header: return err from reader.Peek()

[igorwwwwwwwwwwwwwwwwwwww]

The current behaviour of Read is to discard the underlying error and return ErrNoProxyProtocol. That makes it tricky to debug what is wrong.

In my case, I was trying to nest tls.NewListener inside a proxyproto.Listener but got the ordering wrong, the underlying error was:

tls: first record does not look like a TLS handshake

This patch surfaces that error to the caller.

Note: It may be a good idea to do the same thing with the other .Peek() calls too.

[pires]

Hey @igorwwwwwwwwwwwwwwwwwwww! Thanks for the report and patch. Could you add a test that mimics your scenario so we see the TLS error actually bubbling up? And since we're at it, could you also please change all other Peek() calls to return an error?

[coveralls]

Coverage increased (+0.1%) to 91.176% when pulling fb3158b on igorwwwwwwwwwwwwwwwwwwww:patch-1 into 62dfc14 on pires:master.

[igorwwwwwwwwwwwwwwwwwwww]

@pires I've added a test with a reader that returns a custom error.

I also added some logic to handle EOF differently. Some tests are expecting EOF to return ErrNoProxyProtocol, and that seems reasonable.

The error handling got a bit gnarly, so if you have suggestions for how to refactor this, I'm happy to do so.

[pires]

Your code seems to be easier to read that what I have so no worries there, thanks!

[pires]

Thank you very much for your contribution!

[pires]

👏 https://github.com/pires/go-proxyproto/releases/tag/0.1.2