Enable Route Caching in Lumen to Reduce Bootstrap Time

Desired outcome

Reduce the per‑request bootstrap overhead caused by parsing multiple route files by compiling all routes into a single cached file.

Prerequisites

1. Lumen version that supports route caching (typically 5.5+).
2. Access to the project root with write permissions for the bootstrap/cache directory.
3. All route definitions must be static – no closures that capture external variables, and middleware must not depend on request‑specific state resolved after caching.
4. Running in a production‑like environment where the route set is stable.

Focused procedure

1. Open a terminal and navigate to the Lumen project root.
2. Ensure the cache directory is writable:

   chmod -R u+w bootstrap/cache

   (run as the deployment user).
3. Execute the route cache command:

   php artisan route:cache

4. Verify that bootstrap/cache/routes.php was created and contains a serialized array.
5. Optionally measure bootstrap time before and after caching using a simple microtime snippet in public/index.php or a profiling tool.

Expected checks

• The file bootstrap/cache/routes.php exists and is not empty.
• Its content begins with return array(...); or a similar serialized PHP array.
• A request to any defined route returns the expected response without errors.
• Measured bootstrap time shows a reduction (e.g., 30‑50 % lower CPU time) compared to an uncached run.

Recovery options

1. If a route change is made, clear the cache:

   php artisan route:clear

2. To disable caching entirely, delete the cached file and avoid running route:cache again.
3. In case of unexpected 404s after deployment, run route:clear and redeploy.