scheduler/monitor_db_babysitter

#!/usr/bin/python -u
import os, sys, signal, time, subprocess
from optparse import OptionParser

PAUSE_LENGTH = 60
STALL_TIMEOUT = 2*60*60

parser = OptionParser()
parser.add_option("-r", action="store_true", dest="recover")
(options, args) = parser.parse_args()

autodir = os.path.abspath(os.path.join(os.path.dirname(__file__), '..'))
results_dir = os.path.join(autodir, 'results')
monitor_db = os.path.join(autodir, 'scheduler/monitor_db.py')
recover = (options.recover == True)


if len(args) != 0:
    print "Usage: %s [options]" % __file__
    print "  -r    Run recovery mode.  (Note: recovery is implicit after"
    print "        any crash!)"
    print
    sys.exit(1)


def bprint(msg):
    print "%s> %s" % (time.strftime("%X %x"), msg)


def kill_all_monitors():
    bprint("Killing all monitor_dbs")
    # try shutdown first
    status = os.system("killall -2 monitor_db.py")
    if status == 0: # were any killed?
        # give them some time to shutdown
        time.sleep(30)
        # kill any that are left
        os.system("killall monitor_db.py")


def handle_sigterm(signum, frame):
    bprint('Caught SIGTERM')
    kill_all_monitors()
    sys.exit(1)

signal.signal(signal.SIGTERM, handle_sigterm)


class MonitorProc:
    def __init__(self, do_recovery=False):
        args = [monitor_db]
        if do_recovery:
            args.append("--recover-hosts")
        args.append(results_dir)

        kill_all_monitors()

        self.log_path = os.path.join(autodir, 'logs/monitor.log.%d'
                                     % time.time())
        log = open(self.log_path, "a")
        devnull = open(os.devnull, "r")

        self.log_size = os.path.getsize(self.log_path)
        self.last_log_change = time.time()

        bprint("STARTING monitor_db with log file %s" % self.log_path)
        self.proc = subprocess.Popen(args, stdout=log, stdin=devnull,
                                     stderr=subprocess.STDOUT)
        log.close()
        devnull.close()


    def is_running(self):
        if self.proc.poll() != None:
            bprint("monitor_db DIED")
            return False

        old_size = self.log_size
        new_size = os.path.getsize(self.log_path)
        if old_size != new_size:
            bprint("Log was touched")
            self.log_size = new_size
            self.last_log_change = time.time()
        elif self.last_log_change + STALL_TIMEOUT < time.time():
            bprint("monitor_db STALLED")
            return False

        return True


bprint("initializing")
while True:
    proc = MonitorProc(do_recovery=recover)
    time.sleep(PAUSE_LENGTH)
    while proc.is_running():
        bprint("Tick")
        time.sleep(PAUSE_LENGTH)
    recover = False