Re: curl -v has become too verbose to follow for https requests

On Mon, 30 Jan 2023, Charles Zhang via curl-users wrote:

> I consider "curl -v" to be handy when doing network diagnostics: It will show 
> useful details about DNS resolving, TLS handshake, the HTTP request and 
> response headers that might contain interesting bits, all in the terminal. 
> However its output has become too spammy for https requests when server is 
> sending the bulky response.

I hear you and we should be cautious with what we add to that output. But we 
also need to use the verbose output as a means for users to see what happens 
and to some extent to be able to report problems better when things go wrong.

We should however keep trying to remove unncessary debug outputs, so I 
appreciate this email. I think we developers sometimes forget about this as we 
run our curl builds debug-enabled to a large extent and that makes us a little 
blind for this.

> The problem is more evident when downloading large files, that the scrollback 
> buffer of terminal will be quickly filled up by those "Supplemental data".

I believe we have recently addressed some of the extranous TLS outputs with 
#10299

> curl 7.87.0 behaves mostly the same except for the extra 
> "[CONN-0-0][CF-SSL]" prefix in messages related to the TLS library.

We are in the midst of a refactor of a lot of internals so we have felt a need 
to add more details to the output due to this. Including this output.

I expect us to be able to again cut down on this once we have confirmed things 
are looking good.

> * http2_recv: easy 0x556b6c011e30 (stream 1) win 33553255/33553255

That's because we mistakenly enable h2-debugging by default. See 
https://github.com/curl/curl/pull/10367

> Folding those unnecessary messages behind a new debug flag seems an obvious 
> way to make "-v" less chatty.

We actually put most of the new logging behind specific options only visible 
for debug-builds of curl and we should continue to do this for things that 
clearly are not intersting nor helpful to mortal users.

Somewhat explained here:

   https://github.com/curl/curl/tree/master/tests#log-verbosity

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