clean install

web/modules/migrate_tools/src/Form/MigrationAddForm.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_tools\Form;
+
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Class MigrationAddForm.
+ *
+ * Provides the add form for our migration entity.
+ *
+ * @package Drupal\migrate_tools\Form
+ *
+ * @ingroup migrate_tools
+ */
+class MigrationAddForm extends MigrationFormBase {
+
+  /**
+   * Returns the actions provided by this form.
+   *
+   * For our add form, we only need to change the text of the submit button.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   *
+   * @return array
+   *   An array of supported actions for the current entity form.
+   */
+  protected function actions(array $form, FormStateInterface $form_state): array {
+    $actions = parent::actions($form, $form_state);
+    unset($actions['submit']);
+    return $actions;
+  }
+
+}

web/modules/migrate_tools/src/Form/MigrationDeleteForm.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_tools\Form;
+
+use Drupal\Core\Entity\EntityConfirmFormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\Core\Url;
+
+/**
+ * Provides the delete form for our Migration entity.
+ *
+ * @package Drupal\migrate_tools\Form
+ *
+ * @ingroup migrate_tools
+ */
+class MigrationDeleteForm extends EntityConfirmFormBase {
+
+  /**
+   * Gathers a confirmation question.
+   *
+   * @return string
+   *   Translated string.
+   */
+  public function getQuestion(): TranslatableMarkup {
+    return $this->t('Are you sure you want to delete migration %label?', [
+      '%label' => $this->entity->label(),
+    ]);
+  }
+
+  /**
+   * Gather the confirmation text.
+   *
+   * @return string
+   *   Translated string.
+   */
+  public function getConfirmText(): TranslatableMarkup {
+    return $this->t('Delete Migration');
+  }
+
+  /**
+   * Gets the cancel URL.
+   *
+   * @return \Drupal\Core\Url
+   *   The URL to go to if the user cancels the deletion.
+   */
+  public function getCancelUrl(): Url {
+    return new Url('entity.migration_group.list');
+  }
+
+  /**
+   * The submit handler for the confirm form.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state): void {
+    // Delete the entity.
+    $this->entity->delete();
+
+    // Set a message that the entity was deleted.
+    $this->messenger()->addStatus($this->t('Migration %label was deleted.', [
+      '%label' => $this->entity->label(),
+    ]));
+
+    // Redirect the user to the list controller when complete.
+    $form_state->setRedirectUrl($this->getCancelUrl());
+  }
+
+}

web/modules/migrate_tools/src/Form/MigrationEditForm.php

@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_tools\Form;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Url;
+
+/**
+ * Provides the edit form for our Migration entity.
+ *
+ * @package Drupal\migrate_tools\Form
+ *
+ * @ingroup migrate_tools
+ */
+class MigrationEditForm extends MigrationFormBase {
+
+  /**
+   * Returns the actions provided by this form.
+   *
+   * For the edit form, we only need to change the text of the submit button.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   *
+   * @return array
+   *   An array of supported actions for the current entity form.
+   */
+  public function actions(array $form, FormStateInterface $form_state): array {
+    $actions = parent::actions($form, $form_state);
+    $actions['submit']['#value'] = $this->t('Update Migration');
+
+    return $actions;
+  }
+
+  /**
+   * Add group route parameter.
+   *
+   * @param \Drupal\Core\Url $url
+   *   The URL associated with an operation.
+   * @param string $migration_group
+   *   The migration's parent group.
+   */
+  protected function addGroupParameter(Url $url, string $migration_group): void {
+    $route_parameters = $url->getRouteParameters() + ['migration_group' => $migration_group];
+    $url->setRouteParameters($route_parameters);
+  }
+
+}

