git.iko.soy/distributed-process
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distributed-process/src/Control/Distributed/Process/Node.hs
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1{-# LANGUAGE CPP #-}
2{-# LANGUAGE DeriveDataTypeable #-}
3{-# LANGUAGE ScopedTypeVariables #-}
4{-# LANGUAGE RankNTypes #-}
5{-# LANGUAGE BangPatterns #-}
6{-# LANGUAGE GeneralizedNewtypeDeriving #-}
7{-# LANGUAGE RecordWildCards #-}
9-- | Local nodes
10--
11module Control.Distributed.Process.Node
12 ( LocalNode
13 , newLocalNode
14 , closeLocalNode
15 , forkProcess
16 , runProcess
17 , initRemoteTable
18 , localNodeId
19 ) where
21-- TODO: Calls to 'sendBinary' and co (by the NC) may stall the node controller.
23#if ! MIN_VERSION_base(4,6,0)
24import Prelude hiding (catch)
25#endif
27import System.IO (fixIO, hPutStrLn, stderr)
28import System.Mem.Weak (Weak, deRefWeak)
29import qualified Data.ByteString.Lazy as BSL (fromChunks)
30import Data.Binary (decode)
31import Data.Map (Map)
32import qualified Data.Map as Map
33 ( empty
34 , toList
35 , fromList
36 , filter
37 , partitionWithKey
38 , elems
39 , size
40 , filterWithKey
41 , foldlWithKey
42 )
43import Data.Set (Set)
44import qualified Data.Set as Set
45 ( empty
46 , insert
47 , delete
48 , member
49 , toList
50 )
51import Data.Foldable (forM_)
52import Data.Maybe (isJust, fromJust, isNothing, catMaybes)
53import Data.Typeable (Typeable)
54import Control.Category ((>>>))
55import Control.Applicative (Applicative, (<$>))
56import Control.Monad (void, when)
57import Control.Monad.IO.Class (MonadIO, liftIO)
58import Control.Monad.State.Strict (MonadState, StateT, evalStateT, gets)
59import qualified Control.Monad.State.Strict as StateT (get, put)
60import Control.Monad.Reader (MonadReader, ReaderT, runReaderT, ask)
61import Control.Exception
62 ( throwIO
63 , AsyncException(ThreadKilled)
64 , SomeException
65 , Exception
66 , throwTo
67 , uninterruptibleMask_
68 )
69import qualified Control.Exception as Exception (Handler(..), catches, finally)
70import Control.Concurrent (forkIO, forkIOWithUnmask, myThreadId)
71import Control.Distributed.Process.Internal.StrictMVar
72 ( newMVar
73 , withMVar
74 , modifyMVarMasked
75 , modifyMVar_
76 , newEmptyMVar
77 , putMVar
78 , takeMVar
79 , readMVar
80 )
81import Control.Concurrent.Chan (newChan, writeChan, readChan)
82import qualified Control.Concurrent.MVar as MVar (newEmptyMVar, takeMVar)
83import Control.Concurrent.STM
84 ( atomically
85 )
86import Control.Distributed.Process.Internal.CQueue
87 ( CQueue
88 , enqueue
89 , newCQueue
90 , mkWeakCQueue
91 )
92import qualified Network.Transport as NT
93 ( Transport
94 , EndPoint
95 , newEndPoint
96 , receive
97 , Event(..)
98 , EventErrorCode(..)
99 , TransportError(..)
100 , address
101 , closeEndPoint
102 , ConnectionId
103 , close
104 , EndPointAddress
105 , Reliability(ReliableOrdered)
106 )
107import Data.Accessor (Accessor, accessor, (^.), (^=), (^:))
108import System.Random (randomIO)
109import Control.Distributed.Static (RemoteTable, Closure)
110import qualified Control.Distributed.Static as Static
111 ( unclosure
112 , initRemoteTable
113 )
114import Control.Distributed.Process.Internal.Types
115 ( NodeId(..)
116 , LocalProcessId(..)
117 , ProcessId(..)
118 , LocalNode(..)
119 , MxEventBus(..)
120 , LocalNodeState(..)
121 , LocalProcess(..)
122 , LocalProcessState(..)
123 , Process(..)
124 , DiedReason(..)
125 , NCMsg(..)
126 , ProcessSignal(..)
127 , localPidCounter
128 , localPidUnique
129 , localProcessWithId
130 , localProcesses
131 , localConnections
132 , forever'
133 , MonitorRef(..)
134 , ProcessMonitorNotification(..)
135 , NodeMonitorNotification(..)
136 , PortMonitorNotification(..)
137 , ProcessExitException(..)
138 , ProcessLinkException(..)
139 , NodeLinkException(..)
140 , PortLinkException(..)
141 , DidUnmonitor(..)
142 , DidUnlinkProcess(..)
143 , DidUnlinkNode(..)
144 , DidUnlinkPort(..)
145 , SpawnRef
146 , DidSpawn(..)
147 , Message(..)
148 , TypedChannel(..)
149 , Identifier(..)
150 , nodeOf
151 , ProcessInfo(..)
152 , ProcessInfoNone(..)
153 , NodeStats(..)
154 , SendPortId(..)
155 , typedChannelWithId
156 , RegisterReply(..)
157 , WhereIsReply(..)
158 , payloadToMessage
159 , createUnencodedMessage
160 , runLocalProcess
161 , firstNonReservedProcessId
162 , ImplicitReconnect(WithImplicitReconnect)
163 )
164import Control.Distributed.Process.Management.Internal.Agent
165 ( mxAgentController
166 )
167import qualified Control.Distributed.Process.Management.Internal.Table as Table
168 ( mxTableCoordinator
169 , startTableCoordinator
170 )
171import qualified Control.Distributed.Process.Management.Internal.Trace.Remote as Trace
172 ( remoteTable
173 )
174import Control.Distributed.Process.Management.Internal.Trace.Tracer
175 ( defaultTracer
176 )
177import Control.Distributed.Process.Management.Internal.Trace.Types
178 ( TraceArg(..)
179 , traceEvent
180 , traceLogFmt
181 , enableTrace
182 )
183import Control.Distributed.Process.Management.Internal.Types
184 ( MxEvent(..)
