Nixify website build in GitHub Action

Author: afh

.github/workflows/build_and_deploy.yml

@@ -27,18 +27,17 @@ jobs:
 
    runs-on: ubuntu-latest
    steps:
-   - uses: actions/checkout@v3
-   - name: Set up Ruby
-     uses: ruby/setup-ruby@v1
-     with:
-       ruby-version: 2.7
-       bundler-cache: true # runs 'bundle install' and caches installed gems automatically
-   - name: Build website
-     run: bundle exec middleman build
-
    - uses: cachix/install-nix-action@v20
      with:
        nix_path: nixpkgs=channel:nixos-unstable
+
+   - uses: actions/checkout@v3
+   - name: Build website
+     run: |
+      nix build .
+      mkdir -p build
+      cp -R result/* build
+
    - name: Build documentation
      env:
        OWNER: afh

flake.lock

@@ -0,0 +1,47 @@
+{
+  description = "Website for ledger-cli.org";
+
+  nixConfig.bash-prompt = "ledger-cli.org$ ";
+
+  inputs = {
+    nixpkgs.url = "nixpkgs/nixpkgs-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem( system:
+    let
+      pkgs = import nixpkgs { inherit system; };
+      gems = with pkgs; bundlerEnv {
+        name = "ledger.github.io";
+        inherit ruby;
+        gemdir = ./.;
+      };
+    in
+    {
+      packages = rec {
+        default = pkgs.stdenvNoCC.mkDerivation rec {
+          name = "ledger.github.io";
+          src = self;
+
+          nativeBuildInputs = with pkgs; [ gems ruby ];
+
+          buildPhase = ''
+            runHook preBuild
+            bundle exec middleman build
+            runHook postBuild
+          '';
+
+          installPhase = ''
+            runHook preInstall
+            mv build $out
+            runHook postInstall
+          '';
+        };
+      };
+
+      devShell = pkgs.mkShell {
+        buildInputs = self.packages.${system}.default.nativeBuildInputs;
+      };
+    });
+}