DEBUG-3700 Inject telemetry into metrics client

[p-datadog]

What does this PR do?

Injects telemetry into metrics client instead of retrieving it from the components tree.

Motivation:

References to the components tree currently create the tree if it does not exist by default (allow_initialization option to components). This creation is problematic in the test suite (see #4619). Some components appear to rely on this automatic instantiation (profiling, possibly tracing), therefore removing it is non-trivial. In the meantime, metrics client can have telemetry injected into it to avoid the issue altogether (and remove what is effectively a global variable reference).

Change log entry
None

Additional Notes:

How to test the change?

Existing CI

[github-actions]

Thank you for updating Change log entry section 👏

^{Visited at: 2025-05-12 19:03:24 UTC}

[datadog-datadog-prod-us1]

Datadog Summary

✅ Dependencies

Test Optimization Report

Branch report: components-init-metrics
Commit report: c7359b6
Test service: dd-trace-rb

✅ 0 Failed, 21254 Passed, 1377 Skipped, 3m 46.84s Total Time

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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 97.61905% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.76%. Comparing base (df9dba8) to head (e85c6b5).
Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
lib/datadog/core/metrics/client.rb	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4641      +/-   ##
==========================================
- Coverage   97.77%   97.76%   -0.01%     
==========================================
  Files        1419     1422       +3     
  Lines       86624    86703      +79     
  Branches     4397     4403       +6     
==========================================
+ Hits        84697    84769      +72     
- Misses       1927     1934       +7     

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[pr-commenter]

Benchmarks

Benchmark execution time: 2025-05-15 15:35:48

Comparing candidate commit e85c6b5 in PR branch components-init-metrics with baseline commit df9dba8 in branch master.

Found 0 performance improvements and 2 performance regressions! Performance is the same for 29 metrics, 2 unstable metrics.

scenario:line instrumentation - targeted

• 🟥 throughput [-11197.199op/s; -10612.677op/s] or [-6.697%; -6.348%]

scenario:method instrumentation

• 🟥 throughput [-12488.587op/s; -11843.119op/s] or [-6.947%; -6.588%]

[datadog-datadog-prod-us1]

Datadog Report

Branch report: components-init-metrics
Commit report: e85c6b5
Test service: dd-trace-rb

✅ 0 Failed, 21046 Passed, 1373 Skipped, 3m 44.83s Total Time