Stop testing Python 2

This change removes the requirement for python 2 and removes testing for
it, but tries to leave the code compatible with python2 where possible.

Co-Authored-By: Nate Johnston <nate.johnston@redhat.com>
Change-Id: I711ae939b5eaa1816af15b22527c38858507127f

.zuul.yaml

@@ -4,18 +4,11 @@
       - publish-openstack-docs-pti
       - openstack-cover-jobs
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
+      - openstack-python3-ussuri-jobs
-      - openstack-python3-train-jobs
-      - lib-forward-testing
       - lib-forward-testing-python3
       - release-notes-jobs-python3
     check:
       jobs:
-        # This job comes from lib-forward-testing template,
-        # but it is limited to 2h there and we want to set
-        # for it 3h timeout
-        - tempest-full:
-            timeout: 10800
         # This job comes from lib-forward-testing-python3 template,
         # but it is limited to 2h there and we want to set
         # for it 3h timeout
@@ -23,11 +16,6 @@
             timeout: 10800
     gate:
       jobs:
-        # This job comes from lib-forward-testing template,
-        # but it is limited to 2h there and we want to set
-        # for it 3h timeout
-        - tempest-full:
-            timeout: 10800
         # This job comes from lib-forward-testing-python3 template,
         # but it is limited to 2h there and we want to set
         # for it 3h timeout

neutron_lib/utils/helpers.py

@@ -179,13 +179,7 @@ def safe_decode_utf8(s):
     return s
 
 
-try:
+weak_method = weakref.WeakMethod
-    # PY3
-    weak_method = weakref.WeakMethod
-except AttributeError:
-    # PY2
-    import weakrefmethod
-    weak_method = weakrefmethod.WeakMethod
 
 
 def make_weak_ref(f):

releasenotes/notes/drop-python-2-7-f46dfa10169f70db.yaml

@@ -0,0 +1,5 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. The minimum version of Python now
+    supported by neutron-lib is Python 3.6.

requirements.txt

@@ -26,6 +26,5 @@ oslo.versionedobjects>=1.31.2 # Apache-2.0
 osprofiler>=1.4.0 # Apache-2.0
 setproctitle>=1.1.10 # BSD
 WebOb>=1.7.1 # MIT
-weakrefmethod>=1.0.2;python_version=='2.7'  # PSF
 os-traits>=0.9.0 # Apache-2.0
 

setup.cfg

@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/neutron-lib/latest/
+python-requires = >=3.6
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -13,8 +14,6 @@ classifier =
     License :: OSI Approved :: Apache Software License
     Operating System :: POSIX :: Linux
     Programming Language :: Python
-    Programming Language :: Python :: 2
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
@@ -42,6 +41,3 @@ input_file = neutron_lib/locale/neutron_lib.pot
 keywords = _ gettext ngettext l_ lazy_gettext
 mapping_file = babel.cfg
 output_file = neutron_lib/locale/neutron_lib.pot
-
-[wheel]
-universal = 1

tox.ini

@@ -1,7 +1,8 @@
 [tox]
 minversion = 2.3.2
-envlist = py27,py37,pep8
+envlist = py37,pep8
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
 usedevelop = True
@@ -20,14 +21,12 @@ commands =
   stestr run {posargs}
 
 [testenv:pep8]
-basepython = python3
 commands =
   flake8
   {toxinidir}/tools/check_samples.sh
   {[testenv:bandit]commands}
 
 [testenv:releasenotes]
-basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
   -r{toxinidir}/requirements.txt
@@ -35,11 +34,9 @@ deps =
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:cover]
-basepython = python3
 setenv =
   {[testenv]setenv}
   PYTHON=coverage run --source neutron_lib --parallel-mode
@@ -50,7 +47,6 @@ commands =
   coverage xml -o cover/coverage.xml
 
 [testenv:docs]
-basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
   -r{toxinidir}/requirements.txt
@@ -58,7 +54,6 @@ deps =
 commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:pdf-docs]
-basepython = python3
 envdir = {toxworkdir}/docs
 deps = {[testenv:docs]deps}
 whitelist_externals =
@@ -68,7 +63,6 @@ commands =
   make -C doc/build/pdf
 
 [testenv:api-ref]
-basepython = python3
 whitelist_externals = rm
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
@@ -79,7 +73,6 @@ commands =
   sphinx-build -W -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
 
 [testenv:linkcheck]
-basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
   -r{toxinidir}/requirements.txt
@@ -92,11 +85,9 @@ commands =
   sphinx-build -W -b linkcheck doc/source doc/build/linkcheck
 
 [testenv:debug]
-basepython = python3
 commands = oslo_debug_helper -t neutron_lib/tests/unit {posargs}
 
 [testenv:api-report]
-basepython = python3
 commands =
    {toxinidir}/tools/api_report.sh
 
@@ -123,7 +114,6 @@ import_exceptions = neutron_lib._i18n
 local-check-factory = neutron_lib.hacking.checks._neutron_lib_factory
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt