Using FrankenPHP Workers

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 embedded in the binary, you can add a custom Caddyfile in the root directory of the app. It will be used automatically.

It’s also possible to restart the worker on file changes with the --watch option. The following command will trigger a restart if any file ending in .php in the /path/to/your/app/ directory or subdirectories is modified:

frankenphp php-server --worker /path/to/your/worker/script.php --watch "/path/to/your/app/**/*.php"

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
};

// ...