neutron/tests/functional/agent/linux/test_async_process.py

   1 # Copyright 2013 Red Hat, Inc.
   2 #
   3 #    Licensed under the Apache License, Version 2.0 (the "License"); you may
   4 #    not use this file except in compliance with the License. You may obtain
   5 #    a copy of the License at
   6 #
   7 #         http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 #    Unless required by applicable law or agreed to in writing, software
  10 #    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  11 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  12 #    License for the specific language governing permissions and limitations
  13 #    under the License.
  14
  15 import eventlet
  16 import six
  17
  18 from neutron._i18n import _
  19 from neutron.agent.linux import async_process
  20 from neutron.agent.linux import utils
  21 from neutron.tests import base
  22
  23
  24 class AsyncProcessTestFramework(base.BaseTestCase):
  25
  26     def setUp(self):
  27         super(AsyncProcessTestFramework, self).setUp()
  28         self.test_file_path = self.get_temp_file_path('test_async_process.tmp')
  29         self.data = [six.text_type(x) for x in range(4)]
  30         with open(self.test_file_path, 'w') as f:
  31             f.writelines('%s\n' % item for item in self.data)
  32
  33     def _check_stdout(self, proc):
  34         # Ensure that all the output from the file is read
  35         output = []
  36         while output != self.data:
  37             new_output = list(proc.iter_stdout())
  38             if new_output:
  39                 output += new_output
  40             eventlet.sleep(0.01)
  41
  42
  43 class TestAsyncProcess(AsyncProcessTestFramework):
  44     def _safe_stop(self, proc):
  45         try:
  46             proc.stop()
  47         except async_process.AsyncProcessException:
  48             pass
  49
  50     def test_stopping_async_process_lifecycle(self):
  51         proc = async_process.AsyncProcess(['tail', '-f',
  52                                            self.test_file_path])
  53         self.addCleanup(self._safe_stop, proc)
  54         proc.start(block=True)
  55         self._check_stdout(proc)
  56         proc.stop(block=True)
  57
  58         # Ensure that the process and greenthreads have stopped
  59         proc._process.wait()
  60         self.assertEqual(proc._process.returncode, -9)
  61         for watcher in proc._watchers:
  62             watcher.wait()
  63
  64     def test_async_process_respawns(self):
  65         proc = async_process.AsyncProcess(['tail', '-f',
  66                                            self.test_file_path],
  67                                           respawn_interval=0)
  68         self.addCleanup(self._safe_stop, proc)
  69         proc.start()
  70
  71         # Ensure that the same output is read twice
  72         self._check_stdout(proc)
  73         pid = proc.pid
  74         utils.execute(['kill', '-9', pid])
  75         utils.wait_until_true(
  76             lambda: proc.is_active() and pid != proc.pid,
  77             timeout=5,
  78             sleep=0.01,
  79             exception=RuntimeError(_("Async process didn't respawn")))
  80         self._check_stdout(proc)