Monitoring for EnvHttpProxyAgent

[SuperOleg39]

This would solve...

Hello!

When integrating HTTP proxy for http.request, we often encountered debugging difficulties, the main one being how to understand which requests are going through a proxy?

Before undici, we added logs and metrics in monkeypatched https.Agent.prototype.createConnection method, example.

With EnvHttpProxyAgent, I can't find an obvious mechanism to monitor the operation of the underhood ProxyAgent and its connect method.

The implementation should look like...

So the question is how to intercept proxied requests, and possible solutions that I can suggest:

• additional meta information about proxy in client.beforeConnect / client.connect / 'request:create' channels payload
• new diagnostic channel for proxy connection
• additional meta information about proxy maybe in DispatchOptions, which will allow this information to be collected in a custom interceptor

If you already have a solution, I would be very grateful for the recipe!

[SuperOleg39]

I see indirect signs of proxying, for example:

• in undici:request:create Request - method CONNECT and proxy-connection header
• in undici:client:connected connectParams - i can see proxy server host and port

But how reliable is it?

[mcollina]

Thanks for reporting! Would you like to send a Pull Request to address this issue? Remember to add unit tests.

[SuperOleg39]

Thanks for reporting! Would you like to send a Pull Request to address this issue? Remember to add unit tests.

Of course, will be glad to implement.

What solution do you think is better, reuse existing diagnostic channels?