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:

Strategy	Pros	Cons
Manual (crate2nix generate)	No IFD, full build parallelism	Must regenerate when deps change
Auto (Import From Derivation)	Always in sync with Cargo.lock	May reduce parallelism

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