Support metrics-v3 api in `admin prometheus metrics`

[anjalshireesh]

Community Contribution License

All community contributions in this pull request are licensed to the project maintainers under the terms of the Apache 2 license. By creating this pull request I represent that I have the right to license the contributions to the project maintainers under the Apache 2 license.

Description

Add a flag --api-version with possible values of v2 and v3, with default being v2. So when this flag is not passed, the command will work exactly as it did before.

When using v3, there is a different set of metric types supported. It also supports a new flag:

bucket: the bucket for which the metrics are to be fetched. it is applicable only for the metric types that are available at bucket level, which currently are 'api' and 'replication'

Motivation and Context

Support newly introduced metrics-v3 api

How to test this PR?

• mc admin prometheus metrics ALIAS cluster|node|bucket|resource

  • should continue to work as before
  • should work in same way when --api-version v2 is passed
  • should fail with Flagbucketis not supported with v2 metrics. when --bucket is passed to the command

• mc admin prometheus metrics ALIAS api|system|debug|ilm|audit|logger|replication|notification|scanner

  • should fail with invalid metric type

• mc admin prometheus metrics ALIAS node|bucket|resource --api-version v3

  • should fail with invalid metric type

• mc admin prometheus metrics ALIAS api|system|debug|cluster|ilm|audit|logger|replication|notification|scanner --api-version v3

  • should work fine and return metrics by invoking the v3 api

• mc admin prometheus metrics ALIAS api|replication --api-version v3 --bucket BUCKET

  • should return corresponding metrics for the given bucket only

• mc admin prometheus metrics ALIAS --api-version v3

  • should return all the metrics

• mc admin prometheus metrics ALIAS --api-version v3 --bucket BUCKET

  • should fail with metric type must be passed with --bucket. valid values are 'api, replication'

• mc admin prometheus metrics ALIAS system|debug|cluster|ilm|audit|logger|notification|scanner --api-version v3 --bucket BUCKET

  • should fail with --bucket is applicable only for metric types 'api, replication'

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Optimization (provides speedup with no functional changes)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] Fixes a regression (If yes, please add commit-id or PR # here)
• [ ] Unit tests added/updated
• [ ] Internal documentation updated
• [x] Create a documentation update request here