[express plugin] automatic metrics instrumentation

[naseemkullah]

Describe the solution you'd like

We can draw inspiration from @yuriatgoogle's https://dev.to/yuriatgoogle/custom-metrics-in-node-js-with-opentelemetry-and-prometheus-3dbd to expose the "golden signals"

[OlivierAlbertini]

Having metrics inside our plugins is definitely in the roadmap.
We are working on the express plugin (tracing part only), you can review it for helping @vmarchaud. For the metrics part, we need to wait a bit until the sdk is ready.

[naseemkullah]

Thanks @OlivierAlbertini , if I understand correctly, the express plugin being worked on will eventually encompass both tracing and metrics data within it, that's to say there will not be a separate tracing express plugin and a separate express metrics plugin?

[OlivierAlbertini]

Thanks @OlivierAlbertini , if I understand correctly, the express plugin being worked on will eventually encompass both tracing and metrics data within it, that's to say there will not be a separate tracing express plugin and a separate express metrics plugin?

yes, one plugin for both.

[naseemkullah]

OK so this issue depends on open-telemetry/opentelemetry-js#666 and open-telemetry/opentelemetry-js#402

[vmarchaud]

Moving inside the contrib repo since the express plugin is now there

[mbecca]

Hello, is there any progress?

[legendecas]

The metrics spec, JavaScript API, and SDK are under active development. I'd believe we need to wait for a (generally) stable metrics API to start the work on third-party instrumentation. (The work is being tracked at open-telemetry/opentelemetry-js#2480 and open-telemetry/opentelemetry-js#2574)

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[anikdas]

@legendecas as both the issues linked are now closed. Can we expect any movement on the metrics inside the express plugin?

[legendecas]

@anikdas if you are using the http instrumentation, the instrumentation should start reporting HTTP metrics for you.

See more at https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-http/src/http.ts#L78.

[owlas]

Hey @legendecas I've tried running metrics locally with:

OTEL_METRICS_EXPORTER=console

and I don't see anything showing in the console. I also don't see anything received by my collector in production.

On the other hand traces are working fine for me from the same @opentelemetry/instrumentation-http package. Is there a flag that I could have missed to ensure those histogram metrics are being captured?

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Edit: just discovered this issue, is it actually not possible to configure the metrics entirely via the command line?
open-telemetry/opentelemetry-js#3193

[pichlermarc]

Hey @legendecas I've tried running metrics locally with:

OTEL_METRICS_EXPORTER=console

and I don't see anything showing in the console. I also don't see anything received by my collector in production.

On the other hand traces are working fine for me from the same @opentelemetry/instrumentation-http package. Is there a flag that I could have missed to ensure those histogram metrics are being captured?

Edit: just discovered this issue, is it actually not possible to configure the metrics entirely via the command line? open-telemetry/opentelemetry-js#3193

Yes, automatic setup of metrics exporters via env vars this is not implemented yet. open-telemetry/opentelemetry-js#3193 tracks implementation of that.

[pichlermarc]

Closing this issue as it was the request to emit metrics for express, which the @opentelemetry/instrumentation-http package now does.