perf(ui+ci): cache build artifacts and run vite in single process

SamMorrowDrums · Copilot · SamMorrowDrums · commit b5cfafb32859 · 2026-05-19T10:01:19.000+02:00
Introduce a content-addressable cache for the embedded UI HTML and refactor
the build script to invoke vite once per Node process instead of three
times.

* New ui/scripts/build.mjs runs vite build() in a loop within one process,
  removing the cross-env dev dependency and avoiding redundant plugin/JIT
  warm-up. Local build time drops from ~2.4s to ~1.5s.

* New .github/actions/build-ui composite action restores
  pkg/github/ui_dist/{get-me,issue-write,pr-write}.html from cache keyed on
  hashes of ui/ sources and the lockfile. On cache hit it skips Node setup
  and the build entirely; on miss it sets up Node and runs script/build-ui
  as before. Saves ~6s per workflow on Go-only PRs, which is the common
  case across seven workflows.

* Replace the duplicated setup-node + Build UI pair in seven workflows
  (go, lint, docs-check, license-check, goreleaser, mcp-diff, code-scanning)
  with a single uses: ./.github/actions/build-ui line. code-scanning keeps
  a dedicated setup-node for the JavaScript CodeQL path.

Output files are byte-identical to the pre-refactor build.

Co-authored-by: Copilot &lt;223556219+Copilot@users.noreply.github.com&gt;
diff --git a/.github/actions/build-ui/action.yml b/.github/actions/build-ui/action.yml
@@ -0,0 +1,37 @@
+name: Build UI
+description: Restore cached UI HTML artifacts, or set up Node and run script/build-ui on cache miss.
+
+runs:
+  using: composite
+  steps:
+    - name: Cache UI artifacts
+      id: cache-ui
+      uses: actions/cache@v5
+      with:
+        path: |
+          pkg/github/ui_dist/get-me.html
+          pkg/github/ui_dist/issue-write.html
+          pkg/github/ui_dist/pr-write.html
+        key: ui-dist-v1-${{ hashFiles('ui/package-lock.json', 'ui/package.json', 'ui/index.html', 'ui/tsconfig*.json', 'ui/vite.config.ts', 'ui/src/**', 'ui/scripts/**') }}
+
+    - name: Set up Node.js
+      if: steps.cache-ui.outputs.cache-hit != 'true'
+      uses: actions/setup-node@v6
+      with:
+        node-version: "20"
+        cache: npm
+        cache-dependency-path: ui/package-lock.json
+
+    - name: Build UI
+      if: steps.cache-ui.outputs.cache-hit != 'true'
+      shell: bash
+      run: script/build-ui
+
+    - name: Report UI cache status
+      shell: bash
+      run: |
+        if [ "${{ steps.cache-ui.outputs.cache-hit }}" = "true" ]; then
+          echo "UI artifacts restored from cache (skipped build)."
+        else
+          echo "UI artifacts rebuilt from source."
+        fi
diff --git a/.github/workflows/code-scanning.yml b/.github/workflows/code-scanning.yml
@@ -78,8 +78,8 @@ jobs:
           go-version: ${{ fromJSON(steps.resolve-environment.outputs.environment).configuration.go.version }}
           cache: false
 
-      - name: Set up Node.js
-        if: matrix.language == 'go' || matrix.language == 'javascript'
+      - name: Set up Node.js (for JavaScript CodeQL)
+        if: matrix.language == 'javascript'
         uses: actions/setup-node@v6
         with:
           node-version: "20"
@@ -88,7 +88,7 @@ jobs:
 
       - name: Build UI
         if: matrix.language == 'go'
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Autobuild
         uses: github/codeql-action/autobuild@v4
diff --git a/.github/workflows/docs-check.yml b/.github/workflows/docs-check.yml
@@ -16,15 +16,8 @@ jobs:
     - name: Checkout code
       uses: actions/checkout@v6
 