web/modules/migrate_tools/src/Form/MigrationExecuteForm.php

@@ -0,0 +1,265 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_tools\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\migrate\MigrateMessage;
+use Drupal\migrate\Plugin\MigrationInterface;
+use Drupal\migrate\Plugin\MigrationPluginManagerInterface;
+use Drupal\migrate_tools\MigrateBatchExecutable;
+use Drupal\migrate_tools\MigrateTools;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * This form is specifically for configuring process pipelines.
+ */
+class MigrationExecuteForm extends FormBase {
+
+  /**
+   * Plugin manager for migration plugins.
+   */
+  protected MigrationPluginManagerInterface $migrationPluginManager;
+
+  /**
+   * Constructs a new MigrationExecuteForm object.
+   *
+   * @param \Drupal\migrate\Plugin\MigrationPluginManagerInterface $migration_plugin_manager
+   *   The plugin manager for config entity-based migrations.
+   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
+   *   The current route match.
+   */
+  public function __construct(MigrationPluginManagerInterface $migration_plugin_manager, RouteMatchInterface $route_match) {
+    $this->migrationPluginManager = $migration_plugin_manager;
+    $this->routeMatch = $route_match;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container): self {
+    return new static(
+      $container->get('plugin.manager.migration'),
+      $container->get('current_route_match')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId(): string {
+    return 'migration_execute_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state): array {
+    $form = $form ?: [];
+
+    /** @var \Drupal\migrate_plus\Entity\MigrationInterface $migration */
+    $migration = $this->getRouteMatch()->getParameter('migration');
+    $form['#title'] = $this->t('Execute migration %label', ['%label' => $migration->label()]);
+
+    $form = $this->buildFormOperations($form, $form_state);
+    $form = $this->buildFormOptions($form, $form_state);
+
+    $form['submit'] = [
+      '#type' => 'submit',
+      '#value' => $this->t('Execute'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * Build the operation form field.
+   *
+   * @param array $form
+   *   The execution form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The form state.
+   *
+   * @return array
+   *   The execution form updated with the operations.
+   */
+  protected function buildFormOperations(array $form, FormStateInterface $form_state): array {
+    // Build the migration execution form.
+    $options = [
+      'import' => $this->t('Import'),
+      'rollback' => $this->t('Rollback'),
+      'stop' => $this->t('Stop'),
+      'reset' => $this->t('Reset'),
+    ];
+
+    $form['operation'] = [
+      '#type' => 'radios',
+      '#title' => $this->t('Operation'),
+      '#description' => $this->t('Choose an operation to run.'),
+      '#options' => $options,
+      '#default_value' => 'import',
+      '#required' => TRUE,
+      'import' => [
+        '#description' => $this->t('Imports all previously unprocessed records from the source, plus any records marked for update, into destination Drupal objects.'),
+      ],
+      'rollback' => [
+        '#description' => $this->t('Deletes all Drupal objects created by the import.'),
+      ],
+      'stop' => [
+        '#description' => $this->t('Cleanly interrupts any import or rollback processes that may currently be running.'),
+      ],
+      'reset' => [
+        '#description' => $this->t('Sometimes a process may fail to stop cleanly, and be left stuck in an Importing or Rolling Back status. Choose Reset to clear the status and permit other operations to proceed.'),
+      ],
+    ];
+
+    return $form;
+  }
+
+  /**
+   * Build the execution options form field.
+   *
+   * @param array $form
+   *   The execution form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The form state.
+   *
+   * @return array
+   *   The execution form updated with the execution options.
+   */
+  protected function buildFormOptions(array $form, FormStateInterface $form_state): array {
+    $form['options'] = [
+      '#type' => 'details',
+      '#title' => $this->t('Additional execution options'),
+      '#open' => FALSE,
+    ];
+
+    $form['options']['update'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Update'),
+      '#description' => $this->t('Check this box to update all previously-imported content in addition to importing new content. Leave unchecked to only import new content'),
+    ];
+
