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Workflow

Using the Workflow component inside a Symfony application requires knowing first some basic theory and concepts about workflows and state machines. :doc:`Read this article </workflow/workflow-and-state-machine>` for a quick overview.

Installation

In applications using :ref:`Symfony Flex <symfony-flex>`, run this command to install the workflow feature before using it:

$ composer require symfony/workflow

Configuration

To see all configuration options, if you are using the component inside a Symfony project run this command:

$ php bin/console config:dump-reference framework workflows

Creating a Workflow

A workflow is a process or a lifecycle that your objects go through. Each step or stage in the process is called a place. You also define transitions, which describe the action needed to get from one place to another.

An example state diagram for a workflow, showing transitions and places.

A set of places and transitions creates a definition. A workflow needs a Definition and a way to write the states to the objects (i.e. an instance of a :class:`Symfony\\Component\\Workflow\\MarkingStore\\MarkingStoreInterface`.)

Consider the following example for a blog post. A post can have these places: draft, reviewed, rejected, published. You could define the workflow as follows:

.. configuration-block::

    .. code-block:: yaml

        # config/packages/workflow.yaml
        framework:
            workflows:
                blog_publishing:
                    type: 'workflow' # or 'state_machine'
                    audit_trail:
                        enabled: true
                    marking_store:
                        type: 'method'
                        property: 'currentPlace'
                    supports:
                        - App\Entity\BlogPost
                    initial_marking: draft
                    places:          # defining places manually is optional
                        - draft
                        - reviewed
                        - rejected
                        - published
                    transitions:
                        to_review:
                            from: draft
                            to:   reviewed
                        publish:
                            from: reviewed
                            to:   published
                        reject:
                            from: reviewed
                            to:   rejected

    .. code-block:: xml

        <!-- config/packages/workflow.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
            https://symfony.com/schema/dic/services/services-1.0.xsd
            http://symfony.com/schema/dic/symfony
            https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <!-- or type="state_machine" -->
                <framework:workflow name="blog_publishing" type="workflow">
                    <framework:audit-trail enabled="true"/>
                    <framework:marking-store type="single_state">
                        <framework:argument>currentPlace</framework:argument>
                    </framework:marking-store>
                    <framework:support>App\Entity\BlogPost</framework:support>
                    <framework:initial-marking>draft</framework:initial-marking>

                    <!-- defining places manually is optional -->
                    <framework:place>draft</framework:place>
                    <framework:place>reviewed</framework:place>
                    <framework:place>rejected</framework:place>
                    <framework:place>published</framework:place>

                    <framework:transition name="to_review">
                        <framework:from>draft</framework:from>
                        <framework:to>reviewed</framework:to>
                    </framework:transition>
                    <framework:transition name="publish">
                        <framework:from>reviewed</framework:from>
                        <framework:to>published</framework:to>
                    </framework:transition>
                    <framework:transition name="reject">
                        <framework:from>reviewed</framework:from>
                        <framework:to>rejected</framework:to>
                    </framework:transition>
                </framework:workflow>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/workflow.php
        use App\Entity\BlogPost;
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            $blogPublishing = $framework->workflows()->workflows('blog_publishing');
            $blogPublishing
                ->type('workflow') // or 'state_machine'
                ->supports([BlogPost::class])
                ->initialMarking(['draft']);

            $blogPublishing->auditTrail()->enabled(true);
            $blogPublishing->markingStore()
                ->type('method')
                ->property('currentPlace');

            // defining places manually is optional
            $blogPublishing->place()->name('draft');
            $blogPublishing->place()->name('reviewed');
            $blogPublishing->place()->name('rejected');
            $blogPublishing->place()->name('published');

            $blogPublishing->transition()
                ->name('to_review')
                    ->from(['draft'])
                    ->to(['reviewed']);

            $blogPublishing->transition()
                ->name('publish')
                    ->from(['reviewed'])
                    ->to(['published']);

            $blogPublishing->transition()
                ->name('reject')
                    ->from(['reviewed'])
                    ->to(['rejected']);
        };

Tip

If you are creating your first workflows, consider using the workflow:dump command to :doc:`debug the workflow contents </workflow/dumping-workflows>`.

Tip

You can use PHP constants in YAML files via the !php/const `` notation. E.g. you can use ``!php/const App\Entity\BlogPost::STATE_DRAFT instead of 'draft' or !php/const App\Entity\BlogPost::TRANSITION_TO_REVIEW instead of 'to_review'.

