[AWS] Add API Gateway metrics data stream

[lucian-ioan]

What does this PR do?

Adds API Gateway metrics datastream which covers HTTP, REST and Websocket APIs.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.

Author checklist

• Add unit metric types
• Add docs

Related issues

Concerns #6058
Closes #6270

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• Start Time: 2023-06-05T14:21:24.786+0000

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[shmsr]

Left some comments.

[lucian-ioan]

@shmsr I was also confused by this for the longest time, not sure why AWS chose this naming scheme.

Under https://docs.aws.amazon.com/apigateway/latest/developerguide/welcome.html, there are three "Working with..." for the supported APIs (HTTP, REST, WebSockets), each with variations in metrics/dimensions under Monitor/Metrics tab (ex: 4XXError for REST vs 4xx for HTTP).

There are also some mentions of 4XXError metrics:
https://github.com/aws/aws-cdk/blob/b885ece7285ebe8219dbe4d62ae80554bd657632/packages/aws-cdk-lib/aws-apigateway/test/method.test.ts#L947

Snippet of event I got in elasticsearch from REST:

          "aws": {
            "apigateway": {
              "metrics": {
                "4XXError": {
                  "sum": 0
                },
                "Count": {
                  "sum": 6
                },
                "5XXError": {
                  "sum": 0
                },
                "IntegrationLatency": {
                  "avg": 2.6
                },
                "Latency": {
                  "avg": 4.5
                }
              }
            },
            "cloudwatch": {
              "namespace": "AWS/ApiGateway"
            },
            "dimensions": {
              "ApiName": "PetStore",
              "Stage": "prod"
            }
          }

[shmsr]

Oh, okay. Thanks for sharing!

[shmsr]

Looks good to me.

But as I'm still not much experienced with integrations as of now, I'd like to request you get another pair of eyes to review this PR. I might have missed something.

[gpop63]

LGTM, I'll take a look at the documentation.

[zmoog]

Please considers adding the latency doc from the other PR.

LGTM.

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Package aws - 1.39.0 containing this change is available at https://epr.elastic.co/search?package=aws