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|
<?php
namespace Guzzle\Plugin\Backoff;
use Guzzle\Common\Event;
use Guzzle\Common\AbstractHasDispatcher;
use Guzzle\Http\Message\EntityEnclosingRequestInterface;
use Guzzle\Http\Message\RequestInterface;
use Guzzle\Http\Curl\CurlMultiInterface;
use Guzzle\Http\Exception\CurlException;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
/**
* Plugin to automatically retry failed HTTP requests using a backoff strategy
*/
class BackoffPlugin extends AbstractHasDispatcher implements EventSubscriberInterface
{
const DELAY_PARAM = CurlMultiInterface::BLOCKING;
const RETRY_PARAM = 'plugins.backoff.retry_count';
const RETRY_EVENT = 'plugins.backoff.retry';
/** @var BackoffStrategyInterface Backoff strategy */
protected $strategy;
/**
* @param BackoffStrategyInterface $strategy The backoff strategy used to determine whether or not to retry and
* the amount of delay between retries.
*/
public function __construct(BackoffStrategyInterface $strategy = null)
{
$this->strategy = $strategy;
}
/**
* Retrieve a basic truncated exponential backoff plugin that will retry HTTP errors and cURL errors
*
* @param int $maxRetries Maximum number of retries
* @param array $httpCodes HTTP response codes to retry
* @param array $curlCodes cURL error codes to retry
*
* @return self
*/
public static function getExponentialBackoff(
$maxRetries = 3,
array $httpCodes = null,
array $curlCodes = null
) {
return new self(new TruncatedBackoffStrategy($maxRetries,
new HttpBackoffStrategy($httpCodes,
new CurlBackoffStrategy($curlCodes,
new ExponentialBackoffStrategy()
)
)
));
}
public static function getAllEvents()
{
return array(self::RETRY_EVENT);
}
public static function getSubscribedEvents()
{
return array(
'request.sent' => 'onRequestSent',
'request.exception' => 'onRequestSent',
CurlMultiInterface::POLLING_REQUEST => 'onRequestPoll'
);
}
/**
* Called when a request has been sent and isn't finished processing
*
* @param Event $event
*/
public function onRequestSent(Event $event)
{
$request = $event['request'];
$response = $event['response'];
$exception = $event['exception'];
$params = $request->getParams();
$retries = (int) $params->get(self::RETRY_PARAM);
$delay = $this->strategy->getBackoffPeriod($retries, $request, $response, $exception);
if ($delay !== false) {
// Calculate how long to wait until the request should be retried
$params->set(self::RETRY_PARAM, ++$retries)
->set(self::DELAY_PARAM, microtime(true) + $delay);
// Send the request again
$request->setState(RequestInterface::STATE_TRANSFER);
$this->dispatch(self::RETRY_EVENT, array(
'request' => $request,
'response' => $response,
'handle' => ($exception && $exception instanceof CurlException) ? $exception->getCurlHandle() : null,
'retries' => $retries,
'delay' => $delay
));
}
}
/**
* Called when a request is polling in the curl multi object
*
* @param Event $event
*/
public function onRequestPoll(Event $event)
{
$request = $event['request'];
$delay = $request->getParams()->get(self::DELAY_PARAM);
// If the duration of the delay has passed, retry the request using the pool
if (null !== $delay && microtime(true) >= $delay) {
// Remove the request from the pool and then add it back again. This is required for cURL to know that we
// want to retry sending the easy handle.
$request->getParams()->remove(self::DELAY_PARAM);
// Rewind the request body if possible
if ($request instanceof EntityEnclosingRequestInterface && $request->getBody()) {
$request->getBody()->seek(0);
}
$multi = $event['curl_multi'];
$multi->remove($request);
$multi->add($request);
}
}
}
|
