Returning partial results from activity on error

Community Support
1

The Get() call on a future either returns a non-nil error or assigns result value to the provided pointer. Can it do both?

I have a use-case where I want to return partial results from an activity even when there is an error in the activity.

2

I would include the partial results into the ApplicationError:

func MyActivity(...) error {
	...
	if err != nil {
	   return temporal.NewApplicationErrorWithCause("Activity failure", "partial", err, &PartialDetails{ ... })
	}
	...
}

And then workflow should be able to get them:

err := workflow.ExecuteActivity(ctx, MyActivity, ...).Get(ctx, nil)
if err != nil {
	var applicationErr *ApplicationError
	if errors.As(err, &applicationError) {
		// handle activity errors (created via NewApplicationError() API)
		var details PartialDetails
		applicationErr.Details(&details) // extract strong typed details
                ...
        }
        ...
}
3

Thank you. That works. However, it would be easier if it is possible to achieve the same in the workflow without piggybacking the result on the error.

4

It is not possible as Temporal provides SDKs in many languages and most of them don’t support returning failure and a result at the same time.