feat: Add Nix flake and CI

Author: samuelburnham

.envrc

@@ -0,0 +1 @@
+use flake

.github/workflows/nix.yml

@@ -0,0 +1,40 @@
+name: Nix CI
+
+# If using Garnix, edit to run after Garnix checks using `on: check_suite`
+# https://garnix.io/docs/gh-actions
+on:
+  push:
+    branches: [main, nix-flake]
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  # Runs Rust tests via Nix
+  nix-test:
+    name: Nix Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - uses: cachix/install-nix-action@v31
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+          github_access_token: ${{ secrets.GITHUB_TOKEN }}
+      - run: nix flake check --print-build-logs
+      - run: nix build --print-build-logs --rebuild --accept-flake-config
+
+  # Tests Nix devShell support on Ubuntu
+  nix-devshell:
+    name: Nix devShell Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - uses: cachix/install-nix-action@v31
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+          github_access_token: ${{ secrets.GITHUB_TOKEN }}
+      # Builds and runs tests using Lake as a Nix package
+      - run: nix develop --accept-flake-config --command bash -c "cargo build && cargo nextest run"

.gitignore

@@ -8,3 +8,6 @@ target/
 
 # MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb
+
+.direnv/
+result

Cargo.toml

@@ -4,7 +4,6 @@ version = "0.1.0"
 edition = "2024"
 authors = ["Argument Engineering <[email protected]>"]
 license = "MIT OR Apache-2.0"
-# EDIT AS NEEDED
 rust-version = "1.88"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

README.md

@@ -8,10 +8,10 @@ Base template for a Rust library with CI, config files, and branch protection
 ```
 # Replace all occurrences with the desired library name
 $ rg -i template --glob '!deny.toml'
-# Update Rust toolchain if desired
-$ rg "EDIT AS NEEDED"
+# Update Rust toolchain if desired in `rust-toolchain.toml` and `Cargo.toml`
 # Then rewrite this `README`
 ```
+- Optional: Enable the Warpbuild and Garnix GitHub apps for CI and Nix caching
 - Create a branch protection rule for `main` and enable the following as needed:
   - Require a pull request before merging
     - Require 1 approval

flake.lock

@@ -0,0 +1,124 @@
+{
+  description = "Rust Nix flake";
+
+  # Must first enable Garnix GitHub app for the repo
+  #nixConfig = {
+  #  extra-substituters = [
+  #    "https://cache.garnix.io"
+  #  ];
+  #  extra-trusted-public-keys = [
+  #    "cache.garnix.io:CTFPyKSLcx5RMJKfLo5EEPUObbA78b0YQ2DTCJXqr9g="
+  #  ];
+  #};
+
+  inputs = {
+    # System packages
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+
+    # Helper: flake-parts for easier outputs
+    flake-parts.url = "github:hercules-ci/flake-parts";
+
+    # Rust-related inputs
+    fenix = {
+      url = "github:nix-community/fenix";
+      # Follow top-level nixpkgs so we stay in sync
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
+    crane.url = "github:ipetkov/crane";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = inputs @ { nixpkgs, flake-parts, fenix, crane, ... }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      # Systems we want to build for
+      systems = [
+        "aarch64-darwin"
+        "aarch64-linux"
+        "x86_64-darwin"
+        "x86_64-linux"
+      ];
+
+      perSystem = { system, pkgs, ... }:
+      let
+        # Pins the Rust toolchain
+        rustToolchain = fenix.packages.${system}.fromToolchainFile {
+          file = ./rust-toolchain.toml;
+          # Update this hash when `rust-toolchain.toml` changes
+          # Just copy the expected hash from the `nix build` error message
+          sha256 = "sha256-Qxt8XAuaUR2OMdKbN4u8dBJOhSHxS+uS06Wl9+flVEk=";
+        };
+        # Rust package
+        craneLib = (crane.mkLib pkgs).overrideToolchain rustToolchain;
+        commonArgs = {
+          src = craneLib.cleanCargoSource ./.;
+          strictDeps = true;
+      
+          buildInputs = [
+            # Add additional build inputs here
+          ] ++ pkgs.lib.optionals pkgs.stdenv.isDarwin [
+            # Additional darwin specific inputs can be set here
+            pkgs.libiconv
+          ];
+        };
+        craneLibLLvmTools = craneLib.overrideToolchain rustToolchain;
+        cargoArtifacts = craneLib.buildDepsOnly commonArgs;
+
+        template = craneLib.buildPackage (commonArgs // {
+          inherit cargoArtifacts;
+        });
+
+        # Run tests with cargo-nextest
+        # Consider setting `doCheck = false` on `my-crate` if you do not want
+        # the tests to run twice
+        template-nextest = craneLib.cargoNextest (
+          commonArgs
+          // {
+            inherit cargoArtifacts;
+            partitions = 1;
+            partitionType = "count";
+            cargoNextestPartitionsExtraArgs = "--no-tests=pass";
+          }
+        );
+      
+        # Workspace example for `client` and `server` subcrates
+        # serverPkg = craneLib.buildPackage (commonArgs // {
+        #   inherit cargoArtifacts;
+        #   pname = "server";
+        #   cargoExtraArgs = "-p server";
+        # });
+        # clientPkg = craneLib.buildPackage (commonArgs // {
+        #   inherit cargoArtifacts;
+        #   pname = "client";
+        #   cargoExtraArgs = "-p client";
+        # });
+      in
+      {
+        checks = {
+          inherit template template-nextest;
+        };
+
+        packages = {
+          default = template-nextest;
+
+          # Workspace example
+          # server = serverPkg;
+          # client = clientPkg;
+        };
+
+        # Provide a dev shell with `cargo` and the pinned toolchain
+        devShells.default = pkgs.mkShell {
+          packages = with pkgs; [
+            pkg-config
+            openssl
+            ocl-icd
+            gcc
+            clang
+            rustToolchain
+            rust-analyzer
+            cargo-nextest
+          ];
+        };
+      };
+    };
+}

flake.nix

@@ -1,5 +1,4 @@
 [toolchain]
 # The default profile includes rustc, rust-std, cargo, rust-docs, rustfmt and clippy.
 profile = "default"
-# EDIT AS NEEDED
 channel = "1.88"