skinkade / gleam_opentelemetry_poc

Gleam OpenTelemetry Proof-of-Concept

Gleam OpenTelemetry Proof-of-Concept Application

This PoC provides Erlang FFI for opentelemetry-erlang for a wisp backend and some JS FFI for OpenTelemetry as well for its lustre frontend.

After following the setup below, you should be able to browse to http://localhost:5173 in order to click a button - which will result in an HTTP GET that returns 500. Browsing to Jaeger at http://localhost:16686, you should be able see nested spans from frontend to backend.

Known Quirks

You will see this error starting up the backend:

OTLP exporter failed to initialize with exception error:{badmatch,
                                                         {error,
                                                          inets_not_started}}

glotel/tracing.init() takes care of this by forcing OTP applications to re-load and re-start in the right order.

Running Jaeger to Collect / View Metrics for Testing

docker run --rm --name jaeger \
  -e COLLECTOR_ZIPKIN_HOST_PORT=:9411 \
  -e COLLECTOR_OTLP_HTTP_CORS_ALLOWED_HEADERS="*" \
  -e COLLECTOR_OTLP_HTTP_CORS_ALLOWED_ORIGINS="http://localhost:5173" \
  -p 6831:6831/udp \
  -p 6832:6832/udp \
  -p 5778:5778 \
  -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:1.56

Running the Backend

cd backend
export OTEL_SERVICE_NAME="gleam_otel_poc_backend"
gleam run

Running the Frontend

cd frontend
npm i
export VITE_OTEL_SERVICE_NAME="gleam_otel_poc_frontend"
npm run dev