core -- Add black,isort,flake8 to CI and pre-commit hook

On CI:
- black and isort in check mode must pass.
- flake8 only prints errors
  WIP: make it also failed.

On pre-commit:
- black and isort will format staged files, if installed on path.
- flake8 prints its output if necessary.

.gitlab-ci.yml

@@ -22,25 +22,41 @@ variables:
     # psql password authentication
     PGPASSWORD: $POSTGRES_PASSWORD
 
-cache:
-    paths:
-        - vendor/
-
-before_script:
+test:
+    stage: test
+    before_script:
         - mkdir -p vendor/{pip,apt}
         - apt-get update -q && apt-get -o dir::cache::archives="vendor/apt" install -yqq postgresql-client
         - sed -E 's/^REDIS_HOST.*/REDIS_HOST = "redis"/' cof/settings/secret_example.py > cof/settings/secret.py
         - sed -i.bak -E 's;^REDIS_PASSWD = .*$;REDIS_PASSWD = "";' cof/settings/secret.py
         # Remove the old test database if it has not been done yet
         - psql --username=$POSTGRES_USER --host=$DBHOST -c "DROP DATABASE IF EXISTS test_$POSTGRES_DB"
-    - pip install --upgrade -r requirements.txt
-    - pip install coverage
+        - pip install --upgrade -r requirements.txt coverage
         - python --version
-
-test:
-    stage: test
     script:
         - coverage run manage.py test
+    after_script:
         - coverage report
-    # For GitLab, keep this commented.
+    cache:
+        key: test
+        paths:
+            - vendor/
+    # For GitLab CI to get coverage from build.
+    # Keep this disabled for now, at it may kill GitLab...
     # coverage: '/TOTAL.*\s(\d+\.\d+)\%$/'
+
+linters:
+    image: python:3.6
+    stage: test
+    before_script:
+        - mkdir -p vendor/pip
+        - pip install --upgrade black isort flake8
+    script:
+        - black --check .
+        - isort --recursive --check-only --diff bda cof gestioncof kfet provisioning shared utils
+        # Print errors only
+        - flake8 --exit-zero bda cof gestioncof kfet provisioning shared utils
+    cache:
+        key: linters
+        paths:
+            - vendor/