185 )
186import Control.Distributed.Process.Serializable (Serializable)
187import Control.Distributed.Process.Internal.Messaging
188 ( sendBinary
189 , sendMessage
190 , closeImplicitReconnections
191 , impliesDeathOf
192 )
193import Control.Distributed.Process.Internal.Primitives
194 ( register
195 , finally
196 , receiveWait
197 , match
198 , sendChan
199 , catch
200 , unwrapMessage
201 )
202import Control.Distributed.Process.Internal.Types (SendPort, Tracer(..))
203import qualified Control.Distributed.Process.Internal.Closure.BuiltIn as BuiltIn (remoteTable)
204import Control.Distributed.Process.Internal.WeakTQueue (TQueue, writeTQueue)
205import qualified Control.Distributed.Process.Internal.StrictContainerAccessors as DAC
206 ( mapMaybe
207 , mapDefault
208 )
209import Unsafe.Coerce
211--------------------------------------------------------------------------------
212-- Initialization --
213--------------------------------------------------------------------------------
215initRemoteTable :: RemoteTable
216initRemoteTable = Trace.remoteTable $ BuiltIn.remoteTable Static.initRemoteTable
218-- | Initialize a new local node.
219newLocalNode :: NT.Transport -> RemoteTable -> IO LocalNode
220newLocalNode transport rtable = do
221 mEndPoint <- NT.newEndPoint transport
222 case mEndPoint of
223 Left ex -> throwIO ex
224 Right endPoint -> do
225 localNode <- createBareLocalNode endPoint rtable
226 startServiceProcesses localNode
227 return localNode
229-- | Create a new local node (without any service processes running)
230createBareLocalNode :: NT.EndPoint -> RemoteTable -> IO LocalNode
231createBareLocalNode endPoint rtable = do
232 unq <- randomIO
233 state <- newMVar LocalNodeState
234 { _localProcesses = Map.empty
235 , _localPidCounter = firstNonReservedProcessId
236 , _localPidUnique = unq
237 , _localConnections = Map.empty
238 }
239 ctrlChan <- newChan
240 let node = LocalNode { localNodeId = NodeId $ NT.address endPoint
241 , localEndPoint = endPoint
242 , localState = state
243 , localCtrlChan = ctrlChan
244 , localEventBus = MxEventBusInitialising
245 , remoteTable = rtable
246 }
247 tracedNode <- startMxAgent node
249 -- Once the NC terminates, the endpoint isn't much use,
250 void $ forkIO $ Exception.finally (runNodeController tracedNode)
251 (NT.closeEndPoint (localEndPoint node))
253 -- whilst a closed/failing endpoint will terminate the NC
254 void $ forkIO $ Exception.finally (handleIncomingMessages tracedNode)
255 (stopNC node)
257 return tracedNode
258 where
259 stopNC node =
260 writeChan (localCtrlChan node) NCMsg
261 { ctrlMsgSender = NodeIdentifier (localNodeId node)
262 , ctrlMsgSignal = SigShutdown
263 }
265startMxAgent :: LocalNode -> IO LocalNode
266startMxAgent node = do
267 -- see note [tracer/forkProcess races]
268 let fork = forkProcess node
269 mv <- MVar.newEmptyMVar
270 pid <- fork $ mxAgentController fork mv
271 (tracer', wqRef, mxNew') <- MVar.takeMVar mv
272 return node { localEventBus = (MxEventBus pid tracer' wqRef mxNew') }
274startDefaultTracer :: LocalNode -> IO ()
275startDefaultTracer node' = do
276 let t = localEventBus node'
277 case t of
278 MxEventBus _ (Tracer pid _) _ _ -> do
279 runProcess node' $ register "trace.controller" pid
280 pid' <- forkProcess node' defaultTracer
281 enableTrace (localEventBus node') pid'
282 runProcess node' $ register "tracer.initial" pid'
283 _ -> return ()
285-- TODO: we need a better mechanism for defining and registering services
287-- | Start and register the service processes on a node
288startServiceProcesses :: LocalNode -> IO ()
289startServiceProcesses node = do
290 -- tracing /spawns/ relies on the tracer being enabled, but we start
291 -- the default tracer first, even though it might @nsend@ to the logger
292 -- before /that/ process has started - this is a totally harmless race
293 -- however, so we deliberably ignore it
294 startDefaultTracer node
295 tableCoordinatorPid <- fork $ Table.startTableCoordinator fork
296 runProcess node $ register Table.mxTableCoordinator tableCoordinatorPid
297 logger <- forkProcess node loop
298 runProcess node $ do
299 register "logger" logger
300 -- The trace.logger is used for tracing to the console to avoid feedback
301 -- loops during tracing if the user reregisters the "logger" with a custom
302 -- process which uses 'send' or other primitives which are traced.
303 register "trace.logger" logger
304 where
305 fork = forkProcess node
307 loop = do
308 receiveWait
309 [ match $ \((time, pid, string) ::(String, ProcessId, String)) -> do
310 liftIO . hPutStrLn stderr $ time ++ " " ++ show pid ++ ": " ++ string
311 loop
312 , match $ \((time, string) :: (String, String)) -> do
313 -- this is a 'trace' message from the local node tracer
314 liftIO . hPutStrLn stderr $ time ++ " [trace] " ++ string
315 loop
316 , match $ \(ch :: SendPort ()) -> -- a shutdown request
317 sendChan ch ()
318 ]
320-- | Force-close a local node
321--
322-- TODO: for now we just close the associated endpoint
323closeLocalNode :: LocalNode -> IO ()
324closeLocalNode node =
325 -- TODO: close all our processes, surely!?