+    $form['options']['force'] = [
+      '#type' => 'checkbox',
+      '#title' => $this->t('Ignore dependencies'),
+      '#description' => $this->t('Check this box to ignore dependencies when running imports - all tasks will run whether or not their dependent tasks have completed.'),
+    ];
+
+    $form['options']['limit'] = [
+      '#type' => 'number',
+      '#title' => $this->t('Limit to:'),
+      '#size' => 10,
+      '#description' => $this->t('Set a limit of how many items to process for each migration task.'),
+      '#min' => 1,
+    ];
+
+    $form['options']['idlist'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('ID List'),
+      '#maxlength' => 255,
+      '#size' => 60,
+      '#pattern' => '^[0-9]+(' . MigrateTools::DEFAULT_ID_LIST_DELIMITER . '[0-9]+)?(,?[0-9]+(' . MigrateTools::DEFAULT_ID_LIST_DELIMITER . '[0-9]+)?)*$',
+      '#description' => $this->t('Comma-separated list of IDs to process.'),
+      '#states' => [
+        'enabled' => [
+          ':input[name="operation"]' => [['value' => 'import'], 'or', ['value' => 'rollback']],
+        ],
+      ],
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state): void {
+    $migration = $this->getRouteMatch()->getParameter('migration');
+    if ($migration) {
+      $migration_id = $migration->id();
+      /** @var \Drupal\migrate\Plugin\MigrationInterface $migration_plugin */
+      $migration_plugin = $this->migrationPluginManager->createInstance($migration_id, $migration->toArray());
+      $migrateMessage = new MigrateMessage();
+
+      switch ($form_state->getValue('operation')) {
+        case 'import':
+          $executable = new MigrateBatchExecutable($migration_plugin, $migrateMessage, $this->buildOptions($form_state));
+          $executable->batchImport();
+          break;
+
+        case 'rollback':
+          $executable = new MigrateBatchExecutable($migration_plugin, $migrateMessage, $this->buildOptions($form_state));
+          $status = $executable->rollback();
+          if ($status === MigrationInterface::RESULT_COMPLETED) {
+            $this->messenger()->addStatus($this->t('Rollback completed', ['@id' => $migration_id]));
+          }
+          else {
+            $this->messenger()->addError($this->t('Rollback of !name migration failed.', ['!name' => $migration_id]));
+          }
+          break;
+
+        case 'stop':
+          $migration_plugin->interruptMigration(MigrationInterface::RESULT_STOPPED);
+          $status = $migration_plugin->getStatus();
+          switch ($status) {
+            case MigrationInterface::STATUS_IDLE:
+              $this->messenger()->addStatus($this->t('Migration @id is idle', ['@id' => $migration_id]));
+              break;
+
+            case MigrationInterface::STATUS_DISABLED:
+              $this->messenger()->addWarning($this->t('Migration @id is disabled', ['@id' => $migration_id]));
+              break;
+
+            case MigrationInterface::STATUS_STOPPING:
+              $this->messenger()->addWarning($this->t('Migration @id is already stopping', ['@id' => $migration_id]));
+              break;
+
+            default:
+              $migration->interruptMigration(MigrationInterface::RESULT_STOPPED);
+              $this->messenger()->addStatus($this->t('Migration @id requested to stop', ['@id' => $migration_id]));
+              break;
+          }
+          break;
+
+        case 'reset':
+          $status = $migration_plugin->getStatus();
+          if ($status === MigrationInterface::STATUS_IDLE) {
+            $this->messenger()->addWarning($this->t('Migration @id is already Idle', ['@id' => $migration_id]));
+          }
+          else {
+            $this->messenger()->addStatus($this->t('Migration @id reset to Idle', ['@id' => $migration_id]));
+          }
+          $migration_plugin->setStatus(MigrationInterface::STATUS_IDLE);
+          break;
+      }
+    }
+  }
+
+  /**
+   * Build migrate execute options from the submitted form values.
+   *
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The form state.
+   *
+   * @return array
+   *   Options array for the migrate execution.
+   */
+  protected function buildOptions(FormStateInterface $form_state) {
+    $options = [
+      'limit' => $form_state->getValue('limit') ?: 0,
+      'update' => $form_state->getValue('update') ?: 0,
+      'force' => $form_state->getValue('force') ?: 0,
+    ];
+
+    if ($idlist = $form_state->getValue('idlist')) {
+      $options['idlist'] = $idlist;
+    }
+
+    return $options;
+  }
+
+}