Tip

You can omit the places option if your transitions define all the places that are used in the workflow. Symfony will automatically extract the places from the transitions.

.. versionadded:: 7.1

    The support for omitting the ``places`` option was introduced in
    Symfony 7.1.

The configured property will be used via its implemented getter/setter methods by the marking store:

// src/Entity/BlogPost.php
namespace App\Entity;

class BlogPost
{
    // the configured marking store property must be declared
    private string $currentPlace;
    private string $title;
    private string $content;

    // getter/setter methods must exist for property access by the marking store
    public function getCurrentPlace(): string
    {
        return $this->currentPlace;
    }

    public function setCurrentPlace(string $currentPlace, array $context = []): void
    {
        $this->currentPlace = $currentPlace;
    }

    // you don't need to set the initial marking in the constructor or any other method;
    // this is configured in the workflow with the 'initial_marking' option
}

It is also possible to use public properties for the marking store. The above class would become the following:

// src/Entity/BlogPost.php
namespace App\Entity;

class BlogPost
{
    // the configured marking store property must be declared
    public string $currentPlace;
    public string $title;
    public string $content;
}

When using public properties, context is not supported. In order to support it, you must declare a setter to write your property:

// src/Entity/BlogPost.php
namespace App\Entity;

class BlogPost
{
    public string $currentPlace;
    // ...

    public function setCurrentPlace(string $currentPlace, array $context = []): void
    {
        // assign the property and do something with the context
    }
}

Note

The marking store type could be "multiple_state" or "single_state". A single state marking store does not support a model being on multiple places at the same time. This means a "workflow" must use a "multiple_state" marking store and a "state_machine" must use a "single_state" marking store. Symfony configures the marking store according to the "type" by default, so it's preferable to not configure it.

A single state marking store uses a string to store the data. A multiple state marking store uses an array to store the data. If no state marking store is defined you have to return null in both cases (e.g. the above example should define a return type like App\Entity\BlogPost::getCurrentPlace(): ?array or like App\Entity\BlogPost::getCurrentPlace(): ?string).

Tip

The marking_store.type (the default value depends on the type value) and property (default value ['marking']) attributes of the marking_store option are optional. If omitted, their default values will be used. It's highly recommended to use the default value.

Tip

Setting the audit_trail.enabled option to true makes the application generate detailed log messages for the workflow activity.

With this workflow named blog_publishing, you can get help to decide what actions are allowed on a blog post:

use App\Entity\BlogPost;
use Symfony\Component\Workflow\Exception\LogicException;

$post = new BlogPost();
// you don't need to set the initial marking with code; this is configured
// in the workflow with the 'initial_marking' option

$workflow = $this->container->get('workflow.blog_publishing');
$workflow->can($post, 'publish'); // False
$workflow->can($post, 'to_review'); // True

// Update the currentState on the post
try {
    $workflow->apply($post, 'to_review');
} catch (LogicException $exception) {
    // ...
}

// See all the available transitions for the post in the current state
$transitions = $workflow->getEnabledTransitions($post);
// See a specific available transition for the post in the current state
$transition = $workflow->getEnabledTransition($post, 'publish');

Using a multiple state marking store

If you are creating a :doc:`workflow </workflow/workflow-and-state-machine>`, your marking store may need to contain multiple places at the same time. That's why, if you are using Doctrine, the matching column definition should use the type json:

// src/Entity/BlogPost.php
namespace App\Entity;

use Doctrine\DBAL\Types\Types;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity]
class BlogPost
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private int $id;

    #[ORM\Column(type: Types::JSON)]
    private array $currentPlaces;

    // ...
}

Caution!

You should not use the type simple_array for your marking store. Inside a multiple state marking store, places are stored as keys with a value of one, such as ['draft' => 1]. If the marking store contains only one place, this Doctrine type will store its value only as a string, resulting in the loss of the object's current place.

