Source code for glideinwms.frontend.stopFrontend

#!/usr/bin/env python3

# SPDX-FileCopyrightText: 2009 Fermi Research Alliance, LLC
# SPDX-License-Identifier: Apache-2.0

#
# Project:
#   glideinWMS
#
# File Version:
#
# Description:
#   Stop a running glideinFrontend
#
# Arguments:
#   $1 = work_dir
#
# Author:
#   Igor Sfiligoi
#


import os
import signal
import sys
import time

from glideinwms.frontend import glideinFrontendConfig, glideinFrontendPidLib


# this one should  never throw an exeption


def get_element_pids(work_dir, frontend_pid):
    # get element pids
    frontendDescript = glideinFrontendConfig.FrontendDescript(work_dir)
    groups = sorted(frontendDescript.data["Groups"].split(","))

    element_pids = {}
    for group in groups:
        try:
            element_pid, element_ppid = glideinFrontendPidLib.get_element_pid(work_dir, group)
        except RuntimeError as e:
            print(e)
            continue  # report error and go to next group
        if element_ppid != frontend_pid:
            print(f"Group '{group}' has an unexpected Parent PID: {element_ppid}!={frontend_pid}")
            continue  # report error and go to next group
        element_pids[group] = element_pid

    return element_pids





def main(work_dir, force=False):
    retries_count = 50
    sleep_in_retries = 0.6
    # get the pids
    try:
        frontend_pid = glideinFrontendPidLib.get_frontend_pid(work_dir)
    except RuntimeError as e:
        print(e)
        if str(e) == "Frontend not running":
            # Workaround to distinguish when the frontend is not running
            # string must be the same as in glideinFrontendPidLib
            return 2
        return 1
    # print frontend_pid

    if not glideinFrontendPidLib.pidSupport.check_pid(frontend_pid):
        # Frontend already dead
        return 0

    # kill processes
    # first soft kill the frontend (30s timeout, retries_count*sleep_in_retries )
    try:
        os.kill(frontend_pid, signal.SIGTERM)
    except OSError:
        pass  # frontend likely already dead

    for retries in range(retries_count):
        if glideinFrontendPidLib.pidSupport.check_pid(frontend_pid):
            time.sleep(sleep_in_retries)
        else:
            return 0  # frontend dead

    if not force:
        print("Frontend did not die after the timeout of %s sec" % (retries_count * sleep_in_retries))
        return 1

    # Retry soft kill the frontend ... should exit now
    print("Frontend still alive ... retrying soft kill")
    try:
        os.kill(frontend_pid, signal.SIGTERM)
    except OSError:
        pass  # frontend likely already dead

    for retries in range(retries_count):
        if glideinFrontendPidLib.pidSupport.check_pid(frontend_pid):
            time.sleep(sleep_in_retries)
        else:
            return 0  # frontend dead

    print("Frontend still alive ... sending hard kill")

    element_pids = get_element_pids(work_dir, frontend_pid)
    # print element_pids

    element_keys = sorted(element_pids.keys())

    for element in element_keys:
        if glideinFrontendPidLib.pidSupport.check_pid(element_pids[element]):
            print("Hard killing element %s" % element)
            try:
                os.kill(element_pids[element], signal.SIGKILL)
            except OSError:
                pass  # ignore already dead processes

    if not glideinFrontendPidLib.pidSupport.check_pid(frontend_pid):
        return 0  # Frontend died

    try:
        os.kill(frontend_pid, signal.SIGKILL)
    except OSError:
        pass  # ignore problems
    return 0



USAGE_STRING = """Usage: stopFrontend [-f|force] work_dir
     return values: 0 Frontend stopped,
         1 unable to stop Frontend or wrong invocation, 2 Frontend was not running
"""
if __name__ == "__main__":
    if len(sys.argv) < 2:
        print(USAGE_STRING)
        sys.exit(1)

    if len(sys.argv) > 2:
        if sys.argv[1] == "-force" or sys.argv[1] == "-f":
            sys.exit(main(sys.argv[2], force=True))
        else:
            print(USAGE_STRING)
            sys.exit(1)
    else:
        # sys.exit(main(sys.argv[1]))
        # force should be false but keeping old behavior, always forced stop
        sys.exit(main(sys.argv[1], force=True))