clean install

web/modules/migrate_plus/migrate_example/README.txt

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+INTRODUCTION
+------------
+The migrate_example module demonstrates how to implement custom migrations
+for Drupal 8+. It includes a group of "beer" migrations demonstrating a complete
+simple migration scenario.
+
+THE BEER SITE
+-------------
+In this scenario, we have a beer aficionado site which stores its data in MySQL
+tables - there are content items for each beer on the site, user accounts with
+profile data, categories to classify the beers, and user-generated comments on
+the beers. 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_example_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 migrations and config/install directories.
+   These YAML files describe the migration process and provide the mappings from
+   the source data to Drupal's destination entities. The difference between the
+   two possible directories:
+
+   a. Files in the migrations directory provide configuration directly for the
+   migration plugins. The filenames are of the form <migration ID>.yml. This
+   approach is recommended when your migration configuration is fully hardcoded
+   and does not need to be overridden (e.g., you don't need to change the URL to
+   a source web service through an admin UI). While developing migrations,
+   changes to these files require at most a 'drush cr' to load your changes.
+
+   b. Files in the config/install directory provide migration configuration as
+   configuration entities, and have names of the form
+   migrate_plus.migration.<migration ID>.yml ("migration" because they define
+   entities of the "migration" type, and "migrate_plus" because that is the
+   module which implements the "migration" type). Migrations defined in this way
+   may have their configuration modified (in particular, through a web UI) by
+   loading the configuration entity, modifying its configuration, and saving the
+   entity. When developing, to get edits to the .yml files in config/install to
+   take effect in active configuration, use the config_devel module.
+
+   Configuration in either type of file is identical - the only differences are
+   the directories and filenames.
+
+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.beer.yml
+2. migrate_plus.migration.beer_term.yml
+3. BeerTerm.php
+4. migrate_plus.migration.beer_user.yml
+5. BeerUser.php
+6. migrate_plus.migration.beer_node.yml
+7. BeerNode.php
+8. beer_comment.yml
+9. BeerComment.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_example
+
+# 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 beer migrations.
+drush mi --group=beer  # 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 beer_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=beer  # Abbreviation for migrate-rollback
+
+# You can import specific migrations.
+drush mi beer_term,beer_user
+# At this point, go look at your content listing - you'll see beer nodes named
+# "Stub", generated from the user's favbeers references.
+
+drush mi beer_node,beer_comment
+# Refresh your content listing - the stub nodes have been filled with real beer!
+
+# You can rollback specific migrations.
+drush mr beer_comment,beer_node

web/modules/migrate_plus/migrate_example/config/install/migrate_plus.migration.beer_node.yml

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+# Migration configuration for beer content.
+id: beer_node
+label: Beers of the world
+migration_group: beer
+migration_tags:
+  - example
+source:
+  plugin: beer_node
+destination:
+  plugin: entity:node
+process:
+  # Hardcode the destination node type (bundle) as 'migrate_example_beer'.
+  type:
+    plugin: default_value
+    default_value: migrate_example_beer
+  title: name
+  nid: bid
+  uid:
+    plugin: migration_lookup
+    migration: beer_user
+    source: aid
+  sticky:
+    plugin: default_value
+    default_value: 0
+  field_migrate_example_country: countries
+  field_migrate_example_beer_style:
+    plugin: migration_lookup
+    migration: beer_term
+    source: terms
+  # Some Drupal fields may have multiple components we may want to set
+  # separately. For example, text fields may have summaries (teasers) in
+  # addition to the full text value. We use / to separate the field name from
+  # the internal field value being set, and put it in quotes because / is a
+  # YAML special character.
+  'body/value': body
+  'body/summary': excerpt
+# Our beer nodes have references to terms and users, so we want those to be
+# imported first. We make that dependency explicit here - by putting those
+# migrations under the 'required' key, we ensure that the tools will prevent
+# us from running the beer_node migration unless the beer_term and beer_user
+# migrations are complete (although we can override the dependency check by
+# passing --force to the drush migrate-import command). We can also add
+# 'optional' dependencies - these affect the order in which migrations are
+# displayed, and run by default, but does not force you run them in that
+# order.
+# The general rule of thumb is that any migrations referenced by migration
+# process plugins should be required here.
+migration_dependencies:
+  required:
+    - beer_term
+    - beer_user
+dependencies:
+  enforced:
+    module:
+      - migrate_example

web/modules/migrate_plus/migrate_example/config/install/migrate_plus.migration.beer_term.yml

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+# A "migration" is, in technical terms, a plugin whose configuration describes
+# how to read source data, process it (generally by mapping source fields to
+# destination fields), and write it to Drupal.
+
+# The machine name for a migration, used to uniquely identify it.
+id: beer_term
+
+# A human-friendly description of the migration.
+label: Migrate style categories from the source database to taxonomy terms
+
+# The machine name of the group containing this migration (which contains shared
+# configuration to be merged with our own configuration here).
+migration_group: beer
+
+# The category or tag for the migration.
+migration_tags:
+  - example
+
+# Every migration must have a source plugin, which controls the delivery of our
+# source data. In this case, our source plugin has the name "beer_term", which
+# Drupal resolves to the PHP class defined in
+# src/Plugin/migrate/source/BeerTerm.php.
+source:
+  plugin: beer_term
+
+# Every migration must also have a destination plugin, which handles writing
+# the migrated data in the appropriate form for that particular kind of data.
+# Most Drupal content is an "entity" of one type or another, and we need to
+# specify what entity type we are populating (in this case, taxonomy terms).
+# Unlike the source plugin (which is specific to our particular scenario), this
+# destination plugin is implemented in Drupal itself.
+destination:
+  plugin: entity:taxonomy_term
+
+# Here's the meat of the migration - the processing pipeline. This describes how
+# each destination field is to be populated based on the source data. For each
+# destination field, one or more process plugins may be invoked.
+process:
+  # The simplest process plugin is named 'get' - it is the default plugin, so
+  # does not need to be explicitly named. It simply copies the source value
+  # (the 'style' field from the source database in this case) to the destination
+  # field (the taxonomy term 'name' field). You can see we simply copy the
+  # source 'details' field to destination 'description' field in the same way.
+  name: style
+  description: details
+
+  # Here is a new plugin - default_value. In its simplest usage here, it is used
+  # to hard-code a destination value, the vid (vocabulary ID) our taxonomy terms
+  # should be assigned to. It's important to note that while above the right
+  # side of the mappings was a source field name, here the right side of the
+  # 'default_value:' line is an actual value.
+  vid:
+    plugin: default_value
+    default_value: migrate_example_beer_styles
+
+  # Here's another new plugin - migration. When importing data from another
+  # system, typically the unique identifiers for items on the destination side
+  # are not the same as the identifiers were on the source side. For example, in
+  # our style data the term names are the unique identifiers for each term,
+  # while in Drupal each term is assigned a unique integer term ID (tid). When
+  # any such items are referenced in Drupal, the reference needs to be
+  # translated from the old ID ('ale') to the new ID (1). The migration
+  # framework keeps track of the relationships between source and destination
+  # IDs in map tables, and the migration plugin is the means of performing a
+  # lookup in those map tables during processing.
+  parent:
+    plugin: migration_lookup
+    # Here we reference the migration whose map table we're performing a lookup
+    # against. You'll note that in this case we're actually referencing this
+    # migration itself, since category parents are imported by the same
+    # migration. This works best when we're sure the parents are imported
+    # before the children, and in this case our source plugin is guaranteeing
+    # that.
+    migration: beer_term
+    # 'style_parent' is the parent reference field from the source data. The
+    # result of this plugin is that the destination 'parent' field is populated
+    # with the Drupal term ID of the referenced style (or NULL if style_parent
+    # was empty).
+    source: style_parent
+
+# We'll learn more about dependencies in beer_node - here, we leave them empty.
+migration_dependencies: {}
+
+# By default, configuration entities (like this migration) are not automatically
+# removed when the migration which installed them is uninstalled. To have your
+# migrations uninstalled with your migration module, add an enforced dependency
+# on your module.
+dependencies:
+  enforced:
+    module:
+      - migrate_example