Accessing the Workflow in a Class

You can use the workflow inside a class by using :doc:`service autowiring </service_container/autowiring>` and using camelCased workflow name + Workflow as parameter name. If it is a state machine type, use camelCased workflow name + StateMachine:

use App\Entity\BlogPost;
use Symfony\Component\Workflow\WorkflowInterface;

class MyClass
{
    public function __construct(
        // Symfony will inject the 'blog_publishing' workflow configured before
        private WorkflowInterface $blogPublishingWorkflow,
    ) {
    }

    public function toReview(BlogPost $post): void
    {
        // Update the currentState on the post
        try {
            $this->blogPublishingWorkflow->apply($post, 'to_review');
        } catch (LogicException $exception) {
            // ...
        }
        // ...
    }
}

To get the enabled transition of a Workflow, you can use :method:`Symfony\\Component\\Workflow\\WorkflowInterface::getEnabledTransition` method.

.. versionadded:: 7.1

    The :method:`Symfony\\Component\\Workflow\\WorkflowInterface::getEnabledTransition`
    method was introduced in Symfony 7.1.

Workflows can also be injected thanks to their name and the :class:`Symfony\\Component\\DependencyInjection\\Attribute\\Target` attribute:

use App\Entity\BlogPost;
use Symfony\Component\DependencyInjection\Attribute\Target;
use Symfony\Component\Workflow\WorkflowInterface;

class MyClass
{
    public function __construct(
        #[Target('blog_publishing')]
        private WorkflowInterface $workflow
    ) {
    }

    // ...
}

This allows you to decorrelate the argument name of any implementation name.

Tip

If you want to retrieve all workflows, for documentation purposes for example, you can :doc:`inject all services </service_container/service_subscribers_locators>` with the following tag:

  • workflow: all workflows and all state machine;
  • workflow.workflow: all workflows;
  • workflow.state_machine: all state machines.

Note that workflow metadata are attached to tags under the metadata key, giving you more context and information about the workflow at disposal. Learn more about :ref:`tag attributes <tags_additional-attributes>` and :ref:`storing workflow metadata <workflow_storing-metadata>`.

.. versionadded:: 7.1

    The attached configuration to the tag was introduced in Symfony 7.1.

Tip

You can find the list of available workflow services with the php bin/console debug:autowiring workflow command.

Using Events

To make your workflows more flexible, you can construct the Workflow object with an EventDispatcher. You can now create event listeners to block transitions (i.e. depending on the data in the blog post) and do additional actions when a workflow operation happened (e.g. sending announcements).

Each step has three events that are fired in order:

  • An event for every workflow;
  • An event for the workflow concerned;
  • An event for the workflow concerned with the specific transition or place name.

When a state transition is initiated, the events are dispatched in the following order:

workflow.guard

Validate whether the transition is blocked or not (see :ref:`guard events <workflow-usage-guard-events>` and :ref:`blocking transitions <workflow-blocking-transitions>`).

The three events being dispatched are:

  • workflow.guard
  • workflow.[workflow name].guard
  • workflow.[workflow name].guard.[transition name]
workflow.leave

The subject is about to leave a place.

The three events being dispatched are:

  • workflow.leave
  • workflow.[workflow name].leave
  • workflow.[workflow name].leave.[place name]
workflow.transition

The subject is going through this transition.

The three events being dispatched are:

  • workflow.transition
  • workflow.[workflow name].transition
  • workflow.[workflow name].transition.[transition name]
workflow.enter

The subject is about to enter a new place. This event is triggered right before the subject places are updated, which means that the marking of the subject is not yet updated with the new places.

The three events being dispatched are:

  • workflow.enter
  • workflow.[workflow name].enter
  • workflow.[workflow name].enter.[place name]
workflow.entered

The subject has entered in the places and the marking is updated.

The three events being dispatched are:

  • workflow.entered
  • workflow.[workflow name].entered
  • workflow.[workflow name].entered.[place name]
workflow.completed

The object has completed this transition.

The three events being dispatched are:

  • workflow.completed
  • workflow.[workflow name].completed
  • workflow.[workflow name].completed.[transition name]
workflow.announce

Triggered for each transition that now is accessible for the subject.

The three events being dispatched are:

  • workflow.announce
  • workflow.[workflow name].announce
  • workflow.[workflow name].announce.[transition name]

After a transition is applied, the announce event tests for all available transitions. That will trigger all :ref:`guard events <workflow-usage-guard-events>` once more, which could impact performance if they include intensive CPU or database workloads.

If you don't need the announce event, disable it using the context:

$workflow->apply($subject, $transitionName, [Workflow::DISABLE_ANNOUNCE_EVENT => true]);

Note

The leaving and entering events are triggered even for transitions that stay in the same place.

