Développer votre application autour du composant Workflow

Workflow as middleware

Created by Baptiste Leduc for AFSY 2019-07

Baptiste Leduc

1. Symfony Workflow

C'est quoi ?

Le composant workflow permet de définir un cycle de vie d'un objet.
Chaque étape du processus est appelée une place.

Les actions permettant de passer d'une (ou plusieurs) places à une autre (ou des autres) places via des transitions.
Pour passer une transition, il faut que votre objet soit dans toutes les places en amont.

Votre workflow, dans un YAML

workflow:
  workflows:
    pull_request:
      places: [opened, closed, needs_review, reviewed, merged]
      transitions:
        feedback:
          from: opened
          to:   needs_review
        review:
          from: [opened, needs_review]
          to:   reviewed
        merge:
          from: reviewed
          to:   merged
        close:
          from: [opened, needs_review, reviewed]
          to:   closed
					

Schema

2. Workflow as Middleware

Comment utiliser ça ?

Pour compléter notre Workflow orienté middleware, il nous manque deux choses:

• Subscriber : permet de déclencher vos actions lorsqu'une transition passe
• Action(s) : permet le lien entre votre transition et vos services

Votre YAML, avec des actions

workflow:
  workflows:
    pull_request:
      places:
        # ...
      metadata:
        actions:
          - 'Workflow\Action\Doctrine\Flush'
      transitions:
        merge:
          from: reviewed
          to:   merged
          metadata:
            actions:
              - 'Workflow\Action\PullRequest\Merge'
        # ...
					

Subscriber

    public function handleTransition(TransitionEvent $event)
    {
        $subject = $event->getSubject();
        $transition = $event->getTransition();
        $store = $event->getWorkflow()->getMetadataStore();

        $actions = array_merge(
            $store->getMetadata('actions', $transition) ?? [],
            $store->getMetadata('actions') ?? []
        );

        // Validation ~ Slide suivante 😉

        foreach ($actions as $action) {
            $actionObject = $this->actions[$action];
            $actionObject->transition($subject, $transition->getName());
        }
    }
					

Subscriber

Validation

        $data = $event->getContext()['data'];

        if ($data instanceof TransitionDataInterface) {
            $violations = $this->validator->validate($data, null, $transition->getName());
            if ($violations instanceof ConstraintViolationList && $violations->count() > 0) {
                throw new ValidationException($violations);
            }
        }
					

Subscriber

Configuration

    Workflow\Subscriber\WorkflowSubscriber:
        arguments:
            - !tagged workflow.action
            - '@Symfony\Component\Validator\Validator\ValidatorInterface'
					

    public function __construct(iterable $actions, ValidatorInterface $validator)
    {
        $array = [];
        foreach ($actions as $action) {
            $array[\get_class($action)] = $action;
        }
        $this->actions = $array;

        $this->validator = $validator;
    }
					

Action

Interface

interface ActionTransitionInterface
{
    public function transition(Entity $entity, string $transitionName);
}
					

Configuration

    _instanceof:
        Workflow\Action\ActionTransitionInterface:
            tags: ['workflow.action']
					

Action

Implémentation

class Merge implements ActionTransitionInterface
{
    public function transition(Entity $entity, string $transitionName)
    {
      // ma logique ici 👋
    }
}
					

class Flush implements ActionTransitionInterface
{
    public function transition(Entity $entity, string $transitionName)
    {
        $this->entityManager->persist($entity);
        $this->entityManager->flush();
    }
}
					

3. Aller plus loin...

Toujours plus !

Endpoint API

Votre ressource API Platform

							resources:
							  Entity\PullRequest:
							    itemOperations:
							      get: ~
							      transition:
							        method: 'PUT'
							        path: '/workflow/pull-request/{id}/{transition}'
							        controller: 'Controller\PullRequestTransition'
							        defaults:
							          _api_receive: false
					

Endpoint API

Votre controller

    public function applyTransition(Entity $entity, string $transitionName, Request $request, string $dataClass = null): WorkflowStoreInterface
    {
        $workflow = $this->workflows->get($entity);

        if (!$workflow->can($entity, $transition)) {
            throw new BadRequestHttpException('transition_failed');
        }

        if (null !== $dataClass) {
            $transitionData = $this->serializer->deserialize($request->getContent() ?: '{}', $dataClass, 'json');
        	$workflow->apply($entity, ['data' => $transitionData]);
        } else {
            $workflow->apply($entity);
        }

        return $entity;
    }
					

Endpoint API

Votre vrai controller

class PullRequestTransition extends WorkflowController
{
    public function __invoke(Request $request, PullRequest $pullRequest, string $transition)
    {
        return $this->applyTransition(
          $pullRequest,
          $transition,
          $request,
          PullRequestTransitionData::class
        );
    }
}
					

Audit trail

    private function transitionHistory(Event $event)
    {
        $subject = $event->getSubject();

        $entry = new TransitionEntry();
        $entry->setWorkflow($event->getWorkflow()->getName());
        $entry->setSubject($workflowSubject);
        $entry->setClass(\get_class($workflowSubject));
        $entry->setReference($workflowSubject->getId() ?? 0);
        $entry->setTransition($event->getTransition()->getName());
        $entry->setAdmin('system');
        $entry->setDate(new \DateTime());

        $entry->setPreviousMarking($this->rebuildPreviousMarking($event));
        $entry->setNextMarking($workflowSubject->getMarking());

        $this->entityManager->persist($entry);
    }
					

4. Conclusion

workflow:
  workflows:
    order:
      metadata:
        actions:
          - 'Workflow\Action\Doctrine\Flush'
      transitions:
        pay:
          from: [with_billing, with_shipping, with_user]
          to:   paid
          metadata:
            actions:
              - 'Workflow\Action\Order\DoPayment'
              - 'Workflow\Action\Order\IsPreorder'
              - 'Workflow\Action\Order\IsFirstOrder'
              - 'Workflow\Action\Order\Invoice\Create'
              - 'Workflow\Action\Order\Invoice\Pdf'
              - 'Workflow\Action\Order\SendValidationEmail'
						

5. Merci ! 🎉

6. Questions ?