Create process plugin to log a message

Here's a first stab at this, which someone else can try to finish. It even supports substituting text!

TODO:

* Better docs
* Figure out whether we want to log unconditionally (and use skip_on_empty to not log), or have an implicit condition (eg: if source is some value).
* Figure out how we want substitution to work. I chose to make the entire Row source available for substitution, as well as other things in a 'context' section. But that's pretty complex!
* Figure out where we should log to. Choices include:
* The dblog
* The IdMap message. This allows us to associate the message with a particular row, which is nice! But I think we can have only one message per row.
* The MigrateMessageInterface. I think this is what's shown in the UI. But there's no easy way to get it from a process plugin, so we'll need to build a way. Maybe with a new interface that MigrateExecutable can implement?
* Write tests

namespace Drupal\migrate\Plugin\migrate\process;

use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\migrate\ProcessPluginBase;
use Drupal\migrate\Plugin\MigrationInterface;
use Drupal\migrate\MigrateExecutableInterface;
use Drupal\migrate\Row;
use Psr\Log\LoggerInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Logs a message about a migration, and then passes through the value.
 *
 * Available configuration keys:
 * - level: The message severity.
 * - message: The message, with placeholders.
 *
 * Examples:
 *
 * @code
 * process:
 *   show_notice:
 *     - plugin: log
 *       level: notice
 *       message: 'Item imported!'
 * @endcode
 *
 * @MigrateProcessPlugin(
 *   id = "log"
 * )
 */
class LogMessage extends ProcessPluginBase implements ContainerFactoryPluginInterface {

  /**
   * The logger.
   *
   * @var \Psr\Log\LoggerInterface
   */
  protected $logger;



  /**
   * EntityExists constructor.
   *
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin_id for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param \Psr\Log\LoggerInterface $logger
   *   The logger.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, LoggerInterface $logger) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->logger = $logger;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration = NULL) {
    return new static(
      $configuration,
      $plugin_id,
      $plugin_definition,
      $container->get('logger.factory')->get('migrate')
    );
  }

  /**
   * {@inheritdoc}
   */
  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
    // TODO: Use the current MigrateMessage?
    // TODO: Log to the migrate message table?
    $process = empty($this->configuration['context']) ? []
      : $this->configuration['context'];
    $contextRow = clone $row;
    $migrate_executable->processRow($contextRow, $process);
    $contextItems = $contextRow->getDestination() + $contextRow->getSource();
    $context = [];
    foreach ($contextItems as $key => $value) {
      $context['@' . $key] = $value;
    }
    $this->logger->log(
      $this->configuration['level'],
      $this->configuration['message'],
      $context
    );

    // Return original value.
    return $value;
  }

}

That's really great work @vasi. I had an opportunity to talk to Lucas about this issue and it sounded like instead of using the system's logger to log these we want to use the MigrateExecutable's saveMessage() method. So like the patch I just attached. What do you think?

However, we needed add tests.

Had a light discussion with Mike,

Removed the constructor and create function. Because we are not using either of it. Looks like a simple straight forward one.

Tried rolling the test as well.

Oops new line is missing.

Looks good to me. Also, lol at "buffalo" as the destination. :)

If we log messages this way, will the messages be seen in the Migrate UI? That's the imagined use-case, so we should verify that.

If migrate UI doesn't read messages from the migrate log, that's migrate UI's problem. This patch correctly tests that the message makes it to the migrate log, which is the scope of this issue.

Does the logging actually block that issue, or is this something that could be worked on in parallel?

Could you expound on how the need for logging blocks? I read the comments on the blocked issue but it isn't clear to me.

