INTRODUCTION ------------ The migrate_nd module demonstrates how to implement custom migrations for Drupal 8. It includes a group of "dyn" migrations demonstrating a complete simple migration scenario. THE Dynamic migration SITE ------------- In this scenario, we have a dyn aficionado site which stores its data in MySQL tables - there are content items for each dyn on the site, user accounts with profile data, categories to classify the dyns, and user-generated comments on the dyns. We want to convert this site to Drupal with just a few modifications to the basic structure. To make the example as simple as to run as possible, the source data is placed in tables directly in your Drupal database - in most real-world scenarios, your source data will be in an external database. The migrate_nd_setup submodule creates and populates these tables, as well as configuring your Drupal 8 site (creating a node type, vocabulary, fields, etc.) to receive the data. STRUCTURE --------- There are two primary components to this example: 1. Migration configuration, in the config/install directory. These YAML files describe the migration process and provide the mappings from the source data to Drupal's destination entities. 2. Source plugins, in src/Plugin/migrate/source. These are referenced from the configuration files, and provide the source data to the migration processing pipeline, as well as manipulating that data where necessary to put it into a canonical form for migrations. UNDERSTANDING THE MIGRATIONS ---------------------------- The YAML and PHP files are copiously documented in-line. To best understand the concepts described in a more-or-less narrative form, it is recommended you read the files in the following order: 1. migrate_plus.migration_group.dyn.yml 2. migrate.migration.dyn_term.yml 3. DynTerm.php 4. migrate.migration.dyn_user.yml 5. DynUser.php 6. migrate.migration.dyn_node.yml 7. DynNode.php 8. migrate.migration.dyn_comment.yml 9. DynComment.php RUNNING THE MIGRATIONS ---------------------- The migrate_tools module (https://www.drupal.org/project/migrate_tools) provides the tools you need to perform migration processes. At this time, the web UI only provides status information - to perform migration operations, you need to use the drush commands. # Enable the tools and the example module if you haven't already. drush en -y migrate_tools,migrate_nd # Look at the migrations. Just look at them. Notice that they are displayed in # the order they will be run, which reflects their dependencies. For example, # because the node migration references the imported terms and users, it must # run after those migrations have been run. drush ms # Abbreviation for migrate-status # Run the import operation for all the dyn migrations. drush mi --group=dyn # Abbreviation for migrate-import # Look at what you've done! Also, visit the site and see the imported content, # user accounts, etc. drush ms # Look at the duplicate username message. drush mmsg dyn_user # Abbreviation for migrate-messages # Run the rollback operation for all the migrations (removing all the imported # content, user accounts, etc.). Note that it will rollback the migrations in # the opposite order as they were imported. drush mr --group=dyn # Abbreviation for migrate-rollback # You can import specific migrations. drush mi dyn_term,dyn_user # At this point, go look at your content listing - you'll see dyn nodes named # "Stub", generated from the user's favdyns references. drush mi dyn_node,dyn_comment # Refresh your content listing - the stub nodes have been filled with real dyn! # You can rollback specific migrations. drush mr dyn_comment,dyn_node