Python Code Formatter

Python Code Formatter Skill

Auto-format Python code using modern tools with uv package management. Intelligently handles different file types:

• Databricks notebooks (.py): blackbricks (preserves cell markers and magic commands)
• Regular Python files: black + isort
• All files: ruff for linting and auto-fixing

Workflow

Step 1: Detect File Type

def is_databricks_notebook(file_path: Path) -> bool:
    with open(file_path, 'r') as f:
        first_line = f.readline()
        return '# Databricks notebook source' in first_line

Step 2: Format Based on Type

Databricks Notebooks:

uv run blackbricks <notebook.py>

Regular Python Files:

uv run isort <file.py>
uv run black <file.py>

Linting (all files):

uv run ruff check --fix <file_or_directory>

Step 3: Verify

uv run black --check <file.py>
uv run isort --check <file.py>
uv run ruff check <file.py>

Installation

# Databricks projects
uv add --dev blackbricks ruff

# Regular Python projects
uv add --dev black isort ruff

# Mixed projects
uv add --dev black isort blackbricks ruff

Configuration (pyproject.toml)

[tool.black]
line-length = 100
target-version = ['py311']

[tool.isort]
profile = "black"
line_length = 100

[tool.blackbricks]
line_length = 100
target_version = ['py311']

[tool.ruff]
line-length = 100
target-version = "py311"

[tool.ruff.lint]
select = ["E", "W", "F", "I", "B", "C4", "UP"]
ignore = ["E501"]

[tool.ruff.lint.per-file-ignores]
"__init__.py" = ["F401"]

Usage

Format Single File

uv run python scripts/format_code.py <any_file.py>   # Auto-detects type

Format Entire Project

uv run python scripts/format_code.py .                 # All Python files
uv run python scripts/format_code.py src/               # Specific directory
uv run python scripts/format_code.py src/ --skip-databricks  # Skip notebooks

Check Only (CI/CD)

uv run python scripts/check_format.py .
uv run python scripts/check_format.py src/ --strict     # Exit with error if unformatted

Run Individual Tools

uv run ruff check --fix .
uv run black src/
uv run isort src/
uv run blackbricks notebooks/

Key Rules

• Always detect file type before formatting
• Use blackbricks for Databricks notebooks to preserve cell structure
• Run isort before black for regular files
• Run ruff last for final cleanup
• Use consistent line length (100) across all tools
• Skip formatting for generated or vendored code

Scripts

• scripts/format_code.py - Auto-detects file types and applies correct formatters recursively
• scripts/check_format.py - Validates formatting without modifying files (for CI/CD)

References

• references/databricks-formatting.md - Databricks notebook formatting details and examples
• references/tool-comparison.md - Comparison of formatting tools