Add workflow to a service dynamically in Symfony 6.3

Question

The Symfony 6.3 docs state concerning the workflow registry:

Beware that injecting the Registry into your services is not recommended.

However, I need to get a specific workflow within a service method which decides which workflow to use based on a key. I don't know in advance which workflow to load, so I can't inject a specific workflow. How can I do this? For now, I inject the registry. Could I somehow inject the service_container and get it from there later?

Answer 1

For Symfony 6.4 +

This works around what is probably a bug, namely that when you load a Workflow with a serviceLocator, it's key will be prefixed with 'debug.' and the returned type is TraceableWorkflow. You can adjust this to your environment needs.

use Symfony\Component\HttpKernel\KernelInterface;
use Psr\Container\ContainerExceptionInterface;
use Psr\Container\ContainerInterface;
use Psr\Container\NotFoundExceptionInterface;
use RuntimeException;
use Symfony\Component\DependencyInjection\Attribute\TaggedLocator;
use Symfony\Component\Workflow\WorkflowInterface;

class WorkflowLoader
{
    public function __construct(
        private readonly KernelInterface $kernel,
        #[TaggedLocator('workflow')] private readonly ContainerInterface $serviceLocator
    )
    {
    }

    public function getWorkflow($workflowName): WorkflowInterface
    {
        $prefix = '';
        if ($this->kernel->isDebug()) {
            $prefix = 'debug.';
        }
        try {
            if (!$workflow = $this->serviceLocator->get($prefix . 'state_machine.' . $workflowName)) {
                $workflow = $this->serviceLocator->get($prefix . 'workflow.' . $workflowName);
            }
        } catch (NotFoundExceptionInterface|ContainerExceptionInterface $e) {
            throw new RuntimeException("Process Workflow $workflowName could not be loaded." . PHP_EOL . $e->getMessage());
        }
        return $workflow;
    }
}