Note

If you initialize the marking by calling $workflow->getMarking($object);, then the workflow.[workflow_name].entered.[initial_place_name] event will be called with the default context (Workflow::DEFAULT_INITIAL_CONTEXT).

Here is an example of how to enable logging for every time a "blog_publishing" workflow leaves a place:

// src/App/EventSubscriber/WorkflowLoggerSubscriber.php
namespace App\EventSubscriber;

use Psr\Log\LoggerInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\Workflow\Event\Event;
use Symfony\Component\Workflow\Event\LeaveEvent;

class WorkflowLoggerSubscriber implements EventSubscriberInterface
{
    public function __construct(
        private LoggerInterface $logger,
    ) {
    }

    public function onLeave(Event $event): void
    {
        $this->logger->alert(sprintf(
            'Blog post (id: "%s") performed transition "%s" from "%s" to "%s"',
            $event->getSubject()->getId(),
            $event->getTransition()->getName(),
            implode(', ', array_keys($event->getMarking()->getPlaces())),
            implode(', ', $event->getTransition()->getTos())
        ));
    }

    public static function getSubscribedEvents(): array
    {
        return [
            LeaveEvent::getName('blog_publishing') => 'onLeave',
            // if you prefer, you can write the event name manually like this:
            // 'workflow.blog_publishing.leave' => 'onLeave',
        ];
    }
}

Tip

All built-in workflow events define the getName(?string $workflowName, ?string $transitionOrPlaceName) method to build the full event name without having to deal with strings. You can also use this method in your custom events via the :class:`Symfony\\Component\\Workflow\\Event\\EventNameTrait`.

.. versionadded:: 7.1

    The ``getName()`` method was introduced in Symfony 7.1.

If some listeners update the context during a transition, you can retrieve it via the marking:

$marking = $workflow->apply($post, 'to_review');

// contains the new value
$marking->getContext();

It is also possible to listen to these events by declaring event listeners with the following attributes:

These attributes do work like the :class:`Symfony\\Component\\EventDispatcher\\Attribute\\AsEventListener` attributes:

class ArticleWorkflowEventListener
{
    #[AsTransitionListener(workflow: 'my-workflow', transition: 'published')]
    public function onPublishedTransition(TransitionEvent $event): void
    {
        // ...
    }

    // ...
}

You may refer to the documentation about :ref:`defining event listeners with PHP attributes <event-dispatcher_event-listener-attributes>` for further use.

Guard Events

There are special types of events called "Guard events". Their event listeners are invoked every time a call to Workflow::can(), Workflow::apply() or Workflow::getEnabledTransitions() is executed. With the guard events you may add custom logic to decide which transitions should be blocked or not. Here is a list of the guard event names.

  • workflow.guard
  • workflow.[workflow name].guard
  • workflow.[workflow name].guard.[transition name]

This example stops any blog post being transitioned to "reviewed" if it is missing a title:

// src/App/EventSubscriber/BlogPostReviewSubscriber.php
namespace App\EventSubscriber;

use App\Entity\BlogPost;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\Workflow\Event\GuardEvent;

class BlogPostReviewSubscriber implements EventSubscriberInterface
{
    public function guardReview(GuardEvent $event): void
    {
        /** @var BlogPost $post */
        $post = $event->getSubject();
        $title = $post->title;

        if (empty($title)) {
            $event->setBlocked(true, 'This blog post cannot be marked as reviewed because it has no title.');
        }
    }

    public static function getSubscribedEvents(): array
    {
        return [
            'workflow.blog_publishing.guard.to_review' => ['guardReview'],
        ];
    }
}

Choosing which Events to Dispatch

If you prefer to control which events are fired when performing each transition, use the events_to_dispatch configuration option. This option does not apply to :ref:`Guard events <workflow-usage-guard-events>`, which are always fired:

.. configuration-block::

    .. code-block:: yaml

        # config/packages/workflow.yaml
        framework:
            workflows:
                blog_publishing:
                    # you can pass one or more event names
                    events_to_dispatch: ['workflow.leave', 'workflow.completed']

                    # pass an empty array to not dispatch any event
                    events_to_dispatch: []

                    # ...

    .. code-block:: xml

        <!-- config/packages/workflow.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd"
        >
            <framework:config>
                <framework:workflow name="blog_publishing">
                    <!-- you can pass one or more event names -->
                    <framework:event-to-dispatch>workflow.leave</framework:event-to-dispatch>
                    <framework:event-to-dispatch>workflow.completed</framework:event-to-dispatch>

                    <!-- pass an empty array to not dispatch any event -->
                    <framework:event-to-dispatch></framework:event-to-dispatch>

                    <!-- ... -->
                </framework:workflow>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/workflow.php
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            // ...

