<?php
namespace Aws;
use GuzzleHttp\Promise\PromisorInterface;
use GuzzleHttp\Promise\EachPromise;
/**
* Sends and iterator of commands concurrently using a capped pool size.
*
* The pool will read command objects from an iterator until it is cancelled or
* until the iterator is consumed.
*/
class CommandPool implements PromisorInterface
{
/** @var EachPromise */
private $each;
/**
* The CommandPool constructor accepts a hash of configuration options:
*
* - concurrency: (callable|int) Maximum number of commands to execute
* concurrently. Provide a function to resize the pool dynamically. The
* function will be provided the current number of pending requests and
* is expected to return an integer representing the new pool size limit.
* - before: (callable) function to invoke before sending each command. The
* before function accepts the command and the key of the iterator of the
* command. You can mutate the command as needed in the before function
* before sending the command.
* - fulfilled: (callable) Function to invoke when a promise is fulfilled.
* The function is provided the result object, id of the iterator that the
* result came from, and the aggregate promise that can be resolved/rejected
* if you need to short-circuit the pool.
* - rejected: (callable) Function to invoke when a promise is rejected.
* The function is provided an AwsException object, id of the iterator that
* the exception came from, and the aggregate promise that can be
* resolved/rejected if you need to short-circuit the pool.
* - preserve_iterator_keys: (bool) Retain the iterator key when generating
* the commands.
*
* @param AwsClientInterface $client Client used to execute commands.
* @param array|\Iterator $commands Iterable that yields commands.
* @param array $config Associative array of options.
*/
public function __construct(
AwsClientInterface $client,
$commands,
array $config = []
) {
if (!isset($config['concurrency'])) {
$config['concurrency'] = 25;
}
$before = $this->getBefore($config);
$mapFn = function ($commands) use ($client, $before, $config) {
foreach ($commands as $key => $command) {
if (!($command instanceof CommandInterface)) {
throw new \InvalidArgumentException('Each value yielded by '
. 'the iterator must be an Aws\CommandInterface.');
}
if ($before) {
$before($command, $key);
}
if (!empty($config['preserve_iterator_keys'])) {
yield $key => $client->executeAsync($command);
} else {
yield $client->executeAsync($command);
}
}
};
$this->each = new EachPromise($mapFn($commands), $config);
}
/**
* @return \GuzzleHttp\Promise\PromiseInterface
*/
public function promise()
{
return $this->each->promise();
}
/**
* Executes a pool synchronously and aggregates the results of the pool
* into an indexed array in the same order as the passed in array.
*
* @param AwsClientInterface $client Client used to execute commands.
* @param mixed $commands Iterable that yields commands.
* @param array $config Configuration options.
*
* @return array
* @see \Aws\CommandPool::__construct for available configuration options.
*/
public static function batch(
AwsClientInterface $client,
$commands,
array $config = []
) {
$results = [];
self::cmpCallback($config, 'fulfilled', $results);
self::cmpCallback($config, 'rejected', $results);
return (new self($client, $commands, $config))
->promise()
->then(static function () use (&$results) {
ksort($results);
return $results;
})
->wait();
}
/**
* @return callable
*/
private function getBefore(array $config)
{
if (!isset($config['before'])) {
return null;
}
if (is_callable($config['before'])) {
return $config['before'];
}
throw new \InvalidArgumentException('before must be callable');
}
/**
* Adds an onFulfilled or onRejected callback that aggregates results into
* an array. If a callback is already present, it is replaced with the
* composed function.
*
* @param array $config
* @param $name
* @param array $results
*/
private static function cmpCallback(array &$config, $name, array &$results)
{
if (!isset($config[$name])) {
$config[$name] = function ($v, $k) use (&$results) {
$results[$k] = $v;
};
} else {
$currentFn = $config[$name];
$config[$name] = function ($v, $k) use (&$results, $currentFn) {
$currentFn($v, $k);
$results[$k] = $v;
};
}
}
}