Is there any way to get result of the command executed on server in Mina?

Question

I am moving my Rails application deploy from Capistrano to Mina. The only thing left to do is writing a task to restart a server. I already did the part to start server, but I can't understand how to stop it.

When I was using Capistrano, I had the following task:

desc 'Stop Unicorn'
  task :stop do
    on roles(:app) do
      if test("[ -f #{fetch(:unicorn_pid)} ]")
        execute :kill, capture(:cat, fetch(:unicorn_pid))
      end
    end
  end

This, as I understood, firstly runs test command to determine whether file exists, and then runs kill command if needed. I understand how to do everything of this in Mina except of how to execute test function on server and get its result to do something with it.

Here is what I'm using now,

task :restart_server => :environment do
    queue "cd #{deploy_to}/current"
    if File.exists? unicorn_pid
     queue "kill `cat #{unicorn_pid}`"
    end
    queue "bundle exec unicorn -c #{deploy_to}/#{shared_path}/config/unicorn.rb -E production -D"
end

but this does not work, and I think I understand why (because the File.exists string is executed on client side, not server side).

So, what should I do?

Answer 1

Decided it will be easier to just run test function from queue, like that:

task :restart_server => :environment do
  queue "cd #{deploy_to}/current"

  queue "[ -f #{unicorn_pid} ] && kill $(cat #{unicorn_pid})"
  queue "bundle exec unicorn -c #{deploy_to}/#{shared_path}/config/unicorn.rb -E production -D"
end