fix(ci): use chromium-headless-shell with isolated caches

Fix race condition in parallel test jobs by adding matrix index to cache key.

Use chromium-headless-shell by passing executable_path to Playwright driver.

Changes:

- Add ${{ matrix.ci_node_index }} to cache key for isolated caches per job

- Install chromium-headless-shell instead of full chromium

- Detect and use headless_shell executable in capybara driver config

Author: mroderick

.github/workflows/ruby.yml

@@ -46,14 +46,12 @@ jobs:
       id: playwright-cache
       with:
         path: ~/.cache/ms-playwright
-        key: playwright-${{ runner.os }}-chromium-headless-shell-1.59.0
+        key: playwright-${{ runner.os }}-chromium-headless-shell-1.59.0-${{ matrix.ci_node_index }}
 
-    - name: Install Playwright Chromium Headless Shell (cache miss)
-      if: steps.playwright-cache.outputs.cache-hit != 'true'
+    - name: Install Playwright Chromium Headless Shell
       run: npx --yes playwright@1.59.0 install chromium-headless-shell
 
-    - name: Install Playwright system deps (cache hit)
-      if: steps.playwright-cache.outputs.cache-hit == 'true'
+    - name: Install Playwright system dependencies
       run: npx --yes playwright@1.59.0 install-deps chromium-headless-shell
 
     - name: Setup test databases

spec/support/capybara.rb

@@ -6,10 +6,15 @@
 # See: https://playwright.dev/docs/browsers#chromium-headless-shell
 
 Capybara.register_driver :playwright do |app|
+  # Use chromium-headless-shell if available (CI), fallback to regular chromium
+  headless_shell = Dir.glob(File.expand_path('~/.cache/ms-playwright/chromium_headless_shell-*/chrome-linux/headless_shell')).max
+  executable_path = headless_shell if headless_shell && File.executable?(headless_shell)
+
   Capybara::Playwright::Driver.new(
     app,
     headless: ENV.fetch('PLAYWRIGHT_HEADLESS', 'true') !~ /^(false|no|0)$/i,
-    browser_type: ENV.fetch('PLAYWRIGHT_BROWSER', 'chromium').to_sym
+    browser_type: ENV.fetch('PLAYWRIGHT_BROWSER', 'chromium').to_sym,
+    executablePath: executable_path
   )
 end