            $blogPublishing = $framework->workflows()->workflows('blog_publishing');

            // ...
            // you can pass one or more event names
            $blogPublishing->eventsToDispatch([
                'workflow.leave',
                'workflow.completed',
            ]);

            // pass an empty array to not dispatch any event
            $blogPublishing->eventsToDispatch([]);

            // ...
        };

You can also disable a specific event from being fired when applying a transition:

use App\Entity\BlogPost;
use Symfony\Component\Workflow\Exception\LogicException;

$post = new BlogPost();

$workflow = $this->container->get('workflow.blog_publishing');

try {
    $workflow->apply($post, 'to_review', [
        Workflow::DISABLE_ANNOUNCE_EVENT => true,
        Workflow::DISABLE_LEAVE_EVENT => true,
    ]);
} catch (LogicException $exception) {
    // ...
}

Disabling an event for a specific transition will take precedence over any events specified in the workflow configuration. In the above example the workflow.leave event will not be fired, even if it has been specified as an event to be dispatched for all transitions in the workflow configuration.

These are all the available constants:

  • Workflow::DISABLE_LEAVE_EVENT
  • Workflow::DISABLE_TRANSITION_EVENT
  • Workflow::DISABLE_ENTER_EVENT
  • Workflow::DISABLE_ENTERED_EVENT
  • Workflow::DISABLE_COMPLETED_EVENT

Event Methods

Each workflow event is an instance of :class:`Symfony\\Component\\Workflow\\Event\\Event`. This means that each event has access to the following information:

:method:`Symfony\\Component\\Workflow\\Event\\Event::getMarking`
Returns the :class:`Symfony\\Component\\Workflow\\Marking` of the workflow.
:method:`Symfony\\Component\\Workflow\\Event\\Event::getSubject`
Returns the object that dispatches the event.
:method:`Symfony\\Component\\Workflow\\Event\\Event::getTransition`
Returns the :class:`Symfony\\Component\\Workflow\\Transition` that dispatches the event.
:method:`Symfony\\Component\\Workflow\\Event\\Event::getWorkflowName`
Returns a string with the name of the workflow that triggered the event.
:method:`Symfony\\Component\\Workflow\\Event\\Event::getMetadata`
Returns a metadata.

For Guard Events, there is an extended :class:`Symfony\\Component\\Workflow\\Event\\GuardEvent` class. This class has these additional methods:

:method:`Symfony\\Component\\Workflow\\Event\\GuardEvent::isBlocked`
Returns if transition is blocked.
:method:`Symfony\\Component\\Workflow\\Event\\GuardEvent::setBlocked`
Sets the blocked value.
:method:`Symfony\\Component\\Workflow\\Event\\GuardEvent::getTransitionBlockerList`
Returns the event :class:`Symfony\\Component\\Workflow\\TransitionBlockerList`. See :ref:`blocking transitions <workflow-blocking-transitions>`.
:method:`Symfony\\Component\\Workflow\\Event\\GuardEvent::addTransitionBlocker`
Add a :class:`Symfony\\Component\\Workflow\\TransitionBlocker` instance.

Blocking Transitions

The execution of the workflow can be controlled by calling custom logic to decide if the current transition is blocked or allowed before applying it. This feature is provided by "guards", which can be used in two ways.

First, you can listen to :ref:`the guard events <workflow-usage-guard-events>`. Alternatively, you can define a guard configuration option for the transition. The value of this option is any valid expression created with the :doc:`ExpressionLanguage component </components/expression_language>`:

.. configuration-block::

    .. code-block:: yaml

        # config/packages/workflow.yaml
        framework:
            workflows:
                blog_publishing:
                    # previous configuration
                    transitions:
                        to_review:
                            # the transition is allowed only if the current user has the ROLE_REVIEWER role.
                            guard: "is_granted('ROLE_REVIEWER')"
                            from: draft
                            to:   reviewed
                        publish:
                            # or "is_anonymous", "is_remember_me", "is_fully_authenticated", "is_granted", "is_valid"
                            guard: "is_authenticated"
                            from: reviewed
                            to:   published
                        reject:
                            # or any valid expression language with "subject" referring to the supported object
                            guard: "is_granted('ROLE_ADMIN') and subject.isRejectable()"
                            from: reviewed
                            to:   rejected

