Add style checker and auto-formater to tox

Change-Id: Iea5ee9585f7e662580e8466250d2b7f33decef97

Author: XioNoX

Diff for: .git-blame-ignore-revs

@@ -0,0 +1,2 @@
+# Black autoformater run
+1a7cf38f6fbac267d483597c95b3317cb1e1db10

Diff for: tox.ini

@@ -1,25 +1,37 @@
 [tox]
-envlist=py{37,38,39}-{flake8,mypy}
+envlist=py{39,310}-{flake8,mypy}
 skip_missing_interpreters = True
 skipsdist = true
 
 [testenv]
+allowlist_externals =
+    {toxinidir}/utils/check-style.sh
+    {toxinidir}/utils/format-code.sh
 description =
+    format: Autoformat the changed files to match the style
+    style: Style consistency checker
     flake8: Style consistency checker
     mypy: Static analyzer for type annotations
 basepython =
-    py37: python3.7
-    py38: python3.8
     py39: python3.9
+    py310: python3.10
 deps =
+    format: black
+    format: isort
+    style: black
+    style: isort
     flake8: flake8
     mypy: mypy
     mypy: types-requests
 commands =
+    format: {toxinidir}/utils/format-code.sh
+    style: {toxinidir}/utils/check-style.sh
     flake8: flake8
     mypy: mypy dns tools/ganeti-netbox-sync.py
 
 [flake8]
 max-line-length = 120
 statistics = True
 ignore = W503
+
+[testenv:py{39,310}-{format,style}]

Diff for: utils/check-style.sh

@@ -0,0 +1,41 @@
+#!/bin/bash -e
+# Copied from the Spicerack repo
+
+fail() {
+    echo "The code is not formatted according to the current style. You can autoformat your code running:"
+    echo "    tox -e py3-format"
+    exit 1
+}
+
+UNSTAGED_FILES=(
+    $(git diff HEAD --name-only --diff-filter=d | grep '\.py$' || true)
+)
+STAGED_FILES=(
+    $(git diff HEAD --cached --name-only --diff-filter=d | grep '\.py$' || true)
+)
+
+if [[ "$(git diff HEAD)" == "" ]] && [[ "$(git diff HEAD --cached)" == "" ]]; then
+    echo "No local changes, testing the last commit."
+    COMMITTED_FILES=(
+        $(git diff HEAD^ --name-only --diff-filter=d | grep '\.py$' || true)
+    )
+else
+    COMMITTED_FILES=()
+fi
+
+if [[ "${#UNSTAGED_FILES[@]}" -eq "0" && "${#STAGED_FILES[@]}" -eq "0" && "${#COMMITTED_FILES[@]}" -eq "0" ]]; then
+    echo "No Python file modified, skipping black and isort checks."
+    exit 0
+fi
+
+black \
+    --check \
+    --diff \
+    "${UNSTAGED_FILES[@]}" "${STAGED_FILES[@]}" "${COMMITTED_FILES[@]}" \
+|| fail
+
+isort \
+    --check-only \
+    --diff \
+    "${UNSTAGED_FILES[@]}" "${STAGED_FILES[@]}" "${COMMITTED_FILES[@]}" \
+|| fail

Diff for: utils/format-code.sh

@@ -0,0 +1,20 @@
+#!/bin/bash -e
+# Copied from the Spicerack repo
+
+if [[ -n "$(git diff --name-only --diff-filter=d HEAD)" ]]; then
+    echo "Using staged and unstaged files"
+    REVISION="HEAD"
+else
+    echo "Using files changed in the latest commit"
+    REVISION="HEAD^"
+fi
+
+FILES=( $(git diff --name-only --diff-filter=d "${REVISION}" | grep '\.py$' || true) )
+
+if [[ "${#FILES[@]}" -eq "0" ]]; then
+    echo "No Python files to format"
+    exit 0
+fi
+
+black "${FILES[@]}"
+isort --apply "${FILES[@]}"