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<?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;
use Psr\EventDispatcher\EventDispatcherInterface;
use Psr\Log\LoggerInterface;
use Symfony\Component\Clock\Clock;
use Symfony\Component\Clock\ClockInterface;
use Symfony\Component\Messenger\Event\WorkerMessageFailedEvent;
use Symfony\Component\Messenger\Event\WorkerMessageHandledEvent;
use Symfony\Component\Messenger\Event\WorkerMessageReceivedEvent;
use Symfony\Component\Messenger\Event\WorkerRateLimitedEvent;
use Symfony\Component\Messenger\Event\WorkerRunningEvent;
use Symfony\Component\Messenger\Event\WorkerStartedEvent;
use Symfony\Component\Messenger\Event\WorkerStoppedEvent;
use Symfony\Component\Messenger\Exception\DelayedMessageHandlingException;
use Symfony\Component\Messenger\Exception\HandlerFailedException;
use Symfony\Component\Messenger\Exception\RejectRedeliveredMessageException;
use Symfony\Component\Messenger\Exception\RuntimeException;
use Symfony\Component\Messenger\Stamp\AckStamp;
use Symfony\Component\Messenger\Stamp\ConsumedByWorkerStamp;
use Symfony\Component\Messenger\Stamp\FlushBatchHandlersStamp;
use Symfony\Component\Messenger\Stamp\NoAutoAckStamp;
use Symfony\Component\Messenger\Stamp\ReceivedStamp;
use Symfony\Component\Messenger\Transport\Receiver\QueueReceiverInterface;
use Symfony\Component\Messenger\Transport\Receiver\ReceiverInterface;
use Symfony\Component\RateLimiter\LimiterInterface;
/**
* @author Samuel Roze <samuel.roze@gmail.com>
* @author Tobias Schultze <http://tobion.de>
*
* @final
*/
class Worker
{
private bool $shouldStop = false;
private WorkerMetadata $metadata;
private array $acks = [];
private \SplObjectStorage $unacks;
/**
* @param ReceiverInterface[] $receivers Where the key is the transport name
*/
public function __construct(
private array $receivers,
private MessageBusInterface $bus,
private ?EventDispatcherInterface $eventDispatcher = null,
private ?LoggerInterface $logger = null,
private ?array $rateLimiters = null,
private ClockInterface $clock = new Clock(),
) {
$this->metadata = new WorkerMetadata([
'transportNames' => array_keys($receivers),
]);
$this->unacks = new \SplObjectStorage();
}
/**
* Receive the messages and dispatch them to the bus.
*
* Valid options are:
* * sleep (default: 1000000): Time in microseconds to sleep after no messages are found
* * queues: The queue names to consume from, instead of consuming from all queues. When this is used, all receivers must implement the QueueReceiverInterface
*/
public function run(array $options = []): void
{
$options = array_merge([
'sleep' => 1000000,
], $options);
$queueNames = $options['queues'] ?? null;
$this->metadata->set(['queueNames' => $queueNames]);
$this->eventDispatcher?->dispatch(new WorkerStartedEvent($this));
if ($queueNames) {
// if queue names are specified, all receivers must implement the QueueReceiverInterface
foreach ($this->receivers as $transportName => $receiver) {
if (!$receiver instanceof QueueReceiverInterface) {
throw new RuntimeException(sprintf('Receiver for "%s" does not implement "%s".', $transportName, QueueReceiverInterface::class));
}
}
}
while (!$this->shouldStop) {
$envelopeHandled = false;
$envelopeHandledStart = $this->clock->now();
foreach ($this->receivers as $transportName => $receiver) {
if ($queueNames) {
$envelopes = $receiver->getFromQueues($queueNames);
} else {
$envelopes = $receiver->get();
}
foreach ($envelopes as $envelope) {
$envelopeHandled = true;
$this->rateLimit($transportName);
$this->handleMessage($envelope, $transportName);
$this->eventDispatcher?->dispatch(new WorkerRunningEvent($this, false));
if ($this->shouldStop) {
break 2;
}
}
// after handling a single receiver, quit and start the loop again
// this should prevent multiple lower priority receivers from
// blocking too long before the higher priority are checked
if ($envelopeHandled) {
break;
}
}
if (!$envelopeHandled && $this->flush(false)) {