326 NT.closeEndPoint (localEndPoint node)
328-- | Run a process on a local node and wait for it to finish
329runProcess :: LocalNode -> Process () -> IO ()
330runProcess node proc = do
331 done <- newEmptyMVar
332 tid <- myThreadId
333 void $ forkProcess node $ do
334 catch (proc `finally` liftIO (putMVar done ()))
335 (\(ex :: SomeException) -> liftIO $ throwTo tid ex)
336 takeMVar done
338-- | Spawn a new process on a local node
339forkProcess :: LocalNode -> Process () -> IO ProcessId
340forkProcess node proc =
341 modifyMVarMasked (localState node) startProcess
342 where
343 startProcess :: LocalNodeState -> IO (LocalNodeState, ProcessId)
344 startProcess st = do
345 let lpid = LocalProcessId { lpidCounter = st ^. localPidCounter
346 , lpidUnique = st ^. localPidUnique
347 }
348 let pid = ProcessId { processNodeId = localNodeId node
349 , processLocalId = lpid
350 }
351 pst <- newMVar LocalProcessState { _monitorCounter = 0
352 , _spawnCounter = 0
353 , _channelCounter = 0
354 , _typedChannels = Map.empty
355 }
356 queue <- newCQueue
357 weakQueue <- mkWeakCQueue queue (return ())
358 (_, lproc) <- fixIO $ \ ~(tid, _) -> do
359 let lproc = LocalProcess { processQueue = queue
360 , processWeakQ = weakQueue
361 , processId = pid
362 , processState = pst
363 , processThread = tid
364 , processNode = node
365 }
366 tid' <- uninterruptibleMask_ $ forkIOWithUnmask $ \unmask -> do
367 reason <- Exception.catches
368 (unmask $ runLocalProcess lproc proc >> return DiedNormal)
369 [ (Exception.Handler (\ex@(ProcessExitException from msg) -> do
370 mMsg <- unwrapMessage msg :: IO (Maybe String)
371 case mMsg of
372 Nothing -> return $ DiedException $ show ex
373 Just m -> return $ DiedException ("exit-from=" ++ (show from) ++ ",reason=" ++ m)))
374 , (Exception.Handler
375 (return . DiedException . (show :: SomeException -> String)))]
377 -- [Unified: Table 4, rules termination and exiting]
378 modifyMVar_ (localState node) (cleanupProcess pid)
379 writeChan (localCtrlChan node) NCMsg
380 { ctrlMsgSender = ProcessIdentifier pid
381 , ctrlMsgSignal = Died (ProcessIdentifier pid) reason
382 }
383 return (tid', lproc)
385 -- see note [tracer/forkProcess races]
386 trace node (MxSpawned pid)
388 if lpidCounter lpid == maxBound
389 then do
390 -- TODO: this doesn't look right at all - how do we know
391 -- that newUnique represents a process id that is available!?
392 newUnique <- randomIO
393 return ( (localProcessWithId lpid ^= Just lproc)
394 . (localPidCounter ^= firstNonReservedProcessId)
395 . (localPidUnique ^= newUnique)
396 $ st
397 , pid
398 )
399 else
400 return ( (localProcessWithId lpid ^= Just lproc)
401 . (localPidCounter ^: (+ 1))
402 $ st
403 , pid
404 )
406 cleanupProcess :: ProcessId -> LocalNodeState -> IO LocalNodeState
407 cleanupProcess pid st = do
408 let pid' = ProcessIdentifier pid
409 let (affected, unaffected) = Map.partitionWithKey (\(fr, _to) !_v -> impliesDeathOf pid' fr) (st ^. localConnections)
410 mapM_ (NT.close . fst) (Map.elems affected)
411 return $ (localProcessWithId (processLocalId pid) ^= Nothing)
412 . (localConnections ^= unaffected)
413 $ st
415-- note [tracer/forkProcess races]
416--
417-- Our startTracing function uses forkProcess to start the trace controller
418-- process, and of course forkProcess attempts to call traceEvent once the
419-- process has started. This is harmless, as the localEventBus is not updated
420-- until /after/ the initial forkProcess completes, so the first call to
421-- traceEvent behaves as if tracing were disabled (i.e., it is ignored).
422--
424--------------------------------------------------------------------------------
425-- Handle incoming messages --
426--------------------------------------------------------------------------------
428type IncomingConnection = (NT.EndPointAddress, IncomingTarget)
430data IncomingTarget =
431 Uninit
432 | ToProc ProcessId (Weak (CQueue Message))
433 | ToChan TypedChannel
434 | ToNode
436data ConnectionState = ConnectionState {
437 _incoming :: !(Map NT.ConnectionId IncomingConnection)
438 , _incomingFrom :: !(Map NT.EndPointAddress (Set NT.ConnectionId))
439 }
441initConnectionState :: ConnectionState
442initConnectionState = ConnectionState {
443 _incoming = Map.empty
444 , _incomingFrom = Map.empty
445 }
447incoming :: Accessor ConnectionState (Map NT.ConnectionId IncomingConnection)
448incoming = accessor _incoming (\conns st -> st { _incoming = conns })
450incomingAt :: NT.ConnectionId -> Accessor ConnectionState (Maybe IncomingConnection)
451incomingAt cid = incoming >>> DAC.mapMaybe cid
453incomingFrom :: NT.EndPointAddress -> Accessor ConnectionState (Set NT.ConnectionId)
454incomingFrom addr = aux >>> DAC.mapDefault Set.empty addr
455 where
456 aux = accessor _incomingFrom (\fr st -> st { _incomingFrom = fr })
458handleIncomingMessages :: LocalNode -> IO ()
459handleIncomingMessages node = go initConnectionState
460 where
461 go :: ConnectionState -> IO ()
462 go !st = do
463 event <- NT.receive endpoint
464 case event of
465 NT.ConnectionOpened cid rel theirAddr ->
466 if rel == NT.ReliableOrdered
467 then
468 trace node (MxConnected cid theirAddr)
469 >> go (
470 (incomingAt cid ^= Just (theirAddr, Uninit))
471 . (incomingFrom theirAddr ^: Set.insert cid)
472 $ st
473 )
474 else invalidRequest cid st
475 NT.Received cid payload ->
