Add pre-commit to CI

References:
* casework/CASE-Utilities-Python#37

Signed-off-by: Alex Nelson <alexander.nelson@nist.gov>

Author: ajnelson-nist

.github/workflows/ci.yml

@@ -31,6 +31,10 @@ jobs:
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
+    - name: Pre-commit Checks
+      run: |
+        pip -q install pre-commit
+        pre-commit run --all-files
     - name: Install Python virtualenv for Github runner
       run: |
         python -m pip install --upgrade pip

.gitignore

@@ -2,6 +2,7 @@
 *.swp
 .DS_Store
 .git_submodule_init.done.log
+.venv-pre-commit
 __pycache__
 build
 dist

.pre-commit-config.yaml

@@ -0,0 +1,14 @@
+repos:
+  - repo: https://github.com/psf/black
+    rev: 22.10.0
+    hooks:
+      - id: black
+  - repo: https://github.com/pycqa/flake8
+    rev: 5.0.4
+    hooks:
+      - id: flake8
+  - repo: https://github.com/pycqa/isort
+    rev: 5.10.1
+    hooks:
+      - id: isort
+        name: isort (python)

Makefile

@@ -15,8 +15,8 @@ SHELL := /bin/bash
 
 PYTHON3 ?= python3
 
-# This recipe intentionally blank.
-all:
+all: \
+  .venv-pre-commit/var/.pre-commit-built.log
 
 .PHONY: \
   download
@@ -33,8 +33,32 @@ all:
 	  .git_submodule_init.done.log
 	touch $@
 
+# This virtual environment is meant to be built once and then persist, even through 'make clean'.
+# If a recipe is written to remove this flag file, it should first run `pre-commit uninstall`.
+.venv-pre-commit/var/.pre-commit-built.log:
+	rm -rf .venv-pre-commit
+	test -r .pre-commit-config.yaml \
+	  || (echo "ERROR:Makefile:pre-commit is expected to install for this repository, but .pre-commit-config.yaml does not seem to exist." >&2 ; exit 1)
+	$(PYTHON3) -m venv \
+	  .venv-pre-commit
+	source .venv-pre-commit/bin/activate \
+	  && pip install \
+	    --upgrade \
+	    pip \
+	    setuptools \
+	    wheel
+	source .venv-pre-commit/bin/activate \
+	  && pip install \
+	    pre-commit
+	source .venv-pre-commit/bin/activate \
+	  && pre-commit install
+	mkdir -p \
+	  .venv-pre-commit/var
+	touch $@
+
 check: \
-  .git_submodule_init.done.log
+  .git_submodule_init.done.log \
+  .venv-pre-commit/var/.pre-commit-built.log
 	$(MAKE) \
 	  PYTHON3=$(PYTHON3) \
 	  --directory tests \

setup.cfg

@@ -28,3 +28,14 @@ console_scripts =
 
 [options.package_data]
 case_gnu_time = py.typed
+
+[flake8]
+# https://black.readthedocs.io/en/stable/guides/using_black_with_other_tools.html#flake8
+extend-ignore =
+  E203
+  E302
+  E501
+
+[isort]
+# https://pycqa.github.io/isort/docs/configuration/black_compatibility.html
+profile = black