Haskell ReaderT LoggingT - MonadBaseControl vs. MonadUnliftIO

AsyncMonadBaseControlExample.hs

module AsyncMonadBaseControlExample where

import Blammo.Logging (LoggingT)
import Control.Concurrent.Async.Lifted.Safe (concurrently)
import Control.Monad.Base (MonadBase)
import Control.Monad.Reader (MonadIO, MonadReader, MonadTrans (lift), ReaderT)
import Control.Monad.Trans.Control (MonadBaseControl (liftBaseWith, restoreM), StM)
import Data.Text.Lazy qualified as TL
import Web.Scotty.Trans (ActionT, text)

data AppEnv = AppEnv

newtype App a = App
  { unApp :: ReaderT AppEnv (LoggingT IO) a
  }
  deriving (Functor, Applicative, Monad, MonadIO, MonadReader AppEnv, MonadBase IO)

-- Instance copied from:
-- https://stackoverflow.com/questions/28137838/creating-monadbasecontrol-instance-for-newtype
instance MonadBaseControl IO App where
  type StM App a = a
  liftBaseWith f = App $ liftBaseWith $ \runInBase -> f (runInBase . unApp)
  restoreM = App . restoreM

executeTaskA :: App TL.Text
executeTaskA = undefined

executeTaskB :: App TL.Text
executeTaskB = undefined

exampleHandler :: ActionT TL.Text App ()
exampleHandler = do
  -- ...
  (resultA, resultB) <- lift $ concurrently executeTaskA executeTaskB
  -- ...
  text $ mconcat [resultA, "\n", resultB]

AsyncMonadUnliftIOExample.hs

module AsyncMonadUnliftIOExample where

import Blammo.Logging (LoggingT)
import Control.Monad.Reader (MonadIO, MonadReader, MonadTrans (lift), ReaderT)
import Data.Text.Lazy qualified as TL
import UnliftIO (MonadUnliftIO)
import UnliftIO.Async (concurrently)
import Web.Scotty.Trans (ActionT, text)

data AppEnv = AppEnv

newtype App a = App
  { unApp :: ReaderT AppEnv (LoggingT IO) a
  }
  deriving (Functor, Applicative, Monad, MonadIO, MonadReader AppEnv, MonadUnliftIO)

executeTaskA :: App TL.Text
executeTaskA = undefined

executeTaskB :: App TL.Text
executeTaskB = undefined

exampleHandler :: ActionT TL.Text App ()
exampleHandler = do
  -- ...
  (resultA, resultB) <- lift $ concurrently executeTaskA executeTaskB
  -- ...
  text $ mconcat [resultA, "\n", resultB]