feat: add OpenTelemetry metrics support by ajbozarth · Pull Request #553 · generative-computing/mellea

ajbozarth · 2026-02-19T00:59:52Z

Misc PR

Type of PR

Bug Fix
New Feature
Documentation
Other

Description

Link to Issue: Closes Create the foundational metrics module using OpenTelemetry Metrics API with support for counters, histograms, and gauges #461

Implemented OpenTelemetry metrics support for Mellea:

Changes:

Refactored telemetry module: Moved tracing implementation from __init__.py to dedicated tracing.py module for better organization
Added metrics module: Implemented mellea/telemetry/metrics.py with full OpenTelemetry metrics support including:
- Counter, UpDownCounter, Histogram, and Gauge metric types
- Automatic metric provider initialization with OTLP export
- Context-aware metric recording with span correlation
- Comprehensive unit tests (418 lines) covering all metric types and edge cases

Testing:

Added test/telemetry/test_metrics.py with extensive coverage of metric creation, recording, and export
Updated existing telemetry tests to work with refactored module structure
All tests pass with proper isolation and cleanup

The implementation follows OpenTelemetry standards and integrates seamlessly with Mellea's existing tracing infrastructure.

Testing

Tests added to the respective file if code was changed
New code has 100% coverage if code as added
Ensure existing tests and github automation passes (a maintainer will kick off the github automation when the rest of the PR is populated)

Refactored telemetry module structure to follow Python best practices: - Moved tracing implementation from __init__.py to new tracing.py module - Updated __init__.py to only contain imports and exports - Updated backend_instrumentation.py to import from tracing module This improves code organization and maintainability by separating implementation from the package interface. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

Implemented comprehensive metrics support using OpenTelemetry Metrics API: - Created mellea/telemetry/metrics.py with: - Lazy MeterProvider initialization (similar to tracing pattern) - Environment-based configuration (MELLEA_METRICS_ENABLED, MELLEA_METRICS_CONSOLE) - Zero overhead when disabled (no-op instrument classes) - Named meter: mellea.metrics - Instrument creation helpers: - create_counter() - for monotonically increasing values - create_histogram() - for value distributions - create_up_down_counter() - for values that can increase/decrease - Updated mellea/telemetry/__init__.py to export metrics functions Environment Variables: - MELLEA_METRICS_ENABLED (default: false) - Enable metrics collection - MELLEA_METRICS_CONSOLE (default: false) - Print metrics to console Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

Fixes test failures after f449d9a moved tracing code to submodule. Test fixtures now reload mellea.telemetry.tracing to pick up env var changes. Also moved test file to test/telemetry/test_tracing.py to mirror source structure. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

Comprehensive test coverage for metrics configuration, lazy initialization, instrument creation, no-op behavior, and functional operations. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

After moving tracing code from __init__.py to tracing.py, the test fixture needs to import from mellea.telemetry.tracing instead of mellea.telemetry. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

github-actions · 2026-02-19T01:00:02Z

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mergify · 2026-02-19T01:00:27Z

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ajbozarth · 2026-02-19T01:05:21Z

Opening this with what I have at EOD for peer review, I want to spend more time re-reviewing this myself before final merge as it was primarily ai generated and I've only done one manual review pass so far

…validation Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

Replace hardcoded version strings with importlib.metadata.version() Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

ajbozarth · 2026-02-19T17:45:57Z

I've pushed a couple commits handling review feedback from a couple more ai assistants.

This is now ready for review, approval, and merge.

planetf1

Just one comment on verification of metrics. Otherwise LGTM

ajbozarth · 2026-02-25T23:35:56Z

I have a follow up PR for #462 almost ready once this is merged (I just need to finish updating the docs before opening it)

ajbozarth · 2026-02-25T23:37:24Z

I tagged a few people directly to try and get this reviewed and merged to unblock the followup PR before its ready tomorrow morning

psschwei

One possible issue (flagged by one AI but not others), but otherwise LGTM

Switched from lazy to eager initialization to match tracing module pattern and prevent potential threading issues. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

