What to use for "provider" in fastifyOtelInstrumentation.setTracerProvider(provider) ?

[PrimeDominus]

Prerequisites

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Issue

Maybe it's sleep deprivation, but I've looked through various docs and I'm admittedly stumped. In the README.md example it states:

// ... in your OTEL setup
const FastifyOtelInstrumentation = require('@fastify/otel');

// If serverName is not provided, it will fallback to OTEL_SERVICE_NAME
// as per https://opentelemetry.io/docs/languages/sdk-configuration/general/.
const fastifyOtelInstrumentation = new FastifyOtelInstrumentation({ servername: '<yourCustomApplicationName>' }); 
fastifyOtelInstrumentation.setTracerProvider(provider)

What should the value for the provider parameter (last line above) be if I'm using @fastify/otel with @opentelemetry/auto-instrumentations-node?

[PrimeDominus]

For extra clarification, when starting a new project with Express I would normally just run auto-instrumentation using the following env var and not use a custom instrumentation.ts.

NODE_OPTIONS="--require @opentelemetry/auto-instrumentations-node/register"

Do I now need to set up the exporter and provider in the "OTEL setup" file with something like the following?

const exporter = new CollectorTraceExporter();
const provider = new NodeTracerProvider({
  resource: new Resource({
    [SEMRESATTRS_SERVICE_NAME]: 'basic-service',
  }),
  spanProcessors: [
    new SimpleSpanProcessor(exporter),
  ],
});
provider.register();

[metcoder95]

You can use the following testing file as reference:

otel/test/index.test.js

Line 29 in d75214d

const httpInstrumentation = new HttpInstrumentation()

Currently @opentelemetry/auto-instrumentation-node does not contains Fastify instrumentation.

Do I now need to set up the exporter and provider in the "OTEL setup" file with something like the following?

Yes

[PrimeDominus]

I see. I'll give it a try with other instrumentations as well e.g. @opentelemetry/instrumentation-nestjs-core

Would we need to also instrument @opentelemetry/instrumentation-pino as well, or does @fastify/otel handle that for us since pino is built into fastify?

[metcoder95]

Would we need to also instrument @opentelemetry/instrumentation-pino as well, or does @fastify/otel handle that for us since pino is built into fastify?

Yes, it will require you to manually instrument it @fastify/otel only instruments Fastify app, not its transitive dependencies