feat(monitoring): add Prometheus and Grafana to observability stack

[tomkabel]

Summary

Adds Prometheus as the metrics collection server and Grafana as the visualization layer to the existing monitoring compose, complementing the existing NetData agents.

Changes

Prometheus (docker-compose.monitoring.yml)

• Service: prometheus (v2.50.0)
• Persistent volume: prometheus-data
• Config: infra/prometheus/prometheus.yml (mounted read-only)
• Ports: 127.0.0.1:9090 (loopback-only)
• Health check with /-/healthy endpoint

Grafana (docker-compose.monitoring.yml)

• Service: grafana (v10.3.1)
• Persistent volume: grafana-data
• Provisioning datasources: infra/grafana/datasource.yml (auto-configured Prometheus)
• Provisioning dashboards: infra/grafana/dashboard-provider.yml
• Ports: 127.0.0.1:3000 (loopback-only)
• Default admin credentials: admin/admin (change via env vars)
• Health check with /api/health endpoint

Infrastructure Config

File	Purpose
infra/prometheus/prometheus.yml	Scrape targets for Prometheus itself and API service
infra/grafana/datasource.yml	Prometheus HTTP API endpoint provisioning
infra/grafana/dashboard-provider.yml	File-based dashboard directory provisioning

Usage

# Start with monitoring stack
docker-compose -f docker-compose.yml -f docker-compose.monitoring.yml up -d

# Access Prometheus (local only)
curl http://127.0.0.1:9090

# Access Grafana (local only, default creds admin/admin)
curl http://127.0.0.1:3000

Motivation

NetData provides real-time system metrics but lacks long-term storage and alerting. Prometheus + Grafana provides:

• Long-term metric retention
• Custom dashboarding
• Alerting rules (future)
• Service-level metrics correlation

Testing

• docker-compose -f docker-compose.monitoring.yml config validates successfully
• All services have health checks configured
• Prometheus config file is mounted correctly

Labels

monitoring

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

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Run ID: a2dbbb63-591e-4e53-b304-03d0ae1a2f30

📥 Commits

Reviewing files that changed from the base of the PR and between 10495dc and 3e74985.

📒 Files selected for processing (8)

• docker-compose.monitoring.yml
• docker-compose.test.yml
• pyproject.toml
• tests/conftest.py
• tests/test_worker/test_graceful_shutdown.py
• tests/test_worker/test_main.py
• worker/main.py
• worker/zombie_sweeper.py

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• Create PR with unit tests
• Commit unit tests in branch feat/prometheus-grafana-monitoring

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[codecov]

Codecov Report

❌ Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
app/api/routes/auth.py	0.00%	2 Missing ⚠️

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[tomkabel]

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