feat(eap): add support for virtual columns in the protobuf

[volokluev]

There is a requirement to have the ability to search by virtual columns. Remove the AttributeKeyTransformContext which special cased proejct id and make it generic for any desired virtual column

[colin-sentry]

how would this work for the uint case, everything gets converted to strings?

[volokluev]

how would this work for the uint case, everything gets converted to strings?

That's what I was thinking. I mostly did this because I can't do a oneOf map in protobuf. But if you have another solution that allows specifying both I'm happy to hear it

[Zylphrex]

Few questions here

• Does this mean to_column_name will be the name of the virtual column?
• Is this name constrained anywhere or is it an arbitrary string?
• Will this guarantee the to_column_name will be the name of a column in the response?
• Will this name be accessible in other parts of the query? So think count_unique(project) will get the project names substituted in automatically? (not saying we'll do this, just want to understand the semantics of this context).

[volokluev]

Does this mean to_column_name will be the name of the virtual column?

Yes

Is this name constrained anywhere or is it an arbitrary string?

Whatever you want bb

Will this guarantee the to_column_name will be the name of a column in the response?

Yes

Will this name be accessible in other parts of the query? So think count_unique(project) will get the project names substituted in automatically? (not saying we'll do this, just want to understand the semantics of this context).

This is a good question. I would say for now these virtual columns can be used to order by, filter, and in the result set. aggregations on virtual columns not supported