shrub/pkg/hs-urbit/lib/Vere/Serf.hs

363 lines
10 KiB
Haskell

{-
- TODO: `Serf` type should have something like:
```
getInput :: STM (Writ ())
onComputed :: Writ [Effect] -> STM ()
onExit :: Serf -> IO ()
task :: Async ()
```
- TODO: `recvLen` is not big-endian safe.
-}
{-# OPTIONS_GHC -Wwarn #-}
module Vere.Serf where
import UrbitPrelude hiding (fail)
import Data.Conduit
import Control.Monad.Fail (fail)
import Data.Void
import Noun
import System.Process
import Vere.Pier.Types
import Control.Concurrent (threadDelay)
import Data.ByteString (hGet)
import Data.ByteString.Unsafe (unsafeUseAsCString)
import Foreign.Marshal.Alloc (alloca)
import Foreign.Ptr (castPtr)
import Foreign.Storable (peek, poke)
import System.Exit (ExitCode)
import qualified Data.ByteString.Unsafe as BS
import qualified Data.Text as T
import qualified Urbit.Time as Time
import qualified Vere.Log as Log
-- Types -----------------------------------------------------------------------
data SerfState = SerfState
{ ssNextEv :: EventId
, ssLastMug :: Mug
}
deriving (Eq, Ord, Show)
data Serf = Serf
{ sendHandle :: Handle
, recvHandle :: Handle
, process :: ProcessHandle
, sState :: MVar SerfState
}
type Play = Maybe (EventId, Mug, ShipId)
data Plea
= Play Play
| Work Job
| Done EventId Mug [(Path, Eff)]
| Stdr EventId Cord
| Slog EventId Word32 Tank
deriving (Eq, Show)
type GetJobs = EventId -> Word64 -> IO (Vector Job)
type ReplacementEv = Job
type Fx = [(Path, Eff)]
type WorkResult = (SerfState, Fx)
type SerfResp = Either ReplacementEv WorkResult
data SerfExn
= BadComputeId EventId WorkResult
| BadReplacementId EventId ReplacementEv
| UnexpectedPlay EventId Play
| BadPleaAtom Atom
| BadPleaNoun Noun [Text] Text
| ReplacedEventDuringReplay EventId ReplacementEv
| ReplacedEventDuringBoot EventId ReplacementEv
| EffectsDuringBoot EventId [(Path, Eff)]
| SerfConnectionClosed
| UnexpectedPleaOnNewShip Plea
| InvalidInitialPlea Plea
deriving (Show)
-- Instances -------------------------------------------------------------------
instance Exception SerfExn
deriveNoun ''Plea
-- Utils -----------------------------------------------------------------------
printTank :: Word32 -> Tank -> IO ()
printTank pri = \case
Leaf (Tape s) -> pure () -- traceM ("[SERF]\t" <> s)
t -> pure () -- traceM ("[SERF]\t" <> show (pri, t))
guardExn :: Exception e => Bool -> e -> IO ()
guardExn ok = unless ok . throwIO
fromJustExn :: Exception e => Maybe a -> e -> IO a
fromJustExn Nothing exn = throwIO exn
fromJustExn (Just x) exn = pure x
fromRightExn :: Exception e => Either a b -> (a -> e) -> IO b
fromRightExn (Left m) exn = throwIO (exn m)
fromRightExn (Right x) _ = pure x
-- Process Management ----------------------------------------------------------
{-
TODO Think about how to handle process exit
TODO Tear down subprocess on exit? (terminiteProcess)
TODO `config` is a stub, fill it in.
