Boot your application once and keep it in memory. FrankenPHP will handle incoming requests in a few milliseconds.

Set the value of the FRANKENPHP_CONFIG environment variable to worker /path/to/your/worker/script.php:

docker run \
    -e FRANKENPHP_CONFIG="worker /app/path/to/your/worker/script.php" \
    -v $PWD:/app \
    -p 80:80 -p 443:443 -p 443:443/udp \
    dunglas/frankenphp

Use the --worker option of the php-server command to serve the content of the current directory using a worker:

./frankenphp php-server --worker /path/to/your/worker/script.php

If your PHP app is embeded in the binary, you can add a custom Caddyfile in the root directory of the app. It will be used automatically.

The worker mode of FrankenPHP is supported by the Symfony Runtime Component. To start any Symfony application in a worker, install the FrankenPHP package of PHP Runtime:

composer require runtime/frankenphp-symfony

Start your app server by defining the APP_RUNTIME environment variable to use the FrankenPHP Symfony Runtime:

docker run \
    -e FRANKENPHP_CONFIG="worker ./public/index.php" \
    -e APP_RUNTIME=Runtime\\FrankenPhpSymfony\\Runtime \
    -v $PWD:/app \
    -p 80:80 -p 443:443 -p 443:443/udp \
    dunglas/frankenphp

See the dedicated documentation.

The following example shows how to create your own worker script without relying on a third-party library:

<?php
// public/index.php

// Prevent worker script termination when a client connection is interrupted
ignore_user_abort(true);

// Boot your app
require __DIR__.'/vendor/autoload.php';

$myApp = new \App\Kernel();
$myApp->boot();

// Handler outside the loop for better performance (doing less work)
$handler = static function () use ($myApp) {
    // Called when a request is received,
    // superglobals, php://input and the like are reset
    echo $myApp->handle($_GET, $_POST, $_COOKIE, $_FILES, $_SERVER);
};

$maxRequests = (int)($_SERVER['MAX_REQUESTS'] ?? 0);
for ($nbRequests = 0; !$maxRequests || $nbRequests < $maxRequests; ++$nbRequests) {
    $keepRunning = \frankenphp_handle_request($handler);

    // Do something after sending the HTTP response
    $myApp->terminate();

    // Call the garbage collector to reduce the chances of it being triggered in the middle of a page generation
    gc_collect_cycles();

    if (!$keepRunning) break;
}

// Cleanup
$myApp->shutdown();

Then, start your app and use the FRANKENPHP_CONFIG environment variable to configure your worker:

docker run \
    -e FRANKENPHP_CONFIG="worker ./public/index.php" \
    -v $PWD:/app \
    -p 80:80 -p 443:443 -p 443:443/udp \
    dunglas/frankenphp

By default, 2 workers per CPU are started. You can also configure the number of workers to start:

docker run \
    -e FRANKENPHP_CONFIG="worker ./public/index.php 42" \
    -v $PWD:/app \
    -p 80:80 -p 443:443 -p 443:443/udp \
    dunglas/frankenphp

As PHP was not originally designed for long-running processes, there are still many libraries and legacy codes that leak memory. A workaround to using this type of code in worker mode is to restart the worker script after processing a certain number of requests:

The previous worker snippet allows configuring a maximum number of request to handle by setting an environment variable named MAX_REQUESTS.

If a worker script crashes with a non-zero exit code, FrankenPHP will restart it with an exponential backoff strategy. If the worker script stays up longer than the last backoff * 2, it will not penalize the worker script and restart it again. However, if the worker script continues to fail with a non-zero exit code in a short period of time (for example, having a typo in a script), FrankenPHP will crash with the error: too many consecutive failures.

PHP superglobals ($_SERVER, $_ENV, $_GET...) behave as follows:

• before the first call to frankenphp_handle_request(), superglobals contain values bound to the worker script itself
• during and after the call to frankenphp_handle_request(), superglobals contain values generated from the processed HTTP request, each call to frankenphp_handle_request() changes the superglobals values

To access the superglobals of the worker script inside the callback, you must copy them and import the copy in the scope of the callback:

<?php
// Copy worker's $_SERVER superglobal before the first call to frankenphp_handle_request()
$workerServer = $_SERVER;

$handler = static function () use ($workerServer) {
    var_dump($_SERVER); // Request-bound $_SERVER
    var_dump($workerServer); // $_SERVER of the worker script
};

// ...