more robust Playwright config

.github/playwright-workflow-config.json

@@ -0,0 +1,11 @@
+{
+    "pull_request": {
+        "runnerLabel": "ubuntu-latest",
+        "workers": 4
+    },
+    "production": {
+        "runnerLabel": "ubuntu-latest",
+        "maxParallel": 3,
+        "workers": 1
+    }
+}

.github/scripts/readPlaywrightWorkflowConfig.ts

@@ -0,0 +1,139 @@
+import fs from 'node:fs';
+import path from 'node:path';
+
+const CONFIG_PATH = path.resolve(
+    process.cwd(),
+    '.github',
+    'playwright-workflow-config.json',
+);
+
+type WorkflowTarget = 'pull_request' | 'production';
+
+type BaseWorkflowConfig = {
+    runnerLabel: string;
+    workers: number;
+};
+
+type ProductionWorkflowConfig = BaseWorkflowConfig & {
+    maxParallel: number;
+};
+
+type WorkflowConfig = {
+    pull_request: BaseWorkflowConfig;
+    production: ProductionWorkflowConfig;
+};
+
+function assertPositiveInteger(value: number, fieldName: string): void {
+    if (!Number.isInteger(value) || value < 1) {
+        throw new Error(
+            `Expected "${fieldName}" to be a positive integer, received ${String(value)}.`,
+        );
+    }
+}
+
+function parseWorkflowTarget(rawTarget: string | undefined): WorkflowTarget {
+    if (rawTarget === 'pull_request' || rawTarget === 'production') {
+        return rawTarget;
+    }
+
+    throw new Error(
+        'Expected a workflow target of "pull_request" or "production".',
+    );
+}
+
+function validateBaseConfig(
+    rawConfig: unknown,
+    fieldPrefix: WorkflowTarget,
+): BaseWorkflowConfig {
+    if (
+        typeof rawConfig !== 'object' ||
+        rawConfig === null ||
+        Array.isArray(rawConfig)
+    ) {
+        throw new Error(`Expected "${fieldPrefix}" to be an object.`);
+    }
+
+    const config = rawConfig as Record<string, unknown>;
+    const { runnerLabel, workers } = config;
+
+    if (typeof runnerLabel !== 'string' || runnerLabel === '') {
+        throw new Error(
+            `Expected "${fieldPrefix}.runnerLabel" to be a non-empty string.`,
+        );
+    }
+
+    if (typeof workers !== 'number') {
+        throw new Error(`Expected "${fieldPrefix}.workers" to be a number.`);
+    }
+
+    assertPositiveInteger(workers, `${fieldPrefix}.workers`);
+
+    return {
+        runnerLabel,
+        workers,
+    };
+}
+
+function validateProductionConfig(
+    rawConfig: unknown,
+): ProductionWorkflowConfig {
+    if (
+        typeof rawConfig !== 'object' ||
+        rawConfig === null ||
+        Array.isArray(rawConfig)
+    ) {
+        throw new Error('Expected "production" to be an object.');
+    }
+
+    const config = rawConfig as Record<string, unknown>;
+    const validatedConfig = validateBaseConfig(rawConfig, 'production');
+    const { maxParallel } = config;
+
+    if (typeof maxParallel !== 'number') {
+        throw new Error('Expected "production.maxParallel" to be a number.');
+    }
+
+    assertPositiveInteger(maxParallel, 'production.maxParallel');
+
+    return {
+        ...validatedConfig,
+        maxParallel,
+    };
+}
+
+function parseWorkflowConfig(rawConfig: unknown): WorkflowConfig {
+    if (typeof rawConfig !== 'object' || rawConfig === null) {
+        throw new Error('Expected workflow config to be an object.');
+    }
+
+    const maybeConfig = rawConfig as Record<string, unknown>;
+
+    return {
+        pull_request: validateBaseConfig(
+            maybeConfig.pull_request,
+            'pull_request',
+        ),
+        production: validateProductionConfig(maybeConfig.production),
+    };
+}
+
+const target = parseWorkflowTarget(process.argv[2]);
+const rawConfig = JSON.parse(fs.readFileSync(CONFIG_PATH, 'utf8')) as unknown;
+const parsedConfig = parseWorkflowConfig(rawConfig);
+const outputs: Record<string, string> =
+    target === 'pull_request'
+        ? {
+              runner_label: parsedConfig.pull_request.runnerLabel,
+              workers: String(parsedConfig.pull_request.workers),
+          }
+        : {
+              runner_label: parsedConfig.production.runnerLabel,
+              workers: String(parsedConfig.production.workers),
+              max_parallel: String(parsedConfig.production.maxParallel),
+          };
+
+process.stdout.write(
+    `${Object.entries(outputs)
+        .map(([key, value]) => `${key}=${value}`)
+        .join('\n')}\n`,
+);