476 case st ^. incomingAt cid of
477 Just (_, ToProc pid weakQueue) -> do
478 mQueue <- deRefWeak weakQueue
479 forM_ mQueue $ \queue -> do
480 -- TODO: if we find that the queue is Nothing, should we remove
481 -- it from the NC state? (and same for channels, below)
482 let msg = payloadToMessage payload
483 enqueue queue msg -- 'enqueue' is strict
484 trace node (MxReceived pid msg)
485 go st
486 Just (_, ToChan (TypedChannel chan')) -> do
487 mChan <- deRefWeak chan'
488 -- If mChan is Nothing, the process has given up the read end of
489 -- the channel and we simply ignore the incoming message
490 forM_ mChan $ \chan -> atomically $
491 -- We make sure the message is fully decoded when it is enqueued
492 writeTQueue chan $! decode (BSL.fromChunks payload)
493 go st
494 Just (_, ToNode) -> do
495 let ctrlMsg = decode . BSL.fromChunks $ payload
496 writeChan ctrlChan $! ctrlMsg
497 go st
498 Just (src, Uninit) ->
499 case decode (BSL.fromChunks payload) of
500 ProcessIdentifier pid -> do
501 let lpid = processLocalId pid
502 mProc <- withMVar state $ return . (^. localProcessWithId lpid)
503 case mProc of
504 Just proc ->
505 go (incomingAt cid ^= Just (src, ToProc pid (processWeakQ proc)) $ st)
506 Nothing ->
507 invalidRequest cid st
508 SendPortIdentifier chId -> do
509 let lcid = sendPortLocalId chId
510 lpid = processLocalId (sendPortProcessId chId)
511 mProc <- withMVar state $ return . (^. localProcessWithId lpid)
512 case mProc of
513 Just proc -> do
514 mChannel <- withMVar (processState proc) $ return . (^. typedChannelWithId lcid)
515 case mChannel of
516 Just channel ->
517 go (incomingAt cid ^= Just (src, ToChan channel) $ st)
518 Nothing ->
519 invalidRequest cid st
520 Nothing ->
521 invalidRequest cid st
522 NodeIdentifier nid ->
523 if nid == localNodeId node
524 then go (incomingAt cid ^= Just (src, ToNode) $ st)
525 else invalidRequest cid st
526 Nothing ->
527 invalidRequest cid st
528 NT.ConnectionClosed cid ->
529 case st ^. incomingAt cid of
530 Nothing ->
531 invalidRequest cid st
532 Just (src, _) -> do
533 trace node (MxDisconnected cid src)
534 go ( (incomingAt cid ^= Nothing)
535 . (incomingFrom src ^: Set.delete cid)
536 $ st
537 )
538 NT.ErrorEvent (NT.TransportError (NT.EventConnectionLost theirAddr) _) -> do
539 -- [Unified table 9, rule node_disconnect]
540 let nid = NodeIdentifier $ NodeId theirAddr
541 writeChan ctrlChan NCMsg
542 { ctrlMsgSender = nid
543 , ctrlMsgSignal = Died nid DiedDisconnect
544 }
545 let notLost k = not (k `Set.member` (st ^. incomingFrom theirAddr))
546 closeImplicitReconnections node nid
547 go ( (incomingFrom theirAddr ^= Set.empty)
548 . (incoming ^: Map.filterWithKey (const . notLost))
549 $ st
550 )
551 NT.ErrorEvent (NT.TransportError NT.EventEndPointFailed str) ->
552 fail $ "Cloud Haskell fatal error: end point failed: " ++ str
553 NT.ErrorEvent (NT.TransportError NT.EventTransportFailed str) ->
554 fail $ "Cloud Haskell fatal error: transport failed: " ++ str
555 NT.EndPointClosed ->
556 return ()
557 NT.ReceivedMulticast _ _ ->
558 -- If we received a multicast message, something went horribly wrong
559 -- and we just give up
560 fail "Cloud Haskell fatal error: received unexpected multicast"
562 invalidRequest :: NT.ConnectionId -> ConnectionState -> IO ()
563 invalidRequest cid st = do
564 -- TODO: We should treat this as a fatal error on the part of the remote
565 -- node. That is, we should report the remote node as having died, and we
566 -- should close incoming connections (this requires a Transport layer
567 -- extension).
568 traceEventFmtIO node "" [(TraceStr " [network] invalid request: "),
569 (Trace cid)]
570 go ( incomingAt cid ^= Nothing
571 $ st
572 )
574 state = localState node
575 endpoint = localEndPoint node
576 ctrlChan = localCtrlChan node
578--------------------------------------------------------------------------------
579-- Top-level access to the node controller --
580--------------------------------------------------------------------------------
582runNodeController :: LocalNode -> IO ()
583runNodeController =
584 runReaderT (evalStateT (unNC nodeController) initNCState)
586--------------------------------------------------------------------------------
587-- Internal data types --
588--------------------------------------------------------------------------------
590data NCState = NCState
591 { -- Mapping from remote processes to linked local processes
592 _links :: !(Map Identifier (Set ProcessId))
593 -- Mapping from remote processes to monitoring local processes
594 , _monitors :: !(Map Identifier (Set (ProcessId, MonitorRef)))
595 -- Process registry: names and where they live, mapped to the PIDs
596 , _registeredHere :: !(Map String ProcessId)
597 , _registeredOnNodes :: !(Map ProcessId [(NodeId,Int)])
598 }
600newtype NC a = NC { unNC :: StateT NCState (ReaderT LocalNode IO) a }
601 deriving ( Applicative
602 , Functor
603 , Monad
604 , MonadIO
605 , MonadState NCState
606 , MonadReader LocalNode
607 )
609initNCState :: NCState
610initNCState = NCState { _links = Map.empty
611 , _monitors = Map.empty
612 , _registeredHere = Map.empty
613 , _registeredOnNodes = Map.empty
614 }
616-- | Thrown in response to the user invoking 'kill' (see Primitives.hs). This
617-- type is deliberately not exported so it cannot be caught explicitly.
