What Guarantees Exist (If Any) for Draining Signals?

Community Support
1

Hi,

Let’s say I have the following simple workflow.

func SimpleSignalWorkfow(ctx workflow.Context) error {
	err := workflow.Sleep(ctx, 24*time.Hour)
	ch := workflow.GetSignalChannel(ctx, "signal")
	var s string
	for ch.ReceiveAsync(&s) {
		workflow.GetLogger(ctx).Info(s)
	}
	return err
}

What guarantees exist, if any, that a signal won’t be missed? Couldn’t the Temporal server receive a signal for that workflow run after the worker existed the for-loop? Wouldn’t that result in a signal being dropped?

If so, how should I write this workflow to prevent signal loss?

Thanks!

Albert

2

Temporal detects the race condition you described, rolls back the workflow state to the Sleep line, and then executes the workflow with the new signal.

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