Stream to port example

test.hs

#!/usr/bin/env stack
-- stack --resolver lts-12.7 script
import           Conduit              hiding (connect)
import qualified Data.Conduit.Binary  as CB
import qualified Data.Conduit.Network as CN
import qualified Data.Conduit.Process as CP
import qualified Data.Text            as T
import           Network.Socket
import           System.Directory
import           System.Environment
import           System.Exit


main :: IO ()
main = do
  let cmd = "echo asdfasdfasdf"
  code <- teeSock 8989 cmd "test.log"
  putStrLn . show $ code


teeSock :: Int -- ^ Port to bind to on localhost.
        -> String
        -> FilePath
        -> IO ExitCode
teeSock port cmd logFile = do
  (sock, addr) <- getSocket "127.0.0.1" (show port)
  connect sock $ addrAddress addr
  (CP.Inherited, out, CP.ClosedStream, sph) <- execShellCommand cmd
  runConduitRes $ out .| CN.sinkSocket sock
                  --    .| CB.conduitFile logFile
                  --    .| stdoutC
  CP.waitForStreamingProcess sph


execShellCommand
  :: (CP.InputSource stdin, CP.OutputSink stdout, CP.OutputSink stderr)
  => String
  -> IO (stdin, stdout, stderr, CP.StreamingProcessHandle)
execShellCommand cmd = do
  sourceProfile <- sourceProfileIfExists
  env' <-  getEnvironment
  CP.streamingProcess (CP.shell $ sourceProfile ++ cmd ++ " 2>&1") {CP.env = Just env'}


sourceProfileIfExists :: IO String
sourceProfileIfExists = getEnv "HOME" >>= \root ->
  doesFileExist (root ++ "/.profile") >>= \exists -> return $
    if exists then "source ~/.profile; " else ""


getSocket :: String -> String -> IO (Socket, AddrInfo)
getSocket host port = do
  addr:_ <- getAddrInfo Nothing (Just host) (Just port)
  sock <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr)
  return (sock, addr)