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

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

monasca-transform 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://governance.openstack.org/tc/goals/selected/ussuri/drop-py27.html

Depends-On: https://review.opendev.org/#/c/693631/

Change-Id: Iae694c6f91273a898556fb342121024fadb3586e

.gitignore

@@ -5,3 +5,4 @@ monasca_transform.egg-info
 tools/vagrant/.vagrant
 doc/build/*
 .stestr
+.tox

.zuul.yaml

@@ -4,23 +4,11 @@
       - check-requirements
       - openstack-cover-jobs
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
       - openstack-python3-ussuri-jobs
     check:
       jobs:
-        - legacy-tempest-dsvm-monasca-transform-python-functional:
-            irrelevant-files:
-              - ^(test-|)requirements.txt$
-              - ^setup.cfg$
         - legacy-tempest-dsvm-monasca-transform-python35-functional:
             voting: false
             irrelevant-files:
               - ^(test-|)requirements.txt$
               - ^setup.cfg$
-    gate:
-      jobs:
-        - legacy-tempest-dsvm-monasca-transform-python-functional:
-            irrelevant-files:
-              - ^(test-|)requirements.txt$
-              - ^setup.cfg$
-

releasenotes/notes/drop-py-2-7-297320bc1d9f0280.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. Last release of monasca-transform
+    to support python 2.7 is OpenStack Train. The minimum version of Python now
+    supported by monasca-transform is Python 3.6.

setup.cfg

@@ -12,8 +12,6 @@ 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

test-requirements.txt

@@ -10,7 +10,6 @@ fixtures>=3.0.0 # Apache-2.0/BSD
 pycodestyle==2.5.0 # MIT License
 stestr>=2.0.0 # Apache-2.0
 # required to build documentation
-sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
 sphinx!=1.6.6,!=1.6.7,>=1.6.2,!=2.1.0;python_version>='3.4' # BSD
 #oslosphinx>=4.7.0 # Apache-2.0
 # computes code coverage percentages

tox.ini

@@ -1,9 +1,10 @@
 [tox]
-envlist = py27,py37,pep8
+envlist = py37,pep8
 minversion = 1.6
 skipsdist = True
 
 [testenv]
+basepython = python3
 usedevelop = True
 install_command = pip install {opts} {packages}
 setenv =
@@ -22,7 +23,7 @@ commands =
   stestr run {posargs}
 
 [testenv:functional]
-basepython = python2.7
+basepython = python3.6
 setenv = {[testenv]setenv}
          SPARK_HOME=/opt/spark/current
          SPARK_SCALA_VERSION=2.10
@@ -39,7 +40,6 @@ commands =
   stestr run --serial {posargs}
 
 [testenv:pep8]
-basepython = python3
 commands =
   flake8
 
@@ -48,11 +48,9 @@ commands =
   python setup.py build_sphinx
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:cover]
-basepython = python3
 # Also do not run test_coverage_ext tests while gathering coverage as those
 # tests conflict with coverage.
 setenv =
@@ -80,7 +78,6 @@ show-source = True
 exclude=.venv,.git,.tox,dist,*egg,build
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt