Add support for Express v5

[timfish]

Express v5 has been released and it's not supported: https://github.com/open-telemetry/opentelemetry-js-contrib/blob/80c2f1af6139e43522a944ab496fed68ef912fb2/plugins/node/opentelemetry-instrumentation-express/src/instrumentation.ts#L61-L62

I'm looking into the changes required so you can assign this issue to me!

[pichlermarc]

@timfish It's yours, thanks for looking into it :slightly_smiling_face:

[pichlermarc]

cc @JamieDanielson @pkanal (component owners)

[timfish]

I want to retain the v4 tests, duplicate them and test v5 too. To have both versions installed, I was going to use aliases but then realised this does not work because importing express5 does not get instrumented!

    "express": "4.19.2",
    "express5": "npm:[email protected]",

I can see for redis, there are two seperate instrumentations for v3 and v4 but it doesn't look this this will be required for express because so far it's looking like not much will need to be changed.

Any tips on what I should do to test both versions? I could add another package.json and node_modules inside the v5 test directory?

[hitsthings]

Hi just curious about the future of this. Movement on the PR looks stalled, but it seems like Express team is looking to emit events that would allow for a simpler implementation. Are you waiting for those events or shipping first as-is? Is there any blocker or is it just one of those "need to find the time" things?

Cheers!

[timfish]

Movement on the PR looks stalled, but it seems like Express team is looking to emit events that would allow for a simpler implementation. Are you waiting for those events or shipping first as-is? Is there any blocker or is it just one of those "need to find the time" things?

Yep, that's about it. The plan is to use Node diagnostics_channels to send events from the router package that can be consumed by Open Telemetry. There's an old open PR to do this but it's years old and wasn't specifically created with Otel in mind. I'm looking into getting a new PR working but I don't have any time scale yet.

[hitsthings]

Awesome, thanks for that update! Much appreciated!

[CreativeBrainInc]

Wondering any update on the new PR ?? We are using Express 5 and wanted to implement OpenTelemetry.