MongoDB Subscription Consumer feature

docs/transport/mongodb.md

@@ -10,6 +10,7 @@ Allows to use [MongoDB](https://www.mongodb.com/) as a message queue broker.
 * [Send expiration message](#send-expiration-message)
 * [Send delayed message](#send-delayed-message)
 * [Consume message](#consume-message)
+* [Subscription consumer](#subscription-consumer)
 
 ## Installation
 
@@ -139,4 +140,37 @@ $consumer->acknowledge($message);
 // $consumer->reject($message);
 ```
 
+## Subscription consumer
+
+```php
+<?php
+use Interop\Queue\PsrMessage;
+use Interop\Queue\PsrConsumer;
+
+/** @var \Enqueue\Mongodb\MongodbContext $psrContext */
+/** @var \Enqueue\Mongodb\MongodbDestination $fooQueue */
+/** @var \Enqueue\Mongodb\MongodbDestination $barQueue */
+
+$fooConsumer = $psrContext->createConsumer($fooQueue);
+$barConsumer = $psrContext->createConsumer($barQueue);
+
+$subscriptionConsumer = $psrContext->createSubscriptionConsumer();
+$subscriptionConsumer->subscribe($fooConsumer, function(PsrMessage $message, PsrConsumer $consumer) {
+    // process message
+
+    $consumer->acknowledge($message);
+
+    return true;
+});
+$subscriptionConsumer->subscribe($barConsumer, function(PsrMessage $message, PsrConsumer $consumer) {
+    // process message
+
+    $consumer->acknowledge($message);
+
+    return true;
+});
+
+$subscriptionConsumer->consume(2000); // 2 sec
+```
+
 [back to index](../index.md)

pkg/mongodb/MongodbConsumer.php

@@ -115,7 +115,7 @@ public function reject(Message $message, bool $requeue = false): void
         }
     }
 
-    protected function receiveMessage(): ?MongodbMessage
+    private function receiveMessage(): ?MongodbMessage
     {
         $now = time();
         $collection = $this->context->getCollection();
@@ -137,23 +137,9 @@ protected function receiveMessage(): ?MongodbMessage
             return null;
         }
         if (empty($message['time_to_live']) || $message['time_to_live'] > time()) {
-            return $this->convertMessage($message);
+            return $this->context->convertMessage($message);
         }
 
         return null;
     }
-
-    protected function convertMessage(array $mongodbMessage): MongodbMessage
-    {
-        $properties = JSON::decode($mongodbMessage['properties']);
-        $headers = JSON::decode($mongodbMessage['headers']);
-
-        $message = $this->context->createMessage($mongodbMessage['body'], $properties, $headers);
-        $message->setId((string) $mongodbMessage['_id']);
-        $message->setPriority((int) $mongodbMessage['priority']);
-        $message->setRedelivered((bool) $mongodbMessage['redelivered']);
-        $message->setPublishedAt((int) $mongodbMessage['published_at']);
-
-        return $message;
-    }
 }

pkg/mongodb/MongodbContext.php

@@ -8,7 +8,6 @@
 use Interop\Queue\Context;
 use Interop\Queue\Destination;
 use Interop\Queue\Exception\InvalidDestinationException;
-use Interop\Queue\Exception\SubscriptionConsumerNotSupportedException;
 use Interop\Queue\Exception\TemporaryQueueNotSupportedException;
 use Interop\Queue\Message;
 use Interop\Queue\Producer;
@@ -107,7 +106,26 @@ public function close(): void
 
     public function createSubscriptionConsumer(): SubscriptionConsumer
     {
-        throw SubscriptionConsumerNotSupportedException::providerDoestNotSupportIt();
+        return new MongodbSubscriptionConsumer($this);
+    }
+
+    /**
+     * @internal It must be used here and in the consumer only
+     */
+    public function convertMessage(array $mongodbMessage): MongodbMessage
+    {
+        $mongodbMessageObj = $this->createMessage(
+            $mongodbMessage['body'],
+            JSON::decode($mongodbMessage['properties']),
+            JSON::decode($mongodbMessage['headers'])
+        );
+
+        $mongodbMessageObj->setId((string) $mongodbMessage['_id']);
+        $mongodbMessageObj->setPriority((int) $mongodbMessage['priority']);
+        $mongodbMessageObj->setRedelivered((bool) $mongodbMessage['redelivered']);
+        $mongodbMessageObj->setPublishedAt((int) $mongodbMessage['published_at']);
+
+        return $mongodbMessageObj;
     }
 
     /**

pkg/mongodb/MongodbSubscriptionConsumer.php

@@ -0,0 +1,136 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Enqueue\Mongodb;
+
+use Interop\Queue\Consumer;
+use Interop\Queue\SubscriptionConsumer;
+
+class MongodbSubscriptionConsumer implements SubscriptionConsumer
+{
+    /**
+     * @var MongodbContext
+     */
+    private $context;
+
+    /**
+     * an item contains an array: [MongodbConsumer $consumer, callable $callback];.
+     *
+     * @var array
+     */
+    private $subscribers;
+
+    /**
+     * @param MongodbContext $context
+     */
+    public function __construct(MongodbContext $context)
+    {
+        $this->context = $context;
+        $this->subscribers = [];
+    }
+
