Support file inclusion in the config in the same way that community Collector does

[tigrannajaryan]

The Otel Collector allows including files from the config, e.g.:

receivers:
  otlp:
    protocols:
      grpc:

exporters: ${file:receivers.yaml}

service:
  extensions: [ ]
  pipelines:
    traces:
      receivers:  [ otlp ]
      processors: [  ]
      exporters:  [ otlp ]

This does not work with Splunk distro of the Collector.

[rmfitzpatrick]

This is currently available with the include config source: https://github.com/signalfx/splunk-otel-collector/tree/main/internal/configsource/includeconfigsource

config_sources:
  include:

receivers:
  otlp:
    protocols:
      grpc:

exporters: ${include:exporters.yaml}

However, we should support this by reconciling the different config managers so that unknown* schemes are forwarded to the registered file provider:

splunk-otel-collector/cmd/otelcol/main.go

Line 97 in f9bb21e

fileProvider.Scheme(): configprovider.NewConfigSourceConfigMapProvider(

[tigrannajaryan]

It is good that we have an equivalent feature. I think it is also important to avoid diverging / to converge on both source code and how it is used in the config (e.g. file vs include).

[rmfitzpatrick]

This should be resolved by #2893

[rmfitzpatrick]

Resolved by 70b75c7

[tigrannajaryan]

@rmfitzpatrick nice!