web/modules/migrate_tools/src/Form/MigrationFormBase.php

@@ -0,0 +1,157 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_tools\Form;
+
+use Drupal\Core\Entity\EntityForm;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\migrate_plus\Entity\Migration;
+use Drupal\migrate_plus\Entity\MigrationGroup;
+
+/**
+ * Base form for a migration.
+ *
+ * @package Drupal\migrate_tools\Form
+ *
+ * @ingroup migrate_tools
+ */
+class MigrationFormBase extends EntityForm {
+
+  /**
+   * Overrides Drupal\Core\Entity\EntityFormController::form().
+   *
+   * Builds the entity add/edit form.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   *
+   * @return array
+   *   An associative array containing the migration add/edit form.
+   */
+  public function buildForm(array $form, FormStateInterface $form_state): array {
+    // Get anything we need from the base class.
+    $form = parent::buildForm($form, $form_state);
+
+    $migration = $this->entity;
+    assert($migration instanceof Migration);
+
+    $form['warning'] = [
+      '#markup' => $this->t('Creating migrations is not yet supported. See <a href=":url">:url</a>', [
+        ':url' => 'https://www.drupal.org/node/2573241',
+      ]),
+    ];
+
+    // Build the form.
+    $form['label'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Label'),
+      '#maxlength' => 255,
+      '#default_value' => $migration->label(),
+      '#required' => TRUE,
+    ];
+    $form['id'] = [
+      '#type' => 'machine_name',
+      '#title' => $this->t('Machine name'),
+      '#default_value' => $migration->id(),
+      '#machine_name' => [
+        'exists' => [$this, 'exists'],
+        'replace_pattern' => '([^a-z0-9_]+)|(^custom$)',
+        'error' => 'The machine-readable name must be unique, and can only contain lowercase letters, numbers, and underscores. Additionally, it can not be the reserved word "custom".',
+      ],
+      '#disabled' => !$migration->isNew(),
+    ];
+
+    $groups = MigrationGroup::loadMultiple();
+    $group_options = [];
+    foreach ($groups as $group) {
+      $group_options[$group->id()] = $group->label();
+    }
+    if (!$migration->migration_group && isset($group_options['default'])) {
+      $migration->set('migration_group', 'default');
+    }
+
+    $form['migration_group'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Migration Group'),
+      '#empty_value' => '',
+      '#default_value' => $migration->migration_group,
+      '#options' => $group_options,
+      '#description' => $this->t('Assign this migration to an existing group.'),
+    ];
+
+    return $form;
+  }
+
+  /**
+   * Checks for an existing migration group.
+   *
+   * @param string|int $entity_id
+   *   The entity ID.
+   * @param array $element
+   *   The form element.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The form state.
+   *
+   * @return bool
+   *   TRUE if this format already exists, FALSE otherwise.
+   */
+  public function exists($entity_id, array $element, FormStateInterface $form_state): bool {
+    $query = $this->entityTypeManager->getStorage('migration')
+      ->getQuery()
+      ->accessCheck(TRUE);
+
+    // Query the entity ID to see if its in use.
+    $result = $query->condition('id', $element['#field_prefix'] . $entity_id)
+      ->execute();
+
+    // We don't need to return the ID, only if it exists or not.
+    return (bool) $result;
+  }
+
+  /**
+   * Overrides Drupal\Core\Entity\EntityFormController::actions().
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   *
+   * @return array
+   *   An array of supported actions for the current entity form.
+   */
+  protected function actions(array $form, FormStateInterface $form_state): array {
+    // Get the basic actions from the base class.
+    $actions = parent::actions($form, $form_state);
+
+    // Change the submit button text.
+    $actions['submit']['#value'] = $this->t('Save');
+
+    // Return the result.
+    return $actions;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function save(array $form, FormStateInterface $form_state): void {
+    $migration = $this->getEntity();
+    $status = $migration->save();
+
+    if ($status == SAVED_UPDATED) {
+      // If we edited an existing entity...
+      $this->messenger()->addStatus($this->t('Migration %label has been updated.', ['%label' => $migration->label()]));
+    }
+    else {
+      // If we created a new entity...
+      $this->messenger()->addStatus($this->t('Migration %label has been added.', ['%label' => $migration->label()]));
+    }
+
+    // Redirect the user back to the listing route after the save operation.
+    $form_state->setRedirect('entity.migration.list',
+      ['migration_group' => $migration->get('migration_group')]);
+  }
+
+}

