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https://github.com/unclechu/gRPC-haskell.git
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86 lines
3.1 KiB
Haskell
86 lines
3.1 KiB
Haskell
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
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{-# LANGUAGE StandaloneDeriving #-}
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{-# LANGUAGE MultiParamTypeClasses #-}
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module Network.GRPC.LowLevel.GRPC where
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{-
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-- TODO: remove if not needed
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import Control.Monad.IO.Class (liftIO, MonadIO)
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import Control.Monad.Except (ExceptT(..), runExceptT, throwError,
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MonadError)
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-}
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import Control.Exception
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import qualified Network.GRPC.Unsafe as C
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#ifdef DEBUG
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import GHC.Conc (myThreadId)
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#endif
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-- | Functions as a proof that the gRPC core has been started. The gRPC core
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-- must be initialized to create any gRPC state, so this is a requirement for
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-- the server and client create/start functions.
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data GRPC = GRPC
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withGRPC :: (GRPC -> IO a) -> IO a
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withGRPC = bracket (C.grpcInit >> return GRPC) (const C.grpcShutdown)
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-- | Describes all errors that can occur while running a GRPC-related IO action.
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data GRPCIOError = GRPCIOCallError C.CallError
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-- ^ Errors that can occur while the call is in flight. These
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-- errors come from the core gRPC library directly.
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| GRPCIOTimeout
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-- ^ Indicates that we timed out while waiting for an
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-- operation to complete on the 'CompletionQueue'.
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| GRPCIOShutdown
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-- ^ Indicates that the 'CompletionQueue' is shutting down
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-- and no more work can be processed. This can happen if the
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-- client or server is shutting down.
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| GRPCIOShutdownFailure
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-- ^ Thrown if a 'CompletionQueue' fails to shut down in a
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-- reasonable amount of time.
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| GRPCIOUnknownError
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deriving (Show, Eq)
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throwIfCallError :: C.CallError -> Either GRPCIOError ()
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throwIfCallError C.CallOk = Right ()
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throwIfCallError x = Left $ GRPCIOCallError x
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grpcDebug :: String -> IO ()
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{-# INLINE grpcDebug #-}
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#ifdef DEBUG
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grpcDebug str = do tid <- myThreadId
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putStrLn $ (show tid) ++ ": " ++ str
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#else
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grpcDebug _ = return ()
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#endif
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{-
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-- TODO: remove this once finally decided on whether to use it.
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-- | Monad for running gRPC operations.
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newtype GRPCIO a = GRPCIO {unGRPCIO :: ExceptT GRPCIOError IO a}
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deriving (Functor, Applicative, Monad, MonadIO)
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deriving instance MonadError GRPCIOError GRPCIO
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runGRPCIO :: GRPCIO a -> IO (Either GRPCIOError a)
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runGRPCIO = runExceptT . unGRPCIO
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unrunGRPCIO :: IO (Either GRPCIOError a) -> GRPCIO a
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unrunGRPCIO = GRPCIO . ExceptT
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continueFrom :: (a -> GRPCIO b) -> (Either GRPCIOError a) -> GRPCIO b
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continueFrom f (Left x) = throwError x
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continueFrom f (Right x) = f x
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wrapGRPC :: Either GRPCIOError a -> GRPCIO a
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wrapGRPC (Left x) = throwError x
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wrapGRPC (Right x) = return x
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grpcBracket :: GRPCIO a -> (a -> GRPCIO b) -> (a -> GRPCIO c) -> GRPCIO c
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grpcBracket create destroy f = unrunGRPCIO $ do
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let createAction = runGRPCIO create
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let fAction = runGRPCIO . continueFrom f
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let destroyAction = runGRPCIO . continueFrom destroy
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bracket createAction destroyAction fAction
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-}
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