Drop python 2.7 support and testing

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

Aodh 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: I12158c5f382f832da50d5be90906ca4a7dd8ccdc

.zuul.yaml

@@ -1,7 +1,6 @@
 - project:
     templates:
-      - openstack-python-jobs
-      - openstack-python3-train-jobs
+      - openstack-python3-ussuri-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3
     check:
@@ -51,6 +50,7 @@
       devstack_localrc:
         DATABASE_TYPE: "postgresql"
         AODH_BACKEND: "postgresql"
+        USE_PYTHON3: True
       tempest_test_regex: telemetry_tempest_plugin.aodh
 
 - job:
@@ -60,4 +60,5 @@
     vars:
       devstack_localrc:
         AODH_BACKEND: "mysql"
+        USE_PYTHON3: True
       tempest_test_regex: telemetry_tempest_plugin.aodh

releasenotes/notes/drop-py-2-7-54a9be4bfb8e9172.yaml

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

requirements.txt

@@ -4,7 +4,6 @@
 
 tenacity>=3.2.1  # Apache-2.0
 croniter>=0.3.4 # MIT License
-futures>=3.0;python_version=='2.7' or python_version=='2.6'  # BSD
 futurist>=0.11.0  # Apache-2.0
 jsonschema>=2.6.0 # MIT
 keystonemiddleware>=2.2.0,!=4.19.0

setup.cfg

@@ -14,8 +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

tox.ini

@@ -1,7 +1,7 @@
 [tox]
 minversion = 1.6
 skipsdist = True
-envlist = py{27,37}{,-mysql,-postgresql},functional,pep8
+envlist = py{37}{,-mysql,-postgresql},functional,pep8
 
 [testenv]
 # NOTE(tonyb): This project has chosen to *NOT* consume upper-constraints.txt