Ruby on Rails mysql backup rake task

mysql.rake

# encoding: utf-8
namespace :mysql do

  desc 'backup mysql database'
  task :backup => :environment do

    filename = "#{Rails.root}/config/database.yml"
    config = YAML::load(File.open(filename))[Rails.env]

    if config.nil?
      p "database config file (#{filename}) has no environment setting for #{Rails.env}"
      return
    end

    if config["adapter"] != "mysql2"
      p "database setting for #{Rails.env} is not mysql2"
      return
    end

    database = config["database"]
    host = config["host"] || "localhost"
    username = config["username"]
    password = config["password"]
    outdir = config["backupdir"] || "#{Rails.root}/tmp"
    outfile = "#{outdir}/#{Rails.env}_#{DateTime.now.strftime("%Y%m%d_%H%M%S.sql")}"

    if username.nil?
      p "database setting for #{Rails.env} has no username"
      return
    end

    if password.nil?
      p "database setting for #{Rails.env} has no password"
      return
    end

    begin
      Dir::mkdir(outdir) unless File.exists?(outdir)
    rescue
      p "makedir #{outdir} failed"
      return
    end
    "created: #{outdir}"

    command = "mysqldump --default-character-set=binary #{database} --host=#{host} --user=#{username} --password=#{password} > #{outfile}"
    begin
      exec command
    rescue
      p "execute command failed: #{command}"
    end
    
  end

end