-}
startSerfProcess :: FilePath -> IO Serf
startSerfProcess pier =
do
(Just i, Just o, _, p) <- createProcess pSpec
ss <- newEmptyMVar
pure (Serf i o p ss)
where
chkDir = traceShowId pier
diskKey = ""
config = "0"
args = [chkDir, diskKey, config]
pSpec = (proc "urbit-worker" args)
{ std_in = CreatePipe
, std_out = CreatePipe
}
waitForExit :: Serf -> IO ExitCode
waitForExit serf = waitForProcess (process serf)
kill :: Serf -> IO ExitCode
kill serf = terminateProcess (process serf) >> waitForExit serf
-- Basic Send and Receive Operations -------------------------------------------
withWord64AsByteString :: Word64 -> (ByteString -> IO a) -> IO a
withWord64AsByteString w k = do
alloca $ \wp -> do
poke wp w
bs <- BS.unsafePackCStringLen (castPtr wp, 8)
k bs
sendLen :: Serf -> Int -> IO ()
sendLen s i = do
w <- evaluate (fromIntegral i :: Word64)
withWord64AsByteString (fromIntegral i) (hPut (sendHandle s))
sendOrder :: Serf -> Order -> IO ()
sendOrder w o = do
traceM ("[DEBUG] Serf.sendOrder.toNoun: " <> show o)
n <- evaluate (toNoun o)
traceM ("[DEBUG] Serf.sendOrder.jam")
j <- evaluate (jam n)
traceM ("[DEBUG] Serf.sendOrder.send")
sendAtom w j
sendAtom :: Serf -> Atom -> IO ()
sendAtom s a = do
let bs = unpackAtom a
sendLen s (length bs)
hPut (sendHandle s) bs
hFlush (sendHandle s)
where
unpackAtom :: Atom -> ByteString
unpackAtom = view atomBytes
recvLen :: Serf -> IO Word64
recvLen w = do
bs <- hGet (recvHandle w) 8
case length bs of
8 -> unsafeUseAsCString bs (peek . castPtr)
_ -> throwIO SerfConnectionClosed
recvBytes :: Serf -> Word64 -> IO ByteString
recvBytes w = do
hGet (recvHandle w) . fromIntegral
recvAtom :: Serf -> IO Atom
recvAtom w = do
len <- recvLen w
bs <- recvBytes w len
pure (packAtom bs)
where
packAtom :: ByteString -> Atom
packAtom = view (from atomBytes)
cordString :: Cord -> String
cordString (Cord bs) = unpack $ T.strip $ decodeUtf8 bs
--------------------------------------------------------------------------------
requestSnapshot :: Serf -> SerfState -> IO ()
requestSnapshot serf SerfState{..} = sendOrder serf (OSave $ ssNextEv - 1)
requestShutdown :: Serf -> Word8 -> IO ()
requestShutdown serf code = sendOrder serf (OExit code)
shutdownAndWait :: Serf -> Word8 -> IO ExitCode
shutdownAndWait serf code = do
requestShutdown serf code
waitForExit serf
{-
TODO Find a cleaner way to handle `Stdr` Pleas.
-}
recvPlea :: Serf -> IO Plea
recvPlea w = do
a <- recvAtom w
n <- fromRightExn (cue a) (const $ BadPleaAtom a)
p <- fromRightExn (fromNounErr n) (\(p,m) -> BadPleaNoun (traceShowId n) p m)
case p of Stdr e msg -> do -- traceM ("[SERF]\t" <> (cordString msg))
recvPlea w
Slog _ pri t -> do printTank pri t
recvPlea w
_ -> do traceM ("[DEBUG] Serf.recvPlea: Got " <> show p)
pure p
{-
Waits for initial plea, and then sends boot IPC if necessary.
