tibrvftmon.py

##
# tibrvftmon.py - example TIB/Rendezvous fault tolerant group
#                 monitor program
#
# rewrite TIBRV example: tibrvftmon.c
#
# LAST MODIFIED: V1.0 2016-12-26 ARIEN arien.chen@gmail.com
#
import sys
import signal
import getopt
from pytibrv.api import *
from pytibrv.status import *
from pytibrv.queue import *
from pytibrv.tport import *
from pytibrv.ft import *

# Module Variables
_running = True
_oldNumActives = 0

def signal_proc(signal, frame):
    global _running
    _running = False
    print()
    print('CRTL-C PRESSED')

def usage():
    print()
    print('tibrvftmon.py [options]')
    print('')
    print('options:')
    print('    [--service service]          RVD Service')
    print('    [--network network]          RVD Network')
    print('    [--daemon daemon]            RVD Daemon')
    print()
    sys.exit(1)


def get_params(argv):

    params = ['service=', 'network=', 'daemon=']
    try:
        opts, args = getopt.getopt(argv, '', params)

    except getopt.GetoptError:
        usage()

    service = None
    network = None
    daemon = None

    for opt, arg in opts:
        if opt == '--service':
            service = arg
        elif opt == '--network':
            network = arg
        elif opt == '--daemon':
            daemon = arg
        else:
            usage()

    if len(args) != 0:
        usage()

    return service, network, daemon


def monCB(monitor: tibrvftMonitor, groupName: bytes, numActiveMembers: int, closure):
    global _oldNumActives

    grp = groupName.decode()

    if _oldNumActives > numActiveMembers:
        txt = 'one deactivated'
    else:
        txt = 'one activated'

    print('Group [{}]: has {} active members (after {})'.format(
           grp,
           numActiveMembers,
           txt
         ))

    _oldNumActives = numActiveMembers

    return


# MAIN PROGRAM
def main(argv):

    service, network, daemon = get_params(argv[1:])
    progname = argv[0]
    lostInt = 4.8

    err = tibrv_Open()
    if err != TIBRV_OK:
        print('{}: Failed to open TIB/RV: {}'.format('', progname, tibrvStatus_GetText(err)))
        sys.exit(1)


    err, tx = tibrvTransport_Create(service, network, daemon)
    if err != TIBRV_OK:
        print('{}: Failed to initialize transport: {}'.format(progname, tibrvStatus_GetText(err)))
        sys.exit(1)

    err, monitor = tibrvftMonitor_Create(TIBRV_DEFAULT_QUEUE, monCB, tx, 'TIBRVFT_TIME_EXAMPLE', lostInt, None)

    if err != TIBRV_OK:
        print('{} : Failed to start group monitor - {}', progname, tibrvStatus_GetText(err))
        sys.exit(1)\


    print('{} : Waiting for group information...'.format(progname))

    # Set Signal Handler for Ctrl-C
    global _running
    signal.signal(signal.SIGINT, signal_proc)

    while _running:
        tibrvQueue_TimedDispatch(TIBRV_DEFAULT_QUEUE, 0.5)

    # CTRL-C PRESSED
    # when ftMonitor destroyed,
    # callback would be triggered within numActiveMembers = 0
    # it is fault alert, and should be ignored
    tibrvftMonitor_Destroy(monitor)

    tibrv_Close()


    return

if __name__ == "__main__":
    main(sys.argv)