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Direct registration

The most basic mechanism: the host knows its plugin objects and hands them to the manager itself. Source: demo_01_direct.py.

from pluginkit import PluginManager
from pluginkit_tour.points import IngredientProvider

pm = PluginManager("kitchen")
pm.add_extension_points(points)

berry: IngredientProvider = BerryPlugin()
greens: IngredientProvider = GreensPlugin()
pm.register(berry, name="berry")
pm.register(greens, name="greens")

contributed = pm.caller(Specs.add_ingredients)(base=["banana", "milk"])

What it shows

  • A plugin can be a class instance (or a module, or anything with marked members).
  • add_ingredients is a collecting hook: every plugin runs and the results come back as a list, which the host flattens.
  • The plugins are annotated as IngredientProvider, a runtime_checkable Protocol. The annotation documents the structural contract and lets a type checker verify it - no shared base class.

Run it

make run DEMO=direct

Registered plugins: ['berry', 'greens']
Smoothie: banana, milk, blueberry, strawberry, spinach, kale

When to use it

Direct registration is right when the host owns the list of plugins - built-in extensions, plugins selected from configuration, or tests. When plugins ship as independent packages, prefer entry-point discovery.