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 unix only. If you want to use
this for development you can use the systemfd
utility which implements the systemd protocol.
This library uses an extension to the systemd protocol where if the
LISTEN_PID
variable is not set or empty, the check for the pid is
removed. This is useful when binaries are proxied in between like
cargo-watch.
Example
This example shows how to use this crate with an actix-web
server:
use listenfd::ListenFd; let mut listenfd = ListenFd::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) = listenfd.take_tcp_listener(0)? { server.listener(listener) // otherwise fall back to local listening } else { server.bind("127.0.0.1:3000")? };
You can then use this with cargo watch and systemfd:
$ cargo install systemfd cargo-watch
systemfd --no-pid -s 3000 -- cargo watch -x run
Now systemfd 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 systemfd opened. No more connection resets.
The --no-pid
flag is necessary to ensure that the LISTEN_PID
environment
variable is not set or the socket passing will be prevented by the pid check.
Structs
ListenFd |
A helper object that gives access to raw file descriptors. |