add py36 jobs and tox target

As part of the python 3 first effort [1], this patch adds UT support for
python 3.6 by:
- Updating the zuul.yaml to include the py36 template and jobs.
- Adding a py36-dev target to tox.ini for local testing.
- Updating the upper constraints to use master rather than stable/rocky.
- Updating the version of eventlet used as previous 2x.x versions had
a python 3 bug for monkey patching.
- Consolidating the eventlet monkey patching in the code.

[1] https://governance.openstack.org/tc/goals/stein/python3-first.html

Change-Id: I3c11ac9dff9a2e25b33e8310929c961ffd0bcc52

.zuul.yaml

@@ -3,6 +3,7 @@
       - openstack-python-jobs-neutron
       - check-requirements
       - openstack-python35-jobs-neutron
+      - openstack-python36-jobs
       - periodic-jobs-with-neutron-lib-master
       - build-openstack-docs-pti
     check:
@@ -46,6 +47,19 @@
               - openstack/neutron-vpnaas
               - openstack/tap-as-a-service
               - openstack/octavia
+        - openstack-tox-py36:
+            timeout: 5400
+            required-projects:
+              - openstack/neutron
+              - openstack/networking-l2gw
+              - openstack/networking-sfc
+              - openstack/neutron-lbaas
+              - openstack/vmware-nsxlib
+              - openstack/neutron-fwaas
+              - openstack/neutron-dynamic-routing
+              - openstack/neutron-vpnaas
+              - openstack/tap-as-a-service
+              - openstack/octavia
     gate:
       queue: vmware-nsx
       jobs:
@@ -88,6 +102,19 @@
               - openstack/neutron-vpnaas
               - openstack/tap-as-a-service
               - openstack/octavia
+        - openstack-tox-py36:
+            timeout: 5400
+            required-projects:
+              - openstack/neutron
+              - openstack/networking-l2gw
+              - openstack/networking-sfc
+              - openstack/neutron-lbaas
+              - openstack/vmware-nsxlib
+              - openstack/neutron-fwaas
+              - openstack/neutron-dynamic-routing
+              - openstack/neutron-vpnaas
+              - openstack/tap-as-a-service
+              - openstack/octavia
     post:
       jobs:
         - publish-openstack-python-branch-tarball:

lower-constraints.txt

@@ -19,7 +19,7 @@ deprecation==1.0
 docutils==0.11
 dogpile.cache==0.6.2
 dulwich==0.15.0
-eventlet==0.18.2
+eventlet==0.24.1
 extras==1.0.0
 fasteners==0.7.0
 fixtures==3.0.0

requirements.txt

@@ -3,7 +3,7 @@
 # process, which may cause wedges in the gate later.
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 
-eventlet!=0.18.3,!=0.20.1,>=0.18.2 # MIT
+eventlet>=0.24.1 # MIT
 httplib2>=0.9.1 # MIT
 netaddr>=0.7.18 # BSD
 tenacity>=4.4.0 # Apache-2.0

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py35,py27,pep8,docs
+envlist = py35,py36,py27,pep8,docs
 minversion = 1.6
 skipsdist = True
 
@@ -8,7 +8,7 @@ setenv = VIRTUAL_ENV={envdir}
          PYTHONWARNINGS=default::DeprecationWarning
 passenv = TRACE_FAILONLY GENERATE_HASHES http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 usedevelop = True
-deps = -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt?h=stable/rocky}
+deps = -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 whitelist_externals =
@@ -70,9 +70,11 @@ deps = -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/re
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:py27]
+basepython = python2.7
 setenv = OS_FAIL_ON_MISSING_DEPS=1
 
 [testenv:py36]
+basepython = python3.6
 setenv = OS_FAIL_ON_MISSING_DEPS=1
 
 [testenv:py27-dev]
@@ -84,7 +86,16 @@ whitelist_externals =
     stestr
 
 [testenv:py3-dev]
-basepython = python3
+basepython = python3.5
+commands =
+    {[testenv:dev]commands}
+    pip freeze
+    stestr run {posargs}
+whitelist_externals =
+    stestr
+
+[testenv:py36-dev]
+basepython = python3.6
 commands =
     {[testenv:dev]commands}
     pip freeze

vmware_nsx/__init__.py

@@ -10,7 +10,10 @@
 #  License for the specific language governing permissions and limitations
 #  under the License.
 
+from neutron.common import eventlet_utils
 
-import os
+eventlet_utils.monkey_patch()
+
+import os  # noqa
 
 NSX_EXT_PATH = os.path.join(os.path.dirname(__file__), 'extensions')

vmware_nsx/api_client/eventlet_client.py

@@ -23,7 +23,7 @@ from vmware_nsx.api_client import base
 from vmware_nsx.api_client import eventlet_request
 
 import eventlet
-eventlet.monkey_patch()
+
 
 LOG = logging.getLogger(__name__)
 

vmware_nsx/tests/unit/__init__.py

@@ -17,7 +17,6 @@
 import os
 import time
 
-import eventlet
 import mock
 
 from vmware_nsx.api_client import client as nsx_client
@@ -51,7 +50,6 @@ EDGE_MANAGE_NAME = '%s.%s' % (edge_manage_class.__module__,
                               edge_manage_class.__name__)
 
 # Mock for the tenacity retrying sleeping method
-eventlet.monkey_patch()
 mocked_retry_sleep = mock.patch.object(time, 'sleep')
 mocked_retry_sleep.start()