Implement async call in PHP using guzzle promise

php-guzzle-promise-function.php

<?php

use GuzzleHttp\Promise\Promise;
use GuzzleHttp\Promise\EachPromise;


function promiseFunction($sample_array,$index){  // index is optional params 
  $promise =  new Promise(
             function () use ($sample_array,$index,&$promise) {
                        $response = secondFunction($sample_array);
                        $promise->resolve($response);
             },
             function ($sample_array,$index,&$promise) {
                        // do something that will cancel the promise computation (e.g., close
                        // a socket, cancel a database query, etc...)
                        $promise->reject($index); // just to know which index has failed or rejected.
              }
           );
    return $promise;
}

function sampleFunction($sample_array_set){

            $promises = array();
            foreach($sample_array_set as $index => $sample_array){
                $promises[$index] = promiseFunction($sample_array,$index); 
            }

           $eachPromise = new EachPromise($promises, [
          // how many concurrency we are use
          'concurrency' => count($promises),  // can set to 4 ,10,20 depend on how many iteration but better to used same as count
          'fulfilled' => function ($response,$index) use (&$sample_array)
           {
             //logic for other operation.

            },
          'rejected' => function ($reason) {
          }
        ]);

 }

$sample_array_set = array('One','Two','Three', 'Four', 'Five', 'Six', 'Seven', 'Eight');
sampleFunction($sample_array_set);