crate2nix

crate2nix generates Nix build files for Rust/Cargo projects, building each crate individually for precise, incremental rebuilds.

• Incremental CI builds -- only rebuild the crates that actually changed.
• Full Nix integration -- remote builds, binary caches, Docker images, NixOS modules.
• Local dev unchanged -- keep using cargo and rust-analyzer as usual.

Quick start

Without installing

nix run nixpkgs#crate2nix -- generate
nix build -f Cargo.nix rootCrate.build

With a flake template

nix flake init --template github:nix-community/crate2nix

Installing

# From nixpkgs
nix profile install nixpkgs#crate2nix

# Latest development version
nix profile install github:nix-community/crate2nix

Then, inside your project:

crate2nix generate        # creates Cargo.nix
nix build -f Cargo.nix rootCrate.build

How it works

crate2nix reads Cargo.toml and Cargo.lock, resolves the full dependency tree via cargo metadata, prefetches source hashes, and renders a Cargo.nix file through Tera templates. The generated file contains one Nix derivation per crate, so Nix rebuilds only what changed.

Two generation strategies are supported:

Nix API

tools.nix exposes helpers for use in your own Nix expressions:

let
  crate2nix = builtins.fetchTarball "https://github.com/nix-community/crate2nix/tarball/master";
  tools = import "${crate2nix}/tools.nix" { inherit pkgs; };

  generated = tools.generatedCargoNix {
    name = "my-project";
    src = ./.;
  };

  project = pkgs.callPackage "${generated}/default.nix" {};
in
  project.rootCrate.build

Or the shorthand appliedCargoNix which combines generation and import.

Documentation

Full documentation is at https://nix-community.github.io/crate2nix/, covering:

• Installation options
• Generation strategies
• Building binaries
• Feature selection
• Crate overrides
• Known restrictions
• Changelog

Contributing

Contributions are welcome! See the contributing guide for details.

License

Apache-2.0