618data ProcessKillException =
619 ProcessKillException !ProcessId !String
620 deriving (Typeable)
622instance Exception ProcessKillException
623instance Show ProcessKillException where
624 show (ProcessKillException pid reason) =
625 "killed-by=" ++ show pid ++ ",reason=" ++ reason
627--------------------------------------------------------------------------------
628-- Tracing/Debugging --
629--------------------------------------------------------------------------------
631-- [Issue #104 / DP-13]
633traceNotifyDied :: LocalNode -> Identifier -> DiedReason -> NC ()
634traceNotifyDied node ident reason =
635 -- TODO: sendPortDied notifications
636 liftIO $ withLocalTracer node $ \t ->
637 case ident of
638 (NodeIdentifier nid) -> traceEvent t (MxNodeDied nid reason)
639 (ProcessIdentifier pid) -> traceEvent t (MxProcessDied pid reason)
640 _ -> return ()
642traceEventFmtIO :: LocalNode
643 -> String
644 -> [TraceArg]
645 -> IO ()
646traceEventFmtIO node fmt args =
647 withLocalTracer node $ \t -> traceLogFmt t fmt args
649trace :: LocalNode -> MxEvent -> IO ()
650trace node ev = withLocalTracer node $ \t -> traceEvent t ev
652withLocalTracer :: LocalNode -> (MxEventBus -> IO ()) -> IO ()
653withLocalTracer node act = act (localEventBus node)
655--------------------------------------------------------------------------------
656-- Core functionality --
657--------------------------------------------------------------------------------
659-- [Unified: Table 7]
660nodeController :: NC ()
661nodeController = do
662 node <- ask
663 forever' $ do
664 msg <- liftIO $ readChan (localCtrlChan node)
666 -- [Unified: Table 7, rule nc_forward]
667 case destNid (ctrlMsgSignal msg) of
668 Just nid' | nid' /= localNodeId node ->
669 liftIO $ sendBinary node
670 (ctrlMsgSender msg)
671 (NodeIdentifier nid')
672 WithImplicitReconnect
673 msg
674 _ ->
675 return ()
677 case msg of
678 NCMsg (ProcessIdentifier from) (Link them) ->
679 ncEffectMonitor from them Nothing
680 NCMsg (ProcessIdentifier from) (Monitor ref) ->
681 ncEffectMonitor from (monitorRefIdent ref) (Just ref)
682 NCMsg (ProcessIdentifier from) (Unlink them) ->
683 ncEffectUnlink from them
684 NCMsg (ProcessIdentifier from) (Unmonitor ref) ->
685 ncEffectUnmonitor from ref
686 NCMsg _from (Died ident reason) ->
687 ncEffectDied ident reason
688 NCMsg (ProcessIdentifier from) (Spawn proc ref) ->
689 ncEffectSpawn from proc ref
690 NCMsg (ProcessIdentifier from) (Register label atnode pid force) ->
691 ncEffectRegister from label atnode pid force
692 NCMsg (ProcessIdentifier from) (WhereIs label) ->
693 ncEffectWhereIs from label
694 NCMsg _ (NamedSend label msg') ->
695 ncEffectNamedSend label msg'
696 NCMsg _ (LocalSend to msg') ->
697 ncEffectLocalSend node to msg'
698 NCMsg _ (LocalPortSend to msg') ->
699 ncEffectLocalPortSend to msg'
700 NCMsg (ProcessIdentifier from) (Kill to reason) ->
701 ncEffectKill from to reason
702 NCMsg (ProcessIdentifier from) (Exit to reason) ->
703 ncEffectExit from to reason
704 NCMsg (ProcessIdentifier from) (GetInfo pid) ->
705 ncEffectGetInfo from pid
706 NCMsg _ SigShutdown ->
707 liftIO $ do
708 NT.closeEndPoint (localEndPoint node)
709 `Exception.finally` throwIO ThreadKilled
710 -- ThreadKilled seems to make more sense than fail/error here
711 NCMsg (ProcessIdentifier from) (GetNodeStats nid) ->
712 ncEffectGetNodeStats from nid
713 unexpected ->
714 error $ "nodeController: unexpected message " ++ show unexpected
716-- [Unified: Table 10]
717ncEffectMonitor :: ProcessId -- ^ Who's watching?
718 -> Identifier -- ^ Who's being watched?
719 -> Maybe MonitorRef -- ^ 'Nothing' to link
720 -> NC ()
721ncEffectMonitor from them mRef = do
722 node <- ask
723 shouldLink <-
724 if not (isLocal node them)
725 then return True
726 else isValidLocalIdentifier them
727 case (shouldLink, isLocal node (ProcessIdentifier from)) of
728 (True, _) -> -- [Unified: first rule]
729 case mRef of
730 Just ref -> modify' $ monitorsFor them ^: Set.insert (from, ref)
731 Nothing -> modify' $ linksFor them ^: Set.insert from
732 (False, True) -> -- [Unified: second rule]
733 notifyDied from them DiedUnknownId mRef
734 (False, False) -> -- [Unified: third rule]
735 -- TODO: this is the right sender according to the Unified semantics,
736 -- but perhaps having 'them' as the sender would make more sense
737 -- (see also: notifyDied)
738 liftIO $ sendBinary node
739 (NodeIdentifier $ localNodeId node)
740 (NodeIdentifier $ processNodeId from)
741 WithImplicitReconnect
742 NCMsg
743 { ctrlMsgSender = NodeIdentifier (localNodeId node)
744 , ctrlMsgSignal = Died them DiedUnknownId
745 }
747-- [Unified: Table 11]
748ncEffectUnlink :: ProcessId -> Identifier -> NC ()
749ncEffectUnlink from them = do
750 node <- ask
751 when (isLocal node (ProcessIdentifier from)) $
752 case them of
753 ProcessIdentifier pid ->
754 postAsMessage from $ DidUnlinkProcess pid
755 NodeIdentifier nid ->
756 postAsMessage from $ DidUnlinkNode nid
757 SendPortIdentifier cid ->
758 postAsMessage from $ DidUnlinkPort cid
759 modify' $ linksFor them ^: Set.delete from
761-- [Unified: Table 11]
762ncEffectUnmonitor :: ProcessId -> MonitorRef -> NC ()
763ncEffectUnmonitor from ref = do
764 node <- ask
765 when (isLocal node (ProcessIdentifier from)) $
766 postAsMessage from $ DidUnmonitor ref
767 modify' $ monitorsFor (monitorRefIdent ref) ^: Set.delete (from, ref)
769-- [Unified: Table 12]
770ncEffectDied :: Identifier -> DiedReason -> NC ()
771ncEffectDied ident reason = do
772 node <- ask
773 traceNotifyDied node ident reason
774 (affectedLinks, unaffectedLinks) <- gets (splitNotif ident . (^. links))
775 (affectedMons, unaffectedMons) <- gets (splitNotif ident . (^. monitors))
777-- _registry :: !(Map (String,NodeId) ProcessId)
779 let localOnly = case ident of NodeIdentifier _ -> True ; _ -> False
781 forM_ (Map.toList affectedLinks) $ \(them, uss) ->
782 forM_ uss $ \us ->
