Add autopep8 to tox and pre-commit

autopep8 is a code formating tool that makes python code pep8
compliant without changing everything. Unlike black it will
not radically change all code and the primary change to the
existing codebase is adding a new line after class level doc strings.

This change adds a new tox autopep8 env to manually run it on your
code before you submit a patch, it also adds autopep8 to pre-commit
so if you use pre-commit it will do it for you automatically.

This change runs autopep8 in diff mode with --exit-code in the pep8
tox env so it will fail if autopep8 would modify your code if run
in in-place mode. This allows use to gate on autopep8 not modifying
patches that are submited. This will ensure authorship of patches is
maintianed.

The intent of this change is to save the large amount of time we spend
on ensuring style guidlines are followed automatically to make it
simpler for both new and old contibutors to work on nova and save
time and effort for all involved.

Change-Id: Idd618d634cc70ae8d58fab32f322e75bfabefb9d

1 files changed, 1 insertions, 0 deletions

diff --git a/doc/ext/feature_matrix.py b/doc/ext/feature_matrix.py
index 62f4ec0b94..2bb773a657 100644
--- a/doc/ext/feature_matrix.py
+++ b/doc/ext/feature_matrix.py
@@ -34,6 +34,7 @@ class Matrix(object):
     * self.features is a list of MatrixFeature instances, the rows and cells
     * self.targets is a dict of (MatrixTarget.key, MatrixTarget), the columns
     """
+
     def __init__(self):
         self.features = []
         self.targets = {}