How do we collect User ID on a gallery app?

Question

I want to populate a column with the username based on the user running the analytical app on gallery. I came across an approach using Text Box named as '__cloud:UserId'. However I'm not aware how do we use this concept in the workflow. Can anyone guide me please?

Also it would be really helpful if someone can share a sample workflow for aforementioned. I cant find one anywhere.

gabrielvilella · Answer

That is the user ID from MongoDB, you’ll be able to join the information from the users collection within mongo and get the name and email, for instance. There is some good information about this here. 
https://community.alteryx.com/t5/Alteryx-Designer-Discussions/Get-username-Cloud-not-working/td-p/518481/page/2