web/modules/migrate_plus/migrate_example/config/install/migrate_plus.migration.beer_user.yml

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+# Migration configuration for user accounts. We've described most of what goes
+# into migration configuration in migrate_plus.migration.beer_term.yml, so won't
+# repeat that here.
+id: beer_user
+label: Beer Drinkers of the world
+migration_group: beer
+migration_tags:
+  - example
+source:
+  plugin: beer_user
+destination:
+  plugin: entity:user
+process:
+  pass: password
+  mail: email
+  init: email
+  status: status
+  roles:
+    plugin: default_value
+    default_value: 2
+
+  # Here's a new process plugin - make_unique_entity_field. Our source site allowed there
+  # to be multiple user accounts with the same username, but Drupal wants
+  # usernames to be unique. This plugin allows us to automatically generate
+  # unique usernames when we detect collisions.
+  name:
+    plugin: make_unique_entity_field
+    # The name of the source field containing the username.
+    source: username
+    # These next two settings identify the destination-side field to check for
+    # duplicates. They say "see if the incoming 'name' matches any existing
+    # 'name' field in any 'user' entity".
+    entity_type: user
+    field: name
+    # Finally, this specifies a string to use between the original value and the
+    # sequence number appended to make the value unique. Thus, the first 'alice'
+    # account gets the name 'alice' in Drupal, and the second one gets the name
+    # 'alice_1'.
+    postfix: _
+
+  # Another new process plugin - callback. This allows us to filter an incoming
+  # source value through an arbitrary PHP function. The function called must
+  # have one required argument.
+  created:
+    plugin: callback
+    # The 'registered' timestamp in the source data is a string of the form
+    # 'yyyy-mm-dd hh:mm:ss', but Drupal wants a UNIX timestamp for 'created'.
+    source: registered
+    callable: strtotime
+
+  # Our source data only has a single timestamp value, 'registered', which we
+  # want to use for all four of Drupal's user timestamp fields. We could
+  # duplicate the callback plugin we used for 'created' above - but we have a
+  # shortcut. Putting an @ sign at the beginning of the source value indicates
+  # that it is to be interpreted as a *destination* field name instead of a
+  # *source* field name. Thus, if a value we need in more than one place
+  # requires some processing beyond simply copying it directly, we can perform
+  # that processing a single time and use the result in multiple places.
+  changed: '@created'
+  access: '@created'
+  login: '@created'
+
+  # Yet another new process plugin - static_map. We're making a transformation
+  # in how we represent gender data - formerly it was integer values 0 for male
+  # and 1 for female, but in our modern Drupal site we will be making this a
+  # free-form text field, so we want to replace the obscure integers with
+  # simple strings.
+  field_migrate_example_gender:
+    plugin: static_map
+    # Specify the source field we're reading (containing 0's and 1's).
+    source: sex
+    # Tell it to transform 0 to 'Male', and 1 to 'Female'.
+    map:
+      0: Male
+      1: Female
+    # If the input is missing, leave the field empty. Without this, an empty
+    # or invalid source value would cause the user record to be skipped
+    # entirely.
+    bypass: true
+
+  # This looks like a simple migration process plugin, but there's magic
+  # happening here. We import nodes after terms and users, because they have
+  # references to terms and users, so of course the terms and users must be
+  # migrated first - right? However, the favbeers field is a reference to the
+  # beer nodes which haven't yet been migrated - we have a circular relationship
+  # between users and nodes. The way the migration system resolves this
+  # situation is by creating "stubs". In this case, because no beer nodes have
+  # been created, each time a beer is looked up against the beer_node migration
+  # nothing is found, and by default the migration process plugin creates an
+  # empty stub node as a placeholder so the favbeers reference field has
+  # something to point to. The stub is recorded in the beer_node map table, so
+  # when that migration runs it knows that each incoming beer should overwrite
+  # its stub instead of creating a new node.
+  field_migrate_example_favbeers:
+    plugin: migration_lookup
+    source: beers
+    migration: beer_node
+
+migration_dependencies: {}
+
+# When a module is creating a custom content type it needs to add an 
+# enforced dependency to itself, otherwise the content type will persist
+# after the module is disabled. See: https://www.drupal.org/node/2629516.
+dependencies:
+  enforced:
+    module:
+      - migrate_example

web/modules/migrate_plus/migrate_example/config/install/migrate_plus.migration_group.beer.yml

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+# A "migration group" is - surprise! - a group of migrations. It is used to
+# group migrations for display by our tools, and to perform operations on a
+# specific set of migrations. It can also be used to hold any configuration
+# common to those migrations, so it doesn't have to be duplicated in each one.
+
+# The machine name of the group, by which it is referenced in individual
+# migrations.
+id: beer
+
+# A human-friendly label for the group.
+label: Beer Imports
+
+# More information about the group.
+description: A few simple beer-related imports, to demonstrate how to implement migrations.
+
+# Short description of the type of source, e.g. "Drupal 6" or "WordPress".
+source_type: Custom tables
+
+# Here we add any default configuration settings to be shared among all
+# migrations in the group. For this example, the source tables are in the
+# Drupal (default) database, but usually if your source data is in a
+# database it will be external.
+shared_configuration:
+  # Specifying 'source' here means that this configuration will be merged into
+  # the 'source' configuration of each migration.
+  source:
+    # A better practice for real-world migrations would be to add a database
+    # connection to your external database in settings.php and reference its
+    # key here.
+    key: default
+
+# As with the migration configuration (see beer_term), we add an enforced
+# dependency so the migration_group configuration will be removed on module
+# uninstall.
+dependencies:
+  enforced:
+    module:
+      - migrate_example

web/modules/migrate_plus/migrate_example/migrate_example.info.yml

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+type: module
+name: Migrate Example
+description: 'Examples of how Drupal 8+ migration compares to previous versions.'
+package: Examples
+core_version_requirement: '>=9.1'
+dependencies:
+  - drupal:migrate
+  - migrate_plus:migrate_example_setup
+  - migrate_plus:migrate_plus
+  - drupal:menu_ui
+  - drupal:path
+
+# Information added by Drupal.org packaging script on 2024-11-20
+version: '6.0.5'
+project: 'migrate_plus'
+datestamp: 1732124626

