reqwest download backend is lacking socks support

[Sherlock-Holo]

Problem

Steps

1. run https_proxy=socks5://127.0.0.1:1990 rustup update and it doesn't use proxy because I watch iftop -B and nothing connect to my proxy server
2. use proxychians and see iftop it connects to my proxy server

[kinnison]

@inejge any ideas?

[inejge]

Support for SOCKS proxies in reqwest is behind the socks feature, which (AFAICS) isn't on by default, nor is it enabled in download's Cargo.toml; git blame points to af3ba46. My testing of env_proxy shows that it passes socks5://... through.

[kinnison]

Okay, sounds like we need to turn that on again :D Thanks.

[gaveen]

@kinnison I'd like to work on this since it's marked both 'easy' and 'mentor'. How can I get help on starting with it?

[kinnison]

@gaveen Firstly I suggest that you get a local socks proxy working so that you can confirm if requests are passing through it. Set up the https_proxy variable in the manner suggested in the issue description; and then confirm that RUSTUP_USE_CURL=1 rustup check uses the proxy but that rustup check does not. After that you'll need to fork and clone rustup; and look at what it'll take to turn on the socks support in reqwest. Likely this will involve changing the download/Cargo.toml file to enable the requisite feature.

You can come onto the rust-lang discord and find me in #wg-rustup if you want more discussion, or else respond here.