Bookmarked this a while ago... might be of some help:
http://blog.neoxia.com/laravel-4-on-google-appengine-for-php

Simply note that the neoxia post was from the original launch of PHP on App Engine. Mcrypt has since been added along with possibly a few other additions that make using Laravel within it easier. So do adjust what you see based on what is available now from app engine.

The issue here is ... laravel tires to cache at storage folder .. but by default google appengine root folder doesnt have write permissions .. so we need to write it some where else .. when i pointed my google storage bucket ... its not working propely ... i am still getting this issue : file_put_contents(/meta/services.json): failed to open stream: Read-only file system

need to fix this issue

@popolla .. i tired that too ... but it doesnt helped me

any one please tell how to execute artisan command line commands in Google App Engine .. like php artisan migrate .. etc

I had this exact problem.

I solved it.

Initially I created a bucket called eg. "X".

I then changed the constant BUCKET_NAME to point to X. This is wrong.

You have to use the bucket that is linked to your GAE application. It is not originally in existence but you can click a button in the Google App Engine Application portal -> Application Settings page.

Once you create the bucket that corresponds to your application, the bucket's name will be: "<APP_NAME>.appspot.com".

This is the bucket you must use!

Hi pjebs , I can solved it with your solution. But sometime it still show error

file_put_contents(/meta/services.json): failed to open stream: Read-only file system

I try to fix by stop/start instance and it worked. However do you have another way to fix this problem? or Any advice I always welcome, please.