tvl-depot/users/Profpatsch/arglib/ArglibNetencode.hs

23 lines
864 B
Haskell
Raw Normal View History

{-# LANGUAGE QuasiQuotes #-}
module ArglibNetencode where
import Data.Attoparsec.ByteString qualified as Atto
import ExecHelpers
import Label
import Netencode qualified
import PossehlAnalyticsPrelude
import System.Posix.Env.ByteString qualified as ByteEnv
arglibNetencode :: CurrentProgramName -> Maybe (Label "arglibEnvvar" Text) -> IO Netencode.T
arglibNetencode progName mEnvvar = do
let envvar = mEnvvar <&> (.arglibEnvvar) & fromMaybe "ARGLIB_NETENCODE" & textToBytesUtf8
ByteEnv.getEnv envvar >>= \case
Nothing -> dieUserError progName [fmt|could not read args, envvar {envvar} not set|]
Just bytes ->
case Atto.parseOnly (Netencode.netencodeParser <* Atto.endOfInput) bytes of
Left err -> dieEnvironmentProblem progName [fmt|arglib parsing error: {err}|]
Right t -> do
ByteEnv.unsetEnv envvar
pure t