add flake output for the website root

.gitlab-ci.yml

@@ -57,7 +57,8 @@ pages:
   stage: deploy
   image: nixos/nix:2.18.2
   script:
-    - direnv exec . mdbook build
+    - nix build .#website-root
+    - cp --recursive --dereference result public
   artifacts:
     paths:
       - public

book.toml

@@ -5,7 +5,7 @@ multilingual = false
 src = "book"
 
 [build]
-build-dir = "public"
+build-dir = "target/book"
 
 [output.html]
 git-repository-icon = "fa-git-square"

flake.nix

@@ -65,6 +65,8 @@
               (fenix.targets.${target}.fromManifestFile inputs.rust-manifest)
               .withComponents components)
             targets);
+
+        website-root = self.callPackage ./nix/pkgs/website-root {};
       });
     in
     inputs.flake-utils.lib.eachDefaultSystem (system:
@@ -81,6 +83,7 @@
       {
         packages = {
           default = (mkScope pkgs).default;
+          website-root = (mkScope pkgs).website-root;
         }
         //
         builtins.listToAttrs

nix/pkgs/website-root/default.nix

@@ -0,0 +1,28 @@
+# Keep sorted
+{ inputs
+, lib
+, mdbook
+, stdenv
+}:
+
+stdenv.mkDerivation {
+  name = "website-root";
+
+  src = let filter = inputs.nix-filter.lib; in filter {
+    root = inputs.self;
+
+    # Keep sorted
+    include = [
+      "book"
+      "book.toml"
+    ];
+  };
+
+  buildPhase = ''
+    ${lib.getExe mdbook} build
+  '';
+
+  installPhase = ''
+    mv target/book $out
+  '';
+}