Today I experimented with a few friends how well Rails runs on Google’s App Engine.

App Engine for itself works with python and java, rails works via jruby.
The conditions are great, and for small apps googles engine is free.

But there are several drawbacks. BigTable, googles database does NOT WORK with ActiveRecord. I believe AR is one of the core features of rails. In edge rails, there is the possibility to switch your OR mapper to Data Mapper, an alternative (maybe faster) approach to ORM, which actually has BigTable-Mappings. BUT – DM does not play nicely with JRuby, at least for our experiments it didn’t work out.

And you loose one of rails biggest advantages, the plugins. All those acts_as_ stuff is made for ActiveRecord and not for DM.

So the App Engine is no alternative, except if you want to go through great pain. Maybe this changes when Data Mapper becomes more mature, and Rails 3 is released. Meanwhile, you’re better of with other hosters.

Try Heroku. They let you deploy your rails app within a git push. And the’re free for starting a small app!

Related posts:

1. Demystifiying Rails Model attributes overriding
2. Freezing your Rails version/gems!
3. Rails has_many and dynamic conditions