Python Project Development

This is how I do Python development today.

Tools

• black formatting source files
• isort to organize imports
• mypy static type checking
• pylint linting errors
• poetry for package management
• pyproject.toml centralizes all tooling config

Prerequisites

To run this, you first need to install these tools:

• pyenv https://github.com/pyenv/pyenv
• pipx https://pipx.pypa.io/stable/installation/
• poetry https://python-poetry.org/
• make https://www.gnu.org/software/make/

VSCode Extensions

• MS Python Extension [link]
• Mypy for type checking (I use the pre-release version) [link]
• Black for formatting [link]
• Isort for sorting imports [link]
• Pylint for linting [link]

Note: if you clone this repository and open with VSCode, the .vscode/extensions.json file should suggest you to install them.

VSCode Settings

{
    // makes the project tree cleaner by hiding pycache and other files
    "files.exclude": {
        "**/.classpath": true,
        "**/.factorypath": true,
        "**/.project": true,
        "**/.pytest_cache": true,
        "**/.settings": true,
        "**/__pycache__": true
    },
    // makes the project tree cleaner by adding newlines at the end of files and removing trailing whitespace
    "files.insertFinalNewline": true,
    "files.trimTrailingWhitespace": true,
    // shows in-line suggestions as you type
    "editor.inlineSuggest.enabled": true,
    // sets black as the formatter
    "editor.defaultFormatter": "ms-python.black-formatter",
    // runs black whenever you save a file
    "editor.formatOnSave": true,
    // defines a ruler at 120 characters (matches the configuration in pyproject.toml for black)
    "editor.rulers": [
        120
    ],
    // enables isort
    "isort.check": true,
    // uses isort from the active .venv
    "isort.importStrategy": "fromEnvironment",
    // runs isort whenever you save a file
    "editor.codeActionsOnSave": {
        "source.organizeImports": "explicit"
    },
    // configure cache settings for mypy (faster execution) and force mypy to check untyped definitions
    "mypy-type-checker.args": [
        "--cache-dir=.mypy_cache/.vscode",
        "--check-untyped-defs"
    ],
    // uses mypy from the active .venv
    "mypy-type-checker.importStrategy": "fromEnvironment",
    // mypy runs on workspace (nice to know if you're breaking things elsewhere) but only recommended for smaller repos as it gets slower with larger code bases
    "mypy-type-checker.reportingScope": "workspace",
    "mypy-type-checker.severity": {
        "error": "Error",
        "note": "Information"
    },
    // disables pylint on typing (defaults to lint on save, which is faster)
    "pylint.lintOnChange": false,
    // uses pylint from the active .venv
    "pylint.path": [
        "pylint"
    ],
    // visual aid when reading code by showing function return types, variable types and call argument names
    "python.analysis.inlayHints.callArgumentNames": "all",
    "python.analysis.inlayHints.functionReturnTypes": true,
    "python.analysis.inlayHints.variableTypes": true,
    // enables pytest and disables unittest when collecting and running tests from the workspace
    "python.testing.pytestEnabled": true,
    "python.testing.unittestEnabled": false
}

Checking Formatting, Linting and Type-checking for the entire project

makefile.mov

Linting and Type Checking on Save

linting-and-type-checking.mov

Format, Organize Imports on Save

format-organize-imports-lint-type-check-on-save.mov