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/comment.type.node_comments.yml

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+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - migrate_example_setup
+id: node_comments
+label: 'Node comments'
+target_entity_type_id: node
+description: ''

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/core.entity_form_display.comment.node_comments.default.yml

@@ -0,0 +1,30 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - comment.type.node_comments
+    - field.field.comment.node_comments.comment_body
+  module:
+    - text
+id: comment.node_comments.default
+targetEntityType: comment
+bundle: node_comments
+mode: default
+content:
+  author:
+    weight: -2
+  comment_body:
+    type: text_textarea
+    weight: 11
+    settings:
+      rows: 5
+      placeholder: ''
+    third_party_settings: {  }
+  subject:
+    type: string_textfield
+    weight: 10
+    settings:
+      size: 60
+      placeholder: ''
+    third_party_settings: {  }
+hidden: {  }

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/core.entity_form_display.node.migrate_example_beer.default.yml

@@ -0,0 +1,89 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.field.node.migrate_example_beer.body
+    - field.field.node.migrate_example_beer.field_comments
+    - field.field.node.migrate_example_beer.field_migrate_example_beer_style
+    - field.field.node.migrate_example_beer.field_migrate_example_country
+    - field.field.node.migrate_example_beer.field_migrate_example_image
+    - node.type.migrate_example_beer
+  module:
+    - comment
+    - image
+    - text
+id: node.migrate_example_beer.default
+targetEntityType: node
+bundle: migrate_example_beer
+mode: default
+content:
+  body:
+    type: text_textarea_with_summary
+    weight: 6
+    settings:
+      rows: 9
+      summary_rows: 3
+      placeholder: ''
+    third_party_settings: {  }
+  created:
+    type: datetime_timestamp
+    weight: 2
+    settings: {  }
+    third_party_settings: {  }
+  field_comments:
+    weight: 10
+    settings: {  }
+    third_party_settings: {  }
+    type: comment_default
+  field_migrate_example_beer_style:
+    weight: 7
+    settings:
+      match_operator: CONTAINS
+      match_limit: 10
+      size: 60
+      placeholder: ''
+    third_party_settings: {  }
+    type: entity_reference_autocomplete
+  field_migrate_example_country:
+    weight: 8
+    settings:
+      size: 60
+      placeholder: ''
+    third_party_settings: {  }
+    type: string_textfield
+  field_migrate_example_image:
+    weight: 9
+    settings:
+      progress_indicator: throbber
+      preview_image_style: thumbnail
+    third_party_settings: {  }
+    type: image_image
+  promote:
+    type: boolean_checkbox
+    settings:
+      display_label: true
+    weight: 3
+    third_party_settings: {  }
+  sticky:
+    type: boolean_checkbox
+    settings:
+      display_label: true
+    weight: 4
+    third_party_settings: {  }
+  title:
+    type: string_textfield
+    weight: 0
+    settings:
+      size: 60
+      placeholder: ''
+    third_party_settings: {  }
+  uid:
+    type: entity_reference_autocomplete
+    weight: 1
+    settings:
+      match_operator: CONTAINS
+      match_limit: 10
+      size: 60
+      placeholder: ''
+    third_party_settings: {  }
+hidden: {  }

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/core.entity_view_display.comment.node_comments.default.yml

@@ -0,0 +1,22 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - comment.type.node_comments
+    - field.field.comment.node_comments.comment_body
+  module:
+    - text
+id: comment.node_comments.default
+targetEntityType: comment
+bundle: node_comments
+mode: default
+content:
+  comment_body:
+    label: hidden
+    type: text_default
+    weight: 0
+    settings: {  }
+    third_party_settings: {  }
+  links:
+    weight: 100
+hidden: {  }

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/core.entity_view_display.node.migrate_example_beer.default.yml

@@ -0,0 +1,60 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.field.node.migrate_example_beer.body
+    - field.field.node.migrate_example_beer.field_comments
+    - field.field.node.migrate_example_beer.field_migrate_example_beer_style
+    - field.field.node.migrate_example_beer.field_migrate_example_country
+    - field.field.node.migrate_example_beer.field_migrate_example_image
+    - node.type.migrate_example_beer
+  module:
+    - comment
+    - image
+    - text
+    - user
+id: node.migrate_example_beer.default
+targetEntityType: node
+bundle: migrate_example_beer
+mode: default
+content:
+  body:
+    label: hidden
+    type: text_default
+    weight: 2
+    settings: {  }
+    third_party_settings: {  }
+  field_comments:
+    weight: 5
+    label: above
+    settings:
+      pager_id: 0
+    third_party_settings: {  }
+    type: comment_default
+  field_migrate_example_beer_style:
+    weight: 3
+    label: above
+    settings:
+      link: true
+    third_party_settings: {  }
+    type: entity_reference_label
+  field_migrate_example_country:
+    weight: 4
+    label: above
+    settings:
+      link_to_entity: false
+    third_party_settings: {  }
+    type: string
+  field_migrate_example_image:
+    weight: 1
+    label: above
+    settings:
+      image_style: ''
+      image_link: ''
+    third_party_settings: {  }
+    type: image
+  links:
+    weight: 0
+    settings: {  }
+    third_party_settings: {  }
+hidden: {  }

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/core.entity_view_display.node.migrate_example_beer.teaser.yml

@@ -0,0 +1,35 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - core.entity_view_mode.node.teaser
+    - field.field.node.migrate_example_beer.body
+    - field.field.node.migrate_example_beer.field_comments
+    - field.field.node.migrate_example_beer.field_migrate_example_beer_style
+    - field.field.node.migrate_example_beer.field_migrate_example_country
+    - field.field.node.migrate_example_beer.field_migrate_example_image
+    - node.type.migrate_example_beer
+  module:
+    - text
+    - user
+id: node.migrate_example_beer.teaser
+targetEntityType: node
+bundle: migrate_example_beer
+mode: teaser
+content:
+  body:
+    label: hidden
+    type: text_summary_or_trimmed
+    weight: 1
+    settings:
+      trim_length: 600
+    third_party_settings: {  }
+  links:
+    weight: 0
+    settings: {  }
+    third_party_settings: {  }
+hidden:
+  field_comments: true
+  field_migrate_example_beer_style: true
+  field_migrate_example_country: true
+  field_migrate_example_image: true

