how Drupal refresh/rebuild its route automatically after route programmaticaly created? I try to understand how Drupal Core rebuild the route automatically after route created programaticaly.

here is one example that i tried: I'm installing External Entities Module.
this module will allow you to create entity and generate its route automatically.

question: how is this possible? what trigger Drupal core to rebuild the route?

i did stack trace on entity form-save action as follow: (to understand what's triggered route rebuild)


KernelDesctructionSubscriber.php line 48 --> public function onKernelTerminate(PostResponseEvent $event)
ContainerAwareEventDispacther.php line 111 --> $definition['callable']($event, $event_name, $this);
HttpKernel.php Line 84 --> $this-&gt;dispatcher-&gt;dispatch(KernelEvents::TERMINATE, new PostResponseEvent($this, $request, $response));
StackedHttpKernel.Php Line 32 --> $kernel-&gt;terminate($request, $response);
Drupal Kernel Line 634 --> $this-&gt;getHttpKernel()-&gt;terminate($request, $response);
index.php Line 22 --> $kernel-&gt;terminate($request, $response);


if you see KernelDestructionSubscriber in specific on: onKernelTerminate

public function onKernelTerminate(PostResponseEvent $event) {
    foreach ($this-&gt;services as $id) {
      // Check if the service was initialized during this request, destruction
      // is not necessary if the service was not used.
      if ($this-&gt;container-&gt;initialized($id)) {
        $service = $this-&gt;container-&gt;get($id);
        $service-&gt;destruct();
      }
    }
  }


when the ID equal to drupal.proxy_original_service.router.builder then it goes to: container.php : initialized method below:

  public function initialized($id) {
    if (isset($this-&gt;aliases[$id])) {
      $id = $this-&gt;aliases[$id];
    }

    return isset($this-&gt;services[$id]) || array_key_exists($id, $this-&gt;services);
  }


it will return TRUE because $this-&gt;services[$id] is set

and then it will trigger: $service-&gt;destruct() in onKernelTerminate then rebuild the route.

the question is where in the External Entities code that will make $this-&gt;services[$id] is set then trigger rebuild route?

i've been spending quite sometime and still unable to crack this...

Thanks in advance for the help
I can't see anything in the module doing it, but this is done through the router.builder service.

Either rebuild immediately, with \Drupal::service('router.builder')-&gt;rebuild(); or tell it to rebuild at the end of the request, which is \Drupal::service('router.builder')-&gt;setRebuildNeeded()

Based on what you posted, it looks to me that you went through all the boring, generic stuff and stopped right before if would have gotten interesting, in that services rebuildIfNeeded() method. which checks the rebuildNeeded flag and rebuilds if TRUE.

So, you don't have to do anything to have that method called, that happens automatically if the service got invoked, you just have to make sure that flag is set.