UNIX domain socket support

[jgillich]

I would to to access an UNIX socket with hyper. TcpStream and UnixStream are very similar, but I assume it would still require some heavy changes (or, looking at net::HttpStream, maybe not?). So before I waste any time on this, do you guys think it would make sense to have this in hyper?

[seanmonstar]

The desired goal is to utilize the HTTP protocol over a Unix stream instead of a TCP stream? It should mostly just need an implementation of net::NetworkStream/NetworkConnector. Not sure if the use of Url will cause any issues...

[reem]

It should be pretty simple, as @seanmonstar said all you will need to do is implement the appropriate traits and use listen_network.

[seanmonstar]

As for whether it makes sense in hyper, I don't know. How about other languages/httplibs? Do they include a Unix stream option?

Unless they do, my gut feeling is this could be a separate crate, so as to not add more maintenance required for hyper.

[jgillich]

It would need a Path in addition to Url, but there's still a totally normal Url where the host part gets ignored.

FYI, it would be useful for accessing the Docker remote API, where the Unix socket is the default and also the only standard way to limit access (they don't do authorization over HTTP as far as I know). I am not sure how many other programs do HTTP over Unix sockets. probably not a lot.

About libraries that support it, Node's built-in http library does and some libraries that use it also mention it explicitly (for example request).

I don't mind putting it in a separate crate, it surely is a uncommon feature. It will be a while before I start implementing this anyway, I think it can be decided when it is a bit more clear how the required changes would look like.

[jimmycuadra]

I am also interested in this for use with the fleet API. At least some Ruby HTTP clients support requests to UNIX sockets, e.g. Excon.

[softprops]

This may be of interest to you folks. I just published a new crate called hyperlocal which provides hyper interfaces for unix domain sockets. I realized that while working on a docker client which also supports unix domain sockets that I could support both tcp and domain socket interfaces using hyper's client interface. I'll be rolling hyperlocal into that soon to replace the hand crafted http unix domain socket interface I'm currently using.

[jimmycuadra]

That's awesome, softprops! Thank you.

[jgillich]

Very cool :) I guess this can be closed then.

[softprops]

I really want to emphasize how well designed hyper's internals were made. It made it very straight forward to extend it in this way. +100 @seanmonstar

[valpackett]

Would be nice if hyper itself could listen on unix sockets, without an additional crate.

It also should support listening on user-provided (already opened) sockets (for both tcp and unix), e.g. acquired via socket activation or file descriptor passing.

Actually I think socket activation should be handled in hyper itself as well… even though there's a brilliant pun opportunity for naming a crate that does it ;-)

[prepor]

It's an essential feature for http client library, most popular http client libraries support it. We also have already have support of unix sockets in tokio (https://github.com/tokio-rs/tokio-uds). Is there a chance that such feature will be accepted in case of PR?

[seanmonstar]

I wouldn't expect hyper to explicitly include a UNIX socket implementation. It's already possible to just use any external implementation by using a custom Connect in the Client. hyper's goal is provide HTTP, and be generic over whatever the transport is underneath.

Being built in to a client would make sense for a more batteries-included kind of library, and for this exact feature, see seanmonstar/reqwest#39

[softprops]

FYI, I'm planning on adapting to hypers interfaces for uds in https://github.com/softprops/hyperlocal as soon as there's a new release for hyper