matrix-public-archive/docs/tracing.md

Tracing

Tracing allows you to see the flow of a request through the system and where time is taken up in functions. This is useful for debugging and performance analysis.

Setup

1. Get the all-in-one Jaeger Docker container running (via https://www.jaegertracing.io/docs/1.35/getting-started/)

   docker run -d --name jaeger \
     -e COLLECTOR_ZIPKIN_HOST_PORT=:9411 \
     -e COLLECTOR_OTLP_ENABLED=true \
     -p 6831:6831/udp \
     -p 6832:6832/udp \
     -p 5778:5778 \
     -p 5775:5775/udp \
     -p 16686:16686 \
     -p 4317:4317 \
     -p 4318:4318 \
     -p 14250:14250 \
     -p 14268:14268 \
     -p 14269:14269 \
     -p 9411:9411 \
     jaegertracing/all-in-one:1.35
   

2. Add jaegerTracesEndpoint to your config.json:

   {
     // ...
     jaegerTracesEndpoint: 'http://localhost:14268/api/traces',
   }
   

Run the app with the OpenTelemetry tracing enabled

npm run start -- --tracing
# or
npm run start-dev -- --tracing

Manually:

node --require './server/tracing.js' server/server.js

Viewing traces in Jaeger

Once you have the all-in-one Jaeger Docker container running, just visit http://localhost:16686 to see a dashboard of the collected traces and dive in.

Traces are made up of many spans. Each span defines a traceId which it is associated with.