-    - name: Set up Node.js
-      uses: actions/setup-node@v6
-      with:
-        node-version: "20"
-        cache: "npm"
-        cache-dependency-path: ui/package-lock.json
-
     - name: Build UI
-      run: script/build-ui
+      uses: ./.github/actions/build-ui
 
     - name: Set up Go
       uses: actions/setup-go@v6
diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
@@ -25,16 +25,8 @@ jobs:
       - name: Check out code
         uses: actions/checkout@v6
 
-      - name: Set up Node.js
-        uses: actions/setup-node@v6
-        with:
-          node-version: "20"
-          cache: "npm"
-          cache-dependency-path: ui/package-lock.json
-
       - name: Build UI
-        shell: bash
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Set up Go
         uses: actions/setup-go@v6
diff --git a/.github/workflows/goreleaser.yml b/.github/workflows/goreleaser.yml
@@ -16,15 +16,8 @@ jobs:
       - name: Check out code
         uses: actions/checkout@v6
 
-      - name: Set up Node.js
-        uses: actions/setup-node@v6
-        with:
-          node-version: "20"
-          cache: "npm"
-          cache-dependency-path: ui/package-lock.json
-
       - name: Build UI
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Set up Go
         uses: actions/setup-go@v6
diff --git a/.github/workflows/license-check.yml b/.github/workflows/license-check.yml
@@ -32,15 +32,8 @@ jobs:
           GH_TOKEN: ${{ github.token }}
         run: gh pr checkout ${{ github.event.pull_request.number }}
 
-      - name: Set up Node.js
-        uses: actions/setup-node@v6
-        with:
-          node-version: "20"
-          cache: "npm"
-          cache-dependency-path: ui/package-lock.json
-
       - name: Build UI
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Set up Go
         uses: actions/setup-go@v6
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
@@ -14,13 +14,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
-      - uses: actions/setup-node@v6
-        with:
-          node-version: "20"
-          cache: "npm"
-          cache-dependency-path: ui/package-lock.json
       - name: Build UI
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
       - uses: actions/setup-go@v6
         with:
           go-version: '1.25'
diff --git a/.github/workflows/mcp-diff.yml b/.github/workflows/mcp-diff.yml
@@ -19,13 +19,8 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Set up Node.js
-        uses: actions/setup-node@v6
-        with:
-          node-version: '20'
-
       - name: Build UI
-        run: script/build-ui
+        uses: ./.github/actions/build-ui
 
       - name: Run MCP Server Diff
         uses: SamMorrowDrums/mcp-server-diff@v2.3.5
diff --git a/ui/package-lock.json b/ui/package-lock.json
diff --git a/ui/package.json b/ui/package.json
@@ -8,10 +8,7 @@
     "node": "^20.19.0 || >=22.12.0"
   },
   "scripts": {
-    "build": "npm run build:get-me && npm run build:issue-write && npm run build:pr-write",
-    "build:get-me": "cross-env APP=get-me vite build",
-    "build:issue-write": "cross-env APP=issue-write vite build",
-    "build:pr-write": "cross-env APP=pr-write vite build",
+    "build": "node scripts/build.mjs",
     "dev": "npm run build",
     "typecheck": "tsc --noEmit",
     "clean": "rm -rf dist"
@@ -31,7 +28,6 @@
     "@types/react": "^18.0.0",
     "@types/react-dom": "^18.0.0",
     "@vitejs/plugin-react": "^6.0.2",
-    "cross-env": "^7.0.3",
     "typescript": "^5.7.0",
     "vite": "^8.0.13",
     "vite-plugin-singlefile": "^2.3.3"
diff --git a/ui/scripts/build.mjs b/ui/scripts/build.mjs
@@ -0,0 +1,14 @@
+// Build all UI apps in a single Node process.
+//
+// Replaces three serial `cross-env APP=<app> vite build` invocations: doing it
+// in one process avoids paying Vite/plugin startup cost three times and is
+// portable without `cross-env`.
+
+import { build } from "vite";
+
+const apps = ["get-me", "issue-write", "pr-write"];
+
+for (const app of apps) {
+  process.env.APP = app;
+  await build();
+}
