How to run shell commands on server in Capistrano v3?

Question

I'm new to Capistrano and I've tried using Capistrano's DSL to run shell commands on the server ('run', 'execute', etc.), but it appears that it was deprecated. After searching and searching for a functional equivalent, I still am lost.

Current code:

desc 'Do something'
task :do_something
  execute 'echo sometext'
end

Output:

    cap aborted!
    undefined method `execute' for main:Object
    /Users/Justin/Dropbox/xxxx/xxxx/xxxx/Capfile:45:in `block (2 levels) in <top (required)>'
    /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bundler/gems/capistrano-2dc1627838f9/lib/capistrano/application.rb:12:in `run'
    /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bundler/gems/capistrano-2dc1627838f9/bin/cap:3:in `<top (required)>'
    /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/cap:23:in `load'
    /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/cap:23:in `<main>'
    /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `eval'
    /Users/Justin/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `<main>'
    Tasks: TOP => deploy:do_something

Ashil

I had exactly the same problem with the methods "info" and "error" -- the same problem because the methods belong to SSHKit and must be in an SSHKit block. – Emendation

Answer 1

In Capistrano v3, you must specify where you want to run the code by calling on with a list of hostnames, e.g.

task :execute_on_server do
  on "[email protected]" do
    execute "some_command"
  end
end

If you have roles set up, you can use the roles method as a convenience:

role :mailserver, "[email protected]"

task :check_mail do
  on roles(:mailserver) do
    execute "some_command"
  end
end

There is some v3 documentation here: http://www.capistranorb.com/

Penny

Awesome, I wish they made it clearer in the walkthrough. They only use test, info, etc. – Ashil

Capistrano execute method rely on implementation in sshkit. Right now you can find more information on execute here: github.com/leehambley/sshkit Capistrano 3 documentation is still incomplete. – Paternity

@KitHo Yes, you can use sudo, just as you can with a manual ssh connection. – Fondea

When I had the same problem with 'info' and 'error' methods, I used run_locally { ... } rather than on ... { ... }. That gets you into SSHKit context without connecting to a remote box. – Emendation