How to prevent two distinct flows from running at the same time

[jordanmastel]

Hi,

I am looking for suggestions on how to prevent multiple flows from running at the same time using two separate triggers. 

I have two flows to "Sync" calendars for a specific use case due to the infrastructure in our business, for the usage of Bookings. Basically, employees have two identities that can be used by the same person but are in different tenants. Some may put calendar events on Tenant X, some may put events on Tenant Y, some may put them on both if they are disorganized. So a way to Synchronize the two automatically has been requested. 

I have two flows, "Synchronize X to Y" and "Synchronize Y to X" I would like to prevent "Synchronize X to Y" from running when "Synchronize Y to X" is running and vice versa. Both are triggered by "When an event is added, updated or deleted" on Calendar. So if an event is created on one it creates, updates, or deletes it in the other calendar. It works reasonably well as long as you are not creating events in both calendars at the same time. Which will inevitably happen to one of our users. In which case, there is a loop between the two. 

So is there some sort of mutex for locking between the two to only allow one of the two distinct flows to run at the same time?  Are there any suggestions for how this can be accomplished? Or is there a better structure I should be looking at to accomplish this end result that can be done through the use of a single flow? There are third-party apps out to accomplish this same functionality but as far as I am aware nothing is built into Microsoft Products to synchronize two different calendars. I am open to ideas

Thank you.

[abm]

Hi @jordanmastel 

So you mentioned one of the user created the events in both calendars. Believe its the same event? If it is then try checking that event already exists or not? If not exists then write it.

Thanks

[jordanmastel]

Hi @abm,

The user could create an event on one calendar or the other. Creating events is no problem, the problem there starts if the event is deleted or updated. If it gets deleted on one calendar, needs to be a way to identify the corresponding event on the other calendar. The only way I have been able to be by checking the subject but if the subject doesn't match it can't find the event to update. There doesn't seem to be a unique attribute that can be used in both calendars. I've tried the event ID and ICalUId but they are different for each calendar. 

Thanks,

[abm]

Hi @jordanmastel 

You probably need a temporary storage outside to keep sync on both sides. I was thinking a SharePoint list or a table or something. You could cleanup once the due date is passed. Can't think any other way to maintain this.

Thanks

[abm · Accepted solution]

Hi @jordanmastel 

You probably need a temporary storage outside to keep sync on both sides. I was thinking a SharePoint list or a table or something. You could cleanup once the due date is passed. Can't think any other way to maintain this.

Thanks