Adding pre-commit

Introduced changes:
- pre-commit config and rules
- Add pre-commit to pep8 gate, Flake8 is covered in the pre-commit hooks.
- Applying fixes for pre-commit compliance in all code.

Also commit hash will be used instead of version tags in pre-commit to
prevend arbitrary code from running in developer's machines.

pre-commit will be used to:
- trailing whitespace;
- Replaces or checks mixed line ending (mixed-line-ending);
- Forbid files which have a UTF-8 byte-order marker (check-byte-order-marker);
- Checks that non-binary executables have a proper
  shebang (check-executables-have-shebangs);
- Check for files that contain merge conflict strings (check-merge-conflict);
- Check for debugger imports and py37+ breakpoint()
  calls in python source (debug-statements);
- Attempts to load all yaml files to verify syntax (check-yaml);
- Run flake8 checks (flake8) (local)

For further details about tests please refer to:
https://github.com/pre-commit/pre-commit-hooks

Change-Id: I730018e2bf788be5ac4e993af1746296206edfc1
Signed-off-by: Moisés Guimarães de Medeiros <moguimar@redhat.com>

.pre-commit-config.yaml

@@ -0,0 +1,35 @@
+# We from the Oslo project decided to pin repos based on the
+# commit hash instead of the version tag to prevend arbitrary
+# code from running in developer's machines.  To update to a
+# newer version, run `pre-commit autoupdate` and then replace
+# the newer versions with their commit hash.
+
+default_language_version:
+  python: python3
+
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: ebc15addedad713c86ef18ae9632c88e187dd0af  # v3.1.0
+    hooks:
+      - id: trailing-whitespace
+      # Replaces or checks mixed line ending
+      - id: mixed-line-ending
+        args: ['--fix', 'lf']
+        exclude: '.*\.(svg)$'
+      # Forbid files which have a UTF-8 byte-order marker
+      - id: check-byte-order-marker
+      # Checks that non-binary executables have a proper shebang
+      - id: check-executables-have-shebangs
+      # Check for files that contain merge conflict strings.
+      - id: check-merge-conflict
+      # Check for debugger imports and py37+ breakpoint()
+      # calls in python source
+      - id: debug-statements
+      - id: check-yaml
+        files: .*\.(yaml|yml)$
+  - repo: https://gitlab.com/pycqa/flake8
+    rev: 181bb46098dddf7e2d45319ea654b4b4d58c2840 # 3.8.3
+    hooks:
+      - id: flake8
+        additional_dependencies:
+          - hacking>=3.0.1,<3.1.0

doc/source/conf.py

@@ -1,4 +1,17 @@
 # -*- coding: utf-8 -*-
+# Copyright (C) 2020 Red Hat, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
 
 import os
 import sys

test-requirements.txt

@@ -19,3 +19,5 @@ coverage!=4.4,>=4.0 # Apache-2.0
 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;python_version>='3.4' # BSD
 testrepository>=0.0.18 # Apache-2.0/BSD
+
+pre-commit>=2.6.0;python_version>='3.6' # MIT

tox.ini

@@ -18,7 +18,7 @@ deps =
 commands = stestr run --suppress-attachments {posargs}
 
 [testenv:pep8]
-commands = flake8 {posargs}
+commands = pre-commit run -a
 
 [testenv:docs]
 whitelist_externals = rm