{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE CPP #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
-- | A full tutorial for this module is available at:
-- <https://github.com/snoyberg/conduit/blob/master/PROCESS.md>.
--
-- Note that this is a very thin layer around the @Data.Streaming.Process@ module. In particular, it:
--
-- * Provides orphan instances for conduit
--
-- * Provides some useful helper functions
module Data.Conduit.Process
( -- * Functions
sourceCmdWithConsumer
, sourceProcessWithConsumer
, sourceCmdWithStreams
, sourceProcessWithStreams
, withCheckedProcessCleanup
-- * Reexport
, module Data.Streaming.Process
) where
import Data.Streaming.Process
import Data.Streaming.Process.Internal
import System.Exit (ExitCode (..))
import Control.Monad.IO.Class (MonadIO, liftIO)
import System.IO (hClose)
import Data.Conduit
import Data.Conduit.Binary (sourceHandle, sinkHandle, sinkHandleBuilder, sinkHandleFlush)
import Data.ByteString (ByteString)
import Data.ByteString.Builder (Builder)
import Control.Concurrent.Async (runConcurrently, Concurrently(..))
import Control.Monad.Catch (MonadMask, onException, throwM, finally, bracket)
#if (__GLASGOW_HASKELL__ < 710)
import Control.Applicative ((<$>), (<*>))
#endif
instance (r ~ (), MonadIO m, i ~ ByteString) => InputSource (ConduitM i o m r) where
isStdStream = (\(Just h) -> return $ sinkHandle h, Just CreatePipe)
instance (r ~ (), r' ~ (), MonadIO m, MonadIO n, i ~ ByteString) => InputSource (ConduitM i o m r, n r') where
isStdStream = (\(Just h) -> return (sinkHandle h, liftIO $ hClose h), Just CreatePipe)
-- | Wrapper for input source which accepts 'Data.ByteString.Builder.Builder's.
-- You can pass 'Data.ByteString.Builder.Extra.flush' to flush the input. Note
-- that the pipe will /not/ automatically close when the processing completes.
--
-- @since 1.2.2
newtype BuilderInput o m r = BuilderInput (ConduitM Builder o m r)
-- | Wrapper for input source which accepts @Flush@es. Note that the pipe
-- will /not/ automatically close then processing completes.
--
-- @since 1.2.2
newtype FlushInput o m r = FlushInput (ConduitM (Flush ByteString) o m r)
instance (MonadIO m, r ~ ()) => InputSource (BuilderInput o m r) where
isStdStream = (\(Just h) -> return $ BuilderInput $ sinkHandleBuilder h, Just CreatePipe)
instance (MonadIO m, MonadIO n, r ~ (), r' ~ ()) => InputSource (BuilderInput o m r, n r') where
isStdStream = (\(Just h) -> return (BuilderInput $ sinkHandleBuilder h, liftIO $ hClose h), Just CreatePipe)
instance (MonadIO m, r ~ ()) => InputSource (FlushInput o m r) where
isStdStream = (\(Just h) -> return $ FlushInput $ sinkHandleFlush h, Just CreatePipe)
instance (MonadIO m, MonadIO n, r ~ (), r' ~ ()) => InputSource (FlushInput o m r, n r') where
isStdStream = (\(Just h) -> return (FlushInput $ sinkHandleFlush h, liftIO $ hClose h), Just CreatePipe)
instance (r ~ (), MonadIO m, o ~ ByteString) => OutputSink (ConduitM i o m r) where
osStdStream = (\(Just h) -> return $ sourceHandle h, Just CreatePipe)
instance (r ~ (), r' ~ (), MonadIO m, MonadIO n, o ~ ByteString) => OutputSink (ConduitM i o m r, n r') where
osStdStream = (\(Just h) -> return (sourceHandle h, liftIO $ hClose h), Just CreatePipe)
-- | Given a @CreateProcess@, run the process, with its output being used as a
-- @Source@ to feed the provided @Consumer@. Once the process has completed,
-- return a tuple of the @ExitCode@ from the process and the output collected
-- from the @Consumer@.
