Metrics

Metrics are numeric operational signals emitted by the App.

Generated Apps expose Prometheus-compatible metrics through github.com/goforj/metrics.

Endpoints

Standalone host mode prefers one shared metrics endpoint:

http://localhost:10000/metrics

Direct runtime commands may expose source-specific listeners:

http://localhost:10000/metrics  # HTTP
http://localhost:10001/metrics  # scheduler
http://localhost:10002/metrics  # workers

Named apps get deterministic local defaults so app runtimes do not fight for the same ports.

App	HTTP metrics	Scheduler metrics	Worker metrics
app	10000	10001	10002
first named app	10010	10011	10012
second named app	10020	10021	10022

When the HTTP runtime exposes /metrics, local scraping may use each app's HTTP port instead:

App	HTTP /metrics
app	3000
first named app	3001
second named app	3002

Override named app ports with app-prefixed env vars such as MARKETPLACE_API_HTTP_PORT, MARKETPLACE_METRICS_PORT, MARKETPLACE_SCHEDULER_METRICS_PORT, and MARKETPLACE_WORKER_METRICS_PORT.

When HTTP metrics are enabled, the App may also expose:

GET /metrics

Toggles

Framework metrics can be controlled per surface:

METRICS_HTTP_ENABLED=true
METRICS_CACHE_ENABLED=true
METRICS_STORAGE_ENABLED=true
METRICS_EVENTS_ENABLED=true
METRICS_MAIL_ENABLED=true
METRICS_QUEUE_ENABLED=true
METRICS_DATABASE_ENABLED=true
METRICS_AUTH_ENABLED=true
METRICS_SCHEDULER_ENABLED=true

Disabled instrumentation should be absent or inert enough to make overhead decisions honest.

The generated demo App also uses METRICS_MONITORING_ENABLED for its monitoring surface. See Environment Reference for port precedence and the complete toggle list.

Labels

Labels should be bounded and operator-facing.

Prefer route patterns, queue names, job names, schedule names, cache names, disk names, bus names, and driver names.

Framework metric families emit app directly. Many runtime-aware families also emit source, which is the logical runtime surface such as http, jobs, scheduler, cli, lighthouse, or app.

The local observability stack adds scrape-time metadata such as process, service, and environment:

app=marketplace
source=jobs
process=jobs
service=Example
environment=local

Use source for logical runtime attribution and process for scrape topology.

Avoid user IDs, emails, raw URLs, raw SQL, cache keys, filenames, request IDs, and arbitrary error strings.

Proving Path

GoForj metrics should prove themselves against standard Prometheus-compatible tooling before Lighthouse adapts them into UI views.

This keeps metric names, labels, and dashboards honest.

Common Mistakes

Common mistakes

• Do not add high-cardinality labels.
• Do not count internal scrape traffic as application traffic.
• Do not create a second metrics registry for normal App metrics.
• Do not use metrics as a replacement for logs or inspects.

Next Steps

• Metrics Library
• Environment Reference
• Inspects
• Lighthouse