Synnefo » snf-ganeti » ganeti-local

import logging

from ganeti import constants

def GenericMain(daemon_name, optionparser, dirs, check_fn, exec_fn):

  """Shared main function for daemons.

  @type daemon_name: string

  @param daemon_name: daemon name

  @type optionparser: L{optparse.OptionParser}

  @param optionparser: initialized optionparser with daemon-specific options

                       (common -f -d options will be handled by this module)

  @type options: object @param options: OptionParser result, should contain at

                 least the fork and the debug options

  @type dirs: list of strings

  @param dirs: list of directories that must exist for this daemon to work

  @type check_fn: function which accepts (options, args)

  @param check_fn: function that checks start conditions and exits if they're

                   not met

  @type exec_fn: function which accepts (options, args)

  @param exec_fn: function that's executed with the daemon's pid file held, and

                  runs the daemon itself.

  """

  optionparser.add_option("-f", "--foreground", dest="fork",

                          help="Don't detach from the current terminal",

                          default=True, action="store_false")

  optionparser.add_option("-d", "--debug", dest="debug",

                          help="Enable some debug messages",

                          default=False, action="store_true")

  if daemon_name in constants.DAEMONS_PORTS:

    # for networked daemons we also allow choosing the bind port and address.

    # by default we use the port provided by utils.GetDaemonPort, and bind to

    # 0.0.0.0 (which is represented by and empty bind address.

    port = utils.GetDaemonPort(daemon_name)

    optionparser.add_option("-p", "--port", dest="port",

                            help="Network port (%s default)." % port,

                            default=port, type="int")

    optionparser.add_option("-b", "--bind", dest="bind_address",

                            help="Bind address",

                            default="", metavar="ADDRESS")

  multithread = utils.no_fork = daemon_name in constants.MULTITHREADED_DAEMONS

  options, args = optionparser.parse_args()

  check_fn(options, args)

  utils.EnsureDirs(dirs)

  if options.fork:

    utils.CloseFDs()

    utils.Daemonize(logfile=constants.DAEMONS_LOGFILES[daemon_name])

  utils.WritePidFile(daemon_name)

  try:

    utils.SetupLogging(logfile=constants.DAEMONS_LOGFILES[daemon_name],

                       debug=options.debug,

                       stderr_logging=not options.fork,

                       multithreaded=multithread)

    logging.info("%s daemon startup" % daemon_name)

    exec_fn(options, args)

  finally:

    utils.RemovePidFile(daemon_name)