web/modules/migrate_tools/src/Form/MigrationGroupAddForm.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_tools\Form;
+
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Class MigrationGroupAddForm.
+ *
+ * Provides the add form for our migration_group entity.
+ *
+ * @package Drupal\migrate_tools\Form
+ *
+ * @ingroup migrate_tools
+ */
+class MigrationGroupAddForm extends MigrationGroupFormBase {
+
+  /**
+   * Returns the actions provided by this form.
+   *
+   * For our add form, we only need to change the text of the submit button.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   *
+   * @return array
+   *   An array of supported actions for the current entity form.
+   */
+  protected function actions(array $form, FormStateInterface $form_state): array {
+    $actions = parent::actions($form, $form_state);
+    $actions['submit']['#value'] = $this->t('Create Migration Group');
+    return $actions;
+  }
+
+}

web/modules/migrate_tools/src/Form/MigrationGroupDeleteForm.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_tools\Form;
+
+use Drupal\Core\Entity\EntityConfirmFormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\Core\Url;
+
+/**
+ * Provides the delete form for our Migration Group entity.
+ *
+ * @package Drupal\migrate_tools\Form
+ *
+ * @ingroup migrate_tools
+ */
+class MigrationGroupDeleteForm extends EntityConfirmFormBase {
+
+  /**
+   * Gathers a confirmation question.
+   *
+   * @return string
+   *   Translated string.
+   */
+  public function getQuestion(): TranslatableMarkup {
+    return $this->t('Are you sure you want to delete migration group %label?', [
+      '%label' => $this->entity->label(),
+    ]);
+  }
+
+  /**
+   * Gather the confirmation text.
+   *
+   * @return string
+   *   Translated string.
+   */
+  public function getConfirmText(): TranslatableMarkup {
+    return $this->t('Delete Migration Group');
+  }
+
+  /**
+   * Gets the cancel URL.
+   *
+   * @return \Drupal\Core\Url
+   *   The URL to go to if the user cancels the deletion.
+   */
+  public function getCancelUrl(): Url {
+    return new Url('entity.migration_group.list');
+  }
+
+  /**
+   * The submit handler for the confirm form.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state): void {
+    // Delete the entity.
+    $this->entity->delete();
+
+    // Set a message that the entity was deleted.
+    $this->messenger()->addStatus($this->t('Migration group %label was deleted.', [
+      '%label' => $this->entity->label(),
+    ]));
+
+    // Redirect the user to the list controller when complete.
+    $form_state->setRedirectUrl($this->getCancelUrl());
+  }
+
+}

web/modules/migrate_tools/src/Form/MigrationGroupEditForm.php

@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_tools\Form;
+
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Provides the edit form for our Migration Group entity.
+ *
+ * @package Drupal\migrate_tools\Form
+ *
+ * @ingroup migrate_tools
+ */
+class MigrationGroupEditForm extends MigrationGroupFormBase {
+
+  /**
+   * Returns the actions provided by this form.
+   *
+   * For the edit form, we only need to change the text of the submit button.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   *
+   * @return array
+   *   An array of supported actions for the current entity form.
+   */
+  public function actions(array $form, FormStateInterface $form_state): array {
+    $actions = parent::actions($form, $form_state);
+    $actions['submit']['#value'] = $this->t('Update Migration Group');
+    return $actions;
+  }
+
+}

