31 Days of Drupal Migrations

https://agaric.coop/31-days-drupal-migrations

Day 1 Understanding the ETL process

• A migration is a Extract, transform, and load (ETL) procedure.

• In Drupal, each step is performed by a Migrate plugin:

  • The extract step is provided by source plugins
  • The transform step is provided by process plugins. Nice to use: Migrate Plus
  • The load step is provided by destination plugins

Drupal migrations: A 2 step process

• Migration on Drupal is a 2 step process: Write your migration and then execute it!
• You can only use one source and one destination for each migration file.
• It is important to only write one migration file per entity bundle (i.e one CT per node).
• Usually we will run the migration using drush with Migrate tools
• The migrations UI only detect those that have been defined as configuration entities using the Migrate Plus module

Day 2 Writing your first Drupal migration

https://agaric.coop/blog/writing-your-first-drupal-migration

cd ~/webapps/ddev-d10$
ddev gen module

File: ~/webapps/ddev-d10/web/modules/ud_migrations_first$ cat ud_migrations_first.info.yml

name: 'ud_migrations_first'
type: module
description: 'ud_migrations_first'
package: Custom
core_version_requirement: ^10 || ^11
dependencies:
  - drupal:migrate

File: ~/webapps/ddev-d10/web/modules/ud_migrations_first/migrations/udm_first.yml

id: udm_first
label: 'UD First migration'
source:
  plugin: embedded_data
  data_rows:
    -
      unique_id: 1
      creative_title: 'The versatility of Drupal fields'
      engaging_content: 'Fields are Drupal''s atomic data storage mechanism...'
    -
      unique_id: 2
      creative_title: 'What is a view in Drupal? How do they work?'
      engaging_content: 'In Drupal, a view is a listing of information. It can a list of nodes, users, comments, taxonomy terms, files, etc...'
  ids:
    unique_id:
      type: integer
process:
  title: creative_title
  body: engaging_content
destination:
  plugin: 'entity:node'
  default_bundle: page

• A quick glimpse at the migration configuration file reveals the three major parts: source, process, and destination.
• We use embedded_data source plugin to define the data to migrate right inside the definition file.
• We use as destination CT page.

pierre@7550 ~/webapps/ddev-d10$ ddev drush pm:enable migrate ud_migrations_first                                                                       1 ↵  
 [success] Successfully installed: migrate, ud_migrations_first

pierre@7550 ~/webapps/ddev-d10$ ddev drush ms                                                                                                               
 -------------- -------- ------- ---------- ------------- --------------- 
  Migration ID   Status   Total   Imported   Unprocessed   Last Imported  
 -------------- -------- ------- ---------- ------------- --------------- 
  udm_first      Idle     2       0          2                            
 -------------- -------- ------- ---------- ------------- --------------- 

pierre@7550 ~/webapps/ddev-d10$ ddev drush migrate:import udm_first                                                                                    1 ↵  
 2/2 [▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓] 100%
 [notice] Processed 2 items (2 created, 0 updated, 0 failed, 0 ignored) in 0.2 seconds (708.9/min) - done with 'udm_first'