scalingo mongo backup command

database.rb

#!/usr/bin/env ruby
require 'bundler'
require 'thor'

class Database < Thor
  desc 'restore BACKUP_PATH', 'Restore the database with given backup'
  option :port, default: '27017'
  option :host, default: '127.0.0.1'
  option :database
  def restore(backup_path)
    execute "echo 'db.dropDatabase();' | mongo #{options[:database]}"
    execute "mongorestore -h #{options[:host]} -p #{options[:port]} -d #{options[:database]} #{backup_path}"
  end

  desc 'backup BACKUP_PATH', 'Backup the production database using scalingo'
  option :scalingo_app
  option :tunnel_port, default: 20000
  option :var_name, default: 'DB_URI'
  option :identity, default: '~/.ssh/id_rsa'
  def backup(path)
    puts 'Fetching env variables...'
    env = Hash[execute("scalingo -app #{options[:scalingo_app]} env").split("\n").map{|line| line.split('=', 2)}]
    db_uri = env[options[:var_name]]
    opts = "--port #{options[:tunnel_port]}"
    opts += " --identity #{options[:identity]}" if options[:identity]
    puts 'Establishing db tunnel...'
    command = "scalingo -app #{options[:scalingo_app]} db-tunnel #{opts} #{options[:var_name]}"
    puts "$ #{command}"
    read, write = IO.pipe
    pid = spawn(command, out: write)
    puts 'Waiting 1 second for tunnel to establish'
    sleep(1)
    if Process.waitpid(pid, Process::WNOHANG)
      $stderr.puts 'Unable to establish tunnel.'
      return
    end

    # Ignore first line
    read.gets
    second_line = read.read_nonblock(50)
    if second_line =~ /password/ # ssh asks for passphrase
      print second_line
      puts read.getc
      puts 'Waiting for tunnel to establish'
      read.gets
    end

    userpass, hostdb =  db_uri[10..-1].split('@')
    user, password = userpass.split(':')
    db = hostdb.split('/').last

    execute("mongodump -u #{user} -p #{password} -h 127.0.0.1:#{options[:tunnel_port]} -d #{db} -o #{path} --numThreads 1")
  ensure
    read.close if read
    write.close if write
    if pid
      if !Process.waitpid(pid, Process::WNOHANG)
        puts 'Closing db-tunnel...'
        Process.kill('INT', pid)
      end
    end
    Process.wait
  end

  no_commands do
    def execute(command)
      puts "$ #{command}"
      `#{command}`
    end
  end
end

Database.start(ARGV)

Gemfile

source 'https://rubygems.org'

ruby '2.0.0'

gem 'thor'