#! /usr/local/bin/python

# Copyright (C) 2001-2006 by the Free Software Foundation, Inc.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
# USA.

"""Run one or more qrunners, once or repeatedly.

Each named runner class is run in round-robin fashion.  In other words, the
first named runner is run to consume all the files currently in its
directory.  When that qrunner is done, the next one is run to consume all the
files in /its/ directory, and so on.  The number of total iterations can be
given on the command line.

Usage: %(PROGRAM)s [options]

Options:

    -r runner[:slice:range]
    --runner=runner[:slice:range]
        Run the named qrunner, which must be one of the strings returned by
        the -l option.  Optional slice:range if given, is used to assign
        multiple qrunner processes to a queue.  range is the total number of
        qrunners for this queue while slice is the number of this qrunner from
        [0..range).

        If using the slice:range form, you better make sure that each qrunner
        for the queue is given the same range value.  If slice:runner is not
        given, then 1:1 is used.

        Multiple -r options may be given, in which case each qrunner will run
        once in round-robin fashion.  The special runner `All' is shorthand
        for a qrunner for each listed by the -l option.

    --once
    -o
        Run each named qrunner exactly once through its main loop.  Otherwise,
        each qrunner runs indefinitely, until the process receives a SIGTERM
        or SIGINT.

    -l/--list
        Shows the available qrunner names and exit.

    -v/--verbose
        Spit out more debugging information to the logs/qrunner log file.

    -s/--subproc
        This should only be used when running qrunner as a subprocess of the
        mailmanctl startup script.  It changes some of the exit-on-error
        behavior to work better with that framework.

    -h/--help
        Print this message and exit.

runner is required unless -l or -h is given, and it must be one of the names
displayed by the -l switch.

Note also that this script should be started up from mailmanctl as a normal
operation.  It is only useful for debugging if it is run separately.
"""

import sys
import getopt
import signal

import paths
from Mailman import mm_cfg
from Mailman.i18n import _
from Mailman.Logging.Syslog import syslog
from Mailman.Logging.Utils import LogStdErr

PROGRAM = sys.argv[0]
COMMASPACE = ', '

# Flag which says whether we're running under mailmanctl or not.
AS_SUBPROC = 0



def usage(code, msg=''):
    if code:
        fd = sys.stderr
    else:
        fd = sys.stdout
    print >> fd, _(__doc__)
    if msg:
        print >> fd, msg
    sys.exit(code)



def make_qrunner(name, slice, range, once=0):
    modulename = 'Mailman.Queue.' + name
    try:
        __import__(modulename)
    except ImportError, e:
        if AS_SUBPROC:
            # Exit with SIGTERM exit code so mailmanctl won't try to restart us
            print >> sys.stderr, 'Cannot import runner module', modulename
            print >> sys.stderr, e
            sys.exit(signal.SIGTERM)
        else:
            usage(1, e)
    qrclass = getattr(sys.modules[modulename], name)
    if once:
        # Subclass to hack in the setting of the stop flag in _doperiodic()
        class Once(qrclass):
            def _doperiodic(self):
                self.stop()
        qrunner = Once(slice, range)
    else:
        qrunner = qrclass(slice, range)
    return qrunner



def set_signals(loop):
    # Set up the SIGTERM handler for stopping the loop
    def sigterm_handler(signum, frame, loop=loop):
        # Exit the qrunner cleanly
        loop.stop()
        loop.status = signal.SIGTERM
        syslog('qrunner', '%s qrunner caught SIGTERM.  Stopping.', loop.name())
    signal.signal(signal.SIGTERM, sigterm_handler)
    # Set up the SIGINT handler for stopping the loop.  For us, SIGINT is
    # the same as SIGTERM, but our parent treats the exit statuses
    # differently (it restarts a SIGINT but not a SIGTERM).
    def sigint_handler(signum, frame, loop=loop):
        # Exit the qrunner cleanly
        loop.stop()
        loop.status = signal.SIGINT
        syslog('qrunner', '%s qrunner caught SIGINT.  Stopping.', loop.name())
    signal.signal(signal.SIGINT, sigint_handler)
    # SIGHUP just tells us to close our log files.  They'll be
    # automatically reopened at the next log print :)
    def sighup_handler(signum, frame, loop=loop):
        syslog.close()
        syslog('qrunner', '%s qrunner caught SIGHUP.  Reopening logs.',
               loop.name())
    signal.signal(signal.SIGHUP, sighup_handler)