783 when (localOnly <= isLocal node (ProcessIdentifier us)) $
784 notifyDied us them reason Nothing
786 forM_ (Map.toList affectedMons) $ \(them, refs) ->
787 forM_ refs $ \(us, ref) ->
788 when (localOnly <= isLocal node (ProcessIdentifier us)) $
789 notifyDied us them reason (Just ref)
791 modify' $ (links ^= unaffectedLinks) . (monitors ^= unaffectedMons)
793 modify' $ registeredHere ^: Map.filter (\pid -> not $ ident `impliesDeathOf` ProcessIdentifier pid)
795 remaining <- fmap Map.toList (gets (^. registeredOnNodes)) >>=
796 mapM (\(pid,nidlist) ->
797 case ident `impliesDeathOf` ProcessIdentifier pid of
798 True ->
799 do forM_ nidlist $ \(nid,_) ->
800 when (not $ isLocal node (NodeIdentifier nid))
801 (forwardNameDeath node nid)
802 return Nothing
803 False -> return $ Just (pid,nidlist) )
804 modify' $ registeredOnNodes ^= (Map.fromList (catMaybes remaining))
805 where
806 forwardNameDeath node nid =
807 liftIO $ sendBinary node
808 (NodeIdentifier $ localNodeId node)
809 (NodeIdentifier $ nid)
810 WithImplicitReconnect
811 NCMsg
812 { ctrlMsgSender = NodeIdentifier (localNodeId node)
813 , ctrlMsgSignal = Died ident reason
814 }
816-- [Unified: Table 13]
817ncEffectSpawn :: ProcessId -> Closure (Process ()) -> SpawnRef -> NC ()
818ncEffectSpawn pid cProc ref = do
819 mProc <- unClosure cProc
820 -- If the closure does not exist, we spawn a process that throws an exception
821 -- This allows the remote node to find out what's happening
822 -- TODO:
823 let proc = case mProc of
824 Left err -> fail $ "Error: Could not resolve closure: " ++ err
825 Right p -> p
826 node <- ask
827 pid' <- liftIO $ forkProcess node proc
828 liftIO $ sendMessage node
829 (NodeIdentifier (localNodeId node))
830 (ProcessIdentifier pid)
831 WithImplicitReconnect
832 (DidSpawn ref pid')
834-- Unified semantics does not explicitly describe how to implement 'register',
835-- but mentions it's "very similar to nsend" (Table 14)
836-- We send a response indicated if the operation is invalid
837ncEffectRegister :: ProcessId -> String -> NodeId -> Maybe ProcessId -> Bool -> NC ()
838ncEffectRegister from label atnode mPid reregistration = do
839 node <- ask
840 currentVal <- gets (^. registeredHereFor label)
841 isOk <-
842 case mPid of
843 Nothing -> -- unregister request
844 return $ isJust currentVal
845 Just thepid -> -- register request
846 do isvalidlocal <- isValidLocalIdentifier (ProcessIdentifier thepid)
847 return $ (isNothing currentVal /= reregistration) &&
848 (not (isLocal node (ProcessIdentifier thepid) ) || isvalidlocal )
849 if isLocal node (NodeIdentifier atnode)
850 then do when (isOk) $
851 do modify' $ registeredHereFor label ^= mPid
852 updateRemote node currentVal mPid
853 case mPid of
854 (Just p) -> liftIO $ trace node (MxRegistered p label)
855 Nothing -> liftIO $ trace node (MxUnRegistered (fromJust currentVal) label)
856 liftIO $ sendMessage node
857 (NodeIdentifier (localNodeId node))
858 (ProcessIdentifier from)
859 WithImplicitReconnect
860 (RegisterReply label isOk)
861 else let operation =
862 case reregistration of
863 True -> flip decList
864 False -> flip incList
865 in case mPid of
866 Nothing -> return ()
867 Just pid -> modify' $ registeredOnNodesFor pid ^: (maybeify $ operation atnode)
868 where updateRemote node (Just oldval) (Just newval) | processNodeId oldval /= processNodeId newval =
869 do forward node (processNodeId oldval) (Register label atnode (Just oldval) True)
870 forward node (processNodeId newval) (Register label atnode (Just newval) False)
871 updateRemote node Nothing (Just newval) =
872 forward node (processNodeId newval) (Register label atnode (Just newval) False)
873 updateRemote node (Just oldval) Nothing =
874 forward node (processNodeId oldval) (Register label atnode (Just oldval) True)
875 updateRemote _ _ _ = return ()
876 maybeify f Nothing = unmaybeify $ f []
877 maybeify f (Just x) = unmaybeify $ f x
879 unmaybeify [] = Nothing
880 unmaybeify x = Just x
881 incList [] tag = [(tag,1)]
882 incList ((atag,acount):xs) tag | tag==atag = (atag,acount+1) : xs
883 incList (x:xs) tag = x : incList xs tag
884 decList [] _ = []
885 decList ((atag,1):xs) tag | atag == tag = xs
886 decList ((atag,n):xs) tag | atag == tag = (atag,n-1):xs
887 decList (x:xs) tag = x:decList xs tag
888 forward node to reg =
889 when (not $ isLocal node (NodeIdentifier to)) $
890 liftIO $ sendBinary node
891 (ProcessIdentifier from)
892 (NodeIdentifier to)
893 WithImplicitReconnect
894 NCMsg
895 { ctrlMsgSender = ProcessIdentifier from
896 , ctrlMsgSignal = reg
897 }
900-- Unified semantics does not explicitly describe 'whereis'
901ncEffectWhereIs :: ProcessId -> String -> NC ()
902ncEffectWhereIs from label = do
903 node <- ask
904 mPid <- gets (^. registeredHereFor label)
905 liftIO $ sendMessage node
906 (NodeIdentifier (localNodeId node))
907 (ProcessIdentifier from)
908 WithImplicitReconnect
909 (WhereIsReply label mPid)
911-- [Unified: Table 14]
912ncEffectNamedSend :: String -> Message -> NC ()
913ncEffectNamedSend label msg = do
914 mPid <- gets (^. registeredHereFor label)
915 -- If mPid is Nothing, we just ignore the named send (as per Table 14)
916 forM_ mPid $ \pid -> postMessage pid msg
918-- [Issue #DP-20]
919ncEffectLocalSend :: LocalNode -> ProcessId -> Message -> NC ()
920ncEffectLocalSend node to msg =
921 liftIO $ withLocalProc node to $ \p -> do
922 enqueue (processQueue p) msg
923 trace node (MxReceived to msg)
925-- [Issue #DP-20]
926ncEffectLocalPortSend :: SendPortId -> Message -> NC ()
927ncEffectLocalPortSend from msg = do
928 node <- ask
929 let pid = sendPortProcessId from
930 cid = sendPortLocalId from
931 liftIO $ withLocalProc node pid $ \proc -> do
932 mChan <- withMVar (processState proc) $ return . (^. typedChannelWithId cid)
933 case mChan of
934 -- in the unlikely event we know nothing about this channel id,
935 -- there's little to be done - perhaps some logging/tracing though...
