Laravel - Guzzle: Getting GuzzleHttp\Exception\ConnectException: cURL error 6 Could not resolve host randomly

Question

This is probably the weirdest situation that I ever seen. Basically I have a system built in Laravel 5.1 which needs to make a request to an external system. The thing is, sometimes it works but sometimes I get

GuzzleHttp\Exception\ConnectException: cURL error 6: Could not resolve host: hosthere

Absolutely nothing changes, in terms of code. I run the application with exactly the same parameters and sometimes I get the error, sometimes I get the right response.

Any ideas?

Thanks in advance

EDIT 2 When I execute nslookup domainthatineedtouse.com I get

;; Got SERVFAIL reply from 8.8.8.8, trying next server
Server: 8.8.4.4
Address:    8.8.4.4#53

Non-authoritative answer:
Name:   domainthatineedtouse.com
Address: therealipaddressishere

Can this be related to the issue?

EDIT This is part of the class that is making the connection.

<?php


use GuzzleHttp\ClientInterface;

class MyClass
{
    const ENDPOINT = 'http://example.com/v1/endpoint';

    /**
     * @var \GuzzleHttp\ClientInterface
     */
    protected $client;

    /**
     * @var string The api key used to connect to the service
     */
    protected $apiKey;

    /**
     * Constructor.
     *
     * @param $apiKey
     * @param ClientInterface $client
     */
    public function __construct($apiKey, ClientInterface $client)
    {
        $this->client = $client;
        $this->apiKey = $apiKey;
    }

    /**
     * Here is where I make the request
     *
     * @param $param1
     * @param $param2
     * @return \Psr\Http\Message\ResponseInterface
     */
    public function makeTheRequest($param1, $param2)
    {
        return $this->client->request('get', self::ENDPOINT, [
            'query' => [
                'api_token' => $this->apiKey,
                'parameter_1' => $param1,
                'parameter_2' => $param2,
            ]
        ]);
    }
}

Tariq Khan · Accepted Answer · 2017-03-22 01:38:34Z

7

This is something one should always anticipate while calling external APIs most of them face outages including the very popular Amazon's Product Advertising API. So keeping that in mind this should always be placed in a try/catch along with using retries placed in a do/while.

You should always catch these two types of common timeouts, connection timeouts and request timeouts. \GuzzleHttp\Exception\ConnectException and \GuzzleHttp\Exception\RequestException

// query External API
// retry by using a do/while
$retry_count    = 0;
do {
    try {
        $response = json_decode($this->external_service->runOperation($operation));
    } catch (\GuzzleHttp\Exception\ConnectException $e) {
        // log the error here

        Log::Warning('guzzle_connect_exception', [
                'url' => $this->request->fullUrl(),
                'message' => $e->getMessage()
        ]);
    } catch (\GuzzleHttp\Exception\RequestException $e) {

        Log::Warning('guzzle_connection_timeout', [
                'url' => $this->request->fullUrl(),
                'message' => $e->getMessage()
        ]);
    }

    // Do max 5 attempts
    if (++$retry_count == 5) {
        break;
    }
} while(!is_array($response));

answered Mar 22, 2017 at 1:38

Tariq Khan

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5 Comments

TJ is too short Over a year ago

This is a great strategy. I will implement it to avoid this issue in future releases but still think that currently there is something wrong in terms of server configuration (but the funny thing is that nothing was changed as far as I know)

Tariq Khan Over a year ago

hmm, if its happening everytime then it might be a server issue, but if its random then its definitely the external API's outage. might be better if you try this from a simple script outside of laravel and the server environment.

TJ is too short Over a year ago

Thanks for your reply. I decided to restart the server (is a droplet in Digital Ocean) and made some requests and it looks that now is working. I'm not sure when was the last time the server was restarted but it looks like this was the issue. I was checking the logs and it was failing not only for this request but also when I was trying to send emails (via sendgrid): Swift_TransportException: Connection could not be established with host smtp.sendgrid.net [php_network_getaddresses: getaddrinfo failed: No address associated with hostname #0]

Tariq Khan Over a year ago

ah nothing fixes it like a reboot does ;) however I would still keep this strategy because we never know when the requested DNS of the external api does give an issue.

Zedorg Over a year ago

Some growing delay would be nice to be added, to not fire all retries one after each.

acabala · Accepted Answer · 2017-03-21 17:14:33Z

0

It could be helpful if you share actual code with us.

What I can say now, there are chances to be one of 2 issues:

a) DNS settings problem on your server. You need to try different configuration

b) you are passing http:// as part of the url.

answered Mar 21, 2017 at 17:14

acabala

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2 Comments

TJ is too short Over a year ago

Thanks for your reply @acabala! I edited the question and added part of the class that I'm using to make the request. To actually establish the connection I'm using GuzzleHttp.

TJ is too short Over a year ago

I decided to restart the server (is a droplet in Digital Ocean) and made some requests and it looks like is working (no more errors happening randomly). I'm not sure when was the last time the server was restarted but it looks like this was the issue. The good old reboot... lol

TJ is too short · Accepted Answer · 2017-03-22 15:02:41Z

0

I hope this helps. Basically the problem was related to the server:

https://twitter.com/digitalocean/status/844178536835551233

In my case, I just needed to reboot and everything seems fine now.

answered Mar 22, 2017 at 15:02

TJ is too short

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