Support metrics-v3 api in admin prometheus generate

[anjalshireesh]

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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 generate 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 Flag bucket is not supported with v2 metrics. when --bucket is passed to the command

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

  • should fail with invalid metric type

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

  • should fail with invalid metric type

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

  • should work fine and put the v3 api endpoint in the generated scrape config

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

  • should put the bucket specific v3 api endpoint in the generated scrape config

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

  • should put the base path (/minio/metrics/v3) in the generated scrape config

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

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

• mc admin prometheus generate 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)
• 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
• Create a documentation update request here

[shtripat]

LGTM. Verified.