Invalidate Shopware 6 page cache on entity update via API

We created a custom CMS element which displays entries which are managed via API.

Now when entries are updated and Shopware 6 runs ins production mode, the changes are not reflected on the page. I believe this is due to the page cache. (APP_ENV=prod)

What do we have to do to invalidate the cache automatically?

I checked the docs, but did not find the necessary information.

For the product box it works: When I place a product CMS element on the main page and change the product, the page is updated when I reload in the browser. I was expecting to find some hint in \Shopware\Core\Content\Product\Cms\ProductBoxCmsElementResolver but there are no cache tags or something like this added there.

EDIT: Actually I was a bit inaccurate. The page I have lists the entities, and it is a category page.

So I believe I have too hook into CategoryRouteCacheTagsEvent.

For testing I hard-coded into:

\Shopware\Core\Content\Category\SalesChannel\CachedCategoryRoute::extractProductIds

    $slots = $page->getElementsOfType('jobs');
    /** @var CmsSlotEntity $slot */
    foreach ($slots as $slot) {
        $box = $slot->getData();
        $ids = array_merge($ids, $box['jobs']->getIds());
    }

But this does not yet work.

PS: Also I noticed some code duplication in the core in \Shopware\Core\Content\Category\SalesChannel\CachedCategoryRoute::extractProductIds and \Shopware\Core\Content\LandingPage\SalesChannel\CachedLandingPageRoute::extractIds

Solution

Based on the answers of dneustadt and Uwe, as for the job listings I solved it like with this two subscribes. I do not need any single ID here, because the full listing page has to be invalidated in case a job is deleted or added. This is why I went with the any-jobs tag:

use Shopware\Core\Content\Category\Event\CategoryRouteCacheTagsEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

class CacheKeyEventSubscriber implements EventSubscriberInterface
{
    public static function getSubscribedEvents(): array
    {
    return [
        CategoryRouteCacheTagsEvent::class => 'generateTags'
    ];
    }

    public function generateTags(CategoryRouteCacheTagsEvent $event): void
    {
    $page = $event->getResponse()->getCategory()->getCmsPage();
    $slots = $page->getElementsOfType('jobs');
    if (!empty($slots)) {
        $event->setTags(
            array_merge($event->getTags(), ['any-jobs'])
        );
    }
    }
}

and

class CacheInvalidationSubscriber implements EventSubscriberInterface
{
    private CacheInvalidator $cacheInvalidator;

    public static function getSubscribedEvents(): array
    {
    return [
        EntityWrittenContainerEvent::class => 'invalidateJobs'
    ];
    }

    public function __construct(CacheInvalidator $cacheInvalidator)
    {
    $this->cacheInvalidator = $cacheInvalidator;
    }


    public function invalidateJobs(EntityWrittenContainerEvent $event): void
    {
    if (!empty($event->getPrimaryKeys(\ApplicationManagement\Core\Content\JobAd\JobAdDefinition::ENTITY_NAME))) {
        $this->cacheInvalidator->invalidate(
            ['any-jobs']
        );
    }
    }
}