File: test_pipe_mutex.py

package info (click to toggle)
python-oslo.log 7.2.1-2
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 820 kB
  • sloc: python: 3,815; makefile: 24; sh: 12
file content (209 lines) | stat: -rw-r--r-- 6,603 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
# Copyright (c) 2010-2012 OpenStack Foundation
#
# 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 contextlib
import unittest
from unittest import mock

import eventlet
from eventlet import debug as eventlet_debug
from eventlet import greenpool

from oslo_log import pipe_mutex


@contextlib.contextmanager
def quiet_eventlet_exceptions():
    orig_state = greenpool.DEBUG
    eventlet_debug.hub_exceptions(False)
    try:
        yield
    finally:
        eventlet_debug.hub_exceptions(orig_state)


class TestPipeMutex(unittest.TestCase):
    """From  Swift's test/unit/common/test_utils.py"""
    def setUp(self):
        self.mutex = pipe_mutex.PipeMutex()

    def tearDown(self):
        self.mutex.close()

    def test_nonblocking(self):
        evt_lock1 = eventlet.event.Event()
        evt_lock2 = eventlet.event.Event()
        evt_unlock = eventlet.event.Event()

        def get_the_lock():
            self.mutex.acquire()
            evt_lock1.send('got the lock')
            evt_lock2.wait()
            self.mutex.release()
            evt_unlock.send('released the lock')

        eventlet.spawn(get_the_lock)
        evt_lock1.wait()  # Now, the other greenthread has the lock.

        self.assertFalse(self.mutex.acquire(blocking=False))
        evt_lock2.send('please release the lock')
        evt_unlock.wait()  # The other greenthread has released the lock.
        self.assertTrue(self.mutex.acquire(blocking=False))

    def test_recursive(self):
        self.assertTrue(self.mutex.acquire(blocking=False))
        self.assertTrue(self.mutex.acquire(blocking=False))

        def try_acquire_lock():
            return self.mutex.acquire(blocking=False)

        self.assertFalse(eventlet.spawn(try_acquire_lock).wait())
        self.mutex.release()
        self.assertFalse(eventlet.spawn(try_acquire_lock).wait())
        self.mutex.release()
        self.assertTrue(eventlet.spawn(try_acquire_lock).wait())

    def test_release_without_acquire(self):
        self.assertRaises(RuntimeError, self.mutex.release)

    def test_too_many_releases(self):
        self.mutex.acquire()
        self.mutex.release()
        self.assertRaises(RuntimeError, self.mutex.release)

    def test_wrong_releaser(self):
        self.mutex.acquire()
        with quiet_eventlet_exceptions():
            self.assertRaises(RuntimeError,
                              eventlet.spawn(self.mutex.release).wait)

    def test_blocking(self):
        evt = eventlet.event.Event()

        sequence = []

        def coro1():
            eventlet.sleep(0)  # let coro2 go

            self.mutex.acquire()
            sequence.append('coro1 acquire')
            evt.send('go')
            self.mutex.release()
            sequence.append('coro1 release')

        def coro2():
            evt.wait()  # wait for coro1 to start us
            self.mutex.acquire()
            sequence.append('coro2 acquire')
            self.mutex.release()
            sequence.append('coro2 release')

        c1 = eventlet.spawn(coro1)
        c2 = eventlet.spawn(coro2)

        c1.wait()
        c2.wait()

        self.assertEqual(sequence, [
            'coro1 acquire',
            'coro1 release',
            'coro2 acquire',
            'coro2 release'])

    def test_blocking_tpool(self):
        # Note: this test's success isn't a guarantee that the mutex is
        # working. However, this test's failure means that the mutex is
        # definitely broken.
        sequence = []

        def do_stuff():
            n = 10
            while n > 0:
                self.mutex.acquire()
                sequence.append("<")
                eventlet.sleep(0.0001)
                sequence.append(">")
                self.mutex.release()
                n -= 1

        greenthread1 = eventlet.spawn(do_stuff)
        greenthread2 = eventlet.spawn(do_stuff)

        real_thread1 = eventlet.patcher.original('threading').Thread(
            target=do_stuff)
        real_thread1.start()

        real_thread2 = eventlet.patcher.original('threading').Thread(
            target=do_stuff)
        real_thread2.start()

        greenthread1.wait()
        greenthread2.wait()
        real_thread1.join()
        real_thread2.join()

        self.assertEqual(''.join(sequence), "<>" * 40)

    def test_blocking_preserves_ownership(self):
        pthread1_event = eventlet.patcher.original('threading').Event()
        pthread2_event1 = eventlet.patcher.original('threading').Event()
        pthread2_event2 = eventlet.patcher.original('threading').Event()
        thread_id = []
        owner = []

        def pthread1():
            thread_id.append(id(eventlet.greenthread.getcurrent()))
            self.mutex.acquire()
            owner.append(self.mutex.owner)
            pthread2_event1.set()

            orig_os_write = pipe_mutex.os.write

            def patched_os_write(*a, **kw):
                try:
                    return orig_os_write(*a, **kw)
                finally:
                    pthread1_event.wait()

            with mock.patch.object(pipe_mutex.os, 'write', patched_os_write):
                self.mutex.release()
            pthread2_event2.set()

        def pthread2():
            pthread2_event1.wait()  # ensure pthread1 acquires lock first
            thread_id.append(id(eventlet.greenthread.getcurrent()))
            self.mutex.acquire()
            pthread1_event.set()
            pthread2_event2.wait()
            owner.append(self.mutex.owner)
            self.mutex.release()

        real_thread1 = eventlet.patcher.original('threading').Thread(
            target=pthread1)
        real_thread1.start()

        real_thread2 = eventlet.patcher.original('threading').Thread(
            target=pthread2)
        real_thread2.start()

        real_thread1.join()
        real_thread2.join()
        self.assertEqual(thread_id, owner)
        self.assertIsNone(self.mutex.owner)

    @classmethod
    def tearDownClass(cls):
        # PipeMutex turns this off when you instantiate one
        eventlet.debug.hub_prevent_multiple_readers(True)