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-- | Local nodes
--
-- TODO: Calls to 'sendBinary' and co by the node controller may stall the
-- node controller.
module Control.Distributed.Process.Node
( LocalNode
, newLocalNode
, closeLocalNode
, forkProcess
, runProcess
, initRemoteTable
, localNodeId
) where
#if ! MIN_VERSION_base(4,6,0)
import Prelude hiding (catch)
#endif
import System.IO (fixIO, hPutStrLn, stderr)
import System.Mem.Weak (Weak, deRefWeak)
import qualified Data.ByteString.Lazy as BSL (fromChunks)
import Data.Binary (decode)
import Data.Map (Map)
import qualified Data.Map as Map
( empty
, toList
, fromList
, filter
, partitionWithKey
, elems
, filterWithKey
, foldlWithKey
)
import Data.Set (Set)
import qualified Data.Set as Set
( empty
, insert
, delete
, member
, toList
)
import Data.Foldable (forM_)
import Data.Maybe (isJust, isNothing, catMaybes)
import Data.Typeable (Typeable)
import Control.Category ((>>>))
import Control.Applicative ((<$>))
import Control.Monