Rake tasks for Heroku Deployments.

deployment.rake

#####################################
# Rake tasks for Heroku Deployments #
#####################################
#
# Assumptions:
# - You’re using Heroku to deploy a Rails application or similar.
# - You have two remotes, one called 'production', and one called 'staging'.
# - You have a 'master' branch, and it usually contains stable code.
#
# Usage:
#   rake deploy:ENVIRONMENT[BRANCH]
#
# Where:
# - ENVIRONMENT is one of "production", "staging", or "all" (without quotes).
# - BRANCH is the name of the branch you wish to deploy (defaults to "master").
#
# Note: The [branch] section is optional for all commands.
#
# Mostly stolen from https://gist.github.com/croaky/1189285

namespace :deploy do
  desc "Deploy to staging on Heroku"
  task :staging, :branch do |t, args|
    Deployment.new(environment: "staging", branch: args[:branch]).run
  end

  desc "Deploy to production on Heroku"
  task :production, :branch do |t, args|
    Deployment.new(environment: "production", branch: args[:branch]).run
  end

  desc "Deploy to all environments on Heroku"
  task :all, :branch do |t, args|
    %w[ staging production ].each do |remote|
      Deployment.new(environment: remote, branch: args[:branch]).run
    end
  end
end

class Deployment

  def initialize(opts = {})
    @environment = opts[:environment]
    @branch      = opts[:branch] || "master"
    @start_time  = Time.now
  end

  def run
    debug_output "Started deploying '#{@branch}' to #{@environment}."
    push_heroku
    migrate
    debug_output "Deployment finished in #{duration}."
  end

  private

  def push_heroku
    debug_output "Pushing to Heroku remote…"
    run_command "git push #{@environment} #{@branch}:master --force"
  end

  def migrate
    debug_output "Migrating database…"
    run_command "bundle exec heroku run rake db:migrate --remote #{@environment}"
  end

  def debug_output(message)
    puts "[Deploy] #{message}"
  end

  def run_command(command)
    puts "=> Running `#{command}`"
    `#{command}`
    # `ls -l`
    debug_output "Done."
  end

  def duration
    difference = Time.now - @start_time
    total_seconds = Integer(difference)
    if total_seconds == 0
      "#{difference * 1000}ms"
    else
      hours = total_seconds / (60 * 60)
      minutes = (total_seconds / 60) % 60
      seconds = total_seconds % 60
      hours_output = hours > 0 ? "#{hours} hours" : ""
      hours_output << ", " if hours > 0 && minutes > 0
      minutes_output = minutes > 0 ? "#{minutes} minutes" : ""
      minutes_output << ", " if minutes > 0 && seconds > 0
      seconds_output = seconds > 0 ? "#{seconds} seconds" : ""
      output = hours_output + minutes_output + seconds_output
    end
  end

end