.github/workflows/playwright.yml

@@ -8,9 +8,59 @@ permissions:
     contents: read
 
 jobs:
+    resolve_config:
+        name: Resolve Playwright config
+        runs-on: ubuntu-latest
+        outputs:
+            runner_label: ${{ steps.config.outputs.runner_label }}
+            workers: ${{ steps.config.outputs.workers }}
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v5
+
+            - name: Use Node.js
+              uses: actions/setup-node@v5
+              with:
+                  node-version: '22.x'
+
+            - name: Read Playwright workflow config
+              id: config
+              run: node --experimental-strip-types .github/scripts/readPlaywrightWorkflowConfig.ts pull_request >> "$GITHUB_OUTPUT"
+
+    setup:
+        name: Prepare Playwright E2E
+        needs: resolve_config
+        runs-on: ${{ needs.resolve_config.outputs.runner_label }}
+        timeout-minutes: 30
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v5
+
+            - name: Use Node.js
+              uses: actions/setup-node@v5
+              with:
+                  node-version: '22.x'
+                  cache: 'npm'
+
+            - name: Install dependencies
+              run: npm ci
+
+            - name: Build production output
+              env:
+                  GH_TOKEN: ${{ github.token }}
+              run: npm run build:skip
+
+            - name: Upload built site artifact
+              uses: actions/upload-artifact@v6
+              with:
+                  name: playwright-dist-client
+                  path: dist/client/
+                  if-no-files-found: error
+
     playwright:
         name: Playwright E2E (${{ matrix.engine.name }})
-        runs-on: ubuntu-latest
+        needs: [resolve_config, setup]
+        runs-on: ${{ needs.resolve_config.outputs.runner_label }}
         timeout-minutes: 30
         strategy:
             fail-fast: false
@@ -36,6 +86,7 @@ jobs:
                       mobile_project: Mobile Safari (iPhone 15)
         env:
             PLAYWRIGHT_BLOB_REPORT: 'true'
+            PLAYWRIGHT_CI_WORKERS: ${{ needs.resolve_config.outputs.workers }}
         steps:
             - name: Checkout
               uses: actions/checkout@v5
@@ -49,14 +100,22 @@ jobs:
             - name: Install dependencies
               run: npm ci
 
+            - name: Restore built site artifact
+              uses: actions/download-artifact@v5
+              with:
+                  name: playwright-dist-client
+                  path: dist/client
+
+            - name: Cache Playwright browsers
+              id: playwright-browser-cache
+              uses: actions/cache@v4
+              with:
+                  path: ~/.cache/ms-playwright
+                  key: ${{ runner.os }}-playwright-${{ matrix.engine.browser }}-${{ hashFiles('package-lock.json') }}
+
             - name: Install Playwright browser
               run: npx playwright install --with-deps ${{ matrix.engine.browser }}
 
-            - name: Build production output
-              env:
-                  GH_TOKEN: ${{ github.token }}
-              run: npm run build:skip
-
             - name: Run Playwright tests
               run: |
                   command=(npx playwright test --project "${{ matrix.engine.desktop_project }}" --project "${{ matrix.engine.mobile_project }}")
@@ -89,30 +148,39 @@ jobs:
         name: Merge Playwright report
         runs-on: ubuntu-latest
         steps:
+            - name: Skip merged report on green matrix
+              if: needs.playwright.result == 'success'
+              run: echo "Skipping merged Playwright HTML report because all PR matrix jobs passed."
+
             - name: Checkout
+              if: needs.playwright.result == 'failure' || needs.playwright.result == 'cancelled'
               uses: actions/checkout@v5
 
             - name: Use Node.js
+              if: needs.playwright.result == 'failure' || needs.playwright.result == 'cancelled'
               uses: actions/setup-node@v5
               with:
                   node-version: '22.x'
                   cache: 'npm'
 
             - name: Install dependencies
+              if: needs.playwright.result == 'failure' || needs.playwright.result == 'cancelled'
               run: npm ci
 
             - name: Download Playwright blob reports
+              if: needs.playwright.result == 'failure' || needs.playwright.result == 'cancelled'
               uses: actions/download-artifact@v5
               with:
                   merge-multiple: true
                   path: all-blob-reports
                   pattern: playwright-blob-report-*
 
             - name: Merge Playwright HTML report
+              if: needs.playwright.result == 'failure' || needs.playwright.result == 'cancelled'
               run: npx playwright merge-reports --reporter html ./all-blob-reports
 
             - name: Upload merged Playwright HTML report
-              if: always()
+              if: needs.playwright.result == 'failure' || needs.playwright.result == 'cancelled'
               uses: actions/upload-artifact@v6
               with:
                   name: playwright-report