--- a/migrations/Version00000000000000.php
+++ b/migrations/Version00000000000000.php
@@ -20,7 +20,9 @@ final class Version20200714155905 extends AbstractMigration
     public function up(Schema $schema) : void
     {
         // this up() migration is auto-generated, please modify it to your needs
-        $this->addSql('ALTER TABLE comment ADD state VARCHAR(255) NOT NULL');
+        $this->addSql('ALTER TABLE comment ADD state VARCHAR(255)');
+        $this->addSql("UPDATE comment SET state='published'");
+        $this->addSql('ALTER TABLE comment ALTER COLUMN state SET NOT NULL');
     }

     public function down(Schema $schema) : void

--- a/src/Entity/Comment.php
+++ b/src/Entity/Comment.php
@@ -49,9 +49,9 @@ class Comment
     private $photoFilename;

     /**
-     * @ORM\Column(type="string", length=255)
+     * @ORM\Column(type="string", length=255, options={"default": "submitted"})
      */
-    private $state;
+    private $state = 'submitted';

     public function __toString(): string
     {

--- a/config/packages/easy_admin.yaml
+++ b/config/packages/easy_admin.yaml
@@ -18,6 +18,7 @@ easy_admin:
                     - author
                     - { property: 'email', type: 'email' }
                     - { property: 'photoFilename', type: 'image', 'base_path': "/uploads/photos", label: 'Photo' }
+                    - state
                     - { property: 'createdAt', type: 'datetime' }
                 sort: ['createdAt', 'ASC']
                 filters: ['conference']
@@ -26,5 +27,6 @@ easy_admin:
                     - { property: 'conference' }
                     - { property: 'createdAt', type: datetime, type_options: { attr: { readonly: true } } }
                     - 'author'
+                    - { property: 'state' }
                     - { property: 'email', type: 'email' }
                     - text

--- a/src/DataFixtures/AppFixtures.php
+++ b/src/DataFixtures/AppFixtures.php
@@ -37,8 +37,16 @@ class AppFixtures extends Fixture
         $comment1->setAuthor('Fabien');
         $comment1->setEmail('[email protected]');
         $comment1->setText('This was a great conference.');
+        $comment1->setState('published');
         $manager->persist($comment1);

+        $comment2 = new Comment();
+        $comment2->setConference($amsterdam);
+        $comment2->setAuthor('Lucas');
+        $comment2->setEmail('[email protected]');
+        $comment2->setText('I think this one is going to be moderated.');
+        $manager->persist($comment2);
+
         $admin = new Admin();
         $admin->setRoles(['ROLE_ADMIN']);
         $admin->setUsername('admin');

--- a/tests/Controller/ConferenceControllerTest.php
+++ b/tests/Controller/ConferenceControllerTest.php
@@ -2,6 +2,8 @@

 namespace App\Tests\Controller;

+use App\Repository\CommentRepository;
+use Doctrine\ORM\EntityManagerInterface;
 use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;

 class ConferenceControllerTest extends WebTestCase
@@ -22,11 +24,17 @@ class ConferenceControllerTest extends WebTestCase
         $client->submitForm('Submit', [
             'comment_form[author]' => 'Fabien',
             'comment_form[text]' => 'Some feedback from an automated functional test',
-            'comment_form[email]' => '[email protected]',
+            'comment_form[email]' => $email = '[email protected]',
             'comment_form[photo]' => dirname(__DIR__, 2).'/public/images/under-construction.gif',
         ]);
         $this->assertResponseRedirects();
+
+        // simulate comment validation
+        $comment = self::$container->get(CommentRepository::class)->findOneByEmail($email);
+        $comment->setState('published');
+        self::$container->get(EntityManagerInterface::class)->flush();
+
         $client->followRedirect();
         $this->assertSelectorExists('div:contains("There are 2 comments")');
     }

--- a/src/Controller/ConferenceController.php
+++ b/src/Controller/ConferenceController.php
@@ -5,14 +5,15 @@ namespace App\Controller;
 use App\Entity\Comment;
 use App\Entity\Conference;
 use App\Form\CommentFormType;
+use App\Message\CommentMessage;
 use App\Repository\CommentRepository;
 use App\Repository\ConferenceRepository;
-use App\SpamChecker;
 use Doctrine\ORM\EntityManagerInterface;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\HttpFoundation\File\Exception\FileException;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Routing\Annotation\Route;
 use Twig\Environment;

@@ -20,11 +21,13 @@ class ConferenceController extends AbstractController
 {
     private $twig;
     private $entityManager;
+    private $bus;

