Capistrano 3 sudo task - ruby-on-rails

Question

I want to write a recipe with Capistrano 3 executing a task on the remote server with sudo.
With Capistrano 2 this could be done for example:
default_run_options[:pty] = true
task :hello do
run "#{sudo} cp ~/something /something"
end
With Capistrano 3 I found:
set :pty, true
But I could not get to execute a task running with sudo.
How can I run a task with sudo?

Answer 1

The Capistrano 3 guide recommends the use of passwordless sudo. This allows your less-priveleged user execute the sudo command without having to enter a password via the PTY.
You can use the task that Kentaro wrote above, and add something like the following to your /etc/sudoers file:
deploy ALL=NOPASSWD:/bin/cp ~/something /something
http://www.capistranorb.com/documentation/getting-started/authentication-and-authorisation/#toc_8

Answer 2

I usually write like this:
task :hello do
on roles(:all) do |host|
execute :sudo, :cp, '~/something', '/something'
end
end
Edit
Capistrano 3 does not support sudo with password.
However, I created a small gem, which enables you to use sudo with password in Capistrano 3 task.
Add sshkit-sudo to your application's Gemfile:
# Gemfile
gem 'sshkit-sudo'
And require 'sshkit/sudo' in you Capfile:
# Capfile
require 'sshkit/sudo'
Now, you can execute a command with sudo as follows:
task :hello do
on roles(:all) do
sudo :cp, '~/something', '/something'
end
end

Answer 3

To resolve this issue I needed to add set :pty, true to my deploy.rb file.
I can now run the following:
# config valid only for Capistrano 3.1
lock '3.1.0'
set :application, 'APP_NAME'
set :pty, true
set :ssh_options, {:forward_agent => true}
namespace :deploy do
desc 'Restart NGINX'
task :restart do
on roles(:app), in: :sequence, wait: 1 do
execute :sudo, "./restart.sh"
end
end
end
This task basically runs a shell script called restart.sh that has a command within sudo service nginx restart.

Answer 4

you want "as user do end", like
as "root" do
execute :something
end

Answer 5

If you really need to use sudo you can always map the command like SSHKit.config.command_map[:rm] = 'sudo rm' which will make execute :rm into the proper rm command invoked with sudo. If your deploy user is in the sudoers things will work as expected.