continue;
}
if (!$envelopeHandled) {
$this->eventDispatcher?->dispatch(new WorkerRunningEvent($this, true));
if (0 < $sleep = (int) ($options['sleep'] - 1e6 * ($this->clock->now()->format('U.u') - $envelopeHandledStart->format('U.u')))) {
$this->clock->sleep($sleep / 1e6);
}
}
}
$this->flush(true);
$this->eventDispatcher?->dispatch(new WorkerStoppedEvent($this));
}
private function handleMessage(Envelope $envelope, string $transportName): void
{
$event = new WorkerMessageReceivedEvent($envelope, $transportName);
$this->eventDispatcher?->dispatch($event);
$envelope = $event->getEnvelope();
if (!$event->shouldHandle()) {
return;
}
$acked = false;
$ack = function (Envelope $envelope, \Throwable $e = null) use ($transportName, &$acked) {
$acked = true;
$this->acks[] = [$transportName, $envelope, $e];
};
try {
$e = null;
$envelope = $this->bus->dispatch($envelope->with(new ReceivedStamp($transportName), new ConsumedByWorkerStamp(), new AckStamp($ack)));
} catch (\Throwable $e) {
}
$noAutoAckStamp = $envelope->last(NoAutoAckStamp::class);
if (!$acked && !$noAutoAckStamp) {
$this->acks[] = [$transportName, $envelope, $e];
} elseif ($noAutoAckStamp) {
$this->unacks[$noAutoAckStamp->getHandlerDescriptor()->getBatchHandler()] = [$envelope->withoutAll(AckStamp::class), $transportName];
}
$this->ack();
}
private function ack(): bool
{
$acks = $this->acks;
$this->acks = [];
foreach ($acks as [$transportName, $envelope, $e]) {
$receiver = $this->receivers[$transportName];
if (null !== $e) {
if ($rejectFirst = $e instanceof RejectRedeliveredMessageException) {
// redelivered messages are rejected first so that continuous failures in an event listener or while
// publishing for retry does not cause infinite redelivery loops
$receiver->reject($envelope);
}
if ($e instanceof HandlerFailedException || ($e instanceof DelayedMessageHandlingException && null !== $e->getEnvelope())) {
$envelope = $e->getEnvelope();
}
$failedEvent = new WorkerMessageFailedEvent($envelope, $transportName, $e);
$this->eventDispatcher?->dispatch($failedEvent);
$envelope = $failedEvent->getEnvelope();
if (!$rejectFirst) {
$receiver->reject($envelope);
}
continue;
}
$handledEvent = new WorkerMessageHandledEvent($envelope, $transportName);
$this->eventDispatcher?->dispatch($handledEvent);
$envelope = $handledEvent->getEnvelope();
if (null !== $this->logger) {
$message = $envelope->getMessage();
$context = [
'class' => $message::class,
];
$this->logger->info('{class} was handled successfully (acknowledging to transport).', $context);
}
$receiver->ack($envelope);
}
return (bool) $acks;
}
private function rateLimit(string $transportName): void
{
if (!$this->rateLimiters) {
return;
}
if (!\array_key_exists($transportName, $this->rateLimiters)) {
return;
}
/** @var LimiterInterface $rateLimiter */
$rateLimiter = $this->rateLimiters[$transportName]->create();
if ($rateLimiter->consume()->isAccepted()) {
return;
}
$this->logger?->info('Transport {transport} is being rate limited, waiting for token to become available...', ['transport' => $transportName]);
$this->eventDispatcher?->dispatch(new WorkerRateLimitedEvent($rateLimiter, $transportName));
$rateLimiter->reserve()->wait();
}
private function flush(bool $force): bool
{
$unacks = $this->unacks;
if (!$unacks->count()) {
return false;
}
$this->unacks = new \SplObjectStorage();
foreach ($unacks as $batchHandler) {
[$envelope, $transportName] = $unacks[$batchHandler];
try {
$this->bus->dispatch($envelope->with(new FlushBatchHandlersStamp($force)));
$envelope = $envelope->withoutAll(NoAutoAckStamp::class);
unset($unacks[$batchHandler], $batchHandler);
} catch (\Throwable $e) {
$this->acks[] = [$transportName, $envelope, $e];
}
}
return $this->ack();
}
public function stop(): void
{
$this->logger?->info('Stopping worker.', ['transport_names' => $this->metadata->getTransportNames()]);
$this->shouldStop = true;
}
public function getMetadata(): WorkerMetadata
{
return $this->metadata;
}
}