Implement and manage a custom or inbuilt queue using single data writer to stream

Question

I want to achieve a custom(or inbuilt) queue processor. The objective is to have a admin user who has Write permissions to write to a stream. Other non-admin users can queue write operations which later get processed by the admin user.
I tried the same using event subscription and scheduler but the security context is passed on to the final service call and as the final service doesn't have the permissions set for the non-admin users, they are not able to execute.
I hope my understanding of using the internal event queue is correct.

Is there a way to use the event subscription queue be processed by a specific admin user?
What would be the best way to implement and manage a queue using a single admin user who performs the write operations? Is there any option that the platform supports already?

Note: For custom queue implementation concurrency, synchronization could be potential issues.

VladimirRosu_116627 · Accepted Answer

Hi Soura,

The built-in ThingWorx Stream and Event subsystems do contain a queue, but that is used internally by the platform APIs to queue events to them and are not expected to be directly used by any platform user. While you can see their state, that's more to understand platform health.

In your case, I would go with an approach similar to Baba Shyam, but using platform features.

That is: create a Stream A that holds only the data queued by normal users. When the Administrator would want to approve, he is going to basically move the data to the proper stream B (via querying data from Stream A, adding data to Stream B, then deleting the processed data from Stream A). Users would have permissions to queue entries for Stream A, but no permissions for Stream B.

This is will work as far as I understood your case, but beware that within ThingWorx we don't have a way to impersonate another user in your services (besides the Scheduler/Timer capability, which is not a proper way for your usecase).

Another small note here, even if I don't really think this is what stopped you: I'm not sure if you used the System User capability before. This might help your usecase, because, if you give a Service permission to the System User, that service will be capable to be executed by another service, but not directly by an user. https://support.ptc.com/help/thingworx/platform/r9/en/index.html#page/ThingWorx%2FHelp%2FComposer%2FSecurity%2FSystemUser.html

BABA-SHYAM · Answer

Hi,

As per my experience with queue says whenever we handle queues with events of subscription, thingworx entities performs poorly or just ended up being ghost entities.

My suggestion would be whatever you are doing with queue, just create some datatables in external DB( sql server), now run some subscription which will pick that say top 50 stored data, perform your action may be in for loop and then remove those entities from that table and achieve them if business demands.

I hope I have understood your question correctly and answered it properly.

Regards

Shyam

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