    .. code-block:: xml

        <!-- config/packages/workflow.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
            https://symfony.com/schema/dic/services/services-1.0.xsd
            http://symfony.com/schema/dic/symfony
            https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <framework:workflow name="blog_publishing" type="workflow">

                    <!-- ... previous configuration -->

                    <framework:transition name="to_review">
                        <!-- the transition is allowed only if the current user has the ROLE_REVIEWER role. -->
                        <framework:guard>is_granted("ROLE_REVIEWER")</framework:guard>
                        <framework:from>draft</framework:from>
                        <framework:to>reviewed</framework:to>
                    </framework:transition>

                    <framework:transition name="publish">
                        <!-- or "is_anonymous", "is_remember_me", "is_fully_authenticated", "is_granted" -->
                        <framework:guard>is_authenticated</framework:guard>
                        <framework:from>reviewed</framework:from>
                        <framework:to>published</framework:to>
                    </framework:transition>

                    <framework:transition name="reject">
                        <!-- or any valid expression language with "subject" referring to the post -->
                        <framework:guard>is_granted("ROLE_ADMIN") and subject.isStatusReviewed()</framework:guard>
                        <framework:from>reviewed</framework:from>
                        <framework:to>rejected</framework:to>
                    </framework:transition>

                </framework:workflow>

            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/workflow.php
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            $blogPublishing = $framework->workflows()->workflows('blog_publishing');
            // ... previous configuration

            $blogPublishing->transition()
                ->name('to_review')
                    // the transition is allowed only if the current user has the ROLE_REVIEWER role.
                    ->guard('is_granted("ROLE_REVIEWER")')
                    ->from(['draft'])
                    ->to(['reviewed']);

            $blogPublishing->transition()
                ->name('publish')
                    // or "is_anonymous", "is_remember_me", "is_fully_authenticated", "is_granted"
                    ->guard('is_authenticated')
                    ->from(['reviewed'])
                    ->to(['published']);

            $blogPublishing->transition()
                ->name('reject')
                    // or any valid expression language with "subject" referring to the post
                    ->guard('is_granted("ROLE_ADMIN") and subject.isStatusReviewed()')
                    ->from(['reviewed'])
                    ->to(['rejected']);
        };

You can also use transition blockers to block and return a user-friendly error message when you stop a transition from happening. In the example we get this message from the :class:`Symfony\\Component\\Workflow\\Event\\Event`'s metadata, giving you a central place to manage the text.

This example has been simplified; in production you may prefer to use the :doc:`Translation </translation>` component to manage messages in one place:

// src/App/EventSubscriber/BlogPostPublishSubscriber.php
namespace App\EventSubscriber;

use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\Workflow\Event\GuardEvent;
use Symfony\Component\Workflow\TransitionBlocker;

class BlogPostPublishSubscriber implements EventSubscriberInterface
{
    public function guardPublish(GuardEvent $event): void
    {
        $eventTransition = $event->getTransition();
        $hourLimit = $event->getMetadata('hour_limit', $eventTransition);

        if (date('H') <= $hourLimit) {
            return;
        }

        // Block the transition "publish" if it is more than 8 PM
        // with the message for end user
        $explanation = $event->getMetadata('explanation', $eventTransition);
        $event->addTransitionBlocker(new TransitionBlocker($explanation , '0'));
    }

    public static function getSubscribedEvents(): array
    {
        return [
            'workflow.blog_publishing.guard.publish' => ['guardPublish'],
        ];
    }
}

Creating Your Own Marking Store

You may need to implement your own store to execute some additional logic when the marking is updated. For example, you may have some specific needs to store the marking on certain workflows. To do this, you need to implement the :class:`Symfony\\Component\\Workflow\\MarkingStore\\MarkingStoreInterface`:

namespace App\Workflow\MarkingStore;

use Symfony\Component\Workflow\Marking;
use Symfony\Component\Workflow\MarkingStore\MarkingStoreInterface;

final class BlogPostMarkingStore implements MarkingStoreInterface
{
    /**
     * @param BlogPost $subject
     */
    public function getMarking(object $subject): Marking
    {
        return new Marking([$subject->getCurrentPlace() => 1]);
    }