936 Nothing -> return ()
937 Just (TypedChannel chan') -> do
938 -- If ch is Nothing, the process has given up the read end of
939 -- the channel and we simply ignore the incoming message - this
940 ch <- deRefWeak chan'
941 forM_ ch $ \chan -> deliverChan msg chan
942 where deliverChan :: forall a . Message -> TQueue a -> IO ()
943 deliverChan (UnencodedMessage _ raw) chan' =
944 atomically $ writeTQueue chan' ((unsafeCoerce raw) :: a)
945 deliverChan (EncodedMessage _ _) _ =
946 -- this will not happen unless someone screws with Primitives.hs
947 error "invalid local channel delivery"
949-- [Issue #69]
950ncEffectKill :: ProcessId -> ProcessId -> String -> NC ()
951ncEffectKill from to reason = do
952 node <- ask
953 when (isLocal node (ProcessIdentifier to)) $
954 throwException to $ ProcessKillException from reason
956-- [Issue #69]
957ncEffectExit :: ProcessId -> ProcessId -> Message -> NC ()
958ncEffectExit from to reason = do
959 node <- ask
960 when (isLocal node (ProcessIdentifier to)) $
961 throwException to $ ProcessExitException from reason
963-- [Issue #89]
964ncEffectGetInfo :: ProcessId -> ProcessId -> NC ()
965ncEffectGetInfo from pid =
966 let lpid = processLocalId pid
967 them = (ProcessIdentifier pid)
968 in do
969 node <- ask
970 mProc <- liftIO $
971 withMVar (localState node) $ return . (^. localProcessWithId lpid)
972 case mProc of
973 Nothing -> dispatch (isLocal node (ProcessIdentifier from))
974 from node (ProcessInfoNone DiedUnknownId)
975 Just _ -> do
976 itsLinks <- gets (^. linksFor them)
977 itsMons <- gets (^. monitorsFor them)
978 registered <- gets (^. registeredHere)
980 let reg = registeredNames registered
981 dispatch (isLocal node (ProcessIdentifier from))
982 from
983 node
984 ProcessInfo {
985 infoNode = (processNodeId pid)
986 , infoRegisteredNames = reg
987 -- we cannot populate this field
988 , infoMessageQueueLength = Nothing
989 , infoMonitors = Set.toList itsMons
990 , infoLinks = Set.toList itsLinks
991 }
992 where dispatch :: (Serializable a, Show a)
993 => Bool
994 -> ProcessId
995 -> LocalNode
996 -> a
997 -> NC ()
998 dispatch True dest _ pInfo = postAsMessage dest $ pInfo
999 dispatch False dest node pInfo = do
1000 liftIO $ sendMessage node
1001 (NodeIdentifier (localNodeId node))
1002 (ProcessIdentifier dest)
1003 WithImplicitReconnect
1004 pInfo
1006 registeredNames = Map.foldlWithKey (\ks k v -> if v == pid
1007 then (k:ks)
1008 else ks) []
1010ncEffectGetNodeStats :: ProcessId -> NodeId -> NC ()
1011ncEffectGetNodeStats from _nid = do
1012 node <- ask
1013 ncState <- StateT.get
1014 nodeState <- liftIO $ readMVar (localState node)
1015 let localProcesses' = nodeState ^. localProcesses
1016 stats =
1017 NodeStats {
1018 nodeStatsNode = localNodeId node
1019 , nodeStatsRegisteredNames = Map.size $ ncState ^. registeredHere
1020 , nodeStatsMonitors = Map.size $ ncState ^. monitors
1021 , nodeStatsLinks = Map.size $ ncState ^. links
1022 , nodeStatsProcesses = Map.size localProcesses'
1024 postAsMessage from stats
1025--------------------------------------------------------------------------------
1026-- Auxiliary --
1027--------------------------------------------------------------------------------
1029notifyDied :: ProcessId -- ^ Who to notify?
1030 -> Identifier -- ^ Who died?
1031 -> DiedReason -- ^ How did they die?