--
-- Note that, if an exception is raised by the consumer, the process is /not/
-- terminated. This behavior is different from 'sourceProcessWithStreams' due
-- to historical reasons.
--
-- Since 1.1.2
sourceProcessWithConsumer :: MonadIO m
=> CreateProcess
-> Consumer ByteString m a -- ^ stdout
-> m (ExitCode, a)
sourceProcessWithConsumer cp consumer = do
(ClosedStream, (source, close), ClosedStream, cph) <- streamingProcess cp
res <- source $$ consumer
close
ec <- waitForStreamingProcess cph
return (ec, res)
-- | Like @sourceProcessWithConsumer@ but providing the command to be run as
-- a @String@.
--
-- Since 1.1.2
sourceCmdWithConsumer :: MonadIO m
=> String -- ^command
-> Consumer ByteString m a -- ^stdout
-> m (ExitCode, a)
sourceCmdWithConsumer cmd = sourceProcessWithConsumer (shell cmd)
-- | Given a @CreateProcess@, run the process
-- and feed the provided @Producer@
-- to the stdin @Sink@ of the process.
-- Use the process outputs (stdout, stderr) as @Source@s
-- and feed it to the provided @Consumer@s.
-- Once the process has completed,
-- return a tuple of the @ExitCode@ from the process
-- and the results collected from the @Consumer@s.
--
-- If an exception is raised by any of the streams,
-- the process is terminated.
--
-- IO is required because the streams are run concurrently
-- using the <https://hackage.haskell.org/package/async async> package
--
-- @since 1.1.12
sourceProcessWithStreams :: CreateProcess
-> Producer IO ByteString -- ^stdin
-> Consumer ByteString IO a -- ^stdout
-> Consumer ByteString IO b -- ^stderr
-> IO (ExitCode, a, b)
sourceProcessWithStreams cp producerStdin consumerStdout consumerStderr = do
( (sinkStdin, closeStdin)
, (sourceStdout, closeStdout)
, (sourceStderr, closeStderr)
, sph) <- streamingProcess cp
(_, resStdout, resStderr) <-
runConcurrently (
(,,)
<$> Concurrently ((producerStdin $$ sinkStdin) `finally` closeStdin)
<*> Concurrently (sourceStdout $$ consumerStdout)
<*> Concurrently (sourceStderr $$ consumerStderr))
`finally` (closeStdout >> closeStderr)
`onException` terminateStreamingProcess sph
ec <- waitForStreamingProcess sph
return (ec, resStdout, resStderr)
-- | Like @sourceProcessWithStreams@ but providing the command to be run as
-- a @String@.
--
-- @since 1.1.12
sourceCmdWithStreams :: String -- ^command
-> Producer IO ByteString -- ^stdin
-> Consumer ByteString IO a -- ^stdout
-> Consumer ByteString IO b -- ^stderr
-> IO (ExitCode, a, b)
sourceCmdWithStreams cmd = sourceProcessWithStreams (shell cmd)
-- | Same as 'withCheckedProcess', but kills the child process in the case of
-- an exception being thrown by the provided callback function.
--
-- @since 1.1.11
withCheckedProcessCleanup
:: ( InputSource stdin
, OutputSink stderr
, OutputSink stdout
, MonadIO m
, MonadMask m
)
=> CreateProcess
-> (stdin -> stdout -> stderr -> m b)
-> m b
withCheckedProcessCleanup cp f = bracket
(streamingProcess cp)
(\(_, _, _, sph) -> closeStreamingProcessHandle sph)
$ \(x, y, z, sph) -> do
res <- f x y z `onException` liftIO (terminateStreamingProcess sph)
ec <- waitForStreamingProcess sph
if ec == ExitSuccess
then return res
else throwM $ ProcessExitedUnsuccessfully cp ec
terminateStreamingProcess :: StreamingProcessHandle -> IO ()
terminateStreamingProcess = terminateProcess . streamingProcessHandleRaw