nulogy/Gorgon

require "tmpdir"

module Gorgon
  class RsyncDaemon
    #for now, creates a readonly rsync daemon for the current directory on the mountpath "src"
    RSYNC_DIR_NAME = "#{Dir.tmpdir}/gorgon_rsync_daemon"
    RSYNC_PORT = 43434
    PID_FILE = 'rsync.pid'

    def self.start(directory_bucket)
      if directory_bucket.nil? || !File.directory?(directory_bucket)
        $stderr.puts "Please, expecify a valid directory."
        return false
      end

      if !port_available?
        puts port_busy_msg
        return false
      end

      Dir.mkdir(RSYNC_DIR_NAME)
      success = false
      Dir.chdir(RSYNC_DIR_NAME) do
        File.write("rsyncd.conf", rsyncd_config_string(directory_bucket))

        success = Kernel.system("rsync --daemon --config rsyncd.conf")
      end

      success
    end

    def self.stop
      if !File.directory?(RSYNC_DIR_NAME)
        puts "ERROR: Directory '#{RSYNC_DIR_NAME}' doesn't exists. Maybe rsync daemon is not running!"
        return false
      end

      success = nil
      Dir.chdir(RSYNC_DIR_NAME) do
        pid = File.read(PID_FILE)
        success = Kernel.system("kill #{pid}")
      end

      if success
        FileUtils::remove_entry_secure(RSYNC_DIR_NAME)
        return true
      else
        return false
      end
    end

    private

    def self.rsyncd_config_string(directory_bucket)
      return <<-EOF
port = #{RSYNC_PORT}
pid file = #{PID_FILE}

[src]
  path = #{directory_bucket}
  read only = false
  use chroot = false
      EOF
    end

    def self.port_available?
      begin
        s = TCPServer.new('localhost', RSYNC_PORT)
        s.close
        return true
      rescue Errno::EADDRINUSE => _
        return false
      end
    end

    def self.port_busy_msg
      <<-MSG
  ERROR: port #{RSYNC_PORT} is being used. Maybe another rsync daemon is running.
  Kill pid in #{RSYNC_DIR_NAME}/#{PID_FILE} or check no other process is using that port."
      MSG
    end
  end
end