Sentry + Opentelemetry exports at the same time

[nathanscully]

I am in the process of migration Sentry 7 to 8. We already have an existing Open telemetry integration that is pushing traces and metrics to a otel collector, which we are consuming in grafana.
I have managed to migrate this to using the default sentry.init(..) function and can see traces appearing in my sentry console. However I expected having a locally running collector to also receive data. I'd still like to push the otel data to the collector as well as directly to Sentry. It wasn't clear from the docs (that I could find) how to have multiple transports to achieve this?

Any advice?

[AbhiPrasad]

@nathanscully please see: https://docs.sentry.io/platforms/javascript/guides/node/tracing/instrumentation/opentelemetry/#using-a-custom-opentelemetry-setup

[mydea]

FYI we have shipped new docs for this which should make this clearer, hopefully: https://docs.sentry.io/platforms/javascript/guides/node/opentelemetry/custom-setup/ or https://docs.sentry.io/platforms/javascript/guides/node/opentelemetry/using-opentelemetry-apis/#modifying-the-default-opentelemetry-tracerprovider if you only want to send the trace data to a different backend in addition to Sentry.

[sbriceland]

@AbhiPrasad and @mydea - The documentation does not help with the problem mentioned. SentrySampler "rules them all". When span processors are added they still adhere to the behavior of the sampler.

[mydea]

What do you want to achieve? Do you want to send spans to sentry and other places? Or only to other places?

You can use a custom sampler as described here: https://docs.sentry.io/platforms/javascript/guides/node/opentelemetry/custom-setup/#using-a-custom-sampler
But yes, sampling decisions will apply to sending stuff both to Sentry and to other span processors, but this is the expected behavior. I think this is a general OTEL thing that the sampler applies to all span processors?

[dvictory]

@mydea We use OTEL for instrumentation of our apps. We don't want to use sentry traces at all ( we use another solution for this). There is a section about this - https://docs.sentry.io/platforms/javascript/guides/node/opentelemetry/custom-setup/#using-sentry-for-error-monitoring-only, but it still says to add trace things to the otel setup, ie SentrySampler, SentryContextManager and SentryPropagator. But when I do this, all of my traces go away. Can I just leave Sentry config as is for errors, with enableTracing: false, skipOpenTelemetrySetup: true and not touch my existing otel.NodeSDK configuration? We I do this i get my traces back, but I am not sure if this will "break" the Sentry error handling and reporting?

Thanks

[mydea]

On which version of the Sentry SDK are you? In the latest version, stuff should work, in theory at least.
The SentryContextManager is def. needed, without it you cannot get request isolation which will break a lot of core Sentry functionality.

The sampler and propagator you may skip, but then you will not get proper trace propagation between sentry services. If you do not care about this, stuff should still work, mostly.

We have tests covering this scenario here: https://github.com/getsentry/sentry-javascript/blob/develop/dev-packages/e2e-tests/test-applications/node-otel-without-tracing/src/instrument.ts
Note there is a big difference between enableTracing: false and not configuring this at all - this is a bit unfortunate and will change in v9, but for now, you need to actually omit both enableTracing and tracesSampleRate completely from your config to get your desired outcome. Possibly this is the problem you are facing there.