.pre-commit.sh

@@ -0,0 +1,106 @@
+#!/usr/bin/env bash
+# pre-commit hook for gestioCOF project.
+#
+# Run formatters first, then checkers.
+# Formatters which changed a file must set the flag 'formatter_updated'.
+
+exit_code=0
+formatter_updated=0
+checker_dirty=0
+
+# TODO(AD): We should check only staged changes.
+# Working? -> Stash unstaged changes, run it, pop stash
+STAGED_PYTHON_FILES=$(git diff --cached --name-only --diff-filter=ACM | grep ".py$")
+
+# Formatter: black
+
+printf "> black ... "
+
+if type black &>/dev/null; then
+    if [ -z $STAGED_PYTHON_FILES ]; then
+        printf "OK\n"
+    else
+        BLACK_OUTPUT="/tmp/gc-black-output.log"
+        touch $BLACK_OUTPUT
+        black --check $STAGED_PYTHON_FILES &>$BLACK_OUTPUT
+        printf "OK\n"
+
+        if [ $? -ne 0 ]; then
+            black $STAGED_PYTHON_FILES &>$BLACK_OUTPUT
+            tail -1 $BLACK_OUTPUT
+            formatter_updated=1
+        fi
+    fi
+else
+    printf "SKIP: program not found\n"
+    printf "HINT: Install black with 'pip3 install black' (black requires Python>=3.6)\n"
+fi
+
+# Formatter: isort
+
+printf "> isort ... "
+
+if type isort &>/dev/null; then
+    if [ -z $STAGED_PYTHON_FILES ]; then
+        printf "OK\n"
+    else
+        ISORT_OUTPUT="/tmp/gc-isort-output.log"
+        touch $ISORT_OUTPUT
+        isort --check-only $STAGED_PYTHON_FILES &>$ISORT_OUTPUT
+        printf "OK\n"
+
+        if [ $? -ne 0 ]; then
+            isort $STAGED_PYTHON_FILES &>$ISORT_OUTPUT
+            printf "Reformatted.\n"
+            formatter_updated=1
+        fi
+    fi
+else
+    printf "SKIP: program not found\n"
+    printf "HINT: Install isort with 'pip install isort'\n"
+fi
+
+# Checker: flake8
+
+printf "> flake8 ... "
+
+if type flake8 &>/dev/null; then
+    if [ -z $STAGED_PYTHON_FILES ]; then
+        printf "OK\n"
+    else
+        FLAKE8_OUTPUT="/tmp/gc-flake8-output.log"
+        touch $FLAKE8_OUTPUT
+        flake8 $STAGED_PYTHON_FILES &>$FLAKE8_OUTPUT
+
+        if [ $? -eq 0 ]; then
+            printf "OK\n"
+        else
+            printf "FAIL\n"
+            cat $FLAKE8_OUTPUT
+            checker_dirty=1
+        fi
+    fi
+else
+    printf "SKIP: program not found\n"
+    printf "HINT: Install flake8 with 'pip install flake8'\n"
+fi
+
+# End
+
+if [ $checker_dirty -ne 0 ]
+then
+    printf ">>> Checker(s) detect(s) issue(s)\n"
+    printf "    You can still commit and push :)\n"
+    printf "    Be warned that our CI may cause you more trouble.\n"
+fi
+
+if [ $formatter_updated -ne 0 ]
+then
+    printf ">>> Working tree updated by formatter(s)\n"
+    printf "    Add changes to staging area and retry.\n"
+    exit_code=1
+fi
+
+printf "\n"
+
+exit $exit_code

README.md

@@ -44,6 +44,16 @@ pour profiter de façon transparente des mises à jour du fichier:
 
     ln -s secret_example.py cof/settings/secret.py
 
+Nous avons un git hook de pre-commit pour formatter et vérifier que votre code
+vérifie nos conventions. Pour bénéficier des mises à jour du hook, préférez
+encore l'installation *via* un lien symbolique:
+
+    ln -s ../../.pre-commit.sh .git/hooks/pre-commit
+
+Pour plus d'informations à ce sujet, consulter la
+[page](https://git.eleves.ens.fr/cof-geek/gestioCOF/wikis/coding-style)
+du wiki gestioCOF liée aux conventions.
+
 
 #### Fin d'installation
 

pyproject.toml

@@ -0,0 +1,9 @@
+[tool.black]
+# Automatically ignore files in .gitignore (opened at this time):
+# https://github.com/ambv/black/issues/475
+exclude = '''
+/(
+      \.pyc
+    | venv
+)/
+'''

requirements-devel.txt

@@ -2,3 +2,8 @@
 django-debug-toolbar
 django-debug-panel
 ipython
+
+# Tools
+# black  # Uncomment when GC & most distros run with Python>=3.6
+flake8
+isort

setup.cfg

@@ -14,3 +14,27 @@ branch = true
 [coverage:report]
 precision = 2
 show_missing = true
+
+[flake8]
+exclude = migrations
+max-line-length = 88
+ignore =
+  # whitespace before ':' (not PEP8-compliant for slicing)
+  E203,
+  # lambda expression
+  E731,
+  # line break before binary operator (not PEP8-compliant)
+  W503
+
+[isort]
+# For black compat: https://github.com/ambv/black#how-black-wraps-lines
+combine_as_imports = true
+default_section = THIRDPARTY
+force_grid_wrap = 0
+include_trailing_comma = true
+known_django = django
+known_first_party = bda,cof,gestioncof,kfet,shared,utils
+line_length = 88
+multi_line_output = 3
+not_skip = __init__.py
+sections = FUTURE,STDLIB,THIRDPARTY,FIRSTPARTY,LOCALFOLDER