web/modules/migrate_tools/src/Form/MigrationGroupFormBase.php

@@ -0,0 +1,144 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Drupal\migrate_tools\Form;
+
+use Drupal\Core\Entity\EntityForm;
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Base form for migration groups.
+ *
+ * @package Drupal\migrate_tools\Form
+ *
+ * @ingroup migrate_tools
+ */
+class MigrationGroupFormBase extends EntityForm {
+
+  /**
+   * Overrides Drupal\Core\Entity\EntityFormController::form().
+   *
+   * Builds the entity add/edit form.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   *
+   * @return array
+   *   An associative array containing the migration group add/edit form.
+   */
+  public function buildForm(array $form, FormStateInterface $form_state): array {
+    // Get anything we need from the base class.
+    $form = parent::buildForm($form, $form_state);
+
+    /** @var \Drupal\migrate_plus\Entity\MigrationGroupInterface $migration_group */
+    $migration_group = $this->entity;
+
+    // Build the form.
+    $form['label'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Label'),
+      '#maxlength' => 255,
+      '#default_value' => $migration_group->label(),
+      '#required' => TRUE,
+    ];
+    $form['id'] = [
+      '#type' => 'machine_name',
+      '#title' => $this->t('Machine name'),
+      '#default_value' => $migration_group->id(),
+      '#machine_name' => [
+        'exists' => [$this, 'exists'],
+        'replace_pattern' => '([^a-z0-9_]+)|(^custom$)',
+        'error' => 'The machine-readable name must be unique, and can only contain lowercase letters, numbers, and underscores. Additionally, it can not be the reserved word "custom".',
+      ],
+      '#disabled' => !$migration_group->isNew(),
+    ];
+    $form['description'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Description'),
+      '#maxlength' => 255,
+      '#default_value' => $migration_group->get('description'),
+    ];
+    $form['source_type'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('Source type'),
+      '#description' => $this->t('Type of source system the group is migrating from, for example "Drupal 6" or "WordPress 4".'),
+      '#maxlength' => 255,
+      '#default_value' => $migration_group->get('source_type'),
+    ];
+
+    // Return the form.
+    return $form;
+  }
+
+  /**
+   * Checks for an existing migration group.
+   *
+   * @param string|int $entity_id
+   *   The entity ID.
+   * @param array $element
+   *   The form element.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The form state.
+   *
+   * @return bool
+   *   TRUE if this format already exists, FALSE otherwise.
+   */
+  public function exists($entity_id, array $element, FormStateInterface $form_state): bool {
+    $query = $this->entityTypeManager->getStorage('migration_group')
+      ->getQuery()
+      ->accessCheck(TRUE);
+
+    // Query the entity ID to see if its in use.
+    $result = $query->condition('id', $element['#field_prefix'] . $entity_id)
+      ->execute();
+
+    // We don't need to return the ID, only if it exists or not.
+    return (bool) $result;
+  }
+
+  /**
+   * Overrides Drupal\Core\Entity\EntityFormController::actions().
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   An associative array containing the current state of the form.
+   *
+   * @return array
+   *   An array of supported actions for the current entity form.
+   */
+  protected function actions(array $form, FormStateInterface $form_state): array {
+    // Get the basic actions from the base class.
+    $actions = parent::actions($form, $form_state);
+
+    // Change the submit button text.
+    $actions['submit']['#value'] = $this->t('Save');
+
+    // Return the result.
+    return $actions;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function save(array $form, FormStateInterface $form_state): void {
+    $migration_group = $this->getEntity();
+    $status = $migration_group->save();
+
+    if ($status == SAVED_UPDATED) {
+      // If we edited an existing entity...
+      $this->messenger()->addStatus($this->t('Migration group %label has been updated.', ['%label' => $migration_group->label()]));
+    }
+    else {
+      // If we created a new entity...
+      $this->messenger()->addStatus($this->t('Migration group %label has been added.', ['%label' => $migration_group->label()]));
+    }
+
+    // Redirect the user back to the listing route after the save operation.
+    $form_state->setRedirect('entity.migration_group.list');
+  }
+
+}