Drop python 2.7 support and testing

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

telemetry-tempest-plugin is ready with python 3 and ok to drop the
python 2.7 support.

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://review.opendev.org/#/c/691178/

Change-Id: I72abc58ee67cf0594faa07e0f89b52f1c9cc6c2f

.zuul.yaml

@@ -1,6 +1,57 @@
+- job:
+    name: telemetry-tempest-base
+    description: |
+      This job is for stable branch prior to Ussuri for testing
+      on py2.
+    parent: devstack-tempest
+    irrelevant-files:
+      - ^(test-|)requirements.txt$
+      - ^setup.cfg$
+      - ^doc/.*$
+      - ^.*\.rst$
+      - ^releasenotes/.*$
+    timeout: 7800
+    required-projects:
+      - openstack/devstack-gate
+      - openstack/panko
+      - openstack/aodh
+      - openstack/ceilometer
+      - openstack/telemetry-tempest-plugin
+      - openstack/heat-tempest-plugin
+      - openstack/heat
+      - openstack/dib-utils
+      - openstack/diskimage-builder
+      - openstack/tempest
+    vars:
+      devstack_plugins:
+        heat: https://opendev.org/openstack/heat
+        ceilometer: https://opendev.org/openstack/ceilometer
+        aodh: https://opendev.org/openstack/aodh
+        panko: https://opendev.org/openstack/panko
+      devstack_services:
+        tempest: true
+        tls-proxy: false
+      devstack_localrc:
+        TEMPEST_PLUGINS: '"/opt/stack/telemetry-tempest-plugin /opt/stack/heat-tempest-plugin"'
+        GNOCCHI_ARCHIVE_POLICY_TEMPEST: "ceilometer-high-rate"
+        CEILOMETER_BACKEND: "gnocchi"
+        CEILOMETER_PIPELINE_INTERVAL: 15
+        USE_PYTHON3: False
+      tempest_test_regex: telemetry_tempest_plugin
+      tox_envlist: all
+    branches:
+      - stable/ocata
+      - stable/pike
+      - stable/queens
+      - stable/rocky
+      - stable/stein
+      - stable/train
+
 - job:
     name: telemetry-tempest-base
     parent: devstack-tempest
+    description: |
+      This job is for testing on py3 which is Ussuri onwards.
     irrelevant-files:
       - ^(test-|)requirements.txt$
       - ^setup.cfg$

releasenotes/notes/drop-py-2-7-b86d74653b14779b.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. Last release of telemetry-tempest-plugin
+    to support py2.7 is OpenStack Train. The minimum version of Python now
+    supported by telemetry-tempest-plugin is Python 3.6.

setup.cfg

@@ -13,8 +13,6 @@ 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

tox.ini

@@ -1,9 +1,11 @@
 [tox]
-minversion = 2.0
-envlist = py37,py36,py27,pypy,pep8
+minversion = 3.1.1
+envlist = py37,py36,pypy,pep8
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
+basepython = python3
 usedevelop = True
 install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt} {opts} {packages}
 setenv =
@@ -16,19 +18,15 @@ deps = -r{toxinidir}/test-requirements.txt
 commands = stestr run {posargs}
 
 [testenv:pep8]
-basepython = python3
 commands = flake8 {posargs}
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:docs]
-basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:releasenotes]
-basepython = python3
 commands =
   sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html