patchlevel · DavidBadura · Feb 6, 2024 · Feb 6, 2024 · Feb 6, 2024
diff --git a/docs/pages/event_bus.md b/docs/pages/event_bus.md
@@ -209,6 +209,19 @@ $eventBus = new Psr14EventBus($psr14EventDispatcher);
 
     You can't use the `Subscribe` attribute with the psr-14 event bus.
 
+## Chain Event Bus
+
+If you want to use multiple event buses, you can use the `ChainEventBus`.
+
+```php
+use Patchlevel\EventSourcing\EventBus\ChainEventBus;
+
+$eventBus = new ChainEventBus([
+    $eventBus1,
+    $eventBus2,
+]);
+```
+
 ## Learn more
 
 * [How to decorate messages](message_decorator.md)

diff --git a/docs/pages/getting_started.md b/docs/pages/getting_started.md
@@ -282,10 +282,11 @@ After we have defined everything, we still have to plug the whole thing together
 
 ```php
 use Doctrine\DBAL\DriverManager;
+use Patchlevel\EventSourcing\EventBus\ChainEventBus;
 use Patchlevel\EventSourcing\EventBus\DefaultEventBus;
 use Patchlevel\EventSourcing\Projection\Projection\Store\DoctrineStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
-use Patchlevel\EventSourcing\Projection\Projectionist\SyncProjectionistEventBusWrapper;
+use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistEventBus;
 use Patchlevel\EventSourcing\Projection\Projector\SyncProjectorListener;
 use Patchlevel\EventSourcing\Repository\DefaultRepositoryManager;
 use Patchlevel\EventSourcing\Serializer\DefaultEventSerializer;
@@ -320,12 +321,12 @@ $projectionist = new DefaultProjectionist(
     $projectorRepository,
 );
 
-$eventBus = SyncProjectionistEventBusWrapper::createWithDefaultLockStrategy(
+$eventBus = new ChainEventBus([
     DefaultEventBus::create([
         new SendCheckInEmailProcessor($mailer),
     ]),
-    $projectionist,
-);
+    ProjectionistEventBus::createWithDefaultLockStrategy($projectionist)
+]);
 
 $repositoryManager = new DefaultRepositoryManager(
     $aggregateRegistry,

diff --git a/src/EventBus/ChainEventBus.php b/src/EventBus/ChainEventBus.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\EventBus;
+
+final class ChainEventBus implements EventBus
+{
+    /** @param iterable<EventBus> $eventBuses */
+    public function __construct(
+        private readonly iterable $eventBuses,
+    ) {
+    }
+
+    public function dispatch(Message ...$messages): void
+    {
+        foreach ($this->eventBuses as $eventBus) {
+            $eventBus->dispatch(...$messages);
+        }
+    }
+}
diff --git a/...nist/SyncProjectionistEventBusWrapper.php → ...n/Projectionist/ProjectionistEventBus.php b/...nist/SyncProjectionistEventBusWrapper.php → ...n/Projectionist/ProjectionistEventBus.php
@@ -9,10 +9,9 @@
 use Symfony\Component\Lock\LockFactory;
 use Symfony\Component\Lock\Store\FlockStore;
 
-final class SyncProjectionistEventBusWrapper implements EventBus
+final class ProjectionistEventBus implements EventBus
 {
     public function __construct(
-        private readonly EventBus $parentEventBus,
         private readonly Projectionist $projectionist,
         private readonly LockFactory $lockFactory,
         private readonly bool $throwByError = true,
@@ -21,8 +20,6 @@ public function __construct(
 
     public function dispatch(Message ...$messages): void
     {
-        $this->parentEventBus->dispatch(...$messages);
-
         $lock = $this->lockFactory->createLock('projectionist-run');
 
         if (!$lock->acquire(true)) {
@@ -36,10 +33,9 @@ public function dispatch(Message ...$messages): void
         }
     }
 
-    public static function createWithDefaultLockStrategy(EventBus $parentEventBus, Projectionist $projectionist): self
+    public static function createWithDefaultLockStrategy(Projectionist $projectionist): self
     {
         return new self(
-            $parentEventBus,
             $projectionist,
             new LockFactory(
                 new FlockStore(),

diff --git a/tests/Benchmark/SyncProjectionistBench.php b/tests/Benchmark/SyncProjectionistBench.php
@@ -6,12 +6,13 @@
 
 use Doctrine\DBAL\Driver\PDO\SQLite\Driver;
