how to use RVM to a ruby app engine? - ruby

Question

i wanna make a simple ruby App Engine in rails just like heroku, i'm dealing with a problem now.
My idea was:
1.use rails to establish the App Engine, use a class 'App' to handle all apps.
2.when a user create an ruby app he should offer it's git path
3.when the user deploys it, my app engine will do these things:
clone the git to a path in my server (done
use RVM to designatine the ruby version witch user wanted and make a gemdir for the project (some problems here
create a nginx conf for the project, then include it and reload nginx (i can do it
Problems in the second step:
codes here:
def start_thin
Dir.chdir(proj_path) do
system('rvm use ruby-1.8.7-p352#testname --create')
system('gem env gemdir')
success = system ('thin start -s3 --socket ' + self.proj_sock)
if success
return true
end
end
return false
end
when the code runs here, the log told me "RVM is not a function...blahblah", i know something about the login-shell and non-login-shell, then i try to fix it via editing .bashrc but same problem occurred.
And if i ignore it, the app can't be deployed, because of a Load Error :
myapp.rb:2:in `require': cannot load such file -- sinatra (LoadError)
if i open a terminal in that app directory, i can use thin to start it.
i wanna know how to run cmd just like in a terminal, without all these odd problem?
or how to edit my method to fix it?
Thanks!

Answer 1

Thanks Casper and GhostRider.
The user and rvm settings are correct.
After lots of googles and tests i found it's impossible...
Finally I fixed it by using RVM's ruby api instead of running system command.
Such as :
require 'rvm'
env = RVM.current
env.gemset.create('app1')