[ussuri][goal] Drop python 2.7 support and testing

OpenStack is dropping the py2.7 support in ussuri cycle.

Complete discussion & schedule can be found in
- http://lists.openstack.org/pipermail/openstack-discuss/2019-October/010142.html
- https://etherpad.openstack.org/p/drop-python2-support

Ussuri Communtiy-wide goal:
https://governance.openstack.org/tc/goals/selected/ussuri/drop-py27.html

Change-Id: Ie8e737cfde8b2587ef60cd25ab746e6b04936390

.zuul.yaml

@@ -1,10 +1,8 @@
 - project:
     templates:
       - check-requirements
-      - lib-forward-testing
       - lib-forward-testing-python3
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
       - openstack-python3-train-jobs
       - periodic-stable-jobs
       - publish-openstack-docs-pti

doc/requirements.txt

@@ -4,8 +4,7 @@
 
 # For generating sphinx documentation
 openstackdocstheme>=1.18.1 # Apache-2.0
-sphinx>=1.8.0,<2.0.0;python_version=='2.7' # BSD
-sphinx>=1.8.0,!=2.1.0;python_version>='3.4' # BSD
+sphinx>=1.8.0,!=2.1.0 # BSD
 reno>=2.5.0 # Apache-2.0
 sphinxcontrib-apidoc>=0.2.0  # BSD
 

releasenotes/notes/drop-python-2-7-73d3113c69d724d6.yaml

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

setup.cfg

@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/oslo.cache/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
@@ -54,6 +53,3 @@ input_file = oslo_cache/locale/oslo_cache.pot
 keywords = _ gettext ngettext l_ lazy_gettext
 mapping_file = babel.cfg
 output_file = oslo_cache/locale/oslo_cache.pot
-
-[bdist_wheel]
-universal = true

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 3.1
-envlist = py27,py37,pypy,pep8
+envlist = py37,pypy,pep8
 ignore_basepython_conflict = True
 
 [testenv]
@@ -14,12 +14,6 @@ commands =
   find . -type f -name "*.pyc" -delete
   stestr run --slowest {posargs}
 
-[testenv:py27-functional-etcd3gw]
-basepython = python2.7
-commands =
-  find . -type f -name "*.pyc" -delete
-  {toxinidir}/tools/setup-etcd-env.sh pifpaf -e OSLO_CACHE_TEST run etcd --  stestr run --slowest functional.*
-
 [testenv:py35-functional-etcd3gw]
 basepython = python3.5
 commands =