Fix Python 3 support for eventlet monkey-patching

Use eventlet.green.subprocess if eventlet is used and enable eventlet
tests on Python 3.

This change adds oslo_rootwrap.subprocess which is
eventlet.green.subprocess if eventlet monkey-patching is enabled or
if the TEST_EVENTLET environment variable is set, or subprocess of
the Python standard library otherwise.

When eventlet is used (with monkey-patching or not), it's more
reliable to use eventlet.green.subprocess instead of using directly
subprocess from the Python standard library.

On Python 2, it "works" to use directly subprocess: subprocess.Popen
calls os.pipe() and os.fdopen(fd) which are both monkey-patched. On
Python 3, it doesn't work because subprocess uses os.pipe() and
io.open(fd), and the io module is *not* monkey-patched at all.

Change-Id: Ib859bebe52612b35f0f1f53aedf76222683795e7

oslo_rootwrap/__init__.py

@@ -0,0 +1,30 @@
+# Copyright (c) 2015 Red Hat.
+# All Rights Reserved.
+#
+#    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 os
+
+try:
+    import eventlet.patcher
+except ImportError:
+    _patched_socket = False
+else:
+    # In tests patching happens later, so we'll rely on environment variable
+    _patched_socket = (eventlet.patcher.is_monkey_patched('socket') or
+                       os.environ.get('TEST_EVENTLET', False))
+
+if not _patched_socket:
+    import subprocess
+else:
+    from eventlet.green import subprocess   # noqa

oslo_rootwrap/client.py

@@ -16,24 +16,15 @@
 import logging
 from multiprocessing import managers
 from multiprocessing import util as mp_util
-import os
-import subprocess
 import threading
 import weakref
 
-try:
+import oslo_rootwrap
-    import eventlet.patcher
-except ImportError:
-    patched_socket = False
-else:
-    # In tests patching happens later, so we'll rely on environment variable
-    patched_socket = (eventlet.patcher.is_monkey_patched('socket') or
-                      os.environ.get('TEST_EVENTLET', False))
-
 from oslo_rootwrap import daemon
 from oslo_rootwrap import jsonrpc
+from oslo_rootwrap import subprocess
 
-if patched_socket:
+if oslo_rootwrap._patched_socket:
     # We have to use slow version of recvall with eventlet because of a bug in
     # GreenSocket.recv_into:
     # https://bitbucket.org/eventlet/eventlet/pull-request/41

oslo_rootwrap/daemon.py

@@ -22,12 +22,12 @@ import os
 import shutil
 import signal
 import stat
-import subprocess
 import sys
 import tempfile
 import threading
 
 from oslo_rootwrap import jsonrpc
+from oslo_rootwrap import subprocess
 from oslo_rootwrap import wrapper
 
 LOG = logging.getLogger(__name__)

oslo_rootwrap/tests/run_daemon.py

@@ -14,11 +14,11 @@
 #    under the License.
 
 import logging
-import subprocess
 import sys
 import threading
 
 from oslo_rootwrap import cmd
+from oslo_rootwrap import subprocess
 
 
 def forward_stream(fr, to):

oslo_rootwrap/tests/test_functional.py

@@ -19,7 +19,6 @@ import logging
 import os
 import pwd
 import signal
-import subprocess
 import sys
 import threading
 
@@ -35,6 +34,7 @@ import testtools
 from testtools import content
 
 from oslo_rootwrap import client
+from oslo_rootwrap import subprocess
 from oslo_rootwrap.tests import run_daemon
 from oslo_rootwrap import wrapper
 
@@ -121,7 +121,7 @@ class RootwrapDaemonTest(_FunctionalBase, testtools.TestCase):
 
         # Collect daemon logs
         daemon_log = io.BytesIO()
-        p = mock.patch('subprocess.Popen',
+        p = mock.patch('oslo_rootwrap.subprocess.Popen',
                        run_daemon.forwarding_popen(daemon_log))
         p.start()
         self.addCleanup(p.stop)

oslo_rootwrap/tests/test_rootwrap.py

@@ -15,7 +15,6 @@
 import logging
 import logging.handlers
 import os
-import subprocess
 import uuid
 
 import fixtures
@@ -26,6 +25,7 @@ import testtools
 from oslo_rootwrap import cmd
 from oslo_rootwrap import daemon
 from oslo_rootwrap import filters
+from oslo_rootwrap import subprocess
 from oslo_rootwrap import wrapper
 
 

oslo_rootwrap/wrapper.py

@@ -18,11 +18,11 @@ import logging.handlers
 import os
 import pwd
 import signal
-import subprocess
 
 from six import moves
 
 from oslo_rootwrap import filters
+from oslo_rootwrap import subprocess
 
 
 class NoFilterMatched(Exception):

tox.ini

@@ -16,12 +16,6 @@ commands =
   python setup.py testr --slowest --testr-args='(?!tests.test_functional_eventlet)tests {posargs}'
   env TEST_EVENTLET=1 python setup.py testr --slowest --testr-args='tests.test_functional_eventlet'
 
-[testenv:py34]
-commands =
-  python setup.py testr --slowest --testr-args='{posargs}'
-# FIXME: Eventlet tests does not work yet here
-#  env TEST_EVENTLET=1 python setup.py testr --slowest --testr-args='tests.test_functional_eventlet'
-
 [testenv:pep8]
 commands = flake8