Signals in PHP

use Temporal\Workflow;

#[Workflow\WorkflowInterface]
class YourWorkflow
{
    private bool $value;

    #[Workflow\WorkflowMethod]
    public function run()
    {
        yield Workflow::await(fn()=> $this->value);
        return 'OK';
    }

    #[Workflow\SignalMethod]
    public function setValue(bool $value)
    {
        $this->value = $value;
    }
}

In the example above the workflow updates the protected value. Main workflow coroutine waits for such value to change using Workflow::await function.

To send signal to workflow use WorkflowClient->newWorkflowStub or WorkflowClient->newUntypedWorkflowStub:

$workflow = $workflowClient->newWorkflowStub(YourWorkflow::class);

$run = $workflowClient->start($workflow);

// do something

$workflow->setValue(true);

assert($run->getValue() === true);

Use WorkflowClient->newRunningWorkflowStub or WorkflowClient->newUntypedRunningWorkflowStub with workflow id to send signals to already running workflows.

$workflow = $workflowClient->newRunningWorkflowStub(YourWorkflow::class, 'workflowID');
$workflow->setValue(true);

SignalWithStart

You may not know if a Workflow is running and can accept a signal. The WorkflowClient->startWithSignal API allows you to send a signal to the current Workflow instance if one exists or to create a new run and then send the signal.

$workflow = $workflowClient->newWorkflowStub(YourWorkflow::class);

$run = $workflowClient->startWithSignal(
    $workflow,
    'setValue',
    [true], // signal arguments
    [] // start arguments
);

SignalWithStart​

SignalWithStart