Drop Python 2.7 support

Python 2.7 is deprecated now, and some dependencies have dropped their
support for it. We should also just drop support for it rather than
pinning the dependency versions.

This commit also switches to a generic Python 3 tox environment,
adds additional test jobs for more Python 3 versions, and cleans up
some Python 2 compatibility cruft.

Change-Id: I3e7cc1713dec1bada4a85f75362c4fa4f89ceae6

.zuul.yaml

@@ -87,20 +87,24 @@
             timeout: 6000
         - storyboard-tox-sqlite
         - tox-pep8
-        - tox-py27:
-            timeout: 6000
         - tox-py36:
             timeout: 6000
+        - tox-py37:
+            timeout: 6000
+        - tox-py38:
+            timeout: 6000
         - opendev-buildset-registry
         - storyboard-build-opendev-image
     gate:
       jobs:
         - storyboard-tox-sqlite
         - tox-pep8
-        - tox-py27:
-            timeout: 6000
         - tox-py36:
             timeout: 6000
+        - tox-py37:
+            timeout: 6000
+        - tox-py38:
+            timeout: 6000
         - opendev-buildset-registry
         - storyboard-upload-opendev-image
     post:

doc/source/contribute/contributing.rst

@@ -81,10 +81,10 @@ And to run the style-checker and static analysis tool::
 
   $ tox -e pep8
 
-If you would like to run the test suite with proper database backends or
-with python2 instead of python3 there is one more step to follow. Note
-that the testsuite takes quite a bit longer to run when using the MySQL
-and PostgreSQL database backends.
+If you would like to run the test suite with proper database backends
+there is one more step to follow. Note that the testsuite takes quite
+a bit longer to run when using the MySQL and PostgreSQL database
+backends.
 
 First ensure MySQL and PostgreSQL are running (you may need to start
 these services). Then run the test-setup.sh helper script::
@@ -95,18 +95,14 @@ This script needs to be run with a user that has sudo access. It will
 configure the databases as needed to run the unittests. You can then
 runt the unittests with::
 
-  $ tox -e py27
-
-or for Python 3::
-
-  $ tox -e py35
+  $ tox -e py3
 
 On slower systems, the database migrations may take longer than the
 default timeout of 120 seconds. To override the timeout, set the
 ``OS_TEST_TIMEOUT`` environment variable. For example, to set the
 timeout to 3 minutes, run::
 
-  $ OS_TEST_TIMEOUT=180 tox -e py27
+  $ OS_TEST_TIMEOUT=180 tox -e py3
 
 For More Extensive Testing...
 -------------------------------

requirements.txt

@@ -11,8 +11,7 @@ pecan>=0.4.5
 oslo.db>=4.27.0  # Apache-2.0
 oslo.log>=1.0.0
 pika>=0.9.14
-python-openid ; python_version < '3.0'
-python3-openid ; python_version >= '3.0'
+python3-openid
 PyYAML>=3.1.0
 requests>=1.1
 six>=1.7.0
@@ -22,7 +21,6 @@ WSME>=0.6,<0.8
 SQLAlchemy-FullText-Search>=0.2.3
 stevedore>=1.3.0
 tzlocal>=1.1.2
-email>=4.0.2;python_version<'3.0'
 Jinja2>=2.7.3
 PyMySQL>=0.6.2,!=0.6.4
 apscheduler>=3.0.1,<3.1.0

setup.cfg

@@ -12,6 +12,7 @@ project_urls =
     Bug Reporting = https://storyboard.openstack.org/#!/project/opendev/storyboard
     Documentation = https://docs.openstack.org/infra/storyboard
     Git Clone URL = https://opendev.org/opendev/storyboard
+python_requires = >=3.6
 classifier =
     Environment :: Web Environment
     Intended Audience :: Developers
@@ -21,9 +22,11 @@ classifier =
     Operating System :: OS Independent
     Operating System :: POSIX :: Linux
     Programming Language :: Python
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3 :: Only
     Topic :: Software Development :: Bug Tracking
 
 [files]
@@ -49,9 +52,6 @@ storyboard.plugin.user_preferences =
 storyboard.plugin.scheduler =
     token-cleaner = storyboard.plugin.token_cleaner.cleaner:TokenCleaner
 
-[wheel]
-universal = 1
-
 [build_sphinx]
 warning-is-error = 1
 source-dir = doc/source

setup.py

@@ -16,14 +16,6 @@
 # This file was pulled from the openstack global requirements repo.
 import setuptools
 
-# In python < 2.7.4, a lazy loading of package `pbr` will break
-# setuptools if some other modules registered functions in `atexit`.
-# solution from: http://bugs.python.org/issue15881#msg170215
-try:
-    import multiprocessing  # noqa
-except ImportError:
-    pass
-
 setuptools.setup(
     setup_requires=['pbr>=5'],
     pbr=True)

tox.ini

@@ -1,9 +1,10 @@
 [tox]
 minversion = 2.9.1
 skipsdist = True
-envlist = py35,py27,pep8
+envlist = py3,pep8
 
 [testenv]
+basepython = python3
 usedevelop = True
 install_command = pip install -U {opts} {packages}
 passenv = OS_* STORYBOARD_*
@@ -19,21 +20,17 @@ commands = stestr run {posargs}
 whitelist_externals = bash
 
 [testenv:sqlite]
-basepython = python3
 setenv =
     {[testenv]setenv}
     STORYBOARD_TEST_DB=sqlite:///{envtmpdir}
 
 [testenv:pep8]
-basepython = python3
 commands = flake8
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:docs]
-basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands =
     rm -rf doc/html doc/build
@@ -42,7 +39,6 @@ commands =
 whitelist_externals = rm
 
 [testenv:cover]
-basepython = python3
 setenv =
     {[testenv]setenv}
     PYTHON=coverage run --source storyboard --parallel-mode
@@ -64,7 +60,6 @@ show-source = True
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
 
 [testenv:bindep]
-basepython = python3
 # Do not install any requirements. We want this to be fast and work even if
 # system dependencies are missing, since it's used to tell you what system
 # dependencies are missing! This also means that bindep must be installed
@@ -73,7 +68,6 @@ deps = bindep
 commands = bindep test
 
 [testenv:lpimport]
-basepython = python3
 # The Launchpad bug import tool uses launchpadlib, which is not a typical
 # runtime dependency of anything else in StoryBoard
 deps = launchpadlib