forked from filipg/gonito
137 lines
4.3 KiB
Haskell
137 lines
4.3 KiB
Haskell
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module Handler.Runner where
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import Import
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import System.Process
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import System.Exit
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import Control.Concurrent.STM
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import Control.Concurrent.Lifted (threadDelay)
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import qualified Data.ByteString as BS
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type Channel = TChan (Maybe Text)
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data RunnerStatus a = RunnerOK a | RunnerError ExitCode
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newtype Runner a = Runner { runRunner :: Channel -> Handler (RunnerStatus a) }
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getChannel :: Runner Channel
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getChannel = Runner {
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runRunner = \chan -> return $ RunnerOK chan
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}
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instance Functor Runner where
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fmap f runner = Runner {
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runRunner = \chan -> do
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s <- (runRunner runner) chan
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return $ case s of
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RunnerOK v -> RunnerOK $ f v
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RunnerError e -> RunnerError e
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}
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instance Applicative Runner where
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pure v = Runner {
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runRunner = \_ -> return $ RunnerOK v
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}
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liftA2 f runner1 runner2 = Runner {
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runRunner = \chan -> do
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s1 <- (runRunner runner1) chan
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case s1 of
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RunnerOK v1 -> do
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s2 <- (runRunner runner2) chan
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case s2 of
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RunnerOK v2 -> return $ RunnerOK $ f v1 v2
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RunnerError e -> return $ RunnerError e
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RunnerError e -> return $ RunnerError e
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}
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instance Monad Runner where
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runner >>= k = Runner {
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runRunner = \chan -> do
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s <- (runRunner runner) chan
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case s of
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RunnerError e -> return $ RunnerError e
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RunnerOK v -> do
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sn <- (runRunner (k v)) chan
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return $ case sn of
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RunnerError e -> RunnerError e
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RunnerOK w -> RunnerOK w
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}
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runWithChannel :: Channel -> Runner () -> Handler ExitCode
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runWithChannel chan runner = do
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s <- (runRunner runner) chan
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return $ case s of
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RunnerOK () -> ExitSuccess
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RunnerError e -> e
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runProg :: Maybe FilePath -> FilePath -> [String] -> Runner ()
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runProg workingDir programPath args = Runner {
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runRunner = \chan -> do
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(code, _) <- runProgram workingDir programPath args chan
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case code of
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ExitSuccess -> return $ RunnerOK ()
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_ -> return $ RunnerError code
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}
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runProgram :: Maybe FilePath -> FilePath -> [String] -> Channel -> Handler (ExitCode, Text)
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runProgram workingDir programPath args chan = do
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(_, Just hout, Just herr, pid) <-
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liftIO $ createProcess (proc programPath args){ std_out = CreatePipe,
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std_err = CreatePipe,
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cwd = workingDir}
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(code, out) <- gatherOutput pid hout herr chan
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_ <- liftIO $ waitForProcess pid
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return (code, out)
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gatherOutput :: ProcessHandle -> Handle -> Handle -> Channel -> Handler (ExitCode, Text)
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gatherOutput ph hout herr chan = work mempty mempty
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where
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work accout accerr = do
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-- Read any outstanding input.
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resterr <- takeABit herr accerr
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restout <- takeABit hout accout
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liftIO $ threadDelay 1000000
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-- Check on the process.
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s <- liftIO $ getProcessExitCode ph
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-- Exit or loop.
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case s of
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Nothing -> work restout resterr
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Just ec -> do
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-- Get any last bit written between the read and the status
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-- check.
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_ <- takeFinalBit herr resterr
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all <- takeFinalBit hout restout
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return (ec, all)
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takeABit h acc = do
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bs <- liftIO $ BS.hGetNonBlocking hout (64 * 1024)
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let acc' = acc <> (decodeUtf8 bs)
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let (fullLines, rest) = processOutput acc'
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mapM_ (msg chan) fullLines
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return rest
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takeFinalBit h rest = do
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last <- liftIO $ BS.hGetContents h
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let all = rest <> (decodeUtf8 last)
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mapM_ (msg chan) $ lines all
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return all
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msg :: Channel -> Text -> Handler ()
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msg chan m = liftIO $ atom $ writeTChan chan $ Just (m ++ "\n")
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err :: Channel -> Text -> Handler ()
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err = msg
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raw :: Channel -> Text -> Handler ()
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raw = msg
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atom = Control.Concurrent.STM.atomically
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processOutput :: Text -> ([Text], Text)
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processOutput = processOutput' . lines
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where processOutput' [] = ([], "")
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processOutput' out = (init out, last out)
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init [] = []
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init [x] = []
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init (x:xs) = (x:(init xs))
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last [x] = x
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last (_:xs) = last xs
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