Run Laravel Database Migration after every build on Google App Engine

I am running Laravel 5.5 on GAE with a MySQL instance running database. I want to be able to run database migrations after every build. I have added command "php artisan migrate" on post-install-cmd in composer.json but it does not seem to work.

"post-install-cmd": [ "chmod -R 755 bootstrap/cache", "php artisan migrate --no-interaction --force", "php artisan cache:clear" ] The build log shows command running but looks like down there there is command cancelled. What could be the issue? How can I run migration after every build? I get this error ERROR: SQLSTATE[HY000] [2002] No such file or directory (SQL: select * from information_schema.tables where table_schema = My_DB_NAME and table_name = migrations) SQLSTATE[HY000] [2002] No such file or directory (SQL: select * from information_schema.tables where table_schema = My_DB_NAME and table_name = migrations) at /app/vendor/laravel/framework/src/Illuminate/Database/Connec‌​tion.php:664, PDOException(code: 2002): SQLSTATE[HY000] [2002] No such file or directory

I replaced the actual database name with My_DB_NAME. Any help will be appreciated.