Migrate taxonomy terms with CSV

Question

I would like to import some taxonomy terms with a taxonomy term in it. field_regio2 is a entityreference field to an existing taxonomy term Regio. But for some reason it is not working. Everything is working except the field_regio2.

$ drush mmsg import_gemeentes gives:

the entity_lookup plugin requires a value_key, none located

?

uuid: 7eef6b86-80db-40ab-8359-91d20675e0f2
langcode: en
status: true
dependencies: {  }
id: import_gemeentes
class: null
field_plugin_method: null
cck_plugin_method: null
migration_tags: null
migration_group: migrated_terms
label: 'Migrate gemeentes from the source CSV to taxonomy terms'
source:
  plugin: csv
  path: 'public://gemeentes.csv'
  header_row_count: 1
  keys:
    - id
  column_names:
    -
      id: id
    -
      vid: vid
    -
      name: name
    -
      field_stratenplan_luchtfoto_refe: field_stratenplan_luchtfoto_refe
    -
      rid: rid
    -
      rid22: rid2
process:
  vid:
    plugin: default_value
    default_value: gemeente
  name: name
  field_stratenplan_luchtfoto_refe: field_stratenplan_luchtfoto_refe
  field_regio: rid
  field_regio2:
    plugin: entity_generate
    source: rid22
destination:
  plugin: 'entity:taxonomy_term'
migration_dependencies: null

Answer 1

The syntax for entity_generate is:

field_regio2:
    plugin: entity_generate
    source: rid22
    entity_type: taxonomy_term
    # This is where migration breaks. It need to know which key to look for.
    value_key: name
    bundle_key: vid
    bundle: YOUR_VOCABULARY_MACHINE_NAME

Answer 2

It's important to realize that it's the value_key that will be matched to whatever is coming from the source. So if we say value_key: name then the source should contain strings (not IDs!) that will be matched to or create taxonomy term names.

Here's a working section of code from the process section of a node migration YAML-file. It gets names of category terms via source, matching them to names in vocabulary called "categories". If a a term with the given name does not exist in the vocabulary, it will be created.

# Name of the entityreference field, and we specify its property target_id:
field_category/target_id:
    plugin: entity_generate
    # "category" contains the textual name of the category, coming e.g. from CSV:
    source: category
    # Do not change this:
    entity_type: taxonomy_term
    # Do not change this:
    value_key: name
    # Do not change this:
    bundle_key: vid
    # Machine name of your vocabulary:
    bundle: categories

Here's the best page ever I've found on the subject: https://understanddrupal.com/articles/understanding-entitylookup-and-entitygenerate-process-plugins-migrate-tools