1032 -> Maybe MonitorRef -- ^ 'Nothing' for linking
1033 -> NC ()
1034notifyDied dest src reason mRef = do
1035 node <- ask
1036 case (isLocal node (ProcessIdentifier dest), mRef, src) of
1037 (True, Just ref, ProcessIdentifier pid) ->
1038 postAsMessage dest $ ProcessMonitorNotification ref pid reason
1039 (True, Just ref, NodeIdentifier nid) ->
1040 postAsMessage dest $ NodeMonitorNotification ref nid reason
1041 (True, Just ref, SendPortIdentifier cid) ->
1042 postAsMessage dest $ PortMonitorNotification ref cid reason
1043 (True, Nothing, ProcessIdentifier pid) ->
1044 throwException dest $ ProcessLinkException pid reason
1045 (True, Nothing, NodeIdentifier pid) ->
1046 throwException dest $ NodeLinkException pid reason
1047 (True, Nothing, SendPortIdentifier pid) ->
1048 throwException dest $ PortLinkException pid reason
1049 (False, _, _) ->
1050 -- The change in sender comes from [Unified: Table 10]
1051 liftIO $ sendBinary node
1052 (NodeIdentifier $ localNodeId node)
1053 (NodeIdentifier $ processNodeId dest)
1054 WithImplicitReconnect
1055 NCMsg
1056 { ctrlMsgSender = NodeIdentifier (localNodeId node)
1057 , ctrlMsgSignal = Died src reason
1060-- | [Unified: Table 8]
1061destNid :: ProcessSignal -> Maybe NodeId
1062destNid (Link ident) = Just $ nodeOf ident
1063destNid (Unlink ident) = Just $ nodeOf ident
1064destNid (Monitor ref) = Just $ nodeOf (monitorRefIdent ref)
1065destNid (Unmonitor ref) = Just $ nodeOf (monitorRefIdent ref)
1066destNid (Spawn _ _) = Nothing
1067destNid (Register _ _ _ _) = Nothing
1068destNid (WhereIs _) = Nothing
1069destNid (NamedSend _ _) = Nothing
1070-- We don't need to forward 'Died' signals; if monitoring/linking is setup,
1071-- then when a local process dies the monitoring/linking machinery will take
1072-- care of notifying remote nodes
1073destNid (Died _ _) = Nothing
1074destNid (Kill pid _) = Just $ processNodeId pid
1075destNid (Exit pid _) = Just $ processNodeId pid
1076destNid (GetInfo pid) = Just $ processNodeId pid
1077destNid (GetNodeStats nid) = Just nid
1078destNid (LocalSend pid _) = Just $ processNodeId pid
1079destNid (LocalPortSend cid _) = Just $ processNodeId (sendPortProcessId cid)
1080destNid (SigShutdown) = Nothing
1082-- | Check if a process is local to our own node
1083isLocal :: LocalNode -> Identifier -> Bool
1084isLocal nid ident = nodeOf ident == localNodeId nid
1086-- | Lookup a local closure
1087unClosure :: Typeable a => Closure a -> NC (Either String a)
1088unClosure closure = do
1089 rtable <- remoteTable <$> ask
1090 return (Static.unclosure rtable closure)
1092-- | Check if an identifier refers to a valid local object
1093isValidLocalIdentifier :: Identifier -> NC Bool
1094isValidLocalIdentifier ident = do
1095 node <- ask
1096 liftIO . withMVar (localState node) $ \nSt ->
1097 case ident of
1098 NodeIdentifier nid ->
1099 return $ nid == localNodeId node
1100 ProcessIdentifier pid -> do
1101 let mProc = nSt ^. localProcessWithId (processLocalId pid)
1102 return $ isJust mProc
1103 SendPortIdentifier cid -> do
1104 let pid = sendPortProcessId cid
1105 mProc = nSt ^. localProcessWithId (processLocalId pid)
1106 case mProc of
1107 Nothing -> return False
1108 Just proc -> withMVar (processState proc) $ \pSt -> do
1109 let mCh = pSt ^. typedChannelWithId (sendPortLocalId cid)
1110 return $ isJust mCh
1112--------------------------------------------------------------------------------
1113-- Messages to local processes --
1114--------------------------------------------------------------------------------
1116postAsMessage :: Serializable a => ProcessId -> a -> NC ()
1117postAsMessage pid = postMessage pid . createUnencodedMessage
1119postMessage :: ProcessId -> Message -> NC ()
1120postMessage pid msg = do
1121 node <- ask
1122 liftIO $ withLocalProc node pid $ \p -> enqueue (processQueue p) msg
1124throwException :: Exception e => ProcessId -> e -> NC ()
1125throwException pid e = do
1126 node <- ask
1127 liftIO $ withLocalProc node pid $ \p -> throwTo (processThread p) e
1129withLocalProc :: LocalNode -> ProcessId -> (LocalProcess -> IO ()) -> IO ()
1130withLocalProc node pid p =
1131 -- By [Unified: table 6, rule missing_process] messages to dead processes
1132 -- can silently be dropped
1133 let lpid = processLocalId pid in do
1134 mProc <- withMVar (localState node) $ return . (^. localProcessWithId lpid)
1135 forM_ mProc p
1137--------------------------------------------------------------------------------
1138-- Accessors --
1139--------------------------------------------------------------------------------
1141links :: Accessor NCState (Map Identifier (Set ProcessId))
1142links = accessor _links (\ls st -> st { _links = ls })
1144monitors :: Accessor NCState (Map Identifier (Set (ProcessId, MonitorRef)))
1145monitors = accessor _monitors (\ms st -> st { _monitors = ms })
1147registeredHere :: Accessor NCState (Map String ProcessId)
1148registeredHere = accessor _registeredHere (\ry st -> st { _registeredHere = ry })
1150registeredOnNodes :: Accessor NCState (Map ProcessId [(NodeId, Int)])
1151registeredOnNodes = accessor _registeredOnNodes (\ry st -> st { _registeredOnNodes = ry })
1153linksFor :: Identifier -> Accessor NCState (Set ProcessId)
1154linksFor ident = links >>> DAC.mapDefault Set.empty ident
1156monitorsFor :: Identifier -> Accessor NCState (Set (ProcessId, MonitorRef))
1157monitorsFor ident = monitors >>> DAC.mapDefault Set.empty ident
1159registeredHereFor :: String -> Accessor NCState (Maybe ProcessId)
1160registeredHereFor ident = registeredHere >>> DAC.mapMaybe ident
1162registeredOnNodesFor :: ProcessId -> Accessor NCState (Maybe [(NodeId,Int)])
1163registeredOnNodesFor ident = registeredOnNodes >>> DAC.mapMaybe ident
1165-- | @splitNotif ident@ splits a notifications map into those
1166-- notifications that should trigger when 'ident' fails and those links that
1167-- should not.
1169-- There is a hierarchy between identifiers: failure of a node implies failure
1170-- of all processes on that node, and failure of a process implies failure of
1171-- all typed channels to that process. In other words, if 'ident' refers to a
1172-- node, then the /should trigger/ set will include
1174-- * the notifications for the node specifically
1175-- * the notifications for processes on that node, and
1176-- * the notifications for typed channels to processes on that node.
1178-- Similarly, if 'ident' refers to a process, the /should trigger/ set will
1179-- include
1181-- * the notifications for that process specifically and
1182-- * the notifications for typed channels to that process.
1184-- See https://github.com/haskell/containers/issues/14 for the bang on _v.
1185splitNotif :: Identifier
1186 -> Map Identifier a
1187 -> (Map Identifier a, Map Identifier a)
1188splitNotif ident = Map.partitionWithKey (\k !_v -> ident `impliesDeathOf` k)
1190--------------------------------------------------------------------------------
1191-- Auxiliary --
1192--------------------------------------------------------------------------------
1194-- | Modify and evaluate the state
1195modify' :: MonadState s m => (s -> s) -> m ()
1196modify' f = StateT.get >>= \s -> StateT.put $! f s