title	description
ruff configuration in MegaLinter	How to use ruff (configure, ignore files, ignore errors, help & version documentations) to analyze PYTHON files

ruff

Ruff is an extremely fast Python linter and code formatter written in Rust that aims to be 10-100x faster than existing tools while providing comprehensive functionality behind a single interface.

Key Features:

Lightning Performance: 10-100x faster than Flake8, Black, and other traditional Python tools, with built-in caching for unchanged files
800+ Built-in Rules: Comprehensive rule set with native re-implementations of popular Flake8 plugins like flake8-bugbear, bandit, and more
Drop-in Compatibility: Parity with Flake8, isort, and Black - can replace multiple tools with a single fast solution
Auto-fixing: Automatic error correction for many violations (unused imports, formatting issues, etc.)
Modern Python Support: Full Python 3.13 compatibility with pyproject.toml configuration support
Monorepo-Friendly: Hierarchical and cascading configuration for complex project structures

ruff documentation

Version in MegaLinter: 0.14.0
Visit Official Web Site{target=_blank}
See How to configure ruff rules{target=_blank}
- If custom .ruff.toml config file isn't found, .ruff.toml{target=_blank} will be used
See How to disable ruff rules in files{target=_blank}
See Index of problems detected by ruff{target=_blank}

{target=_blank}

Configuration in MegaLinter

Enable ruff by adding PYTHON_RUFF in ENABLE_LINTERS variable
Disable ruff by adding PYTHON_RUFF in DISABLE_LINTERS variable
Enable autofixes by adding PYTHON_RUFF in APPLY_FIXES variable

Variable	Description	Default value
PYTHON_RUFF_ARGUMENTS	User custom arguments to add in linter CLI call Ex: `-s --foo "bar"`
PYTHON_RUFF_COMMAND_REMOVE_ARGUMENTS	User custom arguments to remove from command line before calling the linter Ex: `-s --foo "bar"`
PYTHON_RUFF_FILTER_REGEX_INCLUDE	Custom regex including filter Ex: `(src\|lib)`	Include every file
PYTHON_RUFF_FILTER_REGEX_EXCLUDE	Custom regex excluding filter Ex: `(test\|examples)`	Exclude no file
PYTHON_RUFF_CLI_LINT_MODE	Override default CLI lint mode - `file`: Calls the linter for each file - `list_of_files`: Call the linter with the list of files as argument - `project`: Call the linter from the root of the project	`list_of_files`
PYTHON_RUFF_FILE_EXTENSIONS	Allowed file extensions. `"*"` matches any extension, `""` matches empty extension. Empty list excludes all files Ex: `[".py", ""]`	`[".py", ".pyi", ".ipynb"]`
PYTHON_RUFF_FILE_NAMES_REGEX	File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files Ex: `["Dockerfile(-.+)?", "Jenkinsfile"]`	Include every file
PYTHON_RUFF_PRE_COMMANDS	List of bash commands to run before the linter	None
PYTHON_RUFF_POST_COMMANDS	List of bash commands to run after the linter	None
PYTHON_RUFF_UNSECURED_ENV_VARIABLES	List of env variables explicitly not filtered before calling PYTHON_RUFF and its pre/post commands	None
PYTHON_RUFF_CONFIG_FILE	ruff configuration file name Use `LINTER_DEFAULT` to let the linter find it	`.ruff.toml`
PYTHON_RUFF_RULES_PATH	Path where to find linter configuration file	Workspace folder, then MegaLinter default rules
PYTHON_RUFF_DISABLE_ERRORS	Run linter but consider errors as warnings	`false`
PYTHON_RUFF_DISABLE_ERRORS_IF_LESS_THAN	Maximum number of errors allowed	`0`
PYTHON_RUFF_CLI_EXECUTABLE	Override CLI executable	`['ruff']`

IDE Integration

Use ruff in your favorite IDE to catch errors before MegaLinter !

	IDE	Extension Name	Install
	IDEA	Ruff	<iframe frameborder="none" width="245px" height="48px" src="https://plugins.jetbrains.com/embeddable/install/20574"></iframe>
	Visual Studio Code	Ruff	{target=_blank}

MegaLinter Flavors

This linter is available in the following flavors

Flavor	Description	Embedded linters
all	Default MegaLinter Flavor	127
cupcake	MegaLinter for the most commonly used languages	88
python	Optimized for PYTHON based projects	65

Behind the scenes

How are identified applicable files

File extensions: .py, .pyi, .ipynb

How the linting is performed

ruff is called once with the list of files as arguments (list_of_files CLI lint mode)

Example calls

ruff check myfile.py

ruff check --config .ruff.toml myfile.py

Help content

Ruff: An extremely fast Python linter and code formatter.

Usage: ruff [OPTIONS] <COMMAND>

Commands:
  check    Run Ruff on the given files or directories
  rule     Explain a rule (or all rules)
  config   List or describe the available configuration options
  linter   List all supported upstream linters
  clean    Clear any caches in the current directory and any subdirectories
  format   Run the Ruff formatter on the given files or directories
  server   Run the language server
  analyze  Run analysis over Python source code
  version  Display Ruff's version
  help     Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Log levels:
  -v, --verbose  Enable verbose logging
  -q, --quiet    Print diagnostics, but nothing else
  -s, --silent   Disable all logging (but still exit with status code "1" upon detecting
                 diagnostics)

Global options:
      --config <CONFIG_OPTION>  Either a path to a TOML configuration file (`pyproject.toml` or
                                `ruff.toml`), or a TOML `<KEY> = <VALUE>` pair (such as you might
                                find in a `ruff.toml` configuration file) overriding a specific
                                configuration option. Overrides of individual settings using this
                                option always take precedence over all configuration files,
                                including configuration files that were also specified using
                                `--config`
      --isolated                Ignore all configuration files

For help with a specific command, see: `ruff help <command>`.

Installation on mega-linter Docker image

Dockerfile commands :

# renovate: datasource=pypi depName=ruff
ARG PIP_RUFF_VERSION=0.14.0

PIP packages (Python):
- ruff==0.14.0

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