setting up an EC2 server with rvm via scripting

I'm looking for a way to install rvm, install a specific ruby version (using rvm) and set this installed ruby version as default. Before I can install rvm I have to install gcc and some other very basic software packages. What I've tried so far:

1) Using net/ssh

I have to simulate a pseudo tty to be able to sudo some commands and up to now, I could not figure out, how to tell a success full command completion from a not success full one.
after installing rvm, I've stumbled over problems using rvm ("rvm is not a function", error messages, leading to not being able to set a default ruby version).

2) Using capistrano

In the ssh output are newlines inserted so that a progress bar for example is been printed in a new line every time, some progress is made. That's something I can live with.
Same Problems with rmv, I'm able to install rvm, but I'm unable to set a default: rvm --default use 1.9.2 for example. No error message, but when I've log in later, no default is set and ruby -vshows the old system ruby.

3) Using capistrano and rvm-capistrano

Now I ran into the problem, that very task that I try to execute prior to installing rvm fails, because there seems to be some magic that fiddles with the shell default:

 * executing "sudo -p 'sudo password: ' yum install --assumeyes git gcc-c++ autoconf automake make patch zlib-devel libtool bzip2-devel"
   servers: ["ec2-54-247-142-214.eu-west-1.compute.amazonaws.com"]
   [ec2-54-247-142-214.eu-west-1.compute.amazonaws.com] executing command
** [out :: ec2-54-247-142-214.eu-west-1.compute.amazonaws.com] bash: /home/ec2-user/.rvm/bin/rvm-shell: No such file or directory
    command finished in 2094ms
failed: "rvm_path=$HOME/.rvm/ $HOME/.rvm/bin/rvm-shell 'default' -c 'sudo -p '\\''sudo password: '\\'' yum install --assumeyes git gcc-c++ autoconf automake make patch zlib-devel libtool bzip2-devel'" on ec2-54-247-142-214.eu-west-1.compute.amazonaws.com
rake aborted!

Here the commands I issue to install rvm/ruby:

run 'curl -L https://get.rvm.io | bash -s stable'
run 'rvm install ruby-1.9.2-p320'
run 'echo "[[ -s \"\$HOME/.rvm/scripts/rvm\" ]] && source \"\$HOME/.rvm/scripts/rvm\"" >> .bashrc'
run 'rvm --default use ruby-1.9.2-p320'
run 'which ruby && ruby -v'

and here the error messages that is issued as response to rvm --default use 1.9.2

RVM is not a function, selecting rubies with 'rvm use ...' will not work.
You need to change your terminal settings to allow shell login.
Please visit https://rvm.io/workflow/screen/ for example.

4.1) Using capistrano and rvm-capistrano and hacking a little bit

Update: With the help from mpapis at the RVM chat, I was able to come up with this working solution now: require "rvm/capistrano"

role :server, ENV[ 'base_image_setup_server' ] if ENV[ 'base_image_setup_server' ]

default_run_options[:pty] = true
default_run_options[:shell] = :bash

set :rvm_ruby_string, 'ruby-1.9.2-p320'
set :rvm_type, :user

def rvm_bin
    '$HOME/.rvm/bin/rvm'
end

namespace :images do

    task :install_basics do
        run "#{sudo} yum install --assumeyes git gcc-c++ autoconf automake make patch zlib-devel libtool bzip2-devel"
        run "#{sudo} yum update --assumeyes"
    end

    task :install_ruby do
        rvm.install_rvm
        rvm.install_ruby
        run "#{rvm_bin} alias create default #{rvm_ruby_string}"
        run 'echo "source ~/.rvm/environments/default" >> $HOME/.bashrc'
        run 'which ruby && ruby -v'
    end

    ... 

    desc 'build the base-image'
    task :base_image do 
        install_basics
        install_ruby
        install_boost
        install_rake_and_rack
        install_sioux
        test_sioux
    end

The main different is, that RVM is not used as a function, but the program direct.

kind regards, Torsten

Check RVM site for Capistrano integration https://rvm.io/integration/capistrano

There are tasks to install RVM and Ruby:

after 'deploy:setup', 'ubuntu:install'
after 'deploy:setup', 'rvm:install_rvm' # do it only with deploy setup
before 'deploy', 'rvm:install_ruby'     # do it on every deploy
namespace :ubuntu do
  desc "setup ubuntu system"
  task :install do
    run "apt-get install -y make ...", :shell => "sh"
    ...
  end
end

And you run the standard:

cap deploy:setup
cap deploy:cold

Also you might want to have a look on my example rails app for simple and working deployment script: https://github.com/mpapis/ad and my blog post about it: http://niczsoft.com/2012/03/fast-deployment-using-capistrano-rvm-and-more/