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.field.comment.node_comments.comment_body.yml

@@ -0,0 +1,20 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - comment.type.node_comments
+    - field.storage.comment.comment_body
+  module:
+    - text
+id: comment.node_comments.comment_body
+field_name: comment_body
+entity_type: comment
+bundle: node_comments
+label: Comment
+description: ''
+required: true
+translatable: true
+default_value: {  }
+default_value_callback: ''
+settings: {  }
+field_type: text_long

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.field.node.migrate_example_beer.body.yml

@@ -0,0 +1,21 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.storage.node.body
+    - node.type.migrate_example_beer
+  module:
+    - text
+id: node.migrate_example_beer.body
+field_name: body
+entity_type: node
+bundle: migrate_example_beer
+label: Body
+description: ''
+required: false
+translatable: true
+default_value: {  }
+default_value_callback: ''
+settings:
+  display_summary: true
+field_type: text_with_summary

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.field.node.migrate_example_beer.field_comments.yml

@@ -0,0 +1,32 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.storage.node.field_comments
+    - node.type.migrate_example_beer
+  module:
+    - comment
+id: node.migrate_example_beer.field_comments
+field_name: field_comments
+entity_type: node
+bundle: migrate_example_beer
+label: Comments
+description: ''
+required: false
+translatable: false
+default_value:
+  -
+    status: 2
+    cid: 0
+    last_comment_timestamp: 0
+    last_comment_name: null
+    last_comment_uid: 0
+    comment_count: 0
+default_value_callback: ''
+settings:
+  default_mode: 1
+  per_page: 50
+  anonymous: 0
+  form_location: true
+  preview: 1
+field_type: comment

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.field.node.migrate_example_beer.field_migrate_example_beer_style.yml

@@ -0,0 +1,26 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.storage.node.field_migrate_example_beer_style
+    - node.type.migrate_example_beer
+    - taxonomy.vocabulary.migrate_example_beer_styles
+id: node.migrate_example_beer.field_migrate_example_beer_style
+field_name: field_migrate_example_beer_style
+entity_type: node
+bundle: migrate_example_beer
+label: 'Migrate Example Beer Styles'
+description: ''
+required: false
+translatable: false
+default_value: {  }
+default_value_callback: ''
+settings:
+  handler: 'default:taxonomy_term'
+  handler_settings:
+    target_bundles:
+      migrate_example_beer_styles: migrate_example_beer_styles
+    sort:
+      field: _none
+    auto_create: false
+field_type: entity_reference

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.field.node.migrate_example_beer.field_migrate_example_country.yml

@@ -0,0 +1,18 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.storage.node.field_migrate_example_country
+    - node.type.migrate_example_beer
+id: node.migrate_example_beer.field_migrate_example_country
+field_name: field_migrate_example_country
+entity_type: node
+bundle: migrate_example_beer
+label: Countries
+description: ''
+required: false
+translatable: false
+default_value: {  }
+default_value_callback: ''
+settings: {  }
+field_type: string

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.field.node.migrate_example_beer.field_migrate_example_image.yml

@@ -0,0 +1,37 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.storage.node.field_migrate_example_image
+    - node.type.migrate_example_beer
+  module:
+    - image
+id: node.migrate_example_beer.field_migrate_example_image
+field_name: field_migrate_example_image
+entity_type: node
+bundle: migrate_example_beer
+label: Image
+description: ''
+required: false
+translatable: false
+default_value: {  }
+default_value_callback: ''
+settings:
+  file_directory: ''
+  file_extensions: 'png gif jpg jpeg'
+  max_filesize: ''
+  max_resolution: ''
+  min_resolution: ''
+  alt_field: true
+  alt_field_required: false
+  title_field: false
+  title_field_required: false
+  default_image:
+    uuid: ''
+    alt: ''
+    title: ''
+    width: null
+    height: null
+  handler: 'default:file'
+  handler_settings: {  }
+field_type: image

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.field.user.user.field_migrate_example_favbeers.yml

@@ -0,0 +1,27 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.storage.user.field_migrate_example_favbeers
+    - node.type.migrate_example_beer
+  module:
+    - user
+id: user.user.field_migrate_example_favbeers
+field_name: field_migrate_example_favbeers
+entity_type: user
+bundle: user
+label: 'Favorite Beers'
+description: ''
+required: false
+translatable: false
+default_value: {  }
+default_value_callback: ''
+settings:
+  handler: 'default:node'
+  handler_settings:
+    target_bundles:
+      migrate_example_beer: migrate_example_beer
+    sort:
+      field: title
+      direction: ASC
+field_type: entity_reference

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.field.user.user.field_migrate_example_gender.yml

@@ -0,0 +1,19 @@
+langcode: en
+status: true
+dependencies:
+  config:
+    - field.storage.user.field_migrate_example_gender
+  module:
+    - user
+id: user.user.field_migrate_example_gender
+field_name: field_migrate_example_gender
+entity_type: user
+bundle: user
+label: Gender
+description: ''
+required: false
+translatable: false
+default_value: {  }
+default_value_callback: ''
+settings: {  }
+field_type: string

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.storage.node.field_comments.yml

@@ -0,0 +1,22 @@
+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - migrate_example_setup
+  module:
+    - comment
+    - node
+id: node.field_comments
+field_name: field_comments
+entity_type: node
+type: comment
+settings:
+  comment_type: node_comments
+module: comment
+locked: false
+cardinality: 1
+translatable: true
+indexes: {  }
+persist_with_no_fields: false
+custom_storage: false

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.storage.node.field_migrate_example_beer_style.yml

@@ -0,0 +1,22 @@
+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - migrate_example_setup
+  module:
+    - node
+    - taxonomy
+id: node.field_migrate_example_beer_style
+field_name: field_migrate_example_beer_style
+entity_type: node
+type: entity_reference
+settings:
+  target_type: taxonomy_term
+module: core
+locked: false
+cardinality: -1
+translatable: true
+indexes: {  }
+persist_with_no_fields: false
+custom_storage: false

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.storage.node.field_migrate_example_country.yml

@@ -0,0 +1,23 @@
+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - migrate_example_setup
+  module:
+    - node
+id: node.field_migrate_example_country
+field_name: field_migrate_example_country
+entity_type: node
+type: string
+settings:
+  max_length: 255
+  is_ascii: false
+  case_sensitive: false
+module: core
+locked: false
+cardinality: -1
+translatable: true
+indexes: {  }
+persist_with_no_fields: false
+custom_storage: false

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.storage.node.field_migrate_example_image.yml

@@ -0,0 +1,32 @@
+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - migrate_example_setup
+  module:
+    - file
+    - image
+    - node
+id: node.field_migrate_example_image
+field_name: field_migrate_example_image
+entity_type: node
+type: image
+settings:
+  uri_scheme: public
+  default_image:
+    uuid: ''
+    alt: ''
+    title: ''
+    width: null
+    height: null
+  target_type: file
+  display_field: false
+  display_default: false
+module: image
+locked: false
+cardinality: 1
+translatable: true
+indexes: {  }
+persist_with_no_fields: false
+custom_storage: false

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.storage.user.field_migrate_example_favbeers.yml

@@ -0,0 +1,22 @@
+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - migrate_example_setup
+  module:
+    - node
+    - user
+id: user.field_migrate_example_favbeers
+field_name: field_migrate_example_favbeers
+entity_type: user
+type: entity_reference
+settings:
+  target_type: node
+module: core
+locked: false
+cardinality: -1
+translatable: true
+indexes: {  }
+persist_with_no_fields: false
+custom_storage: false

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/field.storage.user.field_migrate_example_gender.yml

@@ -0,0 +1,23 @@
+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - migrate_example_setup
+  module:
+    - user
+id: user.field_migrate_example_gender
+field_name: field_migrate_example_gender
+entity_type: user
+type: string
+settings:
+  max_length: 255
+  is_ascii: false
+  case_sensitive: false
+module: core
+locked: false
+cardinality: 1
+translatable: true
+indexes: {  }
+persist_with_no_fields: false
+custom_storage: false

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/node.type.migrate_example_beer.yml

@@ -0,0 +1,13 @@
+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - migrate_example_setup
+name: Beer
+type: migrate_example_beer
+description: 'Beer is what we drink.'
+help: ''
+new_revision: false
+preview_mode: 1
+display_submitted: true

web/modules/migrate_plus/migrate_example/migrate_example_setup/config/install/taxonomy.vocabulary.migrate_example_beer_styles.yml

@@ -0,0 +1,11 @@
+langcode: en
+status: true
+dependencies:
+  enforced:
+    module:
+      - migrate_example_setup
+name: 'Migrate Example Beer Styles'
+vid: migrate_example_beer_styles
+description: 'Use tags to group beers on similar topics into categories.'
+hierarchy: 0
+weight: 0

web/modules/migrate_plus/migrate_example/migrate_example_setup/migrate_example_setup.info.yml

@@ -0,0 +1,17 @@
+type: module
+name: Migrate Example Setup
+description: 'Separate site configuration for the example from the actual migration.'
+package: Migration
+core_version_requirement: '>=9.1'
+hidden: true
+dependencies:
+  - drupal:comment
+  - drupal:image
+  - drupal:text
+  - drupal:options
+  - drupal:taxonomy
+
+# Information added by Drupal.org packaging script on 2024-11-20
+version: '6.0.5'
+project: 'migrate_plus'
+datestamp: 1732124626

web/modules/migrate_plus/migrate_example/migrate_example_setup/migrate_example_setup.install

