Upstart with Puma and chruby for a single app (single mode).

deploy.rb

after "deploy:restart", "puma:restart"

namespace :puma do
  task :restart, roles: :app do
    run "cd #{current_path} && #{bundle_cmd} exec pumactl -S #{shared_path}/pids/puma.state restart"
  end
end

nginx.conf

upstream app_server {
  server unix:///srv/deploy/app/shared/sockets/puma.sock fail_timeout=0;
}

server {
  listen 80;
  server_name _;

  access_log /var/log/nginx/app-access.log combined;

  keepalive_timeout 5;

  root /srv/deploy/app/current/public;

  location / {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://app_server;
  }

  location ~ ^/assets/ {
    root /srv/deploy/app/current/public;
    gzip_static on;
    expires 1y;
    add_header Cache-Control "public";
    add_header ETag "";
    access_log off;
  }

  error_page 500 502 503 504 /500.html;
  location = /500.html {
    root /srv/deploy/app/current/public;
  }
}

puma-production.rb

directory '/srv/deploy/app/current'
rackup '/srv/deploy/app/current/config.ru'
environment 'production'
daemonize false
pidfile '/srv/deploy/app/shared/pids/puma.pid'
state_path '/srv/deploy/app/shared/pids/puma.state'
stdout_redirect '/srv/deploy/app/shared/log/puma-stdout.log', '/srv/deploy/app/shared/log/puma-stderr.log'
threads 0, 32
workers 0
bind 'unix:///srv/deploy/app/shared/sockets/puma.sock'

puma.conf

description "Puma Process Monitoring"
author      "Vincent Durand <[email protected]>"

start on runlevel [12]
stop on shutdown

respawn
respawn limit 5 15

setuid deploy
setgid deploy

script
exec /bin/bash << EOT
  export HOME=/srv/deploy

  source /usr/local/share/chruby/chruby.sh
  source /usr/local/share/chruby/auto.sh

  cd /srv/deploy/app/current && exec bundle exec puma -C config/puma/production.rb
EOT
end script