Kedro plugins¶

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.session import KedroSession


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


@commands.command()
@click.pass_obj
def to_json(metadata):
    """Display the pipeline in JSON format"""
    session = KedroSession.create(metadata.package_name)
    context = session.load_context()
    print(context.pipeline.to_json())

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

setup(
    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.

Project context¶

When they run, plugins may request information about the current project by creating a session and loading its context:

from pathlib import Path

from kedro.framework.startup import _get_project_metadata
from kedro.framework.session import KedroSession


project_path = Path.cwd()
metadata = _get_project_metadata(project_path)
session = KedroSession.create(metadata.package_name, project_path)
context = session.load_context()

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 project context 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

hooks should be an instance of the class defining the Hooks.

CLI Hooks¶

You can also develop hook implementations to extend Kedro’s CLI behaviour in your plugin. To find available CLI hooks, please visit kedro.framework.cli.hooks. To register CLI hooks developed in your plugin with Kedro, add the following entry in your project’s setup.py:

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

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

import logging

from kedro.framework.cli.hooks import cli_hook_impl


class MyCLIHooks:
    @cli_hook_impl
    def before_command_run(self, project_metadata, command_args):
        logging.info(
            "Command %s will be run for project %s", command_args, project_metadata
        )


cli_hooks = MyCLIHooks()

Contributing process¶

When you are ready to submit your code:

Create a separate repository using our naming convention for plugins (kedro-<plugin-name>)
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
Include a README.md describing your plugin’s functionality and all dependencies that should be included
Use GitHub tagging to tag your plugin as a kedro-plugin so that we can find it

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 using the GitHub tag kedro-plugin.