# octavia.cmd.driver_agent

# Source code for octavia.cmd.driver_agent

    # Copyright 2018 Rackspace, US Inc.
    #
    # Licensed under the Apache License, Version 2.0 (the "License"); you may
    # not use this file except in compliance with the License. You may obtain
    # a copy of the License at
    #
    # http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
    # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
    # License for the specific language governing permissions and limitations
    # under the License.

    from functools import partial
    import multiprocessing
    import os
    import signal
    import sys
    import time

    from oslo_config import cfg
    from oslo_log import log as logging
    from oslo_reports import guru_meditation_report as gmr
    import setproctitle
    from stevedore import enabled as stevedore_enabled

    from octavia.api.drivers.driver_agent import driver_listener
    from octavia.common import service
    from octavia import version

    CONF = cfg.CONF
    LOG = logging.getLogger(__name__)
    PROVIDER_AGENT_PROCESSES = []

    def _mutate_config(*args, **kwargs):
        CONF.mutate_config_files()

    def _handle_mutate_config(status_proc_pid, stats_proc_pid, *args, **kwargs):
        LOG.info("Driver agent received HUP signal, mutating config.")
        _mutate_config()
        os.kill(status_proc_pid, signal.SIGHUP)
        os.kill(stats_proc_pid, signal.SIGHUP)

    def _check_if_provider_agent_enabled(extension):
        if extension.name in CONF.driver_agent.enabled_provider_agents:
            return True
        return False

    def _process_wrapper(exit_event, proc_name, function, agent_name=None):
        signal.signal(signal.SIGINT, signal.SIG_IGN)
        signal.signal(signal.SIGHUP, _mutate_config)
        if agent_name:
            process_title = f'octavia-driver-agent - {proc_name} -- {agent_name}'
        else:
            process_title = f'octavia-driver-agent - {proc_name}'
        setproctitle.setproctitle(process_title)
        while not exit_event.is_set():
            try:
                function(exit_event)
            except Exception as e:
                if agent_name:
                    LOG.exception('Provider agent "%s" raised exception: %s. '
                                  'Restarting the "%s" provider agent.',
                                  agent_name, str(e), agent_name)
                else:
                    LOG.exception('%s raised exception: %s. '
                                  'Restarting %s.',
                                  proc_name, str(e), proc_name)
                time.sleep(1)
                continue
            break

    def _start_provider_agents(exit_event):
        extensions = stevedore_enabled.EnabledExtensionManager(
            namespace='octavia.driver_agent.provider_agents',
            check_func=_check_if_provider_agent_enabled)
        for ext in extensions:
            ext_process = multiprocessing.Process(
                name=ext.name, target=_process_wrapper,
                args=(exit_event, 'provider_agent', ext.plugin),
                kwargs={'agent_name': ext.name})
            PROVIDER_AGENT_PROCESSES.append(ext_process)
            ext_process.start()
            LOG.info('Started enabled provider agent: "%s" with PID: %d.',
                     ext.name, ext_process.pid)

    def main():
        service.prepare_service(sys.argv)
        LOG.debug('Full set of CONF:')
        CONF.log_opt_values(LOG, logging.DEBUG)

        gmr.TextGuruMeditation.setup_autorun(version)

        processes = []
        exit_event = multiprocessing.Event()

        status_listener_proc = multiprocessing.Process(
            name='status_listener', target=_process_wrapper,
            args=(exit_event, 'status_listener', driver_listener.status_listener))
        processes.append(status_listener_proc)

        LOG.info("Driver agent status listener process starts:")
        status_listener_proc.start()

        stats_listener_proc = multiprocessing.Process(
            name='stats_listener', target=_process_wrapper,
            args=(exit_event, 'stats_listener', driver_listener.stats_listener))
        processes.append(stats_listener_proc)

        LOG.info("Driver agent statistics listener process starts:")
        stats_listener_proc.start()

        get_listener_proc = multiprocessing.Process(
            name='get_listener', target=_process_wrapper,
            args=(exit_event, 'get_listener', driver_listener.get_listener))
        processes.append(get_listener_proc)

        LOG.info("Driver agent get listener process starts:")
        get_listener_proc.start()

        _start_provider_agents(exit_event)

        def process_cleanup(*args, **kwargs):
            LOG.info("Driver agent exiting due to signal.")
            exit_event.set()
            status_listener_proc.join()
            stats_listener_proc.join()
            get_listener_proc.join()

            for proc in PROVIDER_AGENT_PROCESSES:
                LOG.info('Waiting up to %s seconds for provider agent "%s" to '
                         'shutdown.',
                         CONF.driver_agent.provider_agent_shutdown_timeout,
                         proc.name)
                try:
                    proc.join(CONF.driver_agent.provider_agent_shutdown_timeout)
                    if proc.exitcode is None:
                        # TODO(johnsom) Change to proc.kill() once
                        #               python 3.7 or newer only
                        os.kill(proc.pid, signal.SIGKILL)
                        LOG.warning(
                            'Forcefully killed "%s" provider agent because it '
                            'failed to shutdown in %s seconds.', proc.name,
                            CONF.driver_agent.provider_agent_shutdown_timeout)
                except Exception as e:
                    LOG.warning('Unknown error "%s" while shutting down "%s", '
                                'ignoring and continuing shutdown process.',
                                str(e), proc.name)
                else:
                    LOG.info('Provider agent "%s" has successfully shutdown.',
                             proc.name)

        signal.signal(signal.SIGTERM, process_cleanup)
        signal.signal(signal.SIGHUP, partial(
            _handle_mutate_config, status_listener_proc.pid,
            stats_listener_proc.pid, get_listener_proc.pid))

        try:
            for process in processes:
                process.join()
        except KeyboardInterrupt:
            process_cleanup()

this page last updated: 2025-04-03 17:35:57

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