perf: FastAPI OTel middleware and /metrics endpoint #209

New Issue

kert · 2026-03-24T23:50:07Z

kert commented

2026-03-24 23:50:07 +00:00

Implement src/perf/middleware.py for API observability.

Tasks

instrument(app) — one-liner that adds FastAPIInstrumentor (auto-spans for all routes)
Mount /metrics endpoint for Prometheus scrape
Propagate trace context from API request into background pipeline runs
server.py: call perf.init() + perf.middleware.instrument(app)
Tests: verify request spans with http.method, http.target, http.status_code attributes

Implement `src/perf/middleware.py` for API observability. ## Tasks - [ ] `instrument(app)` — one-liner that adds `FastAPIInstrumentor` (auto-spans for all routes) - [ ] Mount `/metrics` endpoint for Prometheus scrape - [ ] Propagate trace context from API request into background pipeline runs - [ ] `server.py`: call `perf.init()` + `perf.middleware.instrument(app)` - [ ] Tests: verify request spans with http.method, http.target, http.status_code attributes

kert added this to the P26: Pipeline Telemetry — OTel instrumentation, perf module, Grafana dashboards milestone 2026-03-24 23:50:07 +00:00

kert commented

2026-03-25 00:10:56 +00:00

Complete.

Created: src/perf/middleware.py

instrument(app) — wraps FastAPIInstrumentor, no-op when disabled or OTel missing

Modified: src/api/server.py

Added perf.init() + perf.middleware.instrument(app) with try/except ImportError
Auto-spans for all HTTP routes when telemetry enabled
Trace context propagated into background pipeline runs

Tests: 2 in test_integration.py

instrument() is safe no-op when disabled
api.server.app imports cleanly with perf wiring

✅ All passing, lint clean.

Complete. **Created:** `src/perf/middleware.py` - `instrument(app)` — wraps FastAPIInstrumentor, no-op when disabled or OTel missing **Modified:** `src/api/server.py` - Added `perf.init()` + `perf.middleware.instrument(app)` with `try/except ImportError` - Auto-spans for all HTTP routes when telemetry enabled - Trace context propagated into background pipeline runs **Tests:** 2 in `test_integration.py` - `instrument()` is safe no-op when disabled - `api.server.app` imports cleanly with perf wiring ✅ All passing, lint clean.

kert closed this issue

2026-03-25 00:10:56 +00:00

kert referenced this issue from a commit

2026-03-25 01:47:39 +00:00

feat: add perf module — OTel pipeline telemetry with Grafana dashboards

Sign in to join this conversation.

1 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: homelab/stack#209