Crate listenfd [] [src]

listenfd is a crate that provides support for working with externally managed and passed file descriptors. This lets you work with systems that support socket activation or similar.

Currently this supports systemd and catflap on unix only. catflap is very convenient in combination with cargo-watch for development purposes whereas systemd is useful for production deployments on linux.


This example shows how to use this crate with an actix-web server:

use listenfd::ListenFdManager;

let mut manager = ListenFdManager::from_env();
let mut server = make_a_server();

// if we are given a tcp listener on listen fd 0, we use that one
server = if let Some(listener) = manager.take_tcp_listener(0)? {
// otherwise fall back to local listening
} else {

You can then use this with cargo watch and catflap:

$ cargo install catflap cargo-watch
catflap -p 3000 -- cargo watch -x run

Now catflap will open the socket and keep it open. cargo watch will recompile the code on demand and the server will pick up the socket that catflap opened. No more connection resets.



A helper object that gives access to raw file descriptors.