Capistrano 3 recipe for Puma. Put in lib/capistrano/tasks/puma.cap . Expects the use of bundle and a complete Puma config file in config/puma/<environment>.rb . RVM compatible (gem 'capistrano-rvm').

capistrano3_puma.rb

commands = %w(start stop restart phased-restart status stats halt)

namespace :deploy do
  desc 'Puma web server Start'
  task :start do
    on roles(:app), in: :sequence, wait: 5 do
      within current_path do
        execute :bundle, "exec puma -C #{config_file}"
      end
    end
  end

  (commands - ['start']).each do |command|
    desc "Puma web server #{command.capitalize}"
    task command.to_sym do
      on roles(:app), in: :sequence, wait: 5 do
        within current_path do
          if command =~ /restart$/ && !test("[ -f #{pid_path} ]")
            Rake::Task['deploy:start'].invoke
          else
            execute :bundle, "exec pumactl -F #{config_file} #{command}"
          end
        end
      end
    end
  end

  # RVM integration
  if Gem::Specification::find_all_by_name('capistrano-rvm').any?
    commands.each do |command|
      before command.to_sym, 'rvm:hook'
    end
  end
end

def config_file
  "./config/puma/#{fetch(:stage)}.rb"
end

def state_path
  configuration.options[:state]
end

def pid_path
  configuration.options[:pidfile]
end

def configuration
  require 'puma/configuration'

  config = Puma::Configuration.new(config_file: config_file)
  config.load
  config
end