+    public function consume(int $timeout = 0): void
+    {
+        if (empty($this->subscribers)) {
+            throw new \LogicException('No subscribers');
+        }
+
+        $timeout = (int) ceil($timeout / 1000);
+        $endAt = time() + $timeout;
+
+        $queueNames = [];
+        foreach (array_keys($this->subscribers) as $queueName) {
+            $queueNames[$queueName] = $queueName;
+        }
+
+        $currentQueueNames = [];
+        while (true) {
+            if (empty($currentQueueNames)) {
+                $currentQueueNames = $queueNames;
+            }
+
+            $result = $this->context->getCollection()->findOneAndDelete(
+                [
+                    'queue' => ['$in' => array_keys($currentQueueNames)],
+                    '$or' => [
+                        ['delayed_until' => ['$exists' => false]],
+                        ['delayed_until' => ['$lte' => time()]],
+                    ],
+                ],
+                [
+                    'sort' => ['priority' => -1, 'published_at' => 1],
+                    'typeMap' => ['root' => 'array', 'document' => 'array'],
+                ]
+            );
+
+            if ($result) {
+                list($consumer, $callback) = $this->subscribers[$result['queue']];
+
+                $message = $this->context->convertMessage($result);
+
+                if (false === call_user_func($callback, $message, $consumer)) {
+                    return;
+                }
+
+                unset($currentQueueNames[$result['queue']]);
+            } else {
+                $currentQueueNames = [];
+
+                usleep(200000); // 200ms
+            }
+
+            if ($timeout && microtime(true) >= $endAt) {
+                return;
+            }
+        }
+    }
+
+    /**
+     * @param MongodbConsumer $consumer
+     */
+    public function subscribe(Consumer $consumer, callable $callback): void
+    {
+        if (false == $consumer instanceof MongodbConsumer) {
+            throw new \InvalidArgumentException(sprintf('The consumer must be instance of "%s" got "%s"', MongodbConsumer::class, get_class($consumer)));
+        }
+
+        $queueName = $consumer->getQueue()->getQueueName();
+        if (array_key_exists($queueName, $this->subscribers)) {
+            if ($this->subscribers[$queueName][0] === $consumer && $this->subscribers[$queueName][1] === $callback) {
+                return;
+            }
+
+            throw new \InvalidArgumentException(sprintf('There is a consumer subscribed to queue: "%s"', $queueName));
+        }
+
+        $this->subscribers[$queueName] = [$consumer, $callback];
+    }
+
+    /**
+     * @param MongodbConsumer $consumer
+     */
+    public function unsubscribe(Consumer $consumer): void
+    {
+        if (false == $consumer instanceof MongodbConsumer) {
+            throw new \InvalidArgumentException(sprintf('The consumer must be instance of "%s" got "%s"', MongodbConsumer::class, get_class($consumer)));
+        }
+
+        $queueName = $consumer->getQueue()->getQueueName();
+
+        if (false == array_key_exists($queueName, $this->subscribers)) {
+            return;
+        }
+
+        if ($this->subscribers[$queueName][0] !== $consumer) {
+            return;
+        }
+
+        unset($this->subscribers[$queueName]);
+    }
+
+    public function unsubscribeAll(): void
+    {
+        $this->subscribers = [];
+    }
+}

pkg/mongodb/Tests/MongodbContextTest.php

@@ -70,6 +70,32 @@ public function testShouldCreateMessage()
         $this->assertFalse($message->isRedelivered());
     }
 
+    public function testShouldConvertFromArrayToMongodbMessage()
+    {
+        $arrayData = [
+            '_id' => 'stringId',
+            'body' => 'theBody',
+            'properties' => json_encode(['barProp' => 'barPropVal']),
+            'headers' => json_encode(['fooHeader' => 'fooHeaderVal']),
+            'priority' => '12',
+            'published_at' => 1525935820,
+            'redelivered' => false,
+        ];
+
+        $context = new MongodbContext($this->createClientMock());
+        $message = $context->convertMessage($arrayData);
+
+        $this->assertInstanceOf(MongodbMessage::class, $message);
+
+        $this->assertEquals('stringId', $message->getId());
+        $this->assertEquals('theBody', $message->getBody());
+        $this->assertEquals(['barProp' => 'barPropVal'], $message->getProperties());
+        $this->assertEquals(['fooHeader' => 'fooHeaderVal'], $message->getHeaders());
+        $this->assertEquals(12, $message->getPriority());
+        $this->assertEquals(1525935820, $message->getPublishedAt());
+        $this->assertFalse($message->isRedelivered());
+    }
+
     public function testShouldCreateTopic()
     {
         $context = new MongodbContext($this->createClientMock());