Use deriver in Drupal Migration yml

Question

I am trying to use the deriver key in a migration yml to have dynamically build migrations for each bundle of an Entity Type (Drupal 9).

I read this and I am trying to use the deriver key to point to a Deriver class in my migration. However it seems that the deriver key is just ignored.

Is there something else that I need to do beside using the deriver key and create a deriver class that inherits from Drupal\Component\Plugin\Derivative\DeriverBase?

This is the migration yml:

id: person_roles
label: Import 
deriver: Drupal\my_module\PersonRoleImportDeriver
migration_group: my_group
source:
  plugin: url
  data_fetcher_plugin: http
  data_parser_plugin: xml
  urls: public://this.xml
  fields:
    -
      name: position_name
      label: person role name
      selector: funktion
  ids:
    position_name:
      type: string
destination:
  plugin: 'entity:my_entity'
process:
  name:
    -
      plugin: skip_on_empty
      method: row
      source: position_name
      message: 'Empty source person role'
    -
      plugin: make_unique_entity_field
      entity_type: my_entity
      migrated: true
      field: name

Answer 1

It's a plugin, so you need to respect the plugin directory structure and namespace.

Your class should be in my_module/src/Plugin/migrate and have the namespace Drupal\my_module\Plugin\migrate.