Node.js 18 fetch not working with http instrumentations

[djMax]

I don't see opentelemetry headers of any sort on outbound http requests from Node 18 using the fetch api. Is this as intended? Or somehow configured separately from the normal http instrumentation?

[Flarna]

the Http instrumentation applies only to the node http module not the http protocol in general.
fetch, http2 (and also undici) are not using http module therefore no spans are created.

To monitor these modules someone has to write an instrumentation.

[vmarchaud]

As flarna pointed out the fetch implementation comes from undici which is not handled by the http instrumentation, however there is a instrumentation available here for it: https://github.com/gadget-inc/opentelemetry-instrumentations/tree/main/packages/opentelemetry-instrumentation-undici

[djMax]

The way that one works is unlikely to work for the "builtin" undici used by node. But I adapted the one you referenced and another one into something that seems to work: https://github.com/gas-buddy/service/blob/main/src/telemetry/fetchInstrumentation.ts#L44

I'm not sure how to make that more broadly useful, but at least it's out there.

[david-luna]

Hello @djMax

node's fetch global API instrumetation was discussed in the JavaScript SIG this week and there was an agreement on having this instrumentation as part of the auto-instrumentations for node. The group was wondering if this implementation could be donated to https://github.com/open-telemetry/opentelemetry-js repo so we're not starting from scratch.

Do you know if there is any impediment for the aforementioned donation? Would you like to participate on it and give your feedback?

[djMax]

No impediments, and happy to assist or otherwise be helpful.

[coderhammer]

It works great, thank you for the hard work!