Observability — SigNoz (OpenTelemetry)

Self-hosted SigNoz on Coolify collects traces from all four treeper apps via OTLP. Everything is env-gated: with no OTEL_EXPORTER_OTLP_ENDPOINT (or VITE_/--dart-define equivalent) the instrumentation is a complete no-op.

Topology

Service	Coolify domain	Port	Notes
SigNoz UI	https://signoz.itssatya.in	8080 → 443	dashboards, traces, alerts
Otel Collector (HTTP)	https://otelcollectorhttp.itssatya.in	4318 → 443	OTLP/HTTP ingest (/v1/traces)

Cloudflare-proxied serving must be on 443. Set the Coolify service domains without a port (https://signoz.itssatya.in, not :8080) — Coolify/Traefik routes 443 → the container port. A domain with an explicit non-standard port (:8080, :4318) makes Cloudflare’s proxy return 502/000 because it only speaks 443/80 to the origin. After changing a domain, restart the service — Traefik’s loadbalancer.server.port label doesn’t regenerate on its own.

How the apps export

• backend / workers (server-side): point at the collector over Coolify’s internal predefined network — no Cloudflare round-trip: OTEL_EXPORTER_OTLP_ENDPOINT=http://<otel-collector-container>:4318
• web / mobile (client-side): must use the public collector: https://otelcollectorhttp.itssatya.in (browser/mobile POST OTLP directly, hence the CORS requirement below).

All exporters use OTLP/HTTP (/v1/traces is appended automatically).

Collector config — CORS (required for browser + mobile)

Browsers (and the mobile app’s cross-origin POST) need CORS on the HTTP receiver. In the collector config (otel-collector-config.yaml, the file passed via --config), under receivers.otlp.protocols.http:

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318
        cors:
          allowed_origins:
            - "https://treeper.itssatya.in"
            - "https://*.itssatya.in"
            - "http://localhost:5173"   # local web dev (optional)
          allowed_headers:
            - "*"
          max_age: 7200

To apply in Coolify: edit the mounted collector config file → restart the otel-collector container (config is read at startup).

Verify

# UI loads:
curl -sI https://signoz.itssatya.in | head -1                 # 200

# Receiver healthy (GET is not a valid OTLP verb → 404/405, NOT 502):
curl -sI https://otelcollectorhttp.itssatya.in/v1/traces | head -1   # 405

# CORS preflight (browser/mobile gate):
curl -i -X OPTIONS https://otelcollectorhttp.itssatya.in/v1/traces \
  -H "Origin: https://treeper.itssatya.in" \
  -H "Access-Control-Request-Method: POST" \
  -H "Access-Control-Request-Headers: content-type"
# → 204 + access-control-allow-origin: https://treeper.itssatya.in

Per-app env

App	Variable	Where	Value
backend	OTEL_EXPORTER_OTLP_ENDPOINT	Coolify env	internal collector http://…:4318
workers	OTEL_EXPORTER_OTLP_ENDPOINT	Coolify env	internal collector http://…:4318
web	VITE_OTEL_EXPORTER_OTLP_ENDPOINT	Coolify build arg	https://otelcollectorhttp.itssatya.in
mobile	OTEL_EXPORTER_OTLP_ENDPOINT	--dart-define at build	https://otelcollectorhttp.itssatya.in

Optional everywhere: OTEL_SERVICE_NAME (defaults: treeper-backend, treeper-workers, treeper-web, treeper-mobile).

Code: backend apps/backend/src/tracing.ts, workers apps/workers/src/treeper_workers/telemetry.py (+ obs.py spans), web apps/web/src/telemetry.ts, mobile apps/mobile/lib/core/telemetry/telemetry.dart.