Fix circular dependency in Performance Counters on Mac

[jeremydvoss]

Description

Issue: langchain-ai/langchain-azure#234

On Mac, the I/O performance counter is not available. This was a known limitation, but the warning log it produced in _PerformanceCountersManager led to a circular dependency. As a log, it triggered the _PerformanceCountersLogRecordProcessor which in turn relied on _PerformanceCountersManager. This led to an infinite lock on the singleton.

To solve this, I moved the Metrics pipeline set up to before Logs and Tracing. This way, the Performance Counters are fully set up before the _PerformanceCountersLogRecordProcessor and _PerformanceCountersSpanProcessor are added. I also removed the log itself because it is not useful as a warning. If a customer is on a Mac or another OS that does not have process I/O, there is nothing for them to do. They will still be able to get all the other Performance Counters.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

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• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[Copilot]

Pull request overview

This PR fixes a circular dependency issue in Performance Counters on Mac and other platforms where process I/O counters are unavailable. When _PerformanceCountersManager logged a warning about unavailable I/O counters, it triggered the _PerformanceCountersLogRecordProcessor, which in turn tried to access the not-yet-initialized singleton, causing an infinite lock.

Changes:

• Reordered pipeline setup to initialize metrics (with Performance Counters) before tracing and logging
• Removed non-actionable warning log for unavailable I/O counters on Mac/Linux
• Added test coverage to verify metrics setup occurs before logging and tracing setup

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
azure/monitor/opentelemetry/_configure.py	Moved metrics pipeline setup before tracing and logging to ensure Performance Counters are initialized before processors
azure/monitor/opentelemetry/exporter/_performance_counters/_manager.py	Removed non-actionable warning log for unavailable Process I/O Rate counter
tests/test_configure.py	Added test assertions to verify metrics setup order precedes logging and tracing
CHANGELOG.md	Documented bug fix with placeholder PR number