def main():
    global AS_SUBPROC
    try:
        opts, args = getopt.getopt(
            sys.argv[1:], 'hlor:vs',
            ['help', 'list', 'once', 'runner=', 'verbose', 'subproc'])
    except getopt.error, msg:
        usage(1, msg)

    once = 0
    runners = []
    verbose = 0
    for opt, arg in opts:
        if opt in ('-h', '--help'):
            usage(0)
        elif opt in ('-l', '--list'):
            for runnername, slices in mm_cfg.QRUNNERS:
                if runnername.endswith('Runner'):
                    name = runnername[:-len('Runner')]
                else:
                    name = runnername
                print _('%(name)s runs the %(runnername)s qrunner')
            print _('All runs all the above qrunners')
            sys.exit(0)
        elif opt in ('-o', '--once'):
            once = 1
        elif opt in ('-r', '--runner'):
            runnerspec = arg
            parts = runnerspec.split(':')
            if len(parts) == 1:
                runner = parts[0]
                slice = 1
                range = 1
            elif len(parts) == 3:
                runner = parts[0]
                try:
                    slice = int(parts[1])
                    range = int(parts[2])
                except ValueError:
                    usage(1, 'Bad runner specification: %(runnerspec)s')
            else:
                usage(1, 'Bad runner specification: %(runnerspec)s')
            if runner == 'All':
                for runnername, slices in mm_cfg.QRUNNERS:
                    runners.append((runnername, slice, range))
            else:
                if runner.endswith('Runner'):
                    runners.append((runner, slice, range))
                else:
                    runners.append((runner + 'Runner', slice, range))
        elif opt in ('-s', '--subproc'):
            AS_SUBPROC = 1
        elif opt in ('-v', '--verbose'):
            verbose = 1

    if len(args) <> 0:
        usage(1)
    if len(runners) == 0:
        usage(1, _('No runner name given.'))

    # Before we startup qrunners, we redirect the stderr to mailman syslog.
    # We assume !AS_SUBPROC is running for debugging purpose and don't
    # log errors in mailman logs/error but keep printing to stderr.
    if AS_SUBPROC:
        LogStdErr('error', 'qrunner', manual_reprime=0, tee_to_real_stderr=0)

    # Fast track for one infinite runner
    if len(runners) == 1 and not once:
        qrunner = make_qrunner(*runners[0])
        class Loop:
            status = 0
            def __init__(self, qrunner):
                self.__qrunner = qrunner
            def name(self):
                return self.__qrunner.__class__.__name__
            def stop(self):
                self.__qrunner.stop()
        loop = Loop(qrunner)
        set_signals(loop)
        # Now start up the main loop
        syslog('qrunner', '%s qrunner started.', loop.name())
        qrunner.run()
        syslog('qrunner', '%s qrunner exiting.', loop.name())
    else:
        # Anything else we have to handle a bit more specially
        qrunners = []
        for runner, slice, range in runners:
            qrunner = make_qrunner(runner, slice, range, 1)
            qrunners.append(qrunner)
        # This class is used to manage the main loop
        class Loop:
            status = 0
            def __init__(self):
                self.__isdone = 0
            def name(self):
                return 'Main loop'
            def stop(self):
                self.__isdone = 1
            def isdone(self):
                return self.__isdone
        loop = Loop()
        set_signals(loop)
        syslog('qrunner', 'Main qrunner loop started.')
        while not loop.isdone():
            for qrunner in qrunners:
                # In case the SIGTERM came in the middle of this iteration
                if loop.isdone():
                    break
                if verbose:
                    syslog('qrunner', 'Now doing a %s qrunner iteration',
                           qrunner.__class__.__bases__[0].__name__)
                qrunner.run()
            if once:
                break
        syslog('qrunner', 'Main qrunner loop exiting.')
    # All done
    sys.exit(loop.status)



if __name__ == '__main__':
    main()
