GitHub Deploy via Capistrano. Public Repo and SSH works, but Private doesn't - ruby-on-rails

Question

i really need your help. I have a Ruby on Rails Application on my local machine, a Repository at GitHub and an Ubuntu Server, which hosts the application with Nginx.
I had my repo for a lot of time public and the deployment via capistrano worked just fine. Now I converted my repo to a private one and the deployment just doesn't work. When i try to deploy it, i get the following error:
* executing `deploy'
* executing `deploy:update'
** transaction: start
* executing `deploy:update_code'
updating the cached checkout on all servers
executing locally: "git ls-remote git://github.com/GIT_USER/APPLICATION.git master"
fatal: The remote end hung up unexpectedly
*** [deploy:update_code] rolling back
* executing "rm -rf /var/www/APPLICATION/releases/DATE_OF_DEPLOY; true"
servers: ["DOMAIN"]
[DOMAIN] executing command
command finished in 424ms
So, my guess would be, that the authentication doesn't work, but it does. I copied my public key to GitHub and can even SSH there. I can SSH from the server to GitHub and it says that I am successfully authenticated. I can even see which key works. But "git ls-remote [...]" does not work and I get no info running it with trace, besides the information i already got.
So, my main problem is that i don't no where to look for the error. If you know how to solve this or can point my in any direction that would be nice.
And this is the main part of my deploy.rb:
$:.unshift(File.expand_path('./lib', ENV['rvm_path']))
require "rvm/capistrano"
require 'bundler/capistrano'
default_run_options[:pty] = true
set :user, "DEPLOY_USER"
set :domain, "DOMAIN"
set :application, "APPLICATION"
set :repository, "git#github.com:GIT_USER/APPLICATION.git"
set :deploy_to, "/var/www/#{application}"
set :deploy_via, :remote_cache
set :scm, :git
set :git_account, "GIT_USER"
set :branch, "master"
set :git_shallow_clone, 1
set :scm_verbose, true
set :use_sudo, false
set :rvm_bin_path, "/usr/local/rvm/bin"
set :rvm_ruby_string, '1.9.2'
set :rvm_type, :user # Don't use system-wide RVM
ssh_options[:port] = PORT_NUMBER
set :user, user
ssh_options[:keys] = %w(/home/DEPLOY_USER/.ssh/id_rsa)
set :ssh_options, { :forward_agent => true}
server domain, :app, :web
# Your HTTP server, Apache/etc
role :web, domain
# This may be the same as your `Web` server
role :app, domain
# This is where Rails migrations will run
role :db, domain, :primary => true
Sorry that this thing looks so cluttered, but i tried like a thousand hints, tipps and tutorials.
Thanks for every help!
And by the Way: Yes, all the things written in Capslock are just for privacy reasons and are, of course, not the real settings I use.

Answer 1

I seem to remember having a similar issue with deploying using a private github repo. I don't thinkg we ever quite worked out the cause of the problem but in the end I think we solved the issue using ssh-add to add the github key to ssh-agent - might be worth a try

Answer 2

Since this is now a non-public repo, you should be using git#... address.
I see you have this in your deploy.rb file, but ls-remote is still executed on git://...
The problem may be a cached-copy of the repository you have on a server. Check if you have correct origin address in shared/cached-copy/.git/config file. You should have git#... instead of git://... there

Answer 3

for private repos you have to use the https style:
set :repository, "https://github.com/git_name/repo_name.git"
.. but you have to type in your username and password twice on every deploy!
so I write a little Expect-script to do that for me
have a look at this gist
.. or as a walkthrough:
1 - make a file in your home directory ($ cat > ~/git_cap)
#!/usr/bin/expect -f
# Expect script to supply username/password to cap deploy to git private repository
# This script needs username and password as arguments to connect to git server:
# ------------------------------------------------------------------------
# ./git_cap gituser gitpwd
# -------------------------------------------------------------------------
# set Variables
set g_user [lrange $argv 0 0]
set g_pwd [lrange $argv 1 1]
set timeout -1
spawn cap deploy
match_max 100000
# Look for user prompt
expect "*?sername:*"
send -- "$g_user\r"
send -- "\r"
# Look for passwod prompt
expect "*?assword:*"
send -- "$g_pwd\r"
send -- "\r"
# Look for user prompt
expect "*?sername:*"
send -- "$g_user\r"
send -- "\r"
# Look for passwod prompt
expect "*?assword:*"
send -- "$g_pwd\r"
send -- "\r"
expect eof
2 - make it executable
$ chmod 755 ~/git_cap
$ chmod +x ~/git_cap
3 - add a alias in your .profile / .bashrc .. (optional)
alias gcap='~/git_cap gitname gitpwd'
4 - add your sudo-pwd to deploy.rb or extend the expect-script for sudo-pwd
( for that reason username & password expected 2 times, even if it where possible to use it more times .. but this way you can add a line for password with exp_continue so every next password will send the sudo-pwd and not your git-pwd)
5 - deploy with gcap
rails_root$ gcap