Generic cap deploy script

Capfile

#Generic cap deploy script
load 'deploy' if respond_to?(:namespace) # cap2 differentiator

##################################
# Edit these
set :application, "example_node_app"
set :node_file, ""
set :host, "public_domain_name"
ssh_options[:keys] = [File.join(ENV["HOME"], ".ssh", "id_rsa")] #your private ssh key
set :repository, "git@githubrepo_url"
set :branch, "master"
set :deploy_to, "/srv/#{application}"
####################################

set  :scm, :git
set  :deploy_via, :remote_cache
role :app, host
set  :user, "ubuntu"
set  :use_sudo, true
default_run_options[:pty] = true

namespace :deploy do
	#few helper functions to help with deploy type stuff  
	def running?(program);     capture("ps ax | grep -v grep | grep #{program} | xargs")[program] end #I pipe to xargs b/c capture needs some sort of output and xargs will always give a newline at least
	def file_exists?(abs_loc); ! capture("ls #{abs_loc}")['No such file or directory'] end
	def installed?(program);   ! capture("whereis #{program}").sub( /#{program}:(\s)*/,"").empty? end
	def to_screen msg;         puts "\t===============#{msg}===============" end

  task :start, :roles => :app, :except => { :no_release => true } do
		run "#{sudo} rm /data/db/mongod.lock" if file_exists?("/data/db/mongod.lock") and not running?("mongod")
		run "#{sudo} start mongo"
		run "#{sudo} start #{application}"
  end

  task :start, :roles => :app, :except => { :no_release => true } do
		run "#{sudo} start #{application}"
  end

  task :stop, :roles => :app, :except => { :no_release => true } do
		run "#{sudo} stop #{application}"
		run "#{sudo} stop mongo
  end

  task :restart, :roles => :app, :except => { :no_release => true } do
		run "#{sudo} restart #{application} || #{sudo} start #{application}"
  end

  task :create_deploy, :roles => :app do
		to_screen "Checking dependencies..."
		to_screen "Mongo not installed"  unless installed? "mongo"
		to_screen "NPM is not installed" unless installed? "npm"
		to_screen "Nginx not set up"     unless file_exists? "/etc/nginx/sites-enabled"
		to_screen "Ok. I'm done checking your dependencies.  Hopefully you don't need a bad operation."

    run "#{sudo} mkdir -p #{deploy_to}"
    run "#{sudo} chown #{user}:#{user} #{deploy_to}"
  end
#Upstart scripts are the bomb.  Pretty simple to get started if you don't already know how to use - http://upstart.ubuntu.com/getting-started.html
#Obviously the following upstarts are for node and mongo, but they equally apply for other services as well.
  task :write_upstart_script, :roles => :app do
		site_upstart_script = <<-SITE_UPSTART
			description "#{application}"

			start on startup
			stop on shutdown

			script
					#TODO find out if this is necessary
					export HOME="/home/#{admin_runner}"

					cd #{current_path}
					exec sudo -u root sh -c "node #{current_path}/#{node_file} >> #{shared_path}/log/#{application}.log 2>&1"
			end script

			respawn
SITE_UPSTART
		mongo_upstart_script = <<-MONGO_UPSTART
			description "mongo"

			start on startup
			stop on shutdown

			script
					#TODO find out if this is necessary
					export HOME="/home/#{admin_runner}"

					cd #{current_path}
					exec sudo -u root sh -c "mongod"
			end script

			respawn
MONGO_UPSTART

		put site_upstart_script, "/tmp/#{application}_upstart.conf"
		put mongo_upstart_script, "/tmp/mongo_upstart.conf"
		run "#{sudo} mv /tmp/mongo_upstart.conf /etc/init/mongo.conf"
		run "#{sudo} mv /tmp/#{application}_upstart.conf /etc/init/#{application}.conf"
  end
end

before 'deploy:setup', 'deploy:create_deploy'
after 'deploy:setup', 'deploy:write_upstart_script'