ci-scripts/build-docs-multiversion: init with GitHub CI

.github/workflows/book-gh-pages.yml

@@ -4,7 +4,9 @@ on:
   # Allows running this workflow manually
   workflow_dispatch:
   push:
-    branches: [master]
+    branches:
+      - master
+      - nixos-24.05
 
 permissions:
   contents: read
@@ -17,22 +19,38 @@ concurrency:
 jobs:
   deploy:
     if: "github.repository_owner == 'epics-extensions'"
+
     permissions:
       pages: write
       id-token: write
+
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}
+
     runs-on: ubuntu-latest
+
     steps:
+
+      # Checkout all documentation versions
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
+          ref: main
+          path: dev
           persist-credentials: false
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          ref: nixos-24.05
+          path: nixos-24.05
+          persist-credentials: false
+
       - uses: cachix/install-nix-action@3715ab1a11cac9e991980d7b4a28d80c7ebdd8f9 # v27
-      - name: "Build documentation book"
+      - uses: DeterminateSystems/magic-nix-cache-action@87b14cf437d03d37989d87f0fa5ce4f5dc1a330b # v8
+
+      - name: "Build documentation books"
         run: |
-          nix build '.#docs' --print-build-logs
-          cp -Lr --no-preserve=mode,ownership ./result/share/doc/epnix/html ./book
+          nix run --print-build-logs './dev#ci-scripts/build-docs-multiversion'
+
       - name: Setup Pages
         uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5.0.0
       - name: Upload artifact

pkgs/ci-scripts/build-docs-multiversion.nix

@@ -0,0 +1,47 @@
+{
+  writeShellApplication,
+  writeText,
+  writers,
+  epnixLib,
+}: let
+  stable = "nixos-24.05";
+  versions = [
+    "dev"
+    "nixos-24.05"
+  ];
+  baseurl = "https://epics-extensions.github.io/EPNix";
+  # Make a redirection using the <meta> tag,
+  # with a delay of 1 second, because Google considers them not permanent
+  #
+  # We need non-permanent redirections, because the redirection will change
+  # when a new stable version is released
+  redirect = writeText "stable-redirect.html" ''
+    <meta http-equiv=refresh content="1;url=${stable}/">
+  '';
+
+  versionInfo = ver: {
+    name = ver;
+    url = "${baseurl}/${ver}/";
+  };
+  versions_json = writers.writeJSON "versions.json" (map versionInfo versions);
+in
+  writeShellApplication {
+    name = "build-docs-multiversion";
+
+    text = ''
+      for version in ${toString versions}; do
+        mkdir -p "./book/$version"
+        cp ${versions_json} "./$version/docs/versions.json"
+        git -C "$version" add docs/versions.json
+        nix build "./$version#docs" --print-build-logs
+        cp -LrT --no-preserve=mode,ownership ./result/share/doc/epnix/html "./book/$version"
+      done
+      cp ${redirect} ./book/index.html
+    '';
+
+    meta = {
+      description = "Build ";
+      maintainers = with epnixLib.maintainers; [minijackson];
+      hidden = true;
+    };
+  }

pkgs/default.nix

@@ -106,5 +106,9 @@ in
 
       # Documentation support packages
       psu-simulator = callPackage ./doc-support/psu-simulator {};
+
+      ci-scripts = recurseExtensible (_self: {
+        build-docs-multiversion = callPackage ./ci-scripts/build-docs-multiversion.nix {};
+      });
     });
   }