Implementing plugins

This page explains how to implement a plugin for ZEN-garden. Keep plugins small and focused: they should register callbacks for events as defined in ZEN-garden main module.

The callbacks are executed at predefined locations (via events) in the main module.

Plugin contract

• Location: place your plugin as a package under zen_garden.plugins. The loader imports the module …<plugin>.plugin. You can find a template in zen_garden.plugins._template

• Registration: use the Event helper to attach functions to events (see zen_garden.events.Event for available events). The function will be called at the respective event.

• Config: use the dictonary at config.plugins to specify a config to pass to the plugin.

Minimal example

The tests include a minimal plugin used as an example. A shortened version:

# tests/unit_tests/fake_plugin/plugin.py
from zen_garden.plugin_system.events import EventPublisher
from tests.unit_tests.test_events import TestEvent

config = {}


@EventPublisher.register(TestEvent.test_event1)
def first_method(**kwargs):
    pass

@EventPublisher.register(TestEvent.test_event2)
def first_method(**kwargs):
    pass

How the loader uses your plugin

The loader function zen_garden.plugins.loader.register_plugins imports zen_garden.plugins.<name>.plugin and updates the plugin module’s config dict with the configuration provided in config.json. The loader registers the plugin’s callbacks to the events they are decorated with, so that are executed during runtime when the respective event is triggered.