Exclude system services (self-instrumentation) by default

[marevers]

Closes #1454

This replaces the existing attribute allow_self_instrumentation with a new attribute called system_exclude_services. If it is set (it is by default) the exclusion of Beyla, Alloy and OTel Collector executables is automatically added to the ExcludeServices configuration. It must be explicitly set to an empty value (or some other value than the default .*alloy.*|.*otelcol.*|.*beyla.*) to allow self-instrumentation either through the config file or an environment variable.

It also removes the need for the warning in the Helm chart as modifying the exclude_services configuration can no longer lead to users accidentally enabling self-instrumentation when they don't mean to.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 64.35%. Comparing base (b9eaba8) to head (3f949a1).
Report is 5 commits behind head on main.

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@@            Coverage Diff             @@
##             main    #1536      +/-   ##
==========================================
- Coverage   71.72%   64.35%   -7.37%     
==========================================
  Files         195      195              
  Lines       19471    19567      +96     
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- Hits        13965    12593    -1372     
- Misses       4830     6171    +1341     
- Partials      676      803     +127     

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k8s-integration-test	54.70% <100.00%> (-0.04%)	⬇️
oats-test	32.65% <100.00%> (+0.07%)	⬆️
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[marctc]

We have already a field discovery -> allow_self_instrumentation to enable Beyla instrument itself. Could we consolidate this field with your proposed changes?

[marevers]

We have already a field discovery -> allow_self_instrumentation to enable Beyla instrument itself. Could we consolidate this field with your proposed changes?

Good point! I will remove the new config property and instead integrate my changes into that existing property.

[mariomac]

Mostly LGTM!! I wonder if there is a way to do this same functionality exclusively in Helm.

[mariomac]

To make this less dependent to our context, and more expandable, could this be a string instead of a boolean? Then default it to .*alloy.*|.*otelcol.*|.*beyla.*, allowing users to unset it (or empty it), or directly changing it to other regexp.

[marevers]

Mostly LGTM!! I wonder if there is a way to do this same functionality exclusively in Helm.

I've tried exactly that in #1473 but it turned into a mess trying to prevent users from accidentally removing those default excludes if they supplied something else in exclude_services, so it works in a more robust way here.

To make this less dependent to our context, and more expandable, could this be a string instead of a boolean? Then default it to .*alloy.*|.*otelcol.*|.*beyla.*, allowing users to unset it (or empty it), or directly changing it to other regexp.

That sounds good. Seeing as this is probably a 2.0 feature, I would remove allow_self_instrumentation and instead just implement exclude_system_services as a string containing the regex, that should harmonize it a bit.

[grcevski]

LGTM! Thanks again @marevers!