Heroku Deploy Script

deploy.rake

class DeployTask
  attr_accessor :app_suffix, :heroku_app, :git_branch, :force, :enter_maintenance

  def initialize(options = {})
    @app_suffix = options[:app_suffix]
    @heroku_app = options.fetch(:heroku_app, default_app_name)
    @git_branch = options.fetch(:git_branch, current_branch)
    @force = options.fetch(:force, false)
    @enter_maintenance = options.fetch(:enter_maintenance, true)
  end

  def deploy
    start = Time.now
    maintenance do
      push
      migrate
    end
    open
    puts "===== This whole process took #{Time.now - start} seconds"
  end

  def migrate
    start = Time.now
    maintenance do
      migrate
    end
    puts "===== This whole process took #{Time.now - start} seconds"
  end

private

  def default_app_name
    if defined?(Rails)
      name = Rails.application.class.parent_name.underscore.dasherize
      name += "-#{app_suffix}" if app_suffix
      name
    end
  end

  def current_branch
    @current_branch ||= `git rev-parse --abbrev-ref HEAD`.chomp
  end

  def push
    branch_to_branch = (current_branch.length > 0) ? "#{current_branch}:master" : ""
    puts "===== I am going to deploy this application to heroku"
    puts "git push#{ " -f" if force } git@heroku.com:#{heroku_app}.git #{branch_to_branch}"
    puts `git push#{ " -f" if force } git@heroku.com:#{heroku_app}.git #{branch_to_branch}`
  end

  def maintenance
    if enter_maintenance
      maintenance_on
      yield
      maintenance_off
    else
      yield
    end
  end

  def maintenance_on
    puts '===== Putting the app into maintenance mode'
    Bundler.with_clean_env { puts `heroku maintenance:on --app=#{heroku_app}` }
  end

  def maintenance_off
    puts '===== Taking the app out of maintenance mode'
    Bundler.with_clean_env { puts `heroku maintenance:off --app=#{heroku_app}` }
  end

  def migrate
    puts 'Running database migrations'
    Bundler.with_clean_env { puts `heroku run 'rake db:migrate' --app=#{heroku_app}` }
  end

  def open
    sleep(0.2) # wait for any pending requests to finish
    puts '===== Opening the app in your browser'
    Bundler.with_clean_env { puts `heroku open --app=#{heroku_app}` }
  end
end

namespace :deploy do
  namespace :develop do
    task :migrate do
      DeployTask.new({
        app_suffix: 'develop',
      }).migrate
    end
  end

  task :develop do
    DeployTask.new({
      app_suffix: 'develop'
    }).deploy
  end

  namespace :production do
    task :migrate do
      DeployTask.new.migrate
    end
  end

  task :production, [:branch] do |t, args|
    args.with_defaults(branch: 'master')
    DeployTask.new({
      git_branch: args[:branch]
    }).deploy
  end
end

task :deploy do
  DeployTask.new({
    app_suffix: 'develop'
  }).deploy
end

At the moment, this script makes some assumptions:

1. You're deploying a Rails application
2. Your project uses git
3. You're deploying to Heroku
4. You want to deploy the currently checked out git branch
5. The Heroku app uses the dasherized version of your Rails Application name
6. Your development server app name prepends '-develop' to your production app name
7. You don't need to run any seeds or rake tasks during deployment (which should be done with maintenance mode turned on)

For example:

Rails application: CoolApp
Heroku endpoint: https://cool-app.herokuapp.com
Heroku develop (or staging) endpoint: https://cool-app-develop.herokuapp.com