text: # Copyright 2014 Red Hat, 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.
  
  import eventlet
  from oslo_config import cfg
  from six import moves
  
  from neutron.agent.linux import external_process
  from neutron.tests import base
  from neutron.tests.functional.agent.linux import simple_daemon
  
  
  UUID_FORMAT = "test-uuid-%d"
  
  
  class BaseTestProcessMonitor(base.BaseTestCase):
  
      def setUp(self):
          super(BaseTestProcessMonitor, self).setUp()
          cfg.CONF.set_override('check_child_processes_interval', 1, 'AGENT')
          self._child_processes = []
          self._ext_processes = None
          self.create_child_processes_manager('respawn')
          self.addCleanup(self.cleanup_spawned_children)
  
      def create_child_processes_manager(self, action):
          cfg.CONF.set_override('check_child_processes_action', action, 'AGENT')
          self._ext_processes = self.build_process_monitor()
  
      def build_process_monitor(self):
          return external_process.ProcessMonitor(
              config=cfg.CONF,
              resource_type='test')
  
      def _make_cmdline_callback(self, uuid):
          def _cmdline_callback(pidfile):
              cmdline = ["python", simple_daemon.__file__,
                         "--uuid=%s" % uuid,
                         "--pid_file=%s" % pidfile]
              return cmdline
          return _cmdline_callback
  
      def spawn_n_children(self, n, service=None):
          self._child_processes = []
          for child_number in moves.xrange(n):
              uuid = self._child_uuid(child_number)
              _callback = self._make_cmdline_callback(uuid)
              self._ext_processes.enable(uuid=uuid,
                                         cmd_callback=_callback,
                                         service=service)
  
              pm = self._ext_processes.get_process_manager(uuid, service)
              self._child_processes.append(pm)
  
      @staticmethod
      def _child_uuid(child_number):
          return UUID_FORMAT % child_number
  
      def _kill_last_child(self):
          self._child_processes[-1].disable()
  
      def spawn_child_processes_and_kill_last(self, service=None, number=2):
          self.spawn_n_children(number, service)
          self._kill_last_child()
          self.assertFalse(self._child_processes[-1].active)
  
      def wait_for_all_childs_respawned(self):
          def all_childs_active():
              return all(pm.active for pm in self._child_processes)
  
          self._wait_for_condition(all_childs_active)
  
      def _wait_for_condition(self, exit_condition, extra_time=5):
          # we need to allow extra_time for the check process to happen
          # and properly execute action over the gone processes under
          # high load conditions
          max_wait_time = (
              cfg.CONF.AGENT.check_child_processes_interval + extra_time)
          with self.assert_max_execution_time(max_wait_time):
              while not exit_condition():
                  eventlet.sleep(0.01)
  
      def cleanup_spawned_children(self):
          if self._ext_processes:
              self._ext_processes.disable_all()
  
  
  class TestProcessMonitor(BaseTestProcessMonitor):
  
      def test_respawn_handler(self):
          self.spawn_child_processes_and_kill_last()
          self.wait_for_all_childs_respawned()
  
      def test_new_process_monitor_finds_old_process(self):
          self.spawn_n_children(1)
          spawn_process = self._child_processes[-1]
          uuid = spawn_process.uuid
  
          another_pm = self.build_process_monitor()
          self.assertTrue(another_pm.is_active(uuid))
          self.assertEqual(another_pm.get_pid(uuid), spawn_process.pid)
  
      def test_tries_to_get_pid_for_unknown_uuid(self):
          self.assertIsNone(self._ext_processes.get_pid('bad-uuid'))
  