Silex guzzle provider implementation using handler stack consisting of mapRequest, retry, and log middleware

config.php

<?php
/*#############################
* Developer: Mohammad Sharaf Ali
* Designation: Web Developer
* Version: 1.0
*/#############################

$handler = new CurlHandler();
$stack = HandlerStack::create($handler);\

// Sample Guzzle Log Middleware - START
$guzzleLogFormat = 'date_iso_8601::{date_iso_8601}:::date_common_log::{date_common_log}:::uri::{uri}:::host::{host}:::version::{version}:::target::{target}:::hostname::{hostname}:::code::{code}:::phrase::{phrase}:::error::{error}:::req_headers::{req_headers}:::res_headers::{res_headers}:::res_body::{res_body}';

// set logger
$logger = new Logger('api.guzzle.log');

# mongodb handler
try {
    /*
     * Connection pooling: Remote server has closed the connection
     * Try max X no. retries to establish connection to mongodb & atmost one retry is ever needed
     */
    $mongoOptions = [
        'username' => $app['config.file']['MONGO_USER'],
        'password' => $app['config.file']['MONGO_PASSWORD'],
        'db' => $app['config.file']['MONGO_DATABASE_NAME'],
        'connect' => true,
        'w' => 0
    ];
    $mongo = AppHelper::getMongoClient($app['config.file']['MONGO_HOST'], $mongoOptions, $app['config.file']['MONGO_MAX_RETRIES']);
    $mongoHandler = new MongoDBHandler($mongo, $app['config.file']['MONGO_DATABASE_NAME'], 'guzzle');
    $mongoHandler->setFormatter(new MongoDBFormatter());
    $logger->pushHandler($mongoHandler);
} catch (Exception $e) {
    // handle when unable to connect to server after retries
    # send email
    $emailToSend = explode(',', $app['config.file']['TO_EMAIL']);
    $app['emailer']('MongoClient Connection Error!', $e->getTraceAsString(), $emailToSend);

    # end script execution
    AppHelper::toScreen($e->getMessage(), 1);
}

foreach ($logger->getHandlers() as $handler) {
    if ($handler instanceof MongoDBHandler) {
        $handler->pushProcessor(function(array $record) use ($app) {
            //AppHelper::toScreen($record['message'], 1);
            $recordArray = explode(':::', $record['message']);
            //AppHelper::toScreen($recordArray, 1);
            $newRecordArray = [];
            array_walk($array, function($val, $key) use (&$newRecordArray) {
                $nvp = explode('::', $val);
                $newRecordArray[$nvp[0]] = $nvp[1];
            });
            //AppHelper::toScreen($newRecordArray, 1);
            $record['context'] = $newRecordArray;
            $record['extra']['key_action'] = $app['request_stack']->getCurrentRequest()->get('_route');

            unset($record['message']);

            return $record;
        });
    }
}

$stack->push(Middleware::log($logger, new \GuzzleHttp\MessageFormatter($guzzleLogFormat), \Psr\Log\LogLevel::DEBUG));
// Sample Guzzle Log Middleware - END

/*
 * cURL error 6: could not resolve host
 * Retry middleware added for max X no. of retries to host
 */
$stack->push(Middleware::retry(AppHelper::retryDecider($app['config.file']['GUZZLE_MAX_RETRIES']), AppHelper::retryDelay()));
$stack->push(Middleware::mapRequest(function(RequestInterface $request) use ($app) {
    $queryParams = $request->getUri()->getQuery();
    parse_str($queryParams, $queryParams);

    if (!empty($queryParams['exclude_url'])) {
        unset($queryParams['exclude_url']);

        $app['isGuzzleExcludeUrl'] = 1;
    } else {
        $app['isGuzzleExcludeUrl'] = 0;
    }

    return new Request(
        $request->getMethod(),
        $request->getUri(),
        $request->getHeaders(),
        http_build_query($queryParams, null, '&', PHP_QUERY_RFC3986)
    );
}));

$app->register(new GuzzleServiceProvider(), [
    'guzzle.request_options' => [
        RequestOptions::VERIFY => false,
        RequestOptions::ON_STATS => function(TransferStats $stats) use ($app) {
            $app['isGuzzle'] = 1;

            if (empty($app['isGuzzleExcludeUrl'])) {
                $reqeustUri = $stats->getRequest()->getUri();
                $queryParams = $reqeustUri->getQuery();
                parse_str($queryParams, $queryParams);

                // unset secure params
                unset($queryParams['username']);
                unset($queryParams['loginId']);
                unset($queryParams['password']);

                // assign app params for global usage
                $app['query.params'] = $queryParams;
                //$commaSepQueryParams = urldecode(http_build_query($queryParams, '', ', '));
                $strQueryParams = http_build_query($queryParams);

                $app['summary.log'] = [
                    'request_uri' => (string) $reqeustUri->withQuery($strQueryParams),
                    //'request_params' => !empty($commaSepQueryParams) ? $commaSepQueryParams : '-',
                    'request_params' => !empty($queryParams) ? $queryParams : [],
                    'response_time' => $stats->getTransferTime()
                ];
            }
        },
        'curl' => [
            CURLOPT_USERAGENT => 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36'
        ],
        'handler' => $stack
    ]
]);