psschwei

LGTM

* refactor: move tracing implementation from __init__.py to tracing.py Refactored telemetry module structure to follow Python best practices: - Moved tracing implementation from __init__.py to new tracing.py module - Updated __init__.py to only contain imports and exports - Updated backend_instrumentation.py to import from tracing module This improves code organization and maintainability by separating implementation from the package interface. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com> * feat: implement OpenTelemetry metrics module Implemented comprehensive metrics support using OpenTelemetry Metrics API: - Created mellea/telemetry/metrics.py with: - Lazy MeterProvider initialization (similar to tracing pattern) - Environment-based configuration (MELLEA_METRICS_ENABLED, MELLEA_METRICS_CONSOLE) - Zero overhead when disabled (no-op instrument classes) - Named meter: mellea.metrics - Instrument creation helpers: - create_counter() - for monotonically increasing values - create_histogram() - for value distributions - create_up_down_counter() - for values that can increase/decrease - Updated mellea/telemetry/__init__.py to export metrics functions Environment Variables: - MELLEA_METRICS_ENABLED (default: false) - Enable metrics collection - MELLEA_METRICS_CONSOLE (default: false) - Print metrics to console Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com> * style: fix import sorting in telemetry __init__.py Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com> * fix: update test fixtures to reload tracing submodule Fixes test failures after f449d9a moved tracing code to submodule. Test fixtures now reload mellea.telemetry.tracing to pick up env var changes. Also moved test file to test/telemetry/test_tracing.py to mirror source structure. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com> * test: add unit tests for OpenTelemetry metrics module Comprehensive test coverage for metrics configuration, lazy initialization, instrument creation, no-op behavior, and functional operations. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com> * fix: update test to use tracing submodule after refactor After moving tracing code from __init__.py to tracing.py, the test fixture needs to import from mellea.telemetry.tracing instead of mellea.telemetry. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com> * refactor(telemetry): remove unused boundaries param and add exporter validation Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com> * refactor: use dynamic version for telemetry tracers/meters Replace hardcoded version strings with importlib.metadata.version() Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com> * fix: use eager initialization for metrics to avoid race condition Switched from lazy to eager initialization to match tracing module pattern and prevent potential threading issues. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com> --------- Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

ajbozarth added 6 commits February 18, 2026 17:38

style: fix import sorting in telemetry __init__.py

dc16897

Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

test: add unit tests for OpenTelemetry metrics module

9d47e33

Comprehensive test coverage for metrics configuration, lazy initialization, instrument creation, no-op behavior, and functional operations. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

fix: update test to use tracing submodule after refactor

01dfd15

After moving tracing code from __init__.py to tracing.py, the test fixture needs to import from mellea.telemetry.tracing instead of mellea.telemetry. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

ajbozarth self-assigned this Feb 19, 2026

ajbozarth requested a review from a team as a code owner February 19, 2026 00:59

ajbozarth added the area/telemetry OTel spans, metrics, tracing, semconv label Feb 19, 2026

ajbozarth added 2 commits February 19, 2026 11:26

refactor(telemetry): remove unused boundaries param and add exporter …

f4bba21

…validation Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

refactor: use dynamic version for telemetry tracers/meters

b442416

Replace hardcoded version strings with importlib.metadata.version() Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

Merge branch 'main' into feat/opentelemetry-metrics

bb472d2

planetf1 reviewed Feb 25, 2026

View reviewed changes

Comment thread test/telemetry/test_metrics.py

ajbozarth requested review from jakelorocco, planetf1 and psschwei February 25, 2026 23:36

psschwei reviewed Feb 26, 2026

View reviewed changes

Comment thread mellea/telemetry/metrics.py Outdated

psschwei reviewed Feb 26, 2026

View reviewed changes

ajbozarth added 2 commits February 26, 2026 11:01

fix: use eager initialization for metrics to avoid race condition

6f2e6bc

Switched from lazy to eager initialization to match tracing module pattern and prevent potential threading issues. Signed-off-by: Alex Bozarth <ajbozart@us.ibm.com>

Merge branch 'main' into feat/opentelemetry-metrics

0d04877

ajbozarth requested a review from psschwei February 26, 2026 17:04

psschwei approved these changes Feb 26, 2026

View reviewed changes

ajbozarth added this pull request to the merge queue Feb 26, 2026

github-merge-queue Bot removed this pull request from the merge queue due to failed status checks Feb 26, 2026

ajbozarth added this pull request to the merge queue Feb 26, 2026

Merged via the queue into generative-computing:main with commit 78c5aab Feb 26, 2026
4 checks passed

ajbozarth deleted the feat/opentelemetry-metrics branch February 26, 2026 21:01

psschwei mentioned this pull request Mar 20, 2026

chore: use github tooling to build release notes #710

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feat: add OpenTelemetry metrics support#553

feat: add OpenTelemetry metrics support#553
ajbozarth merged 11 commits into
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ajbozarth commented Feb 19, 2026 •

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Misc PR

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ajbozarth commented Feb 19, 2026 •

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