    /**
     * @param BlogPost $subject
     */
    public function setMarking(object $subject, Marking $marking, array $context = []): void
    {
        $marking = key($marking->getPlaces());
        $subject->setCurrentPlace($marking);
    }
}

Once your marking store is implemented, you can configure your workflow to use it:

.. configuration-block::

    .. code-block:: yaml

        # config/packages/workflow.yaml
        framework:
            workflows:
                blog_publishing:
                    # ...
                    marking_store:
                        service: 'App\Workflow\MarkingStore\BlogPostMarkingStore'

    .. code-block:: xml

        <!-- config/packages/workflow.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd"
        >
            <framework:config>
                <framework:workflow name="blog_publishing">
                    <!-- ... -->
                    <framework:marking-store service="App\Workflow\MarkingStore\BlogPostMarkingStore"/>
                </framework:workflow>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/workflow.php
        use App\Workflow\MarkingStore\ReflectionMarkingStore;
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            // ...

            $blogPublishing = $framework->workflows()->workflows('blog_publishing');
            // ...

            $blogPublishing->markingStore()
                ->service(BlogPostMarkingStore::class);
        };

Usage in Twig

Symfony defines several Twig functions to manage workflows and reduce the need of domain logic in your templates:

workflow_can()
Returns true if the given object can make the given transition.
workflow_transitions()
Returns an array with all the transitions enabled for the given object.
workflow_transition()
Returns a specific transition enabled for the given object and transition name.
workflow_marked_places()
Returns an array with the place names of the given marking.
workflow_has_marked_place()
Returns true if the marking of the given object has the given state.
workflow_transition_blockers()
Returns :class:`Symfony\\Component\\Workflow\\TransitionBlockerList` for the given transition.

The following example shows these functions in action:

<h3>Actions on Blog Post</h3>
{% if workflow_can(post, 'publish') %}
    <a href="...">Publish</a>
{% endif %}
{% if workflow_can(post, 'to_review') %}
    <a href="...">Submit to review</a>
{% endif %}
{% if workflow_can(post, 'reject') %}
    <a href="...">Reject</a>
{% endif %}

{# Or loop through the enabled transitions #}
{% for transition in workflow_transitions(post) %}
    <a href="...">{{ transition.name }}</a>
{% else %}
    No actions available.
{% endfor %}

{# Check if the object is in some specific place #}
{% if workflow_has_marked_place(post, 'reviewed') %}
    <p>This post is ready for review.</p>
{% endif %}

{# Check if some place has been marked on the object #}
{% if 'reviewed' in workflow_marked_places(post) %}
    <span class="label">Reviewed</span>
{% endif %}

{# Loop through the transition blockers #}
{% for blocker in workflow_transition_blockers(post, 'publish') %}
    <span class="error">{{ blocker.message }}</span>
{% endfor %}

Storing Metadata

In case you need it, you can store arbitrary metadata in workflows, their places, and their transitions using the metadata option. This metadata can be only the title of the workflow or very complex objects:

.. configuration-block::

    .. code-block:: yaml

        # config/packages/workflow.yaml
        framework:
            workflows:
                blog_publishing:
                    metadata:
                        title: 'Blog Publishing Workflow'
                    # ...
                    places:
                        draft:
                            metadata:
                                max_num_of_words: 500
                        # ...
                    transitions:
                        to_review:
                            from: draft
                            to:   review
                            metadata:
                                priority: 0.5
                        publish:
                            from: reviewed
                            to:   published
                            metadata:
                                hour_limit: 20
                                explanation: 'You can not publish after 8 PM.'

    .. code-block:: xml

        <!-- config/packages/workflow.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd"
        >
            <framework:config>
                <framework:workflow name="blog_publishing">
                    <framework:metadata>
                        <framework:title>Blog Publishing Workflow</framework:title>
                    </framework:metadata>
                    <!-- ... -->
                    <framework:place name="draft">
                        <framework:metadata>
                            <framework:max-num-of-words>500</framework:max-num-of-words>
                        </framework:metadata>
                    </framework:place>
                    <!-- ... -->
                    <framework:transition name="to_review">
                        <framework:from>draft</framework:from>
                        <framework:to>review</framework:to>
                        <framework:metadata>
                            <framework:priority>0.5</framework:priority>
                        </framework:metadata>
                    </framework:transition>
                    <framework:transition name="publish">
                        <framework:from>reviewed</framework:from>
                        <framework:to>published</framework:to>
                        <framework:metadata>
                            <framework:hour_limit>20</framework:hour_limit>
                            <framework:explanation>You can not publish after 8 PM.</framework:explanation>
                        </framework:metadata>
                    </framework:transition>
                </framework:workflow>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/workflow.php
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            $blogPublishing = $framework->workflows()->workflows('blog_publishing');
            // ... previous configuration

            $blogPublishing->metadata([
                'title' => 'Blog Publishing Workflow'
            ]);

            // ...

