[COMMON] Add and run pre-commit linters via tox

- create a .pre-commit-config.yaml configuration file with
  * gitlint
  * trailing blanks linter
  * tabs removal linter
    - exclude .git folder from it
    - exclude Makefiles since tabs are mandatory by default in them
- create a tox pre-commit profile to run it from tox
  note gitlint is not runnable at this pre-commit stage
- create pre-commit-install and pre-commit-uninstall tox profiles to
  (un)install hooks locally and (un)perform tests at each "git commit"
  call (i.e. without calling manually the pre-commit tox profile)
- precise pre-commit stages/types in the pre-commit configuration file
  so that hooks are installed correctly. This avoids messages about
  skipped tests when they are run at a wrong stage.

Issue-ID: OOM-2643
Signed-off-by: guillaume.lambert <guillaume.lambert@orange.com>
Change-Id: Ie95bb4f6f90be80b05a1398973caffeff7936881

1 files changed, 27 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index 5136a3b65d..efe3b38035 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,6 +5,7 @@ envlist =
  docs-linkcheck,
  gitlint,
  checkbashisms,
+ pre-commit,
 skipsdist=true
 
 [doc8]
@@ -67,3 +68,29 @@ whitelist_externals = find
 commands =
     find kubernetes/ TOSCA/ docs/ -name *.py -exec pylint --max-line-length=120 --disable=missing-docstring --method-rgx="(([a-z_][a-zA-Z0-9_]{2,})|(_[a-z0-9_]*)|(__[a-zA-Z][a-zA-Z0-9_]+__))$" --variable-rgx="[a-zA-Z_][a-zA-Z0-9_]{1,30}$" --reports=y --score=y  --output-format=colorized  \{\} +
 
+[testenv:pre-commit-install]
+basepython = python3
+deps = pre-commit
+commands =
+    pre-commit install
+    pre-commit install --hook-type commit-msg
+
+[testenv:pre-commit-uninstall]
+basepython = python3
+deps = pre-commit
+commands =
+    pre-commit uninstall
+    pre-commit uninstall --hook-type commit-msg
+
+[testenv:pre-commit]
+basepython = python3
+deps = pre-commit
+passenv = HOME
+commands =
+    pre-commit run --all-files --show-diff-on-failure
+    pre-commit run gitlint --hook-stage commit-msg --commit-msg-filename .git/COMMIT_EDITMSG
+    # Gitlint only proposes a pre-commit configuration for the commit-msg stage but none for the commit stage.
+    # Its default arguments --passed and --msg-filename are different from CI recommandations.
+    # As a result, the line above is always skipped in jenkins CI since there cannot be a .git/COMMIT_EDITMSG file.
+    # A dedicated gitlint profile for CI is proposed above. Also to behave fine locally, this profile must have access
+    # to the HOME variable so that Gitlint can retrieve Git user settings.