How to properly set up Capistrano 3 with Rails 4? - ruby-on-rails

Question

It's 2 days what I am trying to install Capistrano 3 for a Rails 4 app, my hairs already turned grey...
The problem is that I am unable to deploy the code to server (Ubuntu 14, nginx, running on DigitalOcean).
Here's my config:
Gemfile:
gem 'capistrano', '~> 3.1.0'
gem 'capistrano-rails', '~> 1.1.0'
gem 'capistrano-bundler'
gem 'unicorn'
Capfile:
require 'capistrano/setup'
require 'capistrano/deploy'
require 'capistrano/bundler'
require 'capistrano/rails/assets'
require 'capistrano/rails/migrations'
# Load custom tasks from `lib/capistrano/tasks' if you have any defined
Dir.glob('lib/capistrano/tasks/*.cap').each { |r| import r }
Dir.glob('lib/capistrano/**/*.rb').each { |r| import r }
deploy.rb:
set :application, 'project'
set :deploy_user, 'deployer'
set :scm, :git
set :repo_url, 'git#bitbucket.org:username/project.git"'
set :pty, true
set :use_sudo, false
set :keep_releases, 5
set :linked_files, %w{config/database.yml}
set :linked_dirs, %w{bin log tmp/pids tmp/cache tmp/sockets vendor/bundle public/system}
set(:symlinks, [
{
source: "nginx.conf",
link: "/etc/nginx/sites-enabled/#{fetch(:full_app_name)}"
},
{
source: "unicorn_init.sh",
link: "/etc/init.d/unicorn_#{fetch(:full_app_name)}"
},
{
source: "log_rotation",
link: "/etc/logrotate.d/#{fetch(:full_app_name)}"
},
{
source: "monit",
link: "/etc/monit/conf.d/#{fetch(:full_app_name)}.conf"
}
])
namespace :deploy do
before :deploy, "deploy:check_revision"
before :deploy, "deploy:run_tests"
#after 'deploy:symlink:shared', 'deploy:compile_assets_locally'
after :finishing, 'deploy:cleanup'
before 'deploy:setup_config', 'nginx:remove_default_vhost'
after 'deploy:setup_config', 'nginx:reload'
after 'deploy:setup_config', 'monit:restart'
after 'deploy:publishing', 'deploy:restart'
end
and config/deploy/production.rb:
set :stage, :production
set :branch, "master"
set :full_app_name, "#{fetch(:application)}_#{fetch(:stage)}"
set :server_name, "IP"
server 'IP', user: 'deployer', roles: %w{web app db}, primary: true
set :deploy_to, "/home/#{fetch(:deploy_user)}/apps/#{fetch(:full_app_name)}"
set :rails_env, :production
set :unicorn_worker_count, 5
set :enable_ssl, false
When I am trying to set up capistrano and run cap production deploy:setup_config, I get this output:
/Users/adam/.rvm/gems/ruby-2.0.0-p481/gems/bundler-1.6.5/lib/bundler.rb:301: warning: Insecure world writable dir /usr/local/mysql-5.6.13-osx10.7-x86_64 in PATH, mode 040777
DEBUG [d940e414] Running /usr/bin/env [ -f /etc/nginx/sites-enabled/default ] as deployer#IP
DEBUG [d940e414] Command: [ -f /etc/nginx/sites-enabled/default ]
Text will be echoed in the clear. Please install the HighLine or Termios libraries to suppress echoed text.
deployer#188.166.53.247's password: # HERE I PUT MY PASSWORD, BUT WHEN I TYPE IT, I SEE WHAT I TYPE (THE PASSWORD IS NOT HIDDEN)
DEBUG [d940e414] Finished in 28.324 seconds with exit status 0 (successful).
INFO [cba64b02] Running /usr/bin/env sudo rm /etc/nginx/sites-enabled/default as deployer#IP
DEBUG [cba64b02] Command: /usr/bin/env sudo rm /etc/nginx/sites-enabled/default
DEBUG [cba64b02] [sudo] password for deployer:
And here it stuck - nothing happened. No matter what I do (if I type something/password) -- it stuck here for over 30 minutes.
Could I ask you to help me out with this issue, guys?
Thank you very much in advance, I am not sure how to continue here.

Answer 1

It appears the nginx:remove_default_vhost task you have configured to run before deploy:setup_config is trying to execute rm with sudo. Capistrano 3 requires passwordless sudo to be setup, otherwise you get the symptom you have described. See the authorization section of the documentation.
Setting up the deployer user to execute rm with sudo without a password should get things moving, but before you do that I think it's worth asking: do you really want your deployer user to be able to remove arbitrary files as root without a password? It's not clear to me what the origin of that task is, but IMHO that is more a part of privisioning than of deployment and there are other tools more suited for provisioning than capistrano (chef, puppet, etc.). Or just SSH to your server and remove it. It only needs to be done once.
If you do decide to let your deployer user execute rm with sudo without a password, remember to use visudo and do not edit /etc/sudoers directly.