[Mailer] [Transport] Allow exception logging for RoundRobinTransport mailer

Author: jnoordsij

src/Symfony/Component/Mailer/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+7.4
+---
+
+ * Add `logger` (constructor) property to `RoundRobinTransport`
+
 7.3
 ---
 

src/Symfony/Component/Mailer/Tests/Transport/RoundRobinTransportTest.php

@@ -12,6 +12,7 @@
 namespace Symfony\Component\Mailer\Tests\Transport;
 
 use PHPUnit\Framework\TestCase;
+use Psr\Log\LoggerInterface;
 use Symfony\Component\Mailer\Exception\TransportException;
 use Symfony\Component\Mailer\Exception\TransportExceptionInterface;
 use Symfony\Component\Mailer\Transport\RoundRobinTransport;
@@ -167,19 +168,45 @@ public function testSendOneDeadMessageAlterationsDoNotPersist()
         $this->assertFalse($message->getHeaders()->has('X-Transport-1'));
     }
 
+    public function testLoggerReceivesExceptions()
+    {
+        $t1 = $this->createMock(TransportInterface::class);
+        $t1->expects($this->exactly(2))->method('send');
+
+        $ex = new TransportException();
+        $t2 = $this->createMock(TransportInterface::class);
+        $t2->expects($this->exactly(1))
+            ->method('send')
+            ->willReturnCallback(fn () => throw $ex);
+        $t2->expects($this->atLeast(1))->method('__toString')->willReturn('t2');
+
+        $log = $this->createMock(LoggerInterface::class);
+        $log->expects($this->exactly(1))
+            ->method('error')
+            ->with('Transport "t2" failed.', ['exception' => $ex]);
+
+        $t = new RoundRobinTransport([$t1, $t2], logger: $log);
+        $p = new \ReflectionProperty($t, 'cursor');
+        $p->setValue($t, 0);
+        $t->send(new RawMessage(''));
+        $this->assertTransports($t, 1, []);
+        $t->send(new RawMessage(''));
+        $this->assertTransports($t, 1, [$t2]);
+    }
+
     public function testFailureDebugInformation()
     {
         $t1 = $this->createMock(TransportInterface::class);
         $e1 = new TransportException();
         $e1->appendDebug('Debug message 1');
         $t1->expects($this->once())->method('send')->willThrowException($e1);
-        $t1->expects($this->once())->method('__toString')->willReturn('t1');
+        $t1->expects($this->atLeast(1))->method('__toString')->willReturn('t1');
 
         $t2 = $this->createMock(TransportInterface::class);
         $e2 = new TransportException();
         $e2->appendDebug('Debug message 2');
         $t2->expects($this->once())->method('send')->willThrowException($e2);
-        $t2->expects($this->once())->method('__toString')->willReturn('t2');
+        $t2->expects($this->atLeast(1))->method('__toString')->willReturn('t2');
 
         $t = new RoundRobinTransport([$t1, $t2]);
 

src/Symfony/Component/Mailer/Transport/RoundRobinTransport.php

@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\Mailer\Transport;
 
+use Psr\Log\LoggerInterface;
+use Psr\Log\NullLogger;
 use Symfony\Component\Mailer\Envelope;
 use Symfony\Component\Mailer\Exception\TransportException;
 use Symfony\Component\Mailer\Exception\TransportExceptionInterface;
@@ -36,6 +38,7 @@ class RoundRobinTransport implements TransportInterface
     public function __construct(
         private array $transports,
         private int $retryPeriod = 60,
+        private LoggerInterface $logger = new NullLogger(),
     ) {
         if (!$transports) {
             throw new TransportException(\sprintf('"%s" must have at least one transport configured.', static::class));
@@ -54,6 +57,7 @@ public function send(RawMessage $message, ?Envelope $envelope = null): ?SentMess
             } catch (TransportExceptionInterface $e) {
                 $exception ??= new TransportException('All transports failed.');
                 $exception->appendDebug(\sprintf("Transport \"%s\": %s\n", $transport, $e->getDebug()));
+                $this->logger->error(\sprintf("Transport \"%s\" failed.", $transport), ['exception' => $e]);
                 $this->deadTransports[$transport] = microtime(true);
             }
         }