Remove Python 2.x support

Drop support of Python 2.x as it is being deprecated.

Updated documentation, tox config, requirements.txt.

Job templates added:
- openstack-python35-jobs: openstack-tox-py35
- openstack-python3-ussuri-jobs: openstack-tox-py36, openstack-tox-py37

Job added:
- openstack-tox-pep8

Job templates removed:
- openstack-python-jobs: openstack-tox-pep8, openstack-tox-py27

Jobs removed:
- deckhand-tox-py27-postgresql

Change-Id: I7783ba841258a913f5ecd9d6f1130d378345ab5a

.zuul.yaml

@@ -13,15 +13,15 @@
 - project:
     templates:
       - openstack-cover-jobs
-      - openstack-python-jobs
       - docs-on-readthedocs
+      - openstack-python35-jobs
       - openstack-python3-train-jobs
+      - openstack-python3-ussuri-jobs
     vars:
       rtd_webhook_id: '38572'
       rtd_project_name: 'airship-deckhand'
     check:
       jobs:
-        - deckhand-tox-py27-postgresql
         - deckhand-tox-py35-postgresql
         - deckhand-functional-uwsgi-py35:
             voting: false
@@ -40,13 +40,13 @@
         - deckhand-airskiff-deployment
     gate:
       jobs:
-        - deckhand-tox-py27-postgresql
         - deckhand-tox-py35-postgresql
         - deckhand-functional-docker-py35-ubuntu
         - deckhand-functional-docker-py35-opensuse
         - deckhand-chart-build-gate
         - deckhand-docker-build-gate-ubuntu
         - deckhand-docker-build-gate-opensuse
+        - openstack-tox-pep8
     post:
       jobs:
         - deckhand-upload-git-mirror
@@ -67,14 +67,6 @@
       - name: primary
         label: ubuntu-xenial
 
-- job:
-    name: deckhand-tox-py27-postgresql
-    parent: openstack-tox-py27
-    pre-run:
-      - tools/gate/playbooks/install-postgresql.yaml
-    vars:
-      tox_envlist: py27-postgresql
-
 - job:
     name: deckhand-tox-py35-postgresql
     parent: openstack-tox-py35

deckhand/common/document.py

@@ -184,5 +184,6 @@ def document_dict_representer(dumper, data):
 yaml.add_representer(DocumentDict, document_dict_representer)
 # Required for py27 compatibility: yaml.safe_dump/safe_dump_all doesn't
 # work unless SafeRepresenter add_representer method is called.
+# Upd: somehow required also for py3*.
 safe_representer = yaml.representer.SafeRepresenter
 safe_representer.add_representer(DocumentDict, document_dict_representer)

doc/source/contributor/developer-overview.rst

@@ -101,9 +101,8 @@ Deckhand strives to conform to the
 Python
 ------
 
-The Deckhand code base lives under ``/deckhand``. Deckhand supports py27
+The Deckhand code base lives under ``/deckhand``. Deckhand supports py35 through py37
-and py35 interpreters. Once OpenStack deprecates usage of py27, Deckhand
+versions of interpreters.
-will as well.
 
 See :ref:`coding-guide` for more information on contribution guidelines.
 

doc/source/contributor/testing.rst

@@ -57,19 +57,17 @@ Deckhand.
 
 To run unit tests using SQLite, execute::
 
-    $ tox -epy27
     $ tox -epy35
 
-against a py27- or py35-backed environment, respectively.
+against a py35-backed environment, respectively.
 
 To run unit tests using PostgreSQL, execute::
 
-    $ tox -epy27-postgresql
     $ tox -epy35-postgresql
 
 To run individual unit tests, run (for example)::
 
-    $ tox -e py27 -- deckhand.tests.unit.db.test_revisions
+    $ tox -e py35 -- deckhand.tests.unit.db.test_revisions
 
 .. warning::
 
@@ -169,12 +167,6 @@ Troubleshooting
 
     $ sudo apt-get install tox -y
 
-* For any errors related to running ``tox -e py27``:
-
-  Ensure that ``python-dev`` is installed::
-
-    $ sudo apt-get install python-dev -y
-
 * For any errors related to running ``tox -e py35``:
 
   Ensure that ``python3-dev`` is installed::

doc/source/users/getting-started.rst

@@ -335,9 +335,3 @@ included beneath each bullet.
   Ensure that ``python3-dev`` is installed::
 
     $ [sudo] apt-get install python3-dev -y
-
-* For any errors related to running ``tox -e py27``:
-
-  Ensure that ``python3-dev`` is installed::
-
-    $ [sudo] apt-get install python-dev -y

requirements.txt

@@ -29,6 +29,7 @@ pbr==5.1.0
 PasteDeploy==1.5.2
 Paste==3.0.1
 psycopg2==2.7.5
+pyyaml~=5.1
 
 # TODO(alanmeadows)
 # this must match the container service

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

tox.ini

@@ -1,7 +1,7 @@
 [tox]
 minversion = 2.3.1
 skipsdist = True
-envlist = py{37,36,27},py{37,36,27}-{postgresql},functional,cover,pep8,bandit,docs
+envlist = py{37,36},py{37,36}-{postgresql},functional,cover,pep8,bandit,docs
 
 [testenv]
 usedevelop = True
@@ -25,19 +25,6 @@ basepython=python3
 commands =
   {posargs}
 
-[testenv:py27]
-basepython = python2.7
-commands =
-  {[testenv]commands}
-  stestr run {posargs}
-  stestr slowest
-
-[testenv:py27-postgresql]
-basepython = python2.7
-commands =
-  {[testenv]commands}
-  {toxinidir}/tools/run_pifpaf.sh '{posargs}'
-
 [testenv:py35]
 basepython = python3
 commands =