[confmap] Move confmap.unifyEnvVarExpansion to beta

[TylerHelmuth]

Description

Moves confmap.unifyEnvVarExpansion to beta. This means the collector will, by default, use the env var provider to expand ${FOO} synatx and will error if the expandconverter is used to expand $FOO syntax.

Link to tracking issue

Related to #10161
Related to #8215
Related to #7111

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.41%. Comparing base (227fb82) to head (36c0746).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10435   +/-   ##
=======================================
  Coverage   92.40%   92.41%           
=======================================
  Files         393      393           
  Lines       18584    18584           
=======================================
+ Hits        17173    17174    +1     
  Misses       1056     1056           
+ Partials      355      354    -1     

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[TylerHelmuth]

We'll want to make a big deal in this release notes/changelog about this breaking change.

[mx-psi]

Agreed about the changelog. I would alsp like to check our docs and examples to remove any references to the $ENV syntax. It would also help to have a very clear error message with instructions if you run into this issue

[mx-psi]

I searched on several repositories using rg '\$[A-Z]' -tyaml --glob='!.github/':

• opentelemetry-collector: No relevant hits
• opentelemetry-collector-contrib: No relevant hits (Two unrelated files on exporter/splunkhecexporter/ )
• opentelemetry.io: No relevant hits

[TylerHelmuth]

It would also help to have a very clear error message with instructions if you run into this issue

Updated the error message to resemble the warning log, but with details about the feature gate.

[TylerHelmuth]

I confirmed that opentelemetry-helm-charts and opentelemetry-operator have no relevant hits

[mx-psi]

LGTM. This is likely to impact some users, so I would like to have more reviews from other approvers before merging

[mx-psi]

cc @open-telemetry/collector-approvers I would like more approvals here before merging

[azunna1]

This change is breaking my prometheus receiver config where i have relabelling like

relabel_configs:
                - source_labels: [job]
                  separator: ;
                  regex: (.*)
                  target_label: __tmp_prometheus_job_name
                  replacement: $$1
                  action: replace

How can we now put config variables without otel treating it like an environment variable?

[TylerHelmuth]

@azunna1 I am unable to reproduce your issue, can you open an issue with more details.