Feature request: using functions with session arguments to define computed columns

This is closely related to #2760 with the same motivation, except that I would like to have a view which transforms (not filters!) a table based on X-Hasura-User-Id. A straightforward solution is to expose session variables in queries under current_setting('hasura.user') similarly to how it’s done in mutations. In fact, the change implementing this is simple:

--- a/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
+++ b/server/src-lib/Hasura/GraphQL/Transport/HTTP.hs
@@ -50,7 +50,7 @@ runHasuraGQ reqId query userInfo resolvedOp = do
     E.ExOpQuery tx genSql  -> do
       -- log the generated SQL and the graphql query
       liftIO $ logGraphqlQuery logger $ QueryLog query genSql reqId
-      runLazyTx' pgExecCtx tx
+      runLazyTx pgExecCtx $ withUserInfo userInfo tx
     E.ExOpMutation tx -> do
       -- log the graphql query
       liftIO $ logGraphqlQuery logger $ QueryLog query Nothing reqId

Still, I wanted to make sure the idea itself is sound before opening a PR.

[tirumaraiselvan]

Yes, this is high up in our priority list. Actually, it was being tracked here: https://github.com/hasura/graphql-engine/issues/3846

I am closing this issue in favour of #3846 (as more eyeballs there)

[rakeshkky]

@lexi-lambda No. #3143 only support root SQL function queries to access session information. This needs to be done.