Capistrano deploy with rbenv

deploy.rb

require 'bundler/capistrano'
load 'deploy/assets'

# rbenv stuff
set :default_environment, {
  'PATH' => "$HOME/.rbenv/shims:$HOME/.rbenv/bin:/usr/local/git/bin:$PATH"
}
set :bundle_flags, "--deployment --quiet --binstubs --shebang ruby-local-exec"

set :user, 'rails'
set :application, 'rails'

set :deploy_to, "/home/#{user}/#{application}"
set :rails_env, "production"

set :unicorn_pid, "#{current_path}/tmp/pids/unicorn.pid"

set :scm, "git"
set :scm_command, "/usr/local/git/bin/git"
set :repository,  "git@github.com:<<reponame>>/#{application}.git"
set :deploy_via, :remote_cache
set :scm_verbose, true
set :use_sudo, false

ssh_options[:forward_agent] = true
default_run_options[:pty] = true

set :branch, ENV['BRANCH'] ? ENV['BRANCH'] : "master"

role :web, "server"                          # Your HTTP server, Apache/etc
role :app, "server"                          # This may be the same as your `Web` server
role :db,  "server", :primary => true # This is where Rails migrations will run
#role :db,  "your slave db-server here"

namespace :deploy do
  task :start do ; end
  task :stop do ; end
  task :restart, :roles => :app, :except => { :no_release => true } do
    #run "#{try_sudo} touch #{File.join(current_path,'tmp','restart.txt')}"
  end
end

namespace :unicorn do
  desc "start unicorn"
  task :start, :roles => :app, :except => { :no_release => true } do 
    run "cd #{current_path} && #{try_sudo} bin/unicorn_rails -c #{current_path}/config/unicorn.rb -E #{rails_env} -D"
  end
  desc "stop unicorn"
  task :stop, :roles => :app, :except => { :no_release => true } do 
    run "#{try_sudo} kill `cat #{unicorn_pid}`"
  end
  desc "graceful stop unicorn"
  task :graceful_stop, :roles => :app, :except => { :no_release => true } do
    run "#{try_sudo} kill -s QUIT `cat #{unicorn_pid}`"
  end
  desc "reload unicorn"
  task :reload, :roles => :app, :except => { :no_release => true } do
    run "#{try_sudo} kill -s USR2 `cat #{unicorn_pid}`"
  end
  
  after "deploy:restart", "unicorn:reload"
  after "deploy:start", "unicorn:start"
  after "deploy:stop", "unicorn:stop"
end

unicorn.rb

# Our own variable where we deploy this app to
deploy_to = "/home/rails/appname"

current_path = "#{deploy_to}/current"
shared_path = "#{deploy_to}/shared"

# See http://unicorn.bogomips.org/Sandbox.html
# Helps ensure the correct unicorn_rails is used when upgrading with USR2
Unicorn::HttpServer::START_CTX[0] = "#{current_path}/bin/unicorn_rails"

# Use at least one worker per core if you're on a dedicated server,
# more will usually help for _short_ waits on databases/caches.
worker_processes 4

# Help ensure your application will always spawn in the symlinked
# "current" directory that Capistrano sets up.
working_directory current_path

# listen on both a Unix domain socket and a TCP port,
# we use a shorter backlog for quicker failover when busy
listen "/tmp/app.sock", :backlog => 64
#listen 8080, :tcp_nopush => true

# nuke workers after 30 seconds instead of 60 seconds (the default)
timeout 30

# feel free to point this anywhere accessible on the filesystem
# pid "/var/run/staging_unicorn.pid"
pid "#{shared_path}/pids/unicorn.pid"

# By default, the Unicorn logger will write to stderr.
# Additionally, some applications/frameworks log to stderr or stdout,
# so prevent them from going to /dev/null when daemonized here:
stderr_path "#{shared_path}/log/unicorn.stderr.log"
stdout_path "#{shared_path}/log/unicorn.stdout.log"

# combine REE with "preload_app true" for memory savings
# http://rubyenterpriseedition.com/faq.html#adapt_apps_for_cow
preload_app true
GC.respond_to?(:copy_on_write_friendly=) and
  GC.copy_on_write_friendly = true

before_fork do |server, worker|
  # the following is highly recomended for Rails + "preload_app true"
  # as there's no need for the master process to hold a connection
  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.connection.disconnect!

  # The following is only recommended for memory/DB-constrained
  # installations.  It is not needed if your system can house
  # twice as many worker_processes as you have configured.
  #
  # # This allows a new master process to incrementally
  # # phase out the old master process with SIGTTOU to avoid a
  # # thundering herd (especially in the "preload_app false" case)
  # # when doing a transparent upgrade.  The last worker spawned
  # # will then kill off the old master process with a SIGQUIT.
  old_pid = "#{server.config[:pid]}.oldbin"
  if old_pid != server.pid
    begin
      sig = (worker.nr + 1) >= server.worker_processes ? :QUIT : :TTOU
      Process.kill(sig, File.read(old_pid).to_i)
    rescue Errno::ENOENT, Errno::ESRCH
    end
  end

  # # *optionally* throttle the master from forking too quickly by sleeping
  # sleep 1

end

after_fork do |server, worker|
  # worker.user('deployer', 'deployer') if Process.euid == 0

  # per-process listener ports for debugging/admin/migrations
  # addr = "127.0.0.1:#{9293 + worker.nr}"
  # server.listen(addr, :tries => -1, :delay => 5, :tcp_nopush => true)

  # the following is *required* for Rails + "preload_app true",
  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.establish_connection

  # if preload_app is true, then you may also want to check and
  # restart any other shared sockets/descriptors such as Memcached,
  # and Redis.  TokyoCabinet file handles are safe to reuse
  # between any number of forked children (assuming your kernel
  # correctly implements pread()/pwrite() system calls)

  # Reconnect memcached
  # Rails.cache.reset
end


before_exec do |server|
  ENV['BUNDLE_GEMFILE'] = "#{current_path}/Gemfile"
end