleCounter is not thread safe, which makes it somewhat risky/expensive to use it in a multithreaded context. I opened FLINK-12681 to track making SimpleCounter thread-safe.

Verifying this change

This change is a trivial rework / code cleanup without any test coverage. Also manually verified the metrics by hooking with our internal time-series system.

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

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: no
• The S3 file system connector: no

Documentation

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

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Automated Checks

Last check on commit bdea9df (Thu Sep 23 18:02:36 UTC 2021)

Warnings:

• No documentation files were touched! Remember to keep the Flink docs up to date!
• This pull request references an unassigned Jira ticket. According to the code contribution guide, tickets need to be assigned before starting with the implementation work.

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Review Progress

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

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[piygoyal]

@flinkbot attention @tzulitai

[tankilo]

Will there be any new progess? Currently in 1.9.0, es connector is still a black box. I've tried to turn on logging of org.elasticsearch.client.RequestLogger. Hope there will be metrics such as time cost of bulk request.

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CI report:

• bdea9df Unknown: FAILURE

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[EsmeraldaYS]

影响了哪个版本

[einarjohnson]

are there any metrics available for the elasticsearch sink?

[MartijnVisser]

Connector has been moved to https://github.com/apache/flink-connector-elasticsearch