Adding SizeAwareReceiverInterface to see how many messages are waiting on each receiver

weaverryan · weaverryan · commit b7a472b55ecb · 2019-03-31T12:43:40.000-04:00
diff --git a/src/Symfony/Component/Messenger/CHANGELOG.md b/src/Symfony/Component/Messenger/CHANGELOG.md
@@ -4,6 +4,8 @@ CHANGELOG
 4.3.0
 -----
 
+ * Added optional `MessageCountAwareInterface` that receivers can implement
+   to give information about how many messages are waiting to be processed.
  * [BC BREAK] The `Envelope::__construct()` signature changed:
    you can no longer pass an unlimited number of stamps as the second,
    third, fourth, arguments etc: stamps are now an array passed to the
diff --git a/src/Symfony/Component/Messenger/Tests/Transport/AmqpExt/AmqpExtIntegrationTest.php b/src/Symfony/Component/Messenger/Tests/Transport/AmqpExt/AmqpExtIntegrationTest.php
@@ -167,6 +167,24 @@ public function testItReceivesSignals()
             , $process->getOutput());
     }
 
+    public function testItCountsMessagesInQueue()
+    {
+        $serializer = $this->createSerializer();
+
+        $connection = Connection::fromDsn(getenv('MESSENGER_AMQP_DSN'));
+        $connection->setup();
+        $connection->queue()->purge();
+
+        $sender = new AmqpSender($connection, $serializer);
+
+        $sender->send($first = new Envelope(new DummyMessage('First')));
+        $sender->send($second = new Envelope(new DummyMessage('Second')));
+        $sender->send($second = new Envelope(new DummyMessage('Third')));
+
+        sleep(1); // give amqp a moment to have the messages ready
+        $this->assertSame(3, $connection->countMessagesInQueue());
+    }
+
     private function waitForOutput(Process $process, string $output, $timeoutInSeconds = 10)
     {
         $timedOutTime = time() + $timeoutInSeconds;
diff --git a/src/Symfony/Component/Messenger/Transport/AmqpExt/AmqpReceiver.php b/src/Symfony/Component/Messenger/Transport/AmqpExt/AmqpReceiver.php
@@ -15,6 +15,7 @@
 use Symfony\Component\Messenger\Exception\LogicException;
 use Symfony\Component\Messenger\Exception\MessageDecodingFailedException;
 use Symfony\Component\Messenger\Exception\TransportException;
+use Symfony\Component\Messenger\Transport\Receiver\MessageCountAwareInterface;
 use Symfony\Component\Messenger\Transport\Receiver\ReceiverInterface;
 use Symfony\Component\Messenger\Transport\Serialization\PhpSerializer;
 use Symfony\Component\Messenger\Transport\Serialization\SerializerInterface;
@@ -26,7 +27,7 @@
  *
  * @experimental in 4.2
  */
-class AmqpReceiver implements ReceiverInterface
+class AmqpReceiver implements ReceiverInterface, MessageCountAwareInterface
 {
     private $serializer;
     private $connection;
@@ -87,6 +88,14 @@ public function reject(Envelope $envelope): void
         $this->rejectAmqpEnvelope($this->findAmqpEnvelope($envelope));
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function getMessageCount(): int
+    {
+        return $this->connection->countMessagesInQueue();
+    }
+
     private function rejectAmqpEnvelope(\AMQPEnvelope $amqpEnvelope): void
     {
         try {
diff --git a/src/Symfony/Component/Messenger/Transport/AmqpExt/AmqpTransport.php b/src/Symfony/Component/Messenger/Transport/AmqpExt/AmqpTransport.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\Messenger\Transport\AmqpExt;
 
 use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\Transport\Receiver\MessageCountAwareInterface;
 use Symfony\Component\Messenger\Transport\Serialization\PhpSerializer;
 use Symfony\Component\Messenger\Transport\Serialization\SerializerInterface;
 use Symfony\Component\Messenger\Transport\SetupableTransportInterface;
@@ -22,7 +23,7 @@
  *
  * @experimental in 4.2
  */
-class AmqpTransport implements TransportInterface, SetupableTransportInterface
+class AmqpTransport implements TransportInterface, SetupableTransportInterface, MessageCountAwareInterface
 {
     private $serializer;
     private $connection;
@@ -75,6 +76,14 @@ public function setup(): void
         $this->connection->setup();
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function getMessageCount(): int
+    {
+        ($this->receiver ?? $this->getReceiver())->getMessageCount();
+    }
+
     private function getReceiver()
     {
         return $this->receiver = new AmqpReceiver($this->connection, $this->serializer);
diff --git a/src/Symfony/Component/Messenger/Transport/AmqpExt/Connection.php b/src/Symfony/Component/Messenger/Transport/AmqpExt/Connection.php
@@ -184,6 +184,14 @@ public function publish(string $body, array $headers = [], int $delay = 0): void
         $this->exchange()->publish($body, $this->queueConfiguration['routing_key'] ?? null, $flags, $attributes);
     }
 
+    /**
+     * Returns an approximate count of the messages in a queue.
+     */
+    public function countMessagesInQueue(): int
+    {
+        return $this->queue()->declareQueue();
+    }
+
     /**
      * @throws \AMQPException
      */
diff --git a/src/Symfony/Component/Messenger/Transport/Receiver/MessageCountAwareInterface.php b/src/Symfony/Component/Messenger/Transport/Receiver/MessageCountAwareInterface.php
@@ -0,0 +1,28 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Transport\Receiver;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ * @author Ryan Weaver <ryan@symfonycasts.com>
+ *
+ * @experimental in 4.3
+ */
+interface MessageCountAwareInterface
+{
+    /**
+     * Returns the number of messages waiting to be handled.
+     *
+     * In some systems, this may be an approximate number.
+     */
+    public function getMessageCount(): int;
+}
