feature #40761 [MonologBridge] Reset loggers on workers (l-vo)

This PR was merged into the 5.3-dev branch.

Discussion
----------

[MonologBridge] Reset loggers on workers

| Q             | A
| ------------- | ---
| Branch?       | 5.x
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Tickets       |
| License       | MIT
| Doc PR        |

This PR tries to solve some problems with buffered handlers (FingerCrossed) in workers.

Let's consider the default configuration (`stop_buffering: true`):
- When the threshold is crossed, all logs are flushed. Logs for the current message but also logs of previous messages in the buffer. Although buffer is limited `buffer_size`, it's a shame to keep logs of previous messages.
- When the threshold is crossed, buffering is disabled. So finger crossed configuration is not used anymore, all the logs are flushed as soon as they are written.

Then with (`stop_buffering: false`) (why isn't this the default configuration ?)
- It's a bit better since buffering isn't disabled when the threshold is crossed
- Like with `stop_buffering: true`, logs of previous messages are kept in memory

In a similar way of `DoctrineClearEntityManagerWorkerSubscriber`, this PR adds a `ResetLoggersWorkerSubscribber` to reset resettable loggers.

Integration in Monolog bundle: symfony/monolog-bundle#403

Commits
-------

1d2f7f1f87 [Messenger] Reset loggers on workers

src/Symfony/Bridge/Monolog/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+5.3
+---
+
+* Add `ResetLoggersWorkerSubscriber` to reset buffered logs in messenger workers
+
 5.2.0
 -----
 

src/Symfony/Bridge/Monolog/Messenger/ResetLoggersWorkerSubscriber.php

@@ -0,0 +1,49 @@
+<?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\Bridge\Monolog\Messenger;
+
+use Monolog\ResettableInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\Messenger\Event\WorkerMessageFailedEvent;
+use Symfony\Component\Messenger\Event\WorkerMessageHandledEvent;
+
+/**
+ * Reset loggers between messages being handled to release buffered handler logs.
+ *
+ * @author Laurent VOULLEMIER <laurent.voullemier@gmail.com>
+ */
+class ResetLoggersWorkerSubscriber implements EventSubscriberInterface
+{
+    private $loggers;
+
+    public function __construct(iterable $loggers)
+    {
+        $this->loggers = $loggers;
+    }
+
+    public static function getSubscribedEvents(): array
+    {
+        return [
+            WorkerMessageHandledEvent::class => 'resetLoggers',
+            WorkerMessageFailedEvent::class => 'resetLoggers',
+        ];
+    }
+
+    public function resetLoggers(): void
+    {
+        foreach ($this->loggers as $logger) {
+            if ($logger instanceof ResettableInterface) {
+                $logger->reset();
+            }
+        }
+    }
+}

src/Symfony/Bridge/Monolog/Tests/Messenger/ResetLoggersWorkerSubscriberTest.php

@@ -0,0 +1,85 @@
+<?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\Bridge\Monolog\Tests\Messenger;
+
+use Monolog\Handler\BufferHandler;
+use Monolog\Handler\TestHandler;
+use PHPUnit\Framework\TestCase;
+use Symfony\Bridge\Monolog\Logger;
+use Symfony\Bridge\Monolog\Messenger\ResetLoggersWorkerSubscriber;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\Event\WorkerRunningEvent;
+use Symfony\Component\Messenger\Handler\HandlersLocator;
+use Symfony\Component\Messenger\MessageBus;
+use Symfony\Component\Messenger\Middleware\HandleMessageMiddleware;
+use Symfony\Component\Messenger\Transport\Receiver\ReceiverInterface;
+use Symfony\Component\Messenger\Worker;
+
+class ResetLoggersWorkerSubscriberTest extends TestCase
+{
+    public function testLogsAreFlushed()
+    {
+        $loggerTestHandler = new TestHandler();
+        $loggerTestHandler->setSkipReset(true);
+
+        $logger = new Logger('', [new BufferHandler($loggerTestHandler)]);
+
+        $message = new class() {
+        };
+
+        $handler = static function (object $message) use ($logger): void {
+            $logger->info('Message of class {class} is being handled', ['class' => \get_class($message)]);
+        };
+
+        $handlersMiddleware = new HandleMessageMiddleware(new HandlersLocator([
+            \get_class($message) => [$handler],
+        ]));
+
+        $eventDispatcher = new EventDispatcher();
+        $eventDispatcher->addSubscriber(new ResetLoggersWorkerSubscriber([$logger]));
+        $eventDispatcher->addListener(WorkerRunningEvent::class, static function (WorkerRunningEvent $event): void {
+            $event->getWorker()->stop();  // Limit the worker to one loop
+        });
+
+        $bus = new MessageBus([$handlersMiddleware]);
+        $worker = new Worker([$this->createReceiver($message)], $bus, $eventDispatcher);
+        $worker->run();
+
+        $this->assertCount(1, $loggerTestHandler->getRecords());
+    }
+
+    private function createReceiver(object $message): ReceiverInterface
+    {
+        return new class($message) implements ReceiverInterface {
+            private $message;
+
+            public function __construct(object $message)
+            {
+                $this->message = $message;
+            }
+
+            public function get(): iterable
+            {
+                return [new Envelope($this->message)];
+            }
+
+            public function ack(Envelope $envelope): void
+            {
+            }
+
+            public function reject(Envelope $envelope): void
+            {
+            }
+        };
+    }
+}

src/Symfony/Bridge/Monolog/composer.json

@@ -28,7 +28,8 @@
         "symfony/security-core": "^4.4|^5.0",
         "symfony/var-dumper": "^4.4|^5.0",
         "symfony/mailer": "^4.4|^5.0",
-        "symfony/mime": "^4.4|^5.0"
+        "symfony/mime": "^4.4|^5.0",
+        "symfony/messenger": "^4.4|^5.0"
     },
     "conflict": {
         "symfony/console": "<4.4",