Example mina deploy script using docker

config.rb

require 'mina/git'
require 'mina/nginx'

set :application, 'your_app_name'
set :domain, 'your_server'
set :user, 'ubuntu'
set :deploy_to, '/location/to/deploy'
set :app_path, "#{deploy_to}/#{current_path}"
set :repository, 'your_repo'
set :branch, 'master'
set :forward_agent, true # sorting out credentials for private gems

task :environment do
  invoke :'important_variables'
end

task :important_variables => :environment do
  queue! %[source /home/ubuntu/.secret_key_base]
end

task :setup => :environment do
  queue! %[mkdir -p "#{deploy_to}/#{shared_path}/log"]
  queue! %[chmod g+rx,u+rwx "#{deploy_to}/#{shared_path}/log"]

  queue! %[mkdir -p "#{deploy_to}/#{shared_path}/config"]
  queue! %[touch "#{deploy_to}/#{shared_path}/config/database.yml"]
  queue! %[touch "#{deploy_to}/#{shared_path}/config/secrets.yml"]

  invoke :'nginx:setup'
  invoke :'nginx:link'
end

desc "Deploys the current version to the server."
task :deploy => :environment do
  deploy do
    invoke :'git:clone'
    
    to :launch do
        invoke :'docker:build' 
        invoke :'docker:stop' # stop the previous container
        invoke :'docker:run' # run new container with released code
    end
  end
end

namespace :docker do
  set :image_name, ENV.fetch("IMAGE_NAME", "default_image_name")
  set :dockerfile, ENV.fetch("DOCKERFILE", "Dockerfile")
  set :container_name, ENV.fetch("CONTAINER_NAME", "service")
  
  # Sharing mysql sockets to communicate Host and Container
  set :mysql_socket_volume, "/var/run/mysqld/mysqld.sock:/var/run/mysqld/mysqld.sock"
  # Mount configuration and log folders
  set :configuration_volume, "#{deploy_to}/#{shared_path}/config:/config"
  set :log_volume, "#{deploy_to}/#{shared_path}/log:/log"

  # Rails specific
  set :rails_environment, "production"

  desc "Build docker image"
  task build: :environment do
    queue "cd #{deploy_to}/#{current_path}"
    queue "sudo docker build --no-cache=true -f #{dockerfile} -t #{image_name} ."
  end

  desc "Start docker container"
  task run: :environment do
    queue "sudo docker run -d -p 3000:8080 -e SECRET_KEY_BASE=$SECRET_KEY_BASE -e SECRET_TOKEN=$SECRET_KEY_BASE -e RAILS_ENV=#{rails_environment} -v #{configuration_volume} -v #{log_volume} -v #{mysql_socket_volume} --name #{container_name} #{image_name}"
  end

  desc "Debug docker container"
  task debug: :environment do
    queue "sudo docker run -t -i -p 3000:8080 -e SECRET_KEY_BASE=$SECRET_KEY_BASE -e SECRET_TOKEN=$SECRET_KEY_BASE -e RAILS_ENV=#{rails_environment} -v #{configuration_volume} -v #{log_volume} -v #{mysql_socket_volume} #{image_name} /bin/bash"
  end

  desc "Stop docker container"
  task stop: :environment do
    queue "if [ ! -z \"$(sudo docker ps | grep '#{container_name}')\" ]; then sudo docker stop #{container_name}; sudo docker rm -f #{container_name}; fi"
  end

  desc "Remove all stop container"
  task clean_containers: :environment do
    queue "sudo docker rm $(sudo docker ps -a -q)"
  end
end

nginx_configuration

upstream demo.localhost {
    server 127.0.0.1:3000;
}

server {
    gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;

    server_name demo.localhost;

    location / {
        proxy_pass http://demo.localhost;
        include /etc/nginx/proxy_params;
    }
}