-}
handshake :: Serf -> LogIdentity -> IO SerfState
handshake serf ident = do
ss@SerfState{..} <- recvPlea serf >>= \case
Play Nothing -> pure $ SerfState 1 (Mug 0)
Play (Just (e, m, _)) -> pure $ SerfState e m
x -> throwIO (InvalidInitialPlea x)
when (ssNextEv == 1) $ do
sendOrder serf (OBoot ident)
pure ss
sendWork :: Serf -> Job -> IO SerfResp
sendWork w job@(Job jobId _ _) =
do
sendOrder w (OWork job)
res <- loop
pure res
where
produce :: WorkResult -> IO SerfResp
produce (ss@SerfState{..}, o) = do
guardExn (ssNextEv == (1+jobId)) (BadComputeId jobId (ss, o))
pure $ Right (ss, o)
replace :: ReplacementEv -> IO SerfResp
replace job@(Job i _ _) = do
guardExn (i == jobId) (BadReplacementId jobId job)
pure (Left job)
loop :: IO SerfResp
loop = recvPlea w >>= \case
Play p -> throwIO (UnexpectedPlay jobId p)
Done i m o -> produce (SerfState (i+1) m, o)
Work job -> replace job
Stdr _ cord -> loop -- traceM ("[SERF]\t" <> cordString cord) >> loop
Slog _ pri t -> printTank pri t >> loop
--------------------------------------------------------------------------------
doJob :: Serf -> Job -> IO (Job, SerfState, Fx)
doJob serf job@(Job eId _ _) = do
sendWork serf job >>= \case
Left replaced -> doJob serf replaced
Right (ss, fx) -> pure (job, ss, fx)
bootJob :: Serf -> Job -> IO (Job, SerfState)
bootJob serf job@(Job eId _ _) = do
doJob serf job >>= \case
(job, ss, []) -> pure (job, ss)
(job, ss, fx) -> throwIO (EffectsDuringBoot eId fx)
replayJob :: Serf -> Job -> IO SerfState
replayJob serf job@(Job eId _ _) = do
sendWork serf job >>= \case
Left replaced -> throwIO (ReplacedEventDuringReplay eId replaced)
Right (ss, _) -> pure ss
--------------------------------------------------------------------------------
type BootSeqFn = EventId -> Mug -> Time.Wen -> Job
bootFromSeq :: Serf -> BootSeq -> IO ([Job], SerfState)
bootFromSeq serf (BootSeq ident nocks ovums) = do
handshake serf ident >>= \case
ss@(SerfState 1 (Mug 0)) -> loop [] ss bootSeqFns
_ -> error "ship already booted"
where
loop :: [Job] -> SerfState -> [BootSeqFn] -> IO ([Job], SerfState)
loop acc ss = \case
[] -> pure (reverse acc, ss)
x:xs -> do wen <- Time.now
job <- pure $ x (ssNextEv ss) (ssLastMug ss) wen
(job, ss) <- bootJob serf job
loop (job:acc) ss xs
bootSeqFns :: [BootSeqFn]
bootSeqFns = fmap muckNock nocks <> fmap muckOvum ovums
where
muckNock nok eId mug _ = Job eId mug (LifeCycle nok)
muckOvum ov eId mug wen = Job eId mug (DateOvum wen ov)
{-
The ship is booted, but it is behind. shove events to the worker
until it is caught up.
-}
replayJobs :: Serf -> SerfState -> ConduitT Job Void IO SerfState
replayJobs serf = go
where
go ss = await >>= maybe (pure ss) (liftIO . replayJob serf >=> go)
replay :: Serf -> Log.EventLog -> IO SerfState
replay serf log = do
ss <- handshake serf (Log.identity log)
runConduit $ Log.streamEvents log (ssNextEv ss)
.| toJobs (ssNextEv ss)
.| replayJobs serf ss
toJobs :: EventId -> ConduitT Atom Job IO ()
toJobs eId =
await >>= \case
Nothing -> traceM "no more jobs" >> pure ()
Just at -> do yield =<< liftIO (fromAtom eId at)
traceM (show eId)
toJobs (eId+1)
where
fromAtom eId at = do
traceM ("[DEBUG] Pier.toJob: " <> show (length $ at ^. atomBytes))
traceM ("[DEBUG] Pier.toJob.cue: " <> show eId)
noun <- cueExn at
traceM ("[DEBUG] Pier.toJob.fromNoun")
(mug, payload) <- fromNounExn noun
traceM ("[DEBUG] Pier.toJob.done")
pure (Job eId mug payload)
-- Compute Thread --------------------------------------------------------------
startComputeThread :: Serf -> STM Ovum -> (EventId, Mug) -> IO (Async ())
startComputeThread w getEvent (evendId, mug) = async $ forever $ do
ovum <- atomically $ getEvent
currentDate <- Time.now
let _mat = jam (undefined (mug, currentDate, ovum))
undefined