@@ -0,0 +1,502 @@
+<?php
+
+declare(strict_types = 1);
+
+/**
+ * @file
+ * Install file for migrate example module.
+ *
+ * Set up source data and destination configuration for the migration example
+ * module. We do this in a separate module so migrate_example itself is a pure
+ * migration module.
+ */
+
+/**
+ * Implements hook_schema().
+ */
+function migrate_example_setup_schema(): array {
+  $schema = [];
+  $schema['migrate_example_beer_account'] = migrate_example_beer_schema_account();
+  $schema['migrate_example_beer_node'] = migrate_example_beer_schema_node();
+  $schema['migrate_example_beer_comment'] = migrate_example_beer_schema_comment();
+  $schema['migrate_example_beer_topic'] = migrate_example_beer_schema_topic();
+  $schema['migrate_example_beer_topic_node'] = migrate_example_beer_schema_topic_node();
+
+  return $schema;
+}
+
+/**
+ * Implements hook_install().
+ */
+function migrate_example_setup_install(): void {
+  // Populate our tables.
+  migrate_example_beer_data_account();
+  migrate_example_beer_data_node();
+  migrate_example_beer_data_comment();
+  migrate_example_beer_data_topic();
+  migrate_example_beer_data_topic_node();
+}
+
+/**
+ * The hook_schema definition for node.
+ *
+ *   The schema definition.
+ */
+function migrate_example_beer_schema_node(): array {
+  return [
+    'description' => 'Beers of the world.',
+    'fields' => [
+      'bid'  => [
+        'type' => 'serial',
+        'not null' => TRUE,
+        'description' => 'Beer ID.',
+      ],
+      'name'  => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+      ],
+      'body' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Full description of the beer.',
+      ],
+      'excerpt' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Abstract for this beer.',
+      ],
+      'countries' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Countries of origin. Multiple values, delimited by pipe',
+      ],
+      'aid' => [
+        'type' => 'int',
+        'not null' => FALSE,
+        'description' => 'Account Id of the author.',
+      ],
+      'image' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Image path',
+      ],
+      'image_alt' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Image ALT',
+      ],
+      'image_title' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Image title',
+      ],
+      'image_description' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Image description',
+      ],
+    ],
+    'primary key' => ['bid'],
+  ];
+}
+
+/**
+ * The hook_schema definition for topic.
+ *
+ *   The schema definition.
+ */
+function migrate_example_beer_schema_topic(): array {
+  return [
+    'description' => 'Categories',
+    'fields' => [
+      'style'  => [
+        'type' => 'varchar_ascii',
+        'length' => 255,
+        'not null' => TRUE,
+      ],
+      'details' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+      ],
+      'style_parent' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Parent topic, if any',
+      ],
+      'region' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Region first associated with this style',
+      ],
+      'hoppiness' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Relative hoppiness of the beer',
+      ],
+    ],
+    'primary key' => ['style'],
+  ];
+}
+
+/**
+ * The hook_schema definition for topic node.
+ *
+ *   The schema definition.
+ */
+function migrate_example_beer_schema_topic_node(): array {
+  return [
+    'description' => 'Beers topic pairs.',
+    'fields' => [
+      'bid'  => [
+        'type' => 'int',
+        'not null' => TRUE,
+        'description' => 'Beer ID.',
+      ],
+      'style'  => [
+        'type' => 'varchar_ascii',
+        'length' => 255,
+        'not null' => TRUE,
+        'description' => 'Topic name',
+      ],
+    ],
+    'primary key' => ['style', 'bid'],
+  ];
+}
+
+/**
+ * The hook_schema definition for comment.
+ *
+ *   The schema definition.
+ */
+function migrate_example_beer_schema_comment(): array {
+  return [
+    'description' => 'Beers comments.',
+    'fields' => [
+      'cid'  => [
+        'type' => 'serial',
+        'not null' => TRUE,
+        'description' => 'Comment ID.',
+      ],
+      'bid'  => [
+        'type' => 'int',
+        'not null' => TRUE,
+        'description' => 'Beer ID that is being commented upon',
+      ],
+      'cid_parent' => [
+        'type' => 'int',
+        'not null' => FALSE,
+        'description' => 'Parent comment ID in case of comment replies.',
+      ],
+      'subject' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Comment subject',
+      ],
+      'body' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Comment body',
+      ],
+      'name' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Comment name (if anon)',
+      ],
+      'mail' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Comment email (if anon)',
+      ],
+      'aid' => [
+        'type' => 'int',
+        'not null' => FALSE,
+        'description' => 'Account ID (if any).',
+      ],
+    ],
+    'primary key' => ['cid'],
+  ];
+}
+
+/**
+ * The hook_schema definition for account.
+ *
+ *   The schema definition.
+ */
+function migrate_example_beer_schema_account(): array {
+  return [
+    'description' => 'Beers accounts.',
+    'fields' => [
+      'aid'  => [
+        'type' => 'serial',
+        'not null' => TRUE,
+        'description' => 'Account ID',
+      ],
+      'status'  => [
+        'type' => 'int',
+        'not null' => TRUE,
+        'description' => 'Blocked_Allowed',
+      ],
+      'registered' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'description' => 'Registration date',
+      ],
+      'username' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Account name (for login)',
+      ],
+      'nickname' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Account name (for display)',
+      ],
+      'password' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Account password (raw)',
+      ],
+      'email' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Account email',
+      ],
+      'sex' => [
+        'type' => 'int',
+        'not null' => FALSE,
+        'description' => 'Gender (0 for male, 1 for female)',
+      ],
+      'beers' => [
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => FALSE,
+        'description' => 'Favorite Beers',
+      ],
+    ],
+    'primary key' => ['aid'],
+  ];
+}
+
+/**
+ * Populate node table.
+ */
+function migrate_example_beer_data_node(): void {
+  $fields = [
+    'bid',
+    'name',
+    'body',
+    'excerpt',
+    'countries',
+    'aid',
+    'image',
+    'image_alt',
+    'image_title',
+    'image_description',
+  ];
+  $query = \Drupal::database()->insert('migrate_example_beer_node')
+    ->fields($fields);
+  // Use high bid numbers to avoid overwriting an existing node id.
+  $data = [
+    // Comes with migrate_example project.
+    [
+      99999999,
+      'Heineken',
+      'Blab Blah Blah Green',
+      'Green',
+      'Netherlands|Belgium',
+      1,
+      'heineken.jpg',
+      'Heinekin alt',
+      'Heinekin title',
+      'Heinekin description',
+    ],
+    [
+      99999998,
+      'Miller Lite',
+      'We love Miller Brewing',
+      'Tasteless',
+      'USA|Canada',
+      2,
+      NULL,
+      NULL,
+      NULL,
+      NULL,
+    ],
+    [
+      99999997,
+      'Boddington',
+      'English occasionally get something right',
+      'A treat',
+      'United Kingdom',
+      2,
+      NULL,
+      NULL,
+      NULL,
+      NULL,
+    ],
+  ];
+  foreach ($data as $row) {
+    $query->values(array_combine($fields, $row));
+  }
+  $query->execute();
+}
+
+/**
+ * Populate account table.
+ *
+ * Note that alice has duplicate username. Exercises make_unique_entity_field
+ * plugin.
+ *
+ * @todo Duplicate email also.
+ */
+function migrate_example_beer_data_account(): void {
+  $fields = [
+    'status',
+    'registered',
+    'username',
+    'nickname',
+    'password',
+    'email',
+    'sex',
+    'beers',
+  ];
+  $query = \Drupal::database()->insert('migrate_example_beer_account')
+    ->fields($fields);
+  $data = [
+    [
+      1,
+      '2010-03-30 10:31:05',
+      'alice',
+      'alice in beerland',
+      'alicepass',
+      'alice@example.com',
+      '1',
+      '99999999|99999998|99999997',
+    ],
+    [
+      1,
+      '2010-04-04 10:31:05',
+      'alice',
+      'alice in aleland',
+      'alicepass',
+      'alice2@example.com',
+      '1',
+      '99999999|99999998|99999997',
+    ],
+    [
+      0,
+      '2007-03-15 10:31:05',
+      'bob',
+      'rebob',
+      'bobpass',
+      'bob@example.com',
+      '0',
+      '99999999|99999997',
+    ],
+    [
+      1,
+      '2004-02-29 10:31:05',
+      'charlie',
+      'charlie chocolate',
+      'mykids',
+      'charlie@example.com',
+      '0',
+      '99999999|99999998',
+    ],
+  ];
+  foreach ($data as $row) {
+    $query->values(array_combine($fields, $row));
+  }
+  $query->execute();
+}
+
+/**
+ * Populate comment table.
+ */
+function migrate_example_beer_data_comment(): void {
+  $fields = ['bid', 'cid_parent', 'subject', 'body', 'name', 'mail', 'aid'];
+  $query = \Drupal::database()->insert('migrate_example_beer_comment')
+    ->fields($fields);
+  $data = [
+    [99999998, NULL, 'im first', 'full body', 'alice', 'alice@example.com', 1],
+    [99999998, NULL, 'im second', 'aromatic', 'alice', 'alice@example.com', 1],
+    [99999999, NULL, 'im parent', 'malty', 'alice', 'alice@example.com', 1],
+    [99999999, 1, 'im child', 'cold body', 'bob', NULL, 2],
+    [
+      99999999,
+      4,
+      'im grandchild',
+      'bitter body',
+      'charlie@example.com',
+      NULL,
+      1,
+    ],
+  ];
+  foreach ($data as $row) {
+    $query->values(array_combine($fields, $row));
+  }
+  $query->execute();
+}
+
+/**
+ * Populate topic table.
+ */
+function migrate_example_beer_data_topic(): void {
+  $fields = ['style', 'details', 'style_parent', 'region', 'hoppiness'];
+  $query = \Drupal::database()->insert('migrate_example_beer_topic')
+    ->fields($fields);
+  $data = [
+    ['ale', 'traditional', NULL, 'Medieval British Isles', 'Medium'],
+    ['red ale', 'colorful', 'ale', NULL, NULL],
+    [
+      'pilsner',
+      'refreshing',
+      NULL,
+      'Pilsen, Bohemia (now Czech Republic)',
+      'Low',
+    ],
+  ];
+  foreach ($data as $row) {
+    $query->values(array_combine($fields, $row));
+  }
+  $query->execute();
+}
+
+/**
+ * Populate topic node table.
+ */
+function migrate_example_beer_data_topic_node(): void {
+  $fields = ['bid', 'style'];
+  $query = \Drupal::database()->insert('migrate_example_beer_topic_node')
+    ->fields($fields);
+  $data = [
+    [99999999, 'pilsner'],
+    [99999999, 'red ale'],
+    [99999998, 'red ale'],
+  ];
+  foreach ($data as $row) {
+    $query->values(array_combine($fields, $row));
+  }
+  $query->execute();
+}

