"Doesn't change" as subscription filter for a Fusion webhook

[tibormolnar]

Hi All,

I'd like to run a Fusion scenario when either or both of these 2 events occur on an Issue:

A) Status changes to "Booked" while a user is already assigned.

B) A user gets assigned (as Primary assignee) while the status is "Booked".

("Booked" is a custom status coded as BOC.)

Since the Fusion UI doesn't allow me to create a webhook with multiple subscriptions (so as to achieve the "OR" operator), I used the subscription API to create the 2 subsciptions:

A) (new state) assignedToID EXISTS AND status CHANGES AND status = BOC
B) (new state) assignedToID EXISTS AND assignedToID CHANGES AND status = BOC

This works most of the time, except the situation when the 2 changes happen at the same time, i.e. both assignedToID CHANGES and status CHANGES to BOC in the same update. In this situation the webhook gets 2 notifications with a few nanoseconds difference and my scenario runs twice. (The second run fails because it attempts the operations that the first run completed parallel.)

To avoid this, I would actually need 3 different subscriptions:

A) (new state) assignedToID EXISTS AND assignedToID DOESN'T CHANGE AND status CHANGES AND status = BOC

B) (new state) assignedToID EXISTS AND assignedToID CHANGES AND status = BOC AND status DOESN'T CHANGE

C) (new state) assignedToID EXISTS AND assignedToID CHANGES AND status = BOC AND status CHANGES

Any update would only trigger 1 of these 3.

The problem is that DOESN'T CHANGE is not supported as a filter on a subscription (or at least I'm not aware of that).

So I'm stuck with the original 2 subscriptions.

I managed to come up with a workaround: In the Fusion scenario, straight after the webhook I check for the subscription ID and if that's A), I only proceed if assignedToID did not change (newState assignedToID = oldState assignedToID).

This does the trick actually, because the 1st subscription handles when only the assignedToID changes and when both the assignedToID and the status change, while the 2nd subscription handles when only the status changes.

The only reason I don't like this much is that my scenario still runs twice when both fields get updated simultaneously, which occurs frequently.

I wonder if anyone has a better solution idea.

Thanks,

Tibor

[Sven-iX · Accepted solution]

I find this acceptable: since "notchanged" isn't available as a comparator, you're forced to use filters after the event module. 

I know it's not as clean as we'd like, but this approach is pretty commun. Plus, your logic is visible in the Fusion UI (as opposed to hidden in custom subscriptions)