services.yaml

    App\Command\StateMachineDotCommand:
        autowire: false
        arguments:
            $configs: '%sm.configs%'
        tags:
          - { name: 'console.command', command: 'state-machine:dot' }

StateMachineDotCommand.php

<?php

namespace App\Command;

use RuntimeException;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;

class StateMachineDotCommand extends Command
{
    public const ARG_NAME = 'state-machine';
    public const OPT_RENDER = 'render';
    public const ARG_OUT_PATH = 'path';

    /**
     * @var array<string,mixed>
     */
    private array $configs;

    /**
     * @param array<string,mixed> $configs
     */
    public function __construct(array $configs)
    {
        parent::__construct();
        $this->configs = $configs;
    }

    protected function configure(): void
    {
        $this->setDescription('Generate a dot file (diagram) for a given state machine');
        $this->addArgument(self::ARG_NAME, InputArgument::REQUIRED, 'Name of state machine');
        $this->addArgument(self::ARG_OUT_PATH, InputArgument::REQUIRED, 'File to write dot file to');
    }

    protected function execute(InputInterface $input, OutputInterface $output): int
    {
        $name = $input->getArgument(self::ARG_NAME);
        $outPath = $input->getArgument(self::ARG_OUT_PATH);

        if (!isset($this->configs[$name])) {
            throw new RuntimeException(sprintf('Unknown state machine "%s", known state machines "%s"', $name, implode('", "', array_keys($this->configs))));
        }

        $config = $this->configs[$name];
        $generatedFile = $this->buildGraph($config);

        file_put_contents($outPath, $generatedFile);

        $output->writeln(sprintf('<comment>Written dot file to:</> %s', $outPath));
        $output->writeln(sprintf('<info>Generate a PNG (requires graphviz) with:</> dot %s -Tpng -o out.png', $outPath));

        return 0;
    }

    /**
     * @param array<string,mixed> $config
     */
    private function buildGraph(array $config): string
    {
        $out = [];
        $out[] = 'digraph {';

        foreach ($config['transitions'] ?? [] as $name => $transition) {
            foreach ((array) $transition['from'] as $from) {
                $label = [
                    sprintf('<i>%s</i>', $name),
                ];

                foreach ($this->callbacks($config, 'after', $name) as $callbackName => $callback) {
                    $label[] = sprintf('<font point-size="8" color="darkgreen">after: %s</font>', $callbackName);
                }
                foreach ($this->callbacks($config, 'before', $name) as $callbackName => $callback) {
                    $label[] = sprintf('<font point-size="8" color="darkblue">before: %s</font>', $callbackName);
                }

                $out[] = sprintf('  "%s"->"%s" [label=<%s>]', $from, $transition['to'], implode('<br/>', $label));
            }
        }
        $out[] = '}';

        return implode("\n", $out);
    }

    /**
     * @param array<string,mixed> $config
     *
     * @return array<string,mixed>
     */
    private function callbacks(array $config, string $type, string $transition): array
    {
        $callbacks = [];
        foreach ($config['callbacks'][$type] ?? [] as $name => $callback) {
            if (!isset($callback['on'])) {
                continue;
            }
            if (in_array($transition, (array) $callback['on'])) {
                $callbacks[(string) $name] = $callback;
            }
        }

        return $callbacks;
    }
}