web/modules/migrate_plus/migrate_example/migrations/beer_comment.yml

@@ -0,0 +1,45 @@
+# Migration configuration for beer comments. No new concepts here.
+id: beer_comment
+label: Comments on beers
+migration_group: beer
+source:
+  plugin: beer_comment
+destination:
+  plugin: entity:comment
+process:
+  pid:
+    plugin: migration_lookup
+    migration: beer_comment
+    source: cid_parent
+  entity_id:
+    plugin: migration_lookup
+    migration: beer_node
+    source: bid
+  entity_type:
+    plugin: default_value
+    default_value: node
+  field_name:
+    plugin: default_value
+    default_value: field_comments
+  comment_type:
+    plugin: default_value
+    default_value: node_comments
+  subject: subject
+  uid:
+    plugin: migration_lookup
+    migration: beer_user
+    source: aid
+  name: name
+  mail: mail
+  status:
+    plugin: default_value
+    default_value: 1
+  'comment_body/value': body
+migration_dependencies:
+  required:
+    - beer_node
+    - beer_user
+dependencies:
+  enforced:
+    module:
+      - migrate_example

web/modules/migrate_plus/migrate_example/src/Plugin/migrate/source/BeerComment.php

@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_example\Plugin\migrate\source;
+
+use Drupal\Core\Database\Query\SelectInterface;
+use Drupal\migrate\Plugin\migrate\source\SqlBase;
+
+/**
+ * Source plugin for beer comments.
+ *
+ * @MigrateSource(
+ *   id = "beer_comment"
+ * )
+ */
+final class BeerComment extends SqlBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function query(): SelectInterface {
+    $fields = [
+      'cid',
+      'cid_parent',
+      'name',
+      'mail',
+      'aid',
+      'body',
+      'bid',
+      'subject',
+    ];
+    return $this->select('migrate_example_beer_comment', 'mec')
+      ->fields('mec', $fields)
+      ->orderBy('cid_parent', 'ASC');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function fields(): array {
+    return [
+      'cid' => $this->t('Comment ID'),
+      'cid_parent' => $this->t('Parent comment ID in case of comment replies'),
+      'name' => $this->t('Comment name (if anon)'),
+      'mail' => $this->t('Comment email (if anon)'),
+      'aid' => $this->t('Account ID (if any)'),
+      'bid' => $this->t('Beer ID that is being commented upon'),
+      'subject' => $this->t('Comment subject'),
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIds(): array {
+    return [
+      'cid' => [
+        'type' => 'integer',
+        'alias' => 'mec',
+      ],
+    ];
+  }
+
+}

web/modules/migrate_plus/migrate_example/src/Plugin/migrate/source/BeerNode.php

@@ -0,0 +1,105 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_example\Plugin\migrate\source;
+
+use Drupal\Core\Database\Query\SelectInterface;
+use Drupal\migrate\Plugin\migrate\source\SqlBase;
+use Drupal\migrate\Row;
+
+/**
+ * Source plugin for beer content.
+ *
+ * @MigrateSource(
+ *   id = "beer_node"
+ * )
+ */
+final class BeerNode extends SqlBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function query(): SelectInterface {
+    // An important point to note is that your query *must* return a single row
+    // for each item to be imported. Here we might be tempted to add a join to
+    // migrate_example_beer_topic_node in our query, to pull in the
+    // relationships to our categories. Doing this would cause the query to
+    // return multiple rows for a given node, once per related value, thus
+    // processing the same node multiple times, each time with only one of the
+    // multiple values that should be imported. To avoid that, we simply query
+    // the base node data here, and pull in the relationships in prepareRow()
+    // below.
+    $fields = [
+      'bid',
+      'name',
+      'body',
+      'excerpt',
+      'aid',
+      'countries',
+      'image',
+      'image_alt',
+      'image_title',
+      'image_description',
+    ];
+    return $this->select('migrate_example_beer_node', 'b')
+      ->fields('b', $fields);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function fields(): array {
+    return [
+      'bid' => $this->t('Beer ID'),
+      'name' => $this->t('Name of beer'),
+      'body' => $this->t('Full description of the beer'),
+      'excerpt' => $this->t('Abstract for this beer'),
+      'aid' => $this->t('Account ID of the author'),
+      'countries' => $this->t('Countries of origin. Multiple values, delimited by pipe'),
+      'image' => $this->t('Image path'),
+      'image_alt' => $this->t('Image ALT'),
+      'image_title' => $this->t('Image title'),
+      'image_description' => $this->t('Image description'),
+      // Note that this field is not part of the query above - it is populated
+      // by prepareRow() below. You should document all source properties that
+      // are available for mapping after prepareRow() is called.
+      'terms' => $this->t('Applicable styles'),
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIds(): array {
+    return [
+      'bid' => [
+        'type' => 'integer',
+        'alias' => 'b',
+      ],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function prepareRow(Row $row): bool {
+    // As explained above, we need to pull the style relationships into our
+    // source row here, as an array of 'style' values (the unique ID for
+    // the beer_term migration).
+    $terms = $this->select('migrate_example_beer_topic_node', 'bt')
+      ->fields('bt', ['style'])
+      ->condition('bid', $row->getSourceProperty('bid'))
+      ->execute()
+      ->fetchCol();
+    $row->setSourceProperty('terms', $terms);
+
+    // As we did for favorite beers in the user migration, we need to explode
+    // the multi-value country names.
+    if ($value = $row->getSourceProperty('countries')) {
+      $row->setSourceProperty('countries', explode('|', $value));
+    }
+    return parent::prepareRow($row);
+  }
+
+}

