arbiter-hasql (hasql)

This backend uses hasql and resource-pool. Handlers receive a Hasql.Connection for typed queries in the worker transaction.

env <- ArbH.createHasqlEnv (Proxy @AppRegistry) connStr "arbiter"
ArbH.runHasqlDb env $ Arb.insertJob (Arb.defaultJob $ SendWelcome "alice@example.com" "Alice")

Share a transaction with external hasql work:

-- Session.script (hasql >= 1.10) or Session.sql (hasql < 1.10)
_ <- Hasql.use conn (Session.script "BEGIN")
ArbH.inTransaction @AppRegistry conn "arbiter" $
  Arb.insertJob (Arb.defaultJob (ProcessOrder orderId))
_ <- Hasql.use conn (Session.script "COMMIT")

See the arbiter-hasql haddocks for the env and pool constructors.