Nix Flake · Rust Dev Template

purr · git-hooks · rust · cargo · clippy · nix-flake

Nix flake template for Rust development — batteries-included dev shell, pre-commit guardrails, and reproducible builds via cargo + rustPlatform. Drop into direnv, start hacking.

Part of the develop-templates collection (nix flake init-ready).

Quick Start

nix flake init

nix flake init -t "github:nixcafe/develop-templates#rust" --refresh

Register an alias:

nix registry add beans "github:nixcafe/develop-templates"
nix flake init -t beans#rust

Tip: With cattery-modules, beans is pre-registered.

Create from Template

gh repo create my-rust-project --template nixcafe/rust --clone

Enter the Dev Shell

direnv allow
cargo build

What’s Inside

Tool	Purpose
cargo / rustc / rustLibSrc	Rust toolchain via rustPlatform
clippy	Rust linter — catches common mistakes
rustfmt	Rust formatter — consistent code style
pkg-config	Build dependency discovery
RUST_SRC_PATH	LSP source path for rust-analyzer

Customizing

Change Rust Toolchain

Override rustPlatform in develop/shells/default/default.nix:

# pin to a specific nightly
toolchain = pkgs.rust-bin.nightly.latest.default.override {
  extensions = [ "rust-src" ];
};

Pre-commit Hooks

Defined in develop/checks/git-hooks/default.nix. Runs on every commit:

Hook	What it checks
nixfmt	Nix file formatting
deadnix	Dead code in Nix files
statix	Nix anti-patterns
cargo-check	Type-checks the crate
clippy	Rust lint warnings
rustfmt	Rust code formatting

Pin Dependencies

Dependencies are locked via Cargo.lock. Builds are fully reproducible when combined with Nix’s hashed fetchers. The package builder at develop/packages/default/default.nix reads lockFile directly:

cargoLock.lockFile = ../../../Cargo.lock;

Project Structure

rust/
├── flake.nix                         # flake entrypoint → purr.mkFlake
├── Cargo.toml                        # package manifest
├── Cargo.lock                        # pinned dep tree
├── src/
│   └── main.rs                       # crate entrypoint
├── develop/
│   ├── packages/default/default.nix  # nix build → buildRustPackage
│   ├── shells/default/default.nix    # nix develop → mkShell
│   └── checks/git-hooks/default.nix  # pre-commit hooks
├── .envrc                            # direnv auto-load
└── .gitignore

Why This Exists

• Reproducible: The same lockfile + Nix closure = the same binary every time.
• Guardrails: Zero-warning CI won’t let sloppy code through.
• Editor-ready: RUST_SRC_PATH wired up so rust-analyzer resolves stdlib sources out of the box.
• Offline-capable: All tooling comes from the /nix/store — no network needed after initial fetch.