Helpful pre commit hooks for Python and Django
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The document provides an overview of the pre-commit framework, which manages git pre-commit hooks to perform quality checks on code before committing. It outlines installation methods, configuration steps, and various standard hooks available for different file types and development needs. Pre-commit helps catch minor issues that may arise from collaborative coding efforts, thus improving code quality.
![Configuration
●
Add a file “.pre-commit-config”
●
Add the github repositories and hooks you want to run before each commit.
●
Example:
●
Run “pre-commit install”
●
Hooks are checked on
“git commit ...” and commit in IDE
●
Manually run hooks using
“pre-commit run --all-files”
exclude: "^.idea"
repos:
- repo: git://github.com/pre-commit/pre-commit-hooks
rev: v3.2.0
hooks:
- id: trailing-whitespace
- id: end-of-file-fixer
- id: mixed-line-ending
args: ["--fix=auto"]](https://image.slidesharecdn.com/helpfulpre-commithooksforpythonanddjango-200904064112/85/Helpful-pre-commit-hooks-for-Python-and-Django-4-320.jpg)
![Configuration
●
Add a file “.pre-commit-config”
●
Add the github repositories and hooks you want to run
before each commit.
●
Example: exclude: "^.idea"
repos:
- repo: git://github.com/pre-commit/pre-commit-hooks
rev: v3.2.0
hooks:
- id: trailing-whitespace
- id: end-of-file-fixer
- id: mixed-line-ending
args: ["--fix=auto"]
Regex for files and
folders not to check
Source code repository
and version of hooks
to use
Hooks to use
Parameters for a
specific hook](https://image.slidesharecdn.com/helpfulpre-commithooksforpythonanddjango-200904064112/85/Helpful-pre-commit-hooks-for-Python-and-Django-5-320.jpg)
![Standard hooks – Unwanted files
●
check-byte-order-marker: rejects text files starting with
UTF-8 BOM (as created by various Microsoft tools like
Notepad, causing many Unix tools to fail)
●
check-added-large-files: rejects large files; possibly specify
what is large: args: ["--maxkb=768"]
●
Check-merge-conflict: refuse to commit before all merge
conflicts are resolved](https://image.slidesharecdn.com/helpfulpre-commithooksforpythonanddjango-200904064112/85/Helpful-pre-commit-hooks-for-Python-and-Django-8-320.jpg)
![Pretty print Python
●
Using black (opinionated): https://github.com/psf/black
●
Configure using pyproject.toml
- repo: https://github.com/ambv/black
rev: stable
hooks:
- id: black
[tool.black]
line-length = 120
include = '.pyi?$'
exclude = '''
/(
.eggs
| .git
| venv
| build
| dist
)/
'''](https://image.slidesharecdn.com/helpfulpre-commithooksforpythonanddjango-200904064112/85/Helpful-pre-commit-hooks-for-Python-and-Django-11-320.jpg)
![Sort imports consistently
●
Using isort:
https://github.com/timothycrosley/isort
●
Configure using setup.cfg
●
Can be tricky to work with black
→ see example to the right
- repo: https://github.com/timothycrosley/isort
rev: 5.4.2
hooks:
- id: isort
[tool:isort]
# Use project line length.
line_length = 120
# Packages from own projetc
default_section = THIRDPARTY
known_first_party = mytool, niftysite
# Use same style as black.
force_grid_wrap=0
include_trailing_comma = True
multi_line_output=3
use_parentheses=True
# Skip virtual environments.
skip_glob = venv](https://image.slidesharecdn.com/helpfulpre-commithooksforpythonanddjango-200904064112/85/Helpful-pre-commit-hooks-for-Python-and-Django-12-320.jpg)
![Flake8 – Semantic Python check
●
Find unused imports, shadowed variables, string formatting,
unreachable code, …
●
Configure using setup.cfg
- repo: https://gitlab.com/pycqa/flake8
rev: 3.8.3
hooks:
- id: flake8
[flake8]
max-line-length = 120
ignore = E203, W503
exclude =
.git
build
dist
venv
docs/conf.py](https://image.slidesharecdn.com/helpfulpre-commithooksforpythonanddjango-200904064112/85/Helpful-pre-commit-hooks-for-Python-and-Django-13-320.jpg)
Helpful pre commit hooks for Python and Django
- 1. Thomas Aglassinger https://roskakori.at Helpful pre-commit hooks for Python and Django
- 2. What is pre-commit? ● A framework to manage git pre-commit hooks. ● To perform quality check on code before accepting a commit. ● Many handy hooks available through it. ● Helps you catch many (often minor issues) before they make it into the repository.