web/modules/migrate_plus/migrate_example/src/Plugin/migrate/source/BeerTerm.php

@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_example\Plugin\migrate\source;
+
+use Drupal\Core\Database\Query\SelectInterface;
+use Drupal\migrate\Plugin\migrate\source\SqlBase;
+
+/**
+ * This is an example of a simple SQL-based source plugin.
+ *
+ * Source plugins are classes which deliver source data to the processing
+ * pipeline. For SQL sources, the SqlBase class provides most of the
+ * functionality needed - for a specific migration, you are required to
+ * implement the three simple public methods you see below.
+ *
+ * This annotation tells Drupal that the name of the MigrateSource plugin
+ * implemented by this class is "beer_term". This is the name that the migration
+ * configuration references with the source "plugin" key.
+ *
+ * @MigrateSource(
+ *   id = "beer_term"
+ * )
+ */
+final class BeerTerm extends SqlBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function query(): SelectInterface {
+    // The most important part of a SQL source plugin is the SQL query to
+    // retrieve the data to be imported. Note that the query is not executed
+    // here - the migration process will control execution of the query. Also
+    // note that it is constructed from a $this->select() call - this ensures
+    // that the query is executed against the database configured for this
+    // source plugin.
+    $fields = ['style', 'details', 'style_parent', 'region', 'hoppiness'];
+    return $this->select('migrate_example_beer_topic', 'met')
+      ->fields('met', $fields)
+      // We sort this way to ensure parent terms are imported first.
+      ->orderBy('style_parent', 'ASC');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function fields(): array {
+    // This method simply documents the available source fields provided by the
+    // source plugin, for use by front-end tools. It returns an array keyed by
+    // field/column name, with the value being a translated string explaining
+    // to humans what the field represents.
+    return [
+      'style' => $this->t('Beer style'),
+      'details' => $this->t('Style details'),
+      'style_parent' => $this->t('Parent style'),
+      // These values are not currently migrated - it's OK to skip fields you
+      // don't need.
+      'region' => $this->t('Region the style is associated with'),
+      'hoppiness' => $this->t('Hoppiness of the style'),
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIds(): array {
+    // This method indicates what field(s) from the source row uniquely identify
+    // that source row, and what their types are. This is critical information
+    // for managing the migration. The keys of the returned array are the field
+    // names from the query which comprise the unique identifier. The values are
+    // arrays indicating the type of the field, used for creating compatible
+    // columns in the map tables that track processed items.
+    return [
+      'style' => [
+        'type' => 'string',
+        // 'alias' is the alias for the table containing 'style' in the query
+        // defined above. Optional in this case, but necessary if the same
+        // column may occur in multiple tables in a join.
+        'alias' => 'met',
+      ],
+    ];
+  }
+
+}

web/modules/migrate_plus/migrate_example/src/Plugin/migrate/source/BeerUser.php

@@ -0,0 +1,91 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_example\Plugin\migrate\source;
+
+use Drupal\Core\Database\Query\SelectInterface;
+use Drupal\migrate\Plugin\migrate\source\SqlBase;
+use Drupal\migrate\Row;
+
+/**
+ * Source plugin for beer user accounts.
+ *
+ * @MigrateSource(
+ *   id = "beer_user"
+ * )
+ */
+final class BeerUser extends SqlBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function query(): SelectInterface {
+    $fields = [
+      'aid',
+      'status',
+      'registered',
+      'username',
+      'nickname',
+      'password',
+      'email',
+      'sex',
+      'beers',
+    ];
+    return $this->select('migrate_example_beer_account', 'mea')
+      ->fields('mea', $fields);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function fields(): array {
+    return [
+      'aid' => $this->t('Account ID'),
+      'status' => $this->t('Blocked/Allowed'),
+      'registered' => $this->t('Registered date'),
+      'username' => $this->t('Account name (for login)'),
+      'nickname' => $this->t('Account name (for display)'),
+      'password' => $this->t('Account password (raw)'),
+      'email' => $this->t('Account email'),
+      'sex' => $this->t('Gender'),
+      'beers' => $this->t('Favorite beers, pipe-separated'),
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIds(): array {
+    return [
+      'aid' => [
+        'type' => 'integer',
+        'alias' => 'mea',
+      ],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function prepareRow(Row $row): bool {
+    // A prepareRow() is the most common place to perform custom run-time
+    // processing that isn't handled by an existing process plugin. It is called
+    // when the raw data has been pulled from the source, and provides the
+    // opportunity to modify or add to that data, creating the canonical set of
+    // source data that will be fed into the processing pipeline.
+    // In our particular case, the list of a user's favorite beers is a pipe-
+    // separated list of beer IDs. The processing pipeline deals with arrays
+    // representing multi-value fields naturally, so we want to explode that
+    // string to an array of individual beer IDs.
+    if ($value = $row->getSourceProperty('beers')) {
+      $row->setSourceProperty('beers', explode('|', $value));
+    }
+    // Always call your parent! Essential processing is performed in the base
+    // class. Be mindful that prepareRow() returns a boolean status - if FALSE
+    // that indicates that the item being processed should be skipped. Unless
+    // we're deciding to skip an item ourselves, let the parent class decide.
+    return parent::prepareRow($row);
+  }
+
+}

web/modules/migrate_plus/migrate_example/tests/src/Kernel/MigrateExampleTest.php

@@ -0,0 +1,93 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\Tests\migrate_example\Kernel;
+
+use Drupal\node\Entity\NodeType;
+use Drupal\Tests\migrate_drupal\Kernel\MigrateDrupalTestBase;
+
+/**
+ * Tests migrate_example migrations.
+ *
+ * @group migrate_plus
+ */
+final class MigrateExampleTest extends MigrateDrupalTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'node',
+    'taxonomy',
+    'comment',
+    'text',
+    'migrate_plus',
+    'migrate_example',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $this->installConfig([
+      'node',
+      'comment',
+      'migrate_example',
+    ]);
+
+    $this->installSchema('comment', ['comment_entity_statistics']);
+    $this->installSchema('node', ['node_access']);
+    $this->installSchema('user', ['users_data']);
+
+    // Install the module via installer to trigger hook_install.
+    \Drupal::service('module_installer')->install(['migrate_example_setup']);
+    $this->installConfig(['migrate_example_setup']);
+
+    $this->startCollectingMessages();
+
+    // Execute "beer" migrations from 'migrate_example' module.
+    $this->executeMigration('beer_user');
+    $this->executeMigrations([
+      'beer_term',
+      'beer_node',
+      'beer_comment',
+    ]);
+  }
+
+  /**
+   * Tests the results of "Beer" example migration.
+   */
+  public function testBeerMigration(): void {
+    $users = \Drupal::entityTypeManager()->getStorage('user')->loadMultiple();
+    $this->assertCount(4, $users);
+
+    $terms = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->loadMultiple();
+    $this->assertCount(3, $terms);
+
+    $nodes = \Drupal::entityTypeManager()->getStorage('node')->loadMultiple();
+    $this->assertCount(3, $nodes);
+
+    $comments = \Drupal::entityTypeManager()->getStorage('comment')->loadMultiple();
+    $this->assertCount(5, $comments);
+  }
+
+  /**
+   * Tests whether the module can be uninstalled and installed again.
+   *
+   * Also, checks whether the example configs are removed after uninstall.
+   */
+  public function testModuleCleanup(): void {
+    $test_node_type = 'migrate_example_beer';
+    // Prove that test content type existed before the uninstall process.
+    $this->assertInstanceOf(NodeType::class, NodeType::load($test_node_type));
+    \Drupal::service('module_installer')->uninstall(['migrate_example_setup']);
+    // Make sure the test content type was removed.
+    $this->assertNull(NodeType::load($test_node_type));
+    // Check whether the module can be installed again.
+    \Drupal::service('module_installer')->install(['migrate_example_setup']);
+  }
+
+}