-    public function __construct(Environment $twig, EntityManagerInterface $entityManager)
+    public function __construct(Environment $twig, EntityManagerInterface $entityManager, MessageBusInterface $bus)
     {
         $this->twig = $twig;
         $this->entityManager = $entityManager;
+        $this->bus = $bus;
     }

     /**
@@ -40,7 +43,7 @@ class ConferenceController extends AbstractController
     /**
      * @Route("/conference/{slug}", name="conference")
      */
-    public function show(Request $request, Conference $conference, CommentRepository $commentRepository, SpamChecker $spamChecker, string $photoDir)
+    public function show(Request $request, Conference $conference, CommentRepository $commentRepository, string $photoDir)
     {
         $comment = new Comment();
         $form = $this->createForm(CommentFormType::class, $comment);
@@ -59,6 +62,7 @@ class ConferenceController extends AbstractController
             }

             $this->entityManager->persist($comment);
+            $this->entityManager->flush();

             $context = [
                 'user_ip' => $request->getClientIp(),
@@ -66,11 +70,8 @@ class ConferenceController extends AbstractController
                 'referrer' => $request->headers->get('referer'),
                 'permalink' => $request->getUri(),
             ];
-            if (2 === $spamChecker->getSpamScore($comment, $context)) {
-                throw new \RuntimeException('Blatant spam, go away!');
-            }

-            $this->entityManager->flush();
+            $this->bus->dispatch(new CommentMessage($comment->getId(), $context));

             return $this->redirectToRoute('conference', ['slug' => $conference->getSlug()]);
         }

--- a/src/Repository/CommentRepository.php
+++ b/src/Repository/CommentRepository.php
@@ -25,7 +25,9 @@ class CommentRepository extends ServiceEntityRepository
     {
         return $this->createQueryBuilder('c')
             ->andWhere('c.conference = :conference')
+            ->andWhere('c.state = :state')
             ->setParameter('conference', $conference)
+            ->setParameter('state', 'published')
             ->orderBy('c.createdAt', 'DESC')
             ->setMaxResults($limit)
             ->setFirstResult($offset)

--- a/config/packages/messenger.yaml
+++ b/config/packages/messenger.yaml
@@ -5,10 +5,10 @@ framework:

         transports:
             # https://symfony.com/doc/current/messenger.html#transport-configuration
-            # async: '%env(MESSENGER_TRANSPORT_DSN)%'
+            async: '%env(RABBITMQ_DSN)%'
             # failed: 'doctrine://default?queue_name=failed'
             # sync: 'sync://'

         routing:
             # Route your messages to the transports
-            # 'App\Message\YourMessage': async
+            App\Message\CommentMessage: async

--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -12,3 +12,7 @@ services:
     redis:
         image: redis:5-alpine
         ports: [6379]
+
+    rabbitmq:
+        image: rabbitmq:3.7-management
+        ports: [5672, 15672]

--- a/config/packages/messenger.yaml
+++ b/config/packages/messenger.yaml
@@ -5,10 +5,17 @@ framework:

         transports:
             # https://symfony.com/doc/current/messenger.html#transport-configuration
-            async: '%env(RABBITMQ_DSN)%'
-            # failed: 'doctrine://default?queue_name=failed'
+            async:
+                dsn: '%env(RABBITMQ_DSN)%'
+                retry_strategy:
+                    max_retries: 3
+                    multiplier: 2
+
+            failed: 'doctrine://default?queue_name=failed'
             # sync: 'sync://'

+        failure_transport: failed
+
         routing:
             # Route your messages to the transports
             App\Message\CommentMessage: async

--- a/.symfony/services.yaml
+++ b/.symfony/services.yaml
@@ -5,3 +5,8 @@ db:

 rediscache:
     type: redis:5.0
+
+queue:
+    type: rabbitmq:3.7
+    disk: 1024
+    size: S

--- a/.symfony.cloud.yaml
+++ b/.symfony.cloud.yaml
@@ -4,6 +4,7 @@ type: php:7.4

 runtime:
     extensions:
+        - amqp
         - pdo_pgsql
         - apcu
         - mbstring
@@ -22,6 +23,7 @@ variables:
 relationships:
     database: "db:postgresql"
     redis: "rediscache:redis"
+    rabbitmq: "queue:rabbitmq"

 web:
     locations:

--- a/.symfony.cloud.yaml
+++ b/.symfony.cloud.yaml
@@ -46,3 +46,12 @@ hooks:
         set -x -e

         (>&2 symfony-deploy)
+
+workers:
+    messages:
+        commands:
+            start: |
+                set -x -e
+
+                (>&2 symfony-deploy)
+                php bin/console messenger:consume async -vv --time-limit=3600 --memory-limit=128M