The filament_used_grams field already contains the total filament for
the entire print job (all items combined). The code was incorrectly
multiplying this value by quantity, causing inflated filament totals.
Example: A print with 26 objects using 126g total was being calculated
as 126g * 26 = 3,276g instead of the correct 126g.
Fixes:
- backend/app/api/routes/archives.py: Archive stats endpoint
- backend/app/api/routes/metrics.py: Prometheus metrics endpoint
- frontend/src/components/FilamentTrends.tsx: Trends chart calculations
Closes#229
The filament statistics were under-reporting totals because the quantity
field was not being multiplied with filament_used_grams. When users
printed multiple items (quantity > 1), only the base filament amount
was counted instead of the total.
Closes#229
Expose printer telemetry at /api/v1/metrics in Prometheus text format for
integration with Grafana, Prometheus, and other monitoring systems.
Backend:
- Add metrics.py route with GET /api/v1/metrics endpoint
- Support optional bearer token authentication
- Export printer metrics: connection, state, temperatures, fans, WiFi
- Export print metrics: progress, remaining time, layer count
- Export statistics: prints by status, filament used, print time
- Export queue metrics: pending and active jobs
- Add prometheus_enabled and prometheus_token settings
Frontend:
- Add Prometheus Metrics card in Settings → Network tab
- Toggle to enable/disable metrics endpoint
- Optional bearer token field for authentication
- Display list of available metrics
Tests:
- Add test_metrics_api.py with 7 integration tests
- Test access control (disabled, enabled, token auth)
- Test metrics format and content validation
Neale Swinnerton