Guzzle 6 retry middleware

December 18, 2015 15 By addshore

Recently I switched from using Guzzle 5 to Guzzle 6 in my mediawiki-api-base PHP library. Everything went very smoothly except for there being no compatible version of the retry-subscriber that I had previously used. The subscriber has been replaced by retry middleware of which I was provided an extracted example. In this post I cover my implementation for the mediawiki-api-base library.

Guzzle 5

With Guzzle 5 you would create a retry subscriber with a filter and then attach it to the event emitter for the guzzle client. A full example can be seen below where RetrySubscriber::createStatusFilter can be seen here.

// Retry 500 and 503 responses
$retry = new RetrySubscriber([
    'filter' => RetrySubscriber::createStatusFilter(),
    'delay'  => function ($number, $event) { return 1; },
    'max' => 3,
]);

$client = new GuzzleHttp\Client();
$client->getEmitter()->attach($retry);

Guzzle 6

Guzzle 6 got rid of its event system and switched to the afore mentioned middleware system.

Middleware is added to a handler stack upon Client construction as seen below:

$handlerStack = HandlerStack::create( new CurlHandler() );
$handlerStack->push( Middleware::retry( retryDecider(), retryDelay() ) );
$client = new Client( array( 'handler' => $handlerStack ) );

The retry middleware takes two parameters, the first is the callable function that decides if a request / response should be retried and the last deciding how long to wait before retrying (similar to in Guzzle 6). Each can be seen below.

function retryDecider() {
   return function (
      $retries,
      Request $request,
      Response $response = null,
      RequestException $exception = null
   ) {
      // Limit the number of retries to 5
      if ( $retries >= 5 ) {
         return false;
      }

      // Retry connection exceptions
      if( $exception instanceof ConnectException ) {
         return true;
      }

      if( $response ) {
         // Retry on server errors
         if( $response->getStatusCode() >= 500 ) {
            return true;
         }
      }

      return false;
   };
}
function retryDelay() {
    return function( $numberOfRetries ) {
        return 1000 * $numberOfRetries;
    };
}

When implementing this for the mediawiki-api-base library I actually ended up creating a MiddlewareFactory which can be seen at on github here which is fully tested here.

This implementation includes a more complex retry decider including logging.

Enjoy!

CategoryTech Posts
Tagsaddwiki PHP guzzle

15 Comments

  • Shubham Gupta says:
    September 21, 2017 at 9:22 am

    is there a provision of setting timeout with guzzle retry middleware? I want the retry attempt to be made upon expiration of pre-defined timeout interval

    Reply
  • COil says:
    October 12, 2017 at 8:51 am

    Thanks for the hint. The retry middleware is really a must when having to deal with an API that isn’t 100% reliable.

    Reply
  • jasonjudge says:
    October 26, 2017 at 2:10 pm

    I’m curious, is this where OAuth token refreshes would be performed, or is that something which would have to be down further back up the chain?

    Reply
    • addshore says:
      November 5, 2017 at 1:16 pm

      I have not really worked with OAuth & Guzzle yet so can’t give you the ‘right’ answer. It definitely sounds possible though.

      Reply
  • Les erreurs, ça arrive – notes & réflexions says:
    March 15, 2018 at 9:18 am

    […] Toujours si vous utilisez une librairie comme Guzzle, vous pouvez mettre en place un Retry Middleware. […]

    Reply
  • Misbah says:
    April 8, 2018 at 9:28 am

    I’ve been following your example & making multiple asynchronous requests with Promise/any() functions.
    When retry middleware is not used & some of the api end-points are down, this is working fine. But when adding retry middleware while some end-points are down, the request gets slow. It seems that, though other end-points are up, but the failing points are blocking and retrying.

    trait RetriesRequest {

public function getRetryHandler()
{
    $handlerStack = HandlerStack::create(new CurlHandler());

    $handlerStack->push(Middleware::retry($this->retryDecider(), $this->retryDelay()));

    return $handlerStack;

}

public function retryDecider()
{

    return function (
        $retries,
        Request $request,
        Response $response = null,
        RequestException $exception = null
    ) 

    {


        // Limit the number of retries to 5
        if ($retries >= 5)
        {

            return false;

        }


        // Retry connection exceptions
        if ($exception instanceof ConnectException)
        {

            return true;

        }


        if($exception instanceof AggregateException)
        {

            return true;

        }


        if ($response)
        {
            // Retry on server errors
            if ($response->getStatusCode() >= 500 )
            {

                return true;

            }

        }

        return false;
    };

}



/**
 * delay 1s 2s 3s 4s 5s
 *
 * @return Closure
 */

public function retryDelay()
{

    return function ($numberOfRetries) 
    {
        return 2000;
        // return 1000 * $numberOfRetries;
    };

}

    }

    Request Call Code:
    trait SearchesFlights
    {

    use ParsesJason, RetriesRequest;

private $endPoints = [
                'v1'=> '127.0.0.1:5354', //post request,  body.date
                'v2' => '127.0.0.1:5939', //post request,  body.date
                'v3' => '127.0.0.1:4949', //post request,  body.date
                'v4' => '127.0.0.1:5051', //get request, no body
                'v5' => '127.0.0.1:5052', //get request, no body
            ];



private $postDate = '02/04/2018';


public function searchByDate()
{

    $client = new Client(array('handler' => $this->getRetryHandler()));

    /* $client = new Client();*/

        $promises = $this->getPromiseArray($client);

    $promise = Promise\any($promises)->then(

        function (PsrResponse $response){


            return $this->getAll(json_decode($response->getBody()));


        },

        function ($reason) {

            return $reason;

        }

    );

    $result = $promise->wait();

    return $result;

}




/*Returns Promise Array with post requests*/

private function getPromiseArray($client)
{

    $options = ['form_params' => ['date' => $this->postDate]];

    return $promises = [
        'server1' => $client->requestAsync('POST', $this->endPoints['v1']),
        'server2' => $client->requestAsync('POST', $this->endPoints['v2']),
        'server3' => $client->requestAsync('POST', $this->endPoints['v3'], $options),


    ];


}


}
    Reply
  • Leo S says:
    June 20, 2018 at 1:43 am

    Should Line 20 be \GuzzleHttp\Exception\ConnectException?
    I am getting following error.
    Argument 4 passed to guzzelRetryClient::{closure}() must be an instance of GuzzleHttp\Psr7\RequestException, instance of GuzzleHttp\Exception\ConnectException given

    Reply
  • 2017 Year Review - Addshore says:
    June 27, 2018 at 10:11 am

    […] Guzzle 6 retry middleware […]

    Reply
  • 2018 Year Review - Addshore says:
    January 3, 2019 at 10:54 am

    […] Guzzle 6 retry middleware, (still #1) […]

    Reply
  • Edvinas Gurevičius says:
    February 21, 2020 at 1:20 pm

    Great article 😉 thank you sooo much!

    Reply
  • Retrying and Logging Requests with Guzzle | says:
    May 10, 2020 at 5:16 pm

    […] Guzzle 6 retry middleware […]

    Reply
  • 2020 Year Review - Addshore says:
    December 26, 2020 at 11:51 am

    […] Guzzle 6 retry middleware (was #5, saw increase in views) […]

    Reply
  • 2022 Year Review - addshore says:
    March 4, 2023 at 6:05 pm

    […] Guzzle 6 retry middleware (was #9) […]

    Reply

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