 use Doctrine\DBAL\DriverManager;
+use Patchlevel\EventSourcing\EventBus\ChainEventBus;
 use Patchlevel\EventSourcing\EventBus\DefaultEventBus;
 use Patchlevel\EventSourcing\EventBus\EventBus;
 use Patchlevel\EventSourcing\Lock\DoctrineDbalStoreSchemaAdapter;
 use Patchlevel\EventSourcing\Projection\Projection\Store\InMemoryStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
-use Patchlevel\EventSourcing\Projection\Projectionist\SyncProjectionistEventBusWrapper;
+use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistEventBus;
 use Patchlevel\EventSourcing\Projection\Projector\InMemoryProjectorRepository;
 use Patchlevel\EventSourcing\Repository\DefaultRepository;
 use Patchlevel\EventSourcing\Repository\Repository;
@@ -71,18 +72,18 @@ public function setUp(): void
             $projectionRepository,
         );
 
-        $innerEventStream = DefaultEventBus::create([new SendEmailProcessor()]);
-
         $lockStorage = new LockDoctrineDbalStore($connection);
         $lockStorageAdapter = new DoctrineDbalStoreSchemaAdapter($lockStorage);
 
-        $this->bus = new SyncProjectionistEventBusWrapper(
-            $innerEventStream,
-            $projectionist,
-            new LockFactory(
-                new LockDoctrineDbalStore($connection),
+        $this->bus = new ChainEventBus([
+            DefaultEventBus::create([new SendEmailProcessor()]),
+            new ProjectionistEventBus(
+                $projectionist,
+                new LockFactory(
+                    new LockDoctrineDbalStore($connection),
+                ),
             ),
-        );
+        ]);
 
         $this->repository = new DefaultRepository($this->store, $this->bus, Profile::metadata());
 

diff --git a/tests/Integration/BankAccountSplitStream/IntegrationTest.php b/tests/Integration/BankAccountSplitStream/IntegrationTest.php
@@ -5,6 +5,7 @@
 namespace Patchlevel\EventSourcing\Tests\Integration\BankAccountSplitStream;
 
 use Doctrine\DBAL\Connection;
+use Patchlevel\EventSourcing\EventBus\ChainEventBus;
 use Patchlevel\EventSourcing\EventBus\Decorator\ChainMessageDecorator;
 use Patchlevel\EventSourcing\EventBus\Decorator\SplitStreamDecorator;
 use Patchlevel\EventSourcing\EventBus\DefaultEventBus;
@@ -13,7 +14,7 @@
 use Patchlevel\EventSourcing\Projection\Projection\ProjectionCriteria;
 use Patchlevel\EventSourcing\Projection\Projection\Store\InMemoryStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
-use Patchlevel\EventSourcing\Projection\Projectionist\SyncProjectionistEventBusWrapper;
+use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistEventBus;
 use Patchlevel\EventSourcing\Projection\Projector\InMemoryProjectorRepository;
 use Patchlevel\EventSourcing\Repository\DefaultRepositoryManager;
 use Patchlevel\EventSourcing\Schema\DoctrineSchemaDirector;
@@ -63,18 +64,20 @@ public function testSuccessful(): void
             $projectionRepository,
         );
 
-        $eventStream = new SyncProjectionistEventBusWrapper(
+        $eventBus = new ChainEventBus([
             DefaultEventBus::create(),
-            $projectionist,
-            new LockFactory(
-                new LockInMemoryStore(),
+            new ProjectionistEventBus(
+                $projectionist,
+                new LockFactory(
+                    new LockInMemoryStore(),
+                ),
             ),
-        );
+        ]);
 
         $manager = new DefaultRepositoryManager(
             new AggregateRootRegistry(['bank_account' => BankAccount::class]),
             $store,
-            $eventStream,
+            $eventBus,
             null,
             new ChainMessageDecorator([
                 new SplitStreamDecorator(new AttributeEventMetadataFactory()),
@@ -107,7 +110,7 @@ public function testSuccessful(): void
         $manager = new DefaultRepositoryManager(
             new AggregateRootRegistry(['bank_account' => BankAccount::class]),
             $store,
-            $eventStream,
+            $eventBus,
             null,
