ReactPHP Event Loop Vs AWS Lambda Signals

[gmorel]

Hi,

👏 Thanks for the incredible work.

I tried to build a system with reactphp/http and reactphp/async to do http calls in parallel in cascade.
🚀 Locally in docker working perfectly.

🎁 When deploying on AWS Lambda (Lambda as a Docker Image) via serverless deploy, surprise:

RequestId: 5ad1b639-980b-4f3c-baf6-7ac7d40971ee Error: Runtime exited with error: exit status 141
Runtime.ExitError

I manage to fix it with:

        // Try to handle SIGPIPE and other potential signals gracefully
        \pcntl_async_signals(true);
        \pcntl_signal(SIGPIPE, function() {
            echo 'Caught SIGPIPE, closing socket.' . PHP_EOL; // Remove this line in prod
        });

With \pcntl_async_signals(true);, you enable asynchronous signal handling for your program, allowing it to catch and handle signals.
With the \pcntl_signal(SIGPIPE, ...), you specify a handler function for SIGPIPE.

While it fixes my little PoC. It is not fixing the whole project.

But it feels like a hack. I like it could crash anytime since

AWS Lambda does not provide full support for handling Unix signals as it abstracts many of these lower-level system interactions, which might lead to unexpected behavior or inability to handle signals properly.

I saw you have implemented several EventLoop type of implementation. Did I miss something ?
The bref lambda layer has [pcntl](https://www.php.net/manual/en/book.pcntl.php) by default.

Thanks in advance

Have a great day

<?php

declare(strict_types=1);

namespace App\Model;

use Psr\Log\LoggerInterface;
use React\EventLoop\Loop;
use React\Http\Browser;

use function React\Async\await;
use function React\Promise\all;

class Test
{
    public function __construct(
        private readonly LoggerInterface $logger
    ) {
    }

    public function run(): void
    {
        // Try to handle SIGPIPE and other potential signals gracefully
        \pcntl_async_signals(true);
        \pcntl_signal(SIGPIPE, function() {
//            echo 'Caught SIGPIPE, closing socket.' . PHP_EOL;
        });


        $loop = Loop::get();
        $browser = new Browser($loop);
        $browser->withTimeout(60);
        $url = 'https://httpbin.org/delay/';

        $startAt = microtime(true);

        $stats = new Stats(
            randomDelays: [],
            sequentialTotal: 0,
            realTime: 0,
            percent: 0,
        );

        $promises = $this->fetchRequests($browser, $stats, $url);

        $expectedTotal = max($stats->randomDelays);

        // Wait for all promises to be resolved
        $promisesAll = all($promises)->then(function (array $numbers) use ($startAt, $expectedTotal, $stats) {
            $numbersList = implode(', ', $numbers);
            echo "All tasks completed: $numbersList\n";

            echo "Sequential total: {$stats->sequentialTotal}s\n";
            echo "Expected total: {$expectedTotal}s\n";
            $realTime = round(microtime(true) - $startAt, 2);
            echo "Real time: {$realTime}s\n";
            $percent = round($realTime / $expectedTotal * 100, 2);
            echo "Percent: $percent%\n";
        });
        $firstPasses = await($promisesAll);
        var_dump($firstPasses);

        // 2x
        echo "************************\n";
        echo "2nd time\n";
        $promises = $this->fetchRequests($browser, $stats, $url);

        $expectedTotal = max($stats->randomDelays);

        // Wait for all promises to be resolved
        $promisesAll = all($promises)->then(function (array $numbers) use ($startAt, $expectedTotal, $stats) {
            $numbersList = implode(', ', $numbers);
            echo "All tasks completed: $numbersList\n";

            echo "Sequential total: {$stats->sequentialTotal}s\n";
            echo "Expected total: {$expectedTotal}s\n";
            $realTime = round(microtime(true) - $startAt, 2);
            echo "Real time: {$realTime}s\n";
            $percent = round($realTime / $expectedTotal * 100, 2);
            echo "Percent: $percent%\n";
        });

        $secondPasses = await($promisesAll);
        var_dump($secondPasses);

        // Run the event loop
        $loop->run();
    }

    /**
     * @return \React\Promise\PromiseInterface[]
     */
    private function fetchRequests(Browser $browser, Stats $stats, string $url): array
    {
        $requests = [];
        $time = microtime(true);
        for ($i = 1; $i <= 10; ++$i) {
            $randomDelay = rand(1, 10);
            if (1 === $i) {
                $randomDelay = 10;
            }
            $stats->randomDelays[] = $randomDelay;
            $stats->sequentialTotal += $randomDelay;
            $delayedUrl = $url.$randomDelay;
            $receivedAt = date('H:i:s');
            echo "$receivedAt: Init $i ({$randomDelay}s)\n";

            echo "$receivedAt: Start $delayedUrl\n";
            $timeHttp = microtime(true);
            $logger = $this->logger;
            // Yield the promise from the HTTP request
            $requests[] = $browser->request('GET', $delayedUrl)->then(
                function ($response) use ($i, $time, $timeHttp) {
                    $body = (string) $response->getBody();
                    $receivedAt = date('H:i:s');
                    $timeHttp = round(microtime(true) - $timeHttp, 2);
                    $receivedAt = date('H:i:s');
                    $inSeconds = round(microtime(true) - $time, 2);
                    echo "$receivedAt: End $i in {$inSeconds}s (HTTP {$timeHttp}s)\n";

                    return $i; // Return the number for successful results
                },
                function ($error) use ($i, $logger) {
                    echo "End $i: Error: ".$error->getMessage()."\n";
                    error_log('Request error: '.$error->getMessage());
                    $logger->critical(
                        'Request error',
                        ['error' => $error->getMessage()]
                    );

                    return $i; // Return the number even in case of error
                }
            );
        }

        return $requests;
    }
}

<?php

declare(strict_types=1);

namespace App\Model;

class Stats
{
    public function __construct(
        /** @var int[] */
        public array $randomDelays,
        public int $sequentialTotal,
        public float $realTime,
        public float $percent,
    ) {
    }
}