Update rincon_connector deps: hyper -> 0.12, hyper-tls -> 0.3, native-tls -> 0.2 (fixes openssl 0.9 dependency)

[jeffvandyke]

Openssl 0.9 is breaking on a growing number of Linux systems see this issue. hyper-tls 0.3 is the first to depend on native-tls 0.2, which is the first native-tls version to drop openssl 0.9. Hyper-tls, as far as I can tell, needs hyper 0.12 to work.

We currently use hyper 0.11, and hyper 0.12 is quite an upgrade with a few breaking changes (release notes).

An upgrade also breaks the hyper-timeout dependency, which as far as I can tell, needs hyper 0.11 to work (I've filed another issue here). An idea would be to drop hyper-timeout in favor of using tokio_core::reactor to timeout from outside hyper inside of impl Execute for JsonHttpConnection -> execute() inside rincon_connector/src/http/mod.rs, following advice on hyper's issue "Request timeouts". It also looks like Hyper is working on client timeouts at this issue (last update April 2019).

Another annoying change is that the typed headers (like ContentType::json(), most stuff from hyper::header) were removed, though they might be available in the headers crate, which is related to hyper and has good usage.

The biggest decision is what to do about timeouts, and I don't care for the idea of waiting for other projects to fix issues.

So basically, cargo test doesn't work on a fresh Rincon clone on my Manjaro Linux machine right now, and this is an explanation of the rabbit hole I went down to find out why. Bit of a mess, but there you go. High hopes!

[jeffvandyke]

As something to keep an eye on, Hyper is working on 0.13, but it's uncertain when they'll be finished:Hyper 0.13 milestone

[jeffvandyke]

So it looks like @hjr3 is getting ready for a new release on hyper-timeout to hyper 0.12 - pull request here, which would resolve the timeout question here and allow upgrading Rincon and keep the same dependency. I might try this out as a learning experiment. Would you be open to a pull request to Rincon to upgrade to hyper 0.12?