Kedro plugins

Note: This documentation is based on Kedro 0.16.5, if you spot anything that is incorrect then please create an issue or pull request.

Kedro plugins allow you to create new features for Kedro and inject additional commands into the CLI. Plugins are developed as separate Python packages that exist outside of any Kedro project.

Overview

Kedro uses setuptools, which is a collection of enhancements to the Python distutils to allow developers to build and distribute Python packages. Kedro uses various entry points in pkg_resources to provide plugin functionality.

Example of a simple plugin

Here is a simple example of a plugin that prints the pipeline as JSON:

kedrojson/plugin.py

import click
from kedro.framework.cli import get_project_context


@click.group(name="JSON")
def commands():
    """ Kedro plugin for printing the pipeline in JSON format """
    pass


@commands.command()
def to_json():
    """ Display the pipeline in JSON format """
    context = get_project_context()
    print(context.pipeline.to_json())

The plugin provides the following entry_points config in setup.py:

entry_points={
    "kedro.project_commands": ["kedrojson = kedrojson.plugin:commands"],
}

Once the plugin is installed, you can run it as follows:

kedro to_json

Working with click

Commands must be provided as click Groups

The click Group will be merged into the main CLI Group. In the process, the options on the group are lost, as is any processing that was done as part of its callback function.

ProjectContext

While running, plugins may request information about the current project by calling kedro.framework.cli.get_project_context().

This function provides access to the verbose flag via the key verbose and to anything returned by the project’s KedroContext. The returned instance of ProjectContext(KedroContext) class must contain at least the following properties and methods:

  • project_version: the version of Kedro the project was created with, or None if the project was not created with kedro new.
  • project_path: the path to the directory where either .kedro.yml or pyproject.toml is located.
  • config_loader: an instance of kedro.config.ConfigLoader.
  • catalog: an instance of kedro.io.DataCatalog.
  • pipeline: an instance of kedro.pipeline.Pipeline.

Plugins may require additional keys to be added to ProjectContext in run.py.

Note: kedro.framework.cli.get_project_context(key), where key is get_config, create_catalog, create_pipeline, template_version, project_name and project_path, is deprecated as of Kedro 0.15.0, and will be removed for future versions.

Initialisation

If the plugin initialisation needs to occur prior to Kedro starting, it can declare the entry_point key kedro.init. This entry point must refer to a function that currently has no arguments, but for future proofing you should declare it with **kwargs.

global and project commands

Plugins may also add commands to the Kedro CLI, which supports two types of commands:

  • global - available both inside and outside a Kedro project. Global commands use the entry_point key kedro.global_commands.
  • project - available only when a Kedro project is detected in the current directory. Project commands use the entry_point key kedro.project_commands.

Suggested command convention

We use the following command convention: kedro <plugin-name> <command>, with kedro <plugin-name> acting as a top-level command group. This is our suggested way of structuring your plugin bit it is not necessary for your plugin to work.

Hooks

You can develop hook implementations and have them automatically registered to the ProjectContext when the plugin is installed. To enable this for your custom plugin, simply add the following entry in your setup.py:

setup(
    ...
    entry_points={"kedro.hooks": ["plugin_name = plugin_name.plugin:hooks"]},
)

where plugin.py is the module where you declare hook implementations:

import logging

from kedro.framework.hooks import hook_impl


class MyHooks:
    @hook_impl
    def after_catalog_created(self, catalog):  # pylint: disable=unused-argument
        logging.info("Reached after_catalog_created hook")


hooks = MyHooks()
Note: Here, hooks should be an instance of the class defining the hooks.

Contributing process

When you are ready to submit your code:

  1. Create a separate repository using our naming convention for plugins (kedro-<plugin-name>)
  2. Choose a command approach: global and / or project commands:
    • All global commands should be provided as a single click group
    • All project commands should be provided as another click group
    • The click groups are declared through the pkg_resources entry_point system
  3. Include a README.md describing your plugin’s functionality and all dependencies that should be included
  4. Use GitHub tagging to tag your plugin as a kedro-plugin so that we can find it
Note: In future, we will feature a list of “Plugins by Contributors”. Your plugin needs to have an Apache 2.0 compatible license to be considered for this list.

Supported Kedro plugins

  • Kedro-Docker, a tool for packaging and shipping Kedro projects within containers
  • Kedro-Airflow, a tool for converting your Kedro project into an Airflow project
  • Kedro-Viz, a tool for visualising your Kedro pipelines

Community-developed plugins

see the full list of plugins listed on the GitHub tag kedro-hook