A typesafe interface to the nix CLI.

by flox

Install with cargo add (Rust >= 1.64)

cargo add runix

Alternatively, manually add

runix = "{{current_version}}" # check the latest version before adding

to your Cargo.toml.

runix requires an existing nix installation.

runix is a library that allows you to run nix using a typed interface.

runix converts command structures into an invocation of a NixBackend implementation. The backend currently in development is the command_line::NixCommandLine backend, which uses tokio::process::Command to exec the nix CLI.

While this is the reference implmentation, other backends such as an FFI based implementation or Mocking shims for testing are possible.

Warning runix is still in active development!

It's API is not yet deeply set in stone, more fields will be added as we expand the coverage of the Nix CLI and traits may change if necessary.

We greatly appreciate feedback and contributions.

The easiest way to get familiar with the interface is by way of an example.

Again, mind that you'll need nix on your PATH to use runix and have enabled experimental-features='nix-command flakes'.

// (1) initialize a backend
let cli = NixCommandLine::default();

// (2) define the command
Eval {
    source: SourceArgs {
        expr: Some(r#""Hello Rust""#.into()),
    },
    ..Default::default()
}
// (3) run the command
.run(&cli, &NixArgs::default())
.await

This is the runix equivalent to:

$ nix eval --expr '"Hello Rust"'

While certainly more wordy, than its shell counterpart, its comparable to the same invocation, written manually:

tokio::process::Command::new("nix")
    .args([
        "eval".to_string(),
        "--expr".into(),
        r#""Hello Rust""#.into(),
    ])
    .status()
    .await

The main benefit of runix however is that it abstracts away the plain list of arguments and guides you to correct invocations of the cli.

Interested? Check out the rustdoc for more detailed explanations.

We plan to expand the command line backend with more commands and a comprehensive set of flags. Depending on the state of abstractions in Nix, we plan to approach native bindings to Nix commands and concepts.

Runix is licensed under LGPL-2.1