Add deploy hook to migrate images to media using migration helpers

web/modules/custom/geo_upgrade/geo_upgrade.deploy.php

@@ -0,0 +1,39 @@
+<?php
+
+/**
+ * @file
+ * Implements migration helpers in deploy hook to help migrate images to media.
+ *
+ * Config updates in drutopia utilize media entities for storing images.
+ */
+
+use Psr\Log\LogLevel;
+
+/**
+ * Move data from image fields to media entity reference fields.
+ *
+ * Implements hook_deploy_NAME().
+ */
+function geo_upgrade_deploy_move_images_to_media() {
+  $transformations = [
+    ['paragraph', ['field_image'], 'field_media_image', ['image', 'slide']],
+    ['node', ['field_image'], 'field_media_image', ['person', 'article', 'blog', 'collection', 'gleaning']],
+    // Leaving out the following for now, unless requested later
+    // ['paragraph', ['field_file'], 'field_media_document', ['file']],
+    // field_media_document would need to be created on file paragraph
+    // ['node', ['field_upload'], 'field_media_document', ['article', 'blog', 'gleaning']],
+    // new field would need to be added for generic file media (field_upload contains variety of file types)
+  ];
+
+  \Drupal::logger('geo_upgrade')->log(LogLevel::INFO, "Transformation started.");
+  foreach ($transformations as $transformation) {
+    [$entity_type, $image_field_names, $media_field_name, $bundles] = $transformation;
+
+    /** @var \Drupal\migration_helpers\MigrationHelperFieldTransformations $field_transformations_service */
+    $field_transformations_service = \Drupal::service('migration_helpers.field_transformations');
+    $field_transformations_service->fieldToMediaEntity($entity_type, $image_field_names, $media_field_name, $bundles);
+
+    $source_fields = implode(', ', $image_field_names);
+    \Drupal::logger('geo_upgrade')->log(LogLevel::INFO, "Data in image field(s) $source_fields of $entity_type entity moved to $media_field_name media reference field.");
+  }
+}

web/modules/custom/geo_upgrade/geo_upgrade.info.yml

@@ -8,3 +8,4 @@ dependencies:
   - migrate_plus
   - migrate_source_csv
   - migrate_tools
+  - migration_helpers