Trigger Pub/Sub Event with Duplicate HL7v2 message

[Jared Cobb]

From the documentation, I see the following rules related to configuring Pub/Sub messages on various data store types:

You can use Pub/Sub to receive notifications when clinical events occur in Cloud Healthcare API data stores. These notifications inform you when:

• A DICOM instance is stored in a DICOM store using the dicomStores.dicomWeb.studies.storeInstances method or imported from Cloud Storage.
• A FHIR resource is created, updated, or deleted in a FHIR store. However, notifications are not sent when a FHIR resource is imported from Cloud Storage.
• An HL7v2 message is ingested or created in an HL7v2 store for the first time. Duplicate messages will not trigger a notification.

For an HL7v2 message, what is the best strategy to replay an existing message "insert" and trigger a second Pub/Sub message? The specific scenario is when a downstream system successfully acknowledges the first Pub/Sub message but fails to perform its own task, and we want to make a second attempt starting from the HL7v2 data store.

I can think of two ways that are not ideal, and I'm hoping for some advice on the best practice.

1. Delete the original HL7v2 message, and then submit the message again. It's not great from a data integrity standpoint.
2. Decode the original message and alter some segment values (such as the MSH.7 date/time or MSH.10 control ID). Also not ideal if we need to maintain integrity with what a source system actually sent and when).

How do others handle similar scenarios? Thanks!