@heddn,

After applying the patch#8

I am trying to do the manual testing, Trying to migrate users from a csv file , which is following (migrate_source_csv)

ID,name,email,firstname,lastname,Status,roles,logs
1,rakesh,rakesh.james@gmail.com,Rakesh,James,1,administrator,log1
2,james,james.rakesh@gmail.com,James,Rakesh,1,authenticated,log2
3,dummy,dummy@gmail.com,Dummy,User,1,testuser,log3

Here is yml file

langcode: en
status: true
dependencies: {  }
id: demo_user_migration
class: null
field_plugin_method: null
cck_plugin_method: null
migration_tags: null
migration_group: null
label: 'User migration from CSV'
source:
  plugin: csv
  path: /Users/rakeshjames/Sites/drupal/sites/default/files/demousers_migrate.csv
  header_row_count: 1
  keys:
    - ID
process:
  name: name
  mail: email
  roles: roles
  field_last_name: firstname
  field_first_name: lastname
  status: Status
  test:
    plugin: log
    source: logs
destination:
  plugin: 'entity:user'
migration_dependencies:
  required: {  }
  optional: {  }

which is migrating all the rows. and gives the following status

Group: Default (default)      Status  Total  Imported  Unprocessed  Last imported       
 demo_user_migration           Idle    3      3         0            2017-05-16 20:52:48 

I am trying to find the log, not able to find in the migration table. Am I missing something on the

test:
    plugin: log
    source: logs

?
I know its a stupidity to ask, still Where can I find the logs? :(

I understand that logging could/will block the ability to show a message to the user in the case of an error condition, but does it block anything else in that issue?

@heddn

Cool, its working,

It was my bad, I was not aware of how to check the log, When i am checking

I am getting the following log message.

~  (8.4.x) $ drush mmsg demo_user_migration
 source_ids_hash                             level   message  
 7ad742edb7e866caa78ced1e4455d2e9cbd8adb207  1       log1     
 4e7c323d21b4e67732e755                                       
 2d3ec2b0c547e819346e6ae03f881fd9f5c978ff3c  1       log2     
 be29dfb807d40735e53703                                       
 12a042f72cad9a2a8c7715df0c7695d762975f0687  1       log3     
 d87f5d480725dae1432a6f

I uploaded a testing video in youtube, Please check the following link
Migration log process plugin manual testing

I modified d6_user.yml to log a message:

source:
  plugin: d6_user
  constants:
    log_message: 'The username of this user is '
process:
  ...
  formatted_message:
    plugin: concat
    source:
      - constants/log_message
      - name
  name:
    plugin: log
    source: '@formatted_message'

When running the upgrade process through the UI, the messages displayed as expected:

Code looks good, let's unblock the text format issue...

The impression I got from #2842222: D7 Plain text fields incorrectly migrated to D8 as Text (formatted) was more of a validation step/drupal_set_message() warning before the migration happens, this looks like it will just be logged after the migration runs?

Hmm I guess if we skip the table that's also going to end up as a warning, but that feels like something that we can resolve in the main issue, so committed/pushed to 8.4.x and cherry-picked to 8.3.x

Made the following fixes on commit:

diff --git a/core/modules/migrate/tests/src/Kernel/Plugin/LogTest.php b/core/modules/migrate/tests/src/Kernel/Plugin/LogTest.php
index d861d6d..bb5d04d 100644
--- a/core/modules/migrate/tests/src/Kernel/Plugin/LogTest.php
+++ b/core/modules/migrate/tests/src/Kernel/Plugin/LogTest.php
@@ -19,7 +19,7 @@ class LogTest extends KernelTestBase {
   public static $modules = ['migrate'];
 
   /**
-   * Test the Log plugin
+   * Test the Log plugin.
    */
   public function testLog() {
     $plugin = \Drupal::service('plugin.manager.migrate.process')
@@ -28,7 +28,7 @@ public function testLog() {
     $row = new Row();
     $log_message = "Testing the log message";
 
-    //Ensure the log is getting saved
+    // Ensure the log is getting saved.
     $saved_message = $plugin->transform($log_message, $executable, $row, 'buffalo');
     $this->assertSame($log_message, $saved_message);
   }

awesome!