Code formatting and linting


Code formatting guidelines set a standard for the layout of your code, for stylistic elements such as use of line breaks and whitespace. Format doesn’t have any impact on how the code works, but using a consistent style makes your code more readable, and makes it more likely to be reused.

Linting tools check your code for errors such as a missing bracket or line indent. This can save time and frustration because you can catch errors in advance of running the code.

As a project grows and goes through various stages of development it becomes important to maintain code quality. Using a consistent format and linting your code ensures that it is consistent, readable, and easy to debug and maintain.

Set up Python tools

There are a variety of Python tools available to use with your Kedro projects. This guide shows you how to use black, flake8, and isort to format and lint your Kedro projects.

Install the tools

Install black, flake8, and isort by adding the following lines to your project’s src/requirements.txt file:

black # Used for formatting code
flake8 # Used for linting and formatting
isort # Used for formatting code (sorting module imports)

To install all the project-specific dependencies, including the linting tools, navigate to the root directory of the project and run:

pip install -r src/requirements.txt

Alternatively, you can individually install the linting tools using the following shell commands:

pip install black
pip install flake8
pip install isort

Configure flake8

Store your flake8 configuration in a file named setup.cfg within your project root. The Kedro starters use the following configuration:


Run the tools

Use the following commands to run lint checks:

black --check <project_root>
isort --profile black --check <project_root>

You can also have black and isort automatically format your code by omitting the --check flag. Since isort and black both format your imports, adding --profile black to the isort run helps avoid potential conflicts.

Use the following to invoke flake8:

flake8 <project_root>

Automated formatting and linting with pre-commit hooks

You can automate the process of formatting and linting with pre-commit hooks. These hooks are run before committing your code to your repositories to automatically point out formatting issues, making code reviews easier and less time-consuming.

Install pre-commit

You can install pre-commit along with other dependencies by including it in the src/requirements.txt file of your Kedro project by adding the following line:


You can also install pre-commit using the following command:

pip install pre-commit

Add pre-commit configuration file

Create a file named .pre-commit-config.yaml in your Kedro project root directory. You can add entries for the hooks you want to run before each commit. Below is a sample YAML file with entries for black,flake8, and isort:

  - repo:
    rev: 5.10.1
      - id: isort
        name: isort (python)
        args: ["--profile", "black"]

  - repo:
    rev: ''  # pick a git hash / tag to point to
      - id: flake8

  - repo:
    rev: 22.8.0
      - id: black
        language_version: python3.9

Install git hook scripts

Run the following command to complete installation:

pre-commit install

This enables pre-commit hooks to run automatically every time you execute git commit.