            $blogPublishing->place()
                ->name('draft')
                ->metadata([
                    'max_num_of_words' => 500,
                ]);

            // ...

            $blogPublishing->transition()
                ->name('to_review')
                    ->from(['draft'])
                    ->to(['reviewed'])
                    ->metadata([
                        'priority' => 0.5,
                    ]);

            $blogPublishing->transition()
                ->name('publish')
                    ->from(['reviewed'])
                    ->to(['published'])
                    ->metadata([
                        'hour_limit' => 20,
                        'explanation' => 'You can not publish after 8 PM.',
                    ]);
        };

Then you can access this metadata in your controller as follows:

// src/App/Controller/BlogPostController.php
use App\Entity\BlogPost;
use Symfony\Component\Workflow\WorkflowInterface;
// ...

public function myAction(WorkflowInterface $blogPublishingWorkflow, BlogPost $post): Response
{
    $title = $blogPublishingWorkflow
        ->getMetadataStore()
        ->getWorkflowMetadata()['title'] ?? 'Default title'
    ;

    $maxNumOfWords = $blogPublishingWorkflow
        ->getMetadataStore()
        ->getPlaceMetadata('draft')['max_num_of_words'] ?? 500
    ;

    $aTransition = $blogPublishingWorkflow->getDefinition()->getTransitions()[0];
    $priority = $blogPublishingWorkflow
        ->getMetadataStore()
        ->getTransitionMetadata($aTransition)['priority'] ?? 0
    ;

    // ...
}

There is a getMetadata() method that works with all kinds of metadata:

// get "workflow metadata" passing the metadata key as argument
$title = $workflow->getMetadataStore()->getMetadata('title');

// get "place metadata" passing the metadata key as the first argument and the place name as the second argument
$maxNumOfWords = $workflow->getMetadataStore()->getMetadata('max_num_of_words', 'draft');

// get "transition metadata" passing the metadata key as the first argument and a Transition object as the second argument
$priority = $workflow->getMetadataStore()->getMetadata('priority', $aTransition);

In a :ref:`flash message <flash-messages>` in your controller:

// $transition = ...; (an instance of Transition)

// $workflow is an injected Workflow instance
$title = $workflow->getMetadataStore()->getMetadata('title', $transition);
$this->addFlash('info', "You have successfully applied the transition with title: '$title'");

Metadata can also be accessed in a Listener, from the :class:`Symfony\\Component\\Workflow\\Event\\Event` object.

In Twig templates, metadata is available via the workflow_metadata() function:

<h2>Metadata of Blog Post</h2>
<p>
    <strong>Workflow</strong>:<br>
    <code>{{ workflow_metadata(blog_post, 'title') }}</code>
</p>
<p>
    <strong>Current place(s)</strong>
    <ul>
        {% for place in workflow_marked_places(blog_post) %}
            <li>
                {{ place }}:
                <code>{{ workflow_metadata(blog_post, 'max_num_of_words', place) ?: 'Unlimited'}}</code>
            </li>
        {% endfor %}
    </ul>
</p>
<p>
    <strong>Enabled transition(s)</strong>
    <ul>
        {% for transition in workflow_transitions(blog_post) %}
            <li>
                {{ transition.name }}:
                <code>{{ workflow_metadata(blog_post, 'priority', transition) ?: 0 }}</code>
            </li>
        {% endfor %}
    </ul>
</p>
<p>
    <strong>to_review Priority</strong>
    <ul>
        <li>
            to_review:
            <code>{{ workflow_metadata(blog_post, 'priority', workflow_transition(blog_post, 'to_review')) }}</code>
        </li>
    </ul>
</p>

Learn more

.. toctree::
   :maxdepth: 1

   /workflow/workflow-and-state-machine
   /workflow/dumping-workflows