Datadog plugin should emit service name and status code as tags

[judithpatudith]

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Summary

Issue reported by @irabinovitch

We noticed that it is emitting metrics in the format: kong..request.status.

We generally would encourage service-name and status code to be tags rather than part of the metric name as it significantly improves the experience as one graphs/queries/alerts on the metric. We've had a few customers reach out with similar feedback, so I wanted to circle back and see if it might be possible to make the change in an upcoming Kong release.

Steps To Reproduce

Additional Details & Logs

• Kong version ($ kong version)
• Kong debug-level startup logs ($ kong start --vv)
• Kong error logs (<KONG_PREFIX>/logs/error.log)
• Kong configuration (the output of a GET request to Kong's Admin port - see
  https://docs.konghq.com/latest/admin-api/#retrieve-node-information)
• Operating system

[irabinovitch]

Thanks @judithpatudith. It looks like some of the variables might have gotten mangled by markdown.

The metrics we're seeing are kong.<service-name>.request.status.<status-code>. Ideally it would be something like kong.request.status tagged by service name and status code.

[zhouzhuojie]

Hey Kong team, just to confirm, is this issue fixed in https://github.com/Kong/kong/pull/5154/files?