Cosmos: Support UDFs

[TomasHubelbauer]

I am wondering whether there is an attribute or a fluent API method that would allow me to tell EF Core to map an entity property to a result of a UDF invoked with that document as a parameter so that a context of the collection could be used to compute the value of the property from other documents in the collection.

Specifically, something like this:

SELECT {{ firstName: item.FirstName, lastName: item.LastName, test: udf.test(item) }} FROM AppDbContext item

As opposed to something like this which I assume the Cosmos provider already generates:

SELECT {{ firstName: item.FirstName, lastName: item.LastName, test: item.Test }} FROM AppDbContext item

Further technical details

EF Core version: Microsoft.EntityFrameworkCore.Cosmos 2.2.4
Database Provider: Microsoft.EntityFrameworkCore.Cosmos
Operating system: Windows 10
IDE: VS Code

[ajcvickers]

This is in the master list for Cosmos in issue #12086. Keeping this open to track the specific work, now referenced from the master list.

[smitpatel]

I am adding infrastructure support for this in query pipeline.