- 3. How to get pre-commit ● Visit https://pre-commit.com/ ● Various methods to install: – Plain Python: pip install pre-commit – Anaconda: conda install -c conda-forge pre-commit – Ubuntu: sudo apt-get install pre-commit – MacOS: brew install pre-commit
- 4. Configuration ● Add a file “.pre-commit-config” ● Add the github repositories and hooks you want to run before each commit. ● Example: ● Run “pre-commit install” ● Hooks are checked on “git commit ...” and commit in IDE ● Manually run hooks using “pre-commit run --all-files” exclude: "^.idea" repos: - repo: git://github.com/pre-commit/pre-commit-hooks rev: v3.2.0 hooks: - id: trailing-whitespace - id: end-of-file-fixer - id: mixed-line-ending args: ["--fix=auto"]
- 5. Configuration ● Add a file “.pre-commit-config” ● Add the github repositories and hooks you want to run before each commit. ● Example: exclude: "^.idea" repos: - repo: git://github.com/pre-commit/pre-commit-hooks rev: v3.2.0 hooks: - id: trailing-whitespace - id: end-of-file-fixer - id: mixed-line-ending args: ["--fix=auto"] Regex for files and folders not to check Source code repository and version of hooks to use Hooks to use Parameters for a specific hook
- 6. Standard hooks – Text files ● - repo: git://github.com/pre-commit/pre-commit-hooks rev: v3.2.0 ● trailing-whitespace: remove white space at end of line in text files ● mixed-line-ending: detect or fix mixed line endings (e.g developers on Windows and Unix working on same code) ● end-of-file-fixer: Ensures that text files end with a newline character.
- 8. Standard hooks – Unwanted files ● check-byte-order-marker: rejects text files starting with UTF-8 BOM (as created by various Microsoft tools like Notepad, causing many Unix tools to fail) ● check-added-large-files: rejects large files; possibly specify what is large: args: ["--maxkb=768"] ● Check-merge-conflict: refuse to commit before all merge conflicts are resolved
- 9. Standard hooks - Python ● check-ast: check Python syntax ● requirements-txt-fixer: sorts entries in requirements.txt ● debug-statements: refuse to commit calls to breakpoints() and imports of debugger
- 10. Standard hooks – Syntax checks ● check-json ● check-toml ● check-xml ● check-yaml
- 11. Pretty print Python ● Using black (opinionated): https://github.com/psf/black ● Configure using pyproject.toml - repo: https://github.com/ambv/black rev: stable hooks: - id: black [tool.black] line-length = 120 include = '.pyi?$' exclude = ''' /( .eggs | .git | venv | build | dist )/ '''
- 12. Sort imports consistently ● Using isort: https://github.com/timothycrosley/isort ● Configure using setup.cfg ● Can be tricky to work with black → see example to the right - repo: https://github.com/timothycrosley/isort rev: 5.4.2 hooks: - id: isort [tool:isort] # Use project line length. line_length = 120 # Packages from own projetc default_section = THIRDPARTY known_first_party = mytool, niftysite # Use same style as black. force_grid_wrap=0 include_trailing_comma = True multi_line_output=3 use_parentheses=True # Skip virtual environments. skip_glob = venv
- 13. Flake8 – Semantic Python check ● Find unused imports, shadowed variables, string formatting, unreachable code, … ● Configure using setup.cfg - repo: https://gitlab.com/pycqa/flake8 rev: 3.8.3 hooks: - id: flake8 [flake8] max-line-length = 120 ignore = E203, W503 exclude = .git build dist venv docs/conf.py
- 14. Prettier – Pretty print various formats for web development ● Supports JavaScript, CSS, Markdown, HTML, GraphQL, YAML and others by means of plugins ● Does not work with Django HTML templates → exclude using “.prettierignore” (uses same format as .gitignore) - repo: https://github.com/prettier/prettier rev: 2.0.5 hooks: - id: prettier **/coverage.xml **/templates/**/*.html
- 15. Summary ● Pre-commit is easy to install and configure. ● Solves minor minor issues arising when multiple developers work on the same code. ● Plenty of available hooks.