             new ChainMessageDecorator([
                 new SplitStreamDecorator(new AttributeEventMetadataFactory()),
@@ -141,7 +144,7 @@ public function testSuccessful(): void
         $manager = new DefaultRepositoryManager(
             new AggregateRootRegistry(['bank_account' => BankAccount::class]),
             $store,
-            $eventStream,
+            $eventBus,
             null,
             new ChainMessageDecorator([
                 new SplitStreamDecorator(new AttributeEventMetadataFactory()),

diff --git a/tests/Integration/BasicImplementation/BasicIntegrationTest.php b/tests/Integration/BasicImplementation/BasicIntegrationTest.php
@@ -5,12 +5,13 @@
 namespace Patchlevel\EventSourcing\Tests\Integration\BasicImplementation;
 
 use Doctrine\DBAL\Connection;
+use Patchlevel\EventSourcing\EventBus\ChainEventBus;
 use Patchlevel\EventSourcing\EventBus\DefaultEventBus;
 use Patchlevel\EventSourcing\Metadata\AggregateRoot\AggregateRootRegistry;
 use Patchlevel\EventSourcing\Projection\Projection\ProjectionCriteria;
 use Patchlevel\EventSourcing\Projection\Projection\Store\InMemoryStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
-use Patchlevel\EventSourcing\Projection\Projectionist\SyncProjectionistEventBusWrapper;
+use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistEventBus;
 use Patchlevel\EventSourcing\Projection\Projector\InMemoryProjectorRepository;
 use Patchlevel\EventSourcing\Repository\DefaultRepositoryManager;
 use Patchlevel\EventSourcing\Schema\DoctrineSchemaDirector;
@@ -62,20 +63,22 @@ public function testSuccessful(): void
             $projectorRepository,
         );
 
-        $innerEventStream = DefaultEventBus::create([new SendEmailProcessor()]);
-
-        $eventStream = new SyncProjectionistEventBusWrapper(
-            $innerEventStream,
-            $projectionist,
-            new LockFactory(
-                new LockInMemoryStore(),
+        $eventBus = new ChainEventBus([
+            DefaultEventBus::create([
+                new SendEmailProcessor(),
+            ]),
+            new ProjectionistEventBus(
+                $projectionist,
+                new LockFactory(
+                    new LockInMemoryStore(),
+                ),
             ),
-        );
+        ]);
 
         $manager = new DefaultRepositoryManager(
             new AggregateRootRegistry(['profile' => Profile::class]),
             $store,
-            $eventStream,
+            $eventBus,
             null,
             new FooMessageDecorator(),
         );
@@ -103,7 +106,7 @@ public function testSuccessful(): void
         $manager = new DefaultRepositoryManager(
             new AggregateRootRegistry(['profile' => Profile::class]),
             $store,
-            $eventStream,
+            $eventBus,
         );
         $repository = $manager->get(Profile::class);
         $profile = $repository->load($profileId);
@@ -134,20 +137,22 @@ public function testSnapshot(): void
             $projectorRepository,
         );
 
-        $innerEventStream = DefaultEventBus::create([new SendEmailProcessor()]);
-
-        $eventStream = new SyncProjectionistEventBusWrapper(
-            $innerEventStream,
-            $projectionist,
-            new LockFactory(
-                new LockInMemoryStore(),
+        $eventBus = new ChainEventBus([
+            DefaultEventBus::create([
+                new SendEmailProcessor(),
+            ]),
+            new ProjectionistEventBus(
+                $projectionist,
+                new LockFactory(
+                    new LockInMemoryStore(),
+                ),
             ),
-        );
+        ]);
 
         $manager = new DefaultRepositoryManager(
             new AggregateRootRegistry(['profile' => Profile::class]),
             $store,
-            $eventStream,
+            $eventBus,
             new DefaultSnapshotStore(['default' => new InMemorySnapshotAdapter()]),
             new FooMessageDecorator(),
         );
@@ -175,7 +180,7 @@ public function testSnapshot(): void
         $manager = new DefaultRepositoryManager(
             new AggregateRootRegistry(['profile' => Profile::class]),
             $store,
-            $eventStream,
+            $eventBus,
         );
         $repository = $manager->get(Profile::class);
         $profile = $repository->load($profileId);

diff --git a/tests/Integration/Outbox/OutboxTest.php b/tests/Integration/Outbox/OutboxTest.php
@@ -5,6 +5,7 @@
 namespace Patchlevel\EventSourcing\Tests\Integration\Outbox;
 
 use Doctrine\DBAL\Connection;
+use Patchlevel\EventSourcing\EventBus\ChainEventBus;
 use Patchlevel\EventSourcing\EventBus\DefaultConsumer;
 use Patchlevel\EventSourcing\Outbox\DoctrineOutboxStore;
 use Patchlevel\EventSourcing\Outbox\EventBusPublisher;
@@ -13,7 +14,7 @@
 use Patchlevel\EventSourcing\Projection\Projection\ProjectionCriteria;
 use Patchlevel\EventSourcing\Projection\Projection\Store\InMemoryStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
-use Patchlevel\EventSourcing\Projection\Projectionist\SyncProjectionistEventBusWrapper;
+use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistEventBus;
 use Patchlevel\EventSourcing\Projection\Projector\InMemoryProjectorRepository;
 use Patchlevel\EventSourcing\Repository\DefaultRepository;
 use Patchlevel\EventSourcing\Schema\ChainSchemaConfigurator;
@@ -76,15 +77,17 @@ public function testSuccessful(): void
 
         $eventBusConsumer = DefaultConsumer::create([new SendEmailProcessor()]);
 
-        $eventStream = new SyncProjectionistEventBusWrapper(
+        $eventBus = new ChainEventBus([
             $outboxEventBus,
-            $projectionist,
-            new LockFactory(
-                new LockInMemoryStore(),
+            new ProjectionistEventBus(
+                $projectionist,
+                new LockFactory(
+                    new LockInMemoryStore(),
+                ),
             ),
-        );
+        ]);
 
-        $repository = new DefaultRepository($store, $eventStream, Profile::metadata());
+        $repository = new DefaultRepository($store, $eventBus, Profile::metadata());
 
         $schemaDirector = new DoctrineSchemaDirector(
             $this->connection,

diff --git a/tests/Integration/Projectionist/ProjectionistTest.php b/tests/Integration/Projectionist/ProjectionistTest.php
@@ -5,14 +5,15 @@
 namespace Patchlevel\EventSourcing\Tests\Integration\Projectionist;
 
 use Doctrine\DBAL\Connection;
+use Patchlevel\EventSourcing\EventBus\ChainEventBus;
 use Patchlevel\EventSourcing\EventBus\DefaultEventBus;
 use Patchlevel\EventSourcing\Lock\DoctrineDbalStoreSchemaAdapter;
 use Patchlevel\EventSourcing\Metadata\AggregateRoot\AggregateRootRegistry;
 use Patchlevel\EventSourcing\Metadata\AggregateRoot\AttributeAggregateRootRegistryFactory;
 use Patchlevel\EventSourcing\Projection\Projection\ProjectionCriteria;
 use Patchlevel\EventSourcing\Projection\Projection\Store\DoctrineStore;
 use Patchlevel\EventSourcing\Projection\Projectionist\DefaultProjectionist;
-use Patchlevel\EventSourcing\Projection\Projectionist\SyncProjectionistEventBusWrapper;
+use Patchlevel\EventSourcing\Projection\Projectionist\ProjectionistEventBus;
 use Patchlevel\EventSourcing\Projection\Projector\InMemoryProjectorRepository;
 use Patchlevel\EventSourcing\Repository\DefaultRepositoryManager;
 use Patchlevel\EventSourcing\Schema\ChainSchemaConfigurator;
@@ -117,11 +118,13 @@ public function testSync(): void
         $manager = new DefaultRepositoryManager(
             $aggregateRegistry,
             $store,
-            new SyncProjectionistEventBusWrapper(
+            new ChainEventBus([
                 DefaultEventBus::create(),
-                $projectionist,
-                new LockFactory($lockStore),
-            ),
+                new ProjectionistEventBus(
+                    $projectionist,
+                    new LockFactory($lockStore),
+                ),
+            ]),
         );
 
         $repository = $manager->get(Profile::class);