hyperlocal

Hyper client and server bindings for Unix domain sockets

Hyper is a rock solid Rust HTTP client and server toolkit. Unix domain sockets provide a mechanism for host-local interprocess communication. hyperlocal builds on and complements Hyper's interfaces for building Unix domain socket HTTP clients and servers.

This is useful for exposing simple HTTP interfaces for your Unix daemons in cases where you want to limit access to the current host, in which case, opening and exposing tcp ports is not needed. Examples of Unix daemons that provide this kind of host local interface include Docker, a process container manager.

Installation

Add the following to your Cargo.toml file

[dependencies]
hyperlocal = "0.8"

Usage

Servers

A typical server can be built with hyperlocal::server::UnixServerExt.

use std::{error::Error, fs, path::Path};
use hyper::{
    service::{make_service_fn, service_fn},
    Body, Response, Server,
};
use hyperlocal::UnixServerExt;

const PHRASE: &str = "It's a Unix system. I know this.";

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
    let path = Path::new("/tmp/hyperlocal.sock");

    if path.exists() {
        fs::remove_file(path)?;
    }

    let make_service = make_service_fn(|_| async {
        Ok::<_, hyper::Error>(service_fn(|_req| async {
            Ok::<_, hyper::Error>(Response::new(Body::from(PHRASE)))
        }))
    });

    Server::bind_unix(path)?.serve(make_service).await?;

    Ok(())
}

To test that your server is working you can use an out of the box tool like curl

$ curl --unix-socket /tmp/hyperlocal.sock localhost

It's a Unix system. I know this.

Clients

hyperlocal also provides bindings for writing unix domain socket based HTTP clients using Hyper's native Client interface.

Configure your Hyper client using hyper::Client::builder().

Hyper's client interface makes it easy to send typical HTTP methods like GET, POST, DELETE with factory methods, get, post, delete, etc. These require an argument that can be tranformed into a hyper::Uri.

Since Unix domain sockets aren't represented with hostnames that resolve to ip addresses coupled with network ports, your standard over the counter URL string won't do. Instead, use a hyperlocal::Uri, which represents both file path to the domain socket and the resource URI path and query string.

use std::error::Error;
use hyper::{body::HttpBody, Client};
use hyperlocal::{UnixClientExt, Uri};
use tokio::io::{self, AsyncWriteExt as _};

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
    let url = Uri::new("/tmp/hyperlocal.sock", "/").into();

    let client = Client::unix();

    let mut response = client.get(url).await?;

    while let Some(next) = response.data().await {
        let chunk = next?;
        io::stdout().write_all(&chunk).await?;
    }

    Ok(())
}

Doug Tangren (softprops) 2015-2020