Child Workflow Signaling

[rmcdaniel]

I have a PR open that will be merged soon. It will allow users to signal child workflows from parent workflows. This was already possible but it wasn't obvious how to do it. Feel free to test it out and leave me any feedback. Thanks!

[chipotlegroove]

Hey rmcdaniel! Thank you for this very cool update. I was reading through the documentation and on storing child workflow's IDs there's this little snippet:

yield ActivityStub::make(StoreWorkflowIdActivity::class, $this->child()->id());

Is there any particular reason you are using an activity for this? I tried storing the IDs as private variables and then using query methods (to return these variables, not the result of $this->child()/children()) from my livewire component to fetch them and it worked as I had hoped.

    private ?int $child1_id = null;
    private ?int $child2_id = null;

    #[QueryMethod]
    public function getChild1Id(): ?int
    {
        return $this->child1_id;
    }

    #[QueryMethod]
    public function getChild2Id(): ?int
    {
        return $this->child2_id;
    }

public function execute()
    {
        ...

        $child1 = ChildWorkflowStub::make(MyChildWorkflow::class);

        $this->child1_id = $this->child()->id();

        $child2 = ChildWorkflowStub::make(MyChildWorkflow2::class);

        $this->child2_id = $this->child()->id();

        ...
    }

And from my livewire component I just load parent workflow -> fetch child ID -> load child -> do whatever I need to do with the child:

        $workflow = WorkflowStub::load($this->workflowId);
        $child_id = $workflow->getChild1Id();
        $child_workflow = WorkflowStub::load($child_id);
        $child_workflow->setApproval3(true);

[rmcdaniel]

No, it was just another example of how you could tell an activity to do something with the ID like send it in an email. Your method is fine too!

[rmcdaniel]

@chipotlegroove I documented your method and also there's a little "gotcha" to be aware of when doing it your way. If you try to get the child id too soon, you might cause an exception. To ensure that doesn't happen, you can await the child handle first.

https://laravel-workflow.com/docs/features/child-workflows