Plugin Managers¶

The Modeler API defines five plugin managers. Two use PHP attribute-based discovery for code-heavy plugins; three use YAML-based discovery for declarative configuration.

Attribute-based plugin managers¶

These manage plugins that are PHP classes annotated with PHP 8 attributes. They extend Drupal's DefaultPluginManager and follow the standard plugin discovery pattern.

Plugin Manager	Description	Details
Model Owner	Owns config entities that can be modeled	Defines components, storage, CRUD
Modeler	Provides visual editing UI	Renders canvas, parses/serializes data

Both managers provide an getAllInstances() method that returns all available plugin instances, which is useful for building UI elements like selection lists.

YAML-based plugin managers¶

These manage plugins defined in YAML files placed in each module's root directory. They do not require any PHP code, making them ideal for declarative metadata that can be contributed by any module.

Plugin Manager	YAML file pattern	Description	Details
Context	`MODULE.modeler_api.contexts.yml`	Available components per use case	Defines plugin lists per component type
Plugin Dependency	`MODULE.modeler_api.dependencies.yml`	Predecessor constraints	Restricts component ordering
Template Token	`MODULE.modeler_api.template_tokens.yml`	Token trees for templates	Recursive key-value tokens

Alter hooks¶

Every plugin manager supports an alter hook that allows other modules to modify plugin definitions at discovery time:

Plugin type	Alter hook
Model Owner	`hook_modeler_api_model_owner_info_alter()`
Modeler	`hook_modeler_api_modeler_info_alter()`
Context	`hook_modeler_api_context_info_alter()`
Dependency	`hook_modeler_api_dependency_info_alter()`
Template Token	`hook_modeler_api_template_token_info_alter()`

Plugin relationship diagram¶

Context ----+
            |
Dependency -+--> Model Owner <----> Modeler
            |
Template ---+
 Token

The three YAML-based plugin types always reference a specific Model Owner via their model_owner key. The Modeler, on the other hand, is Model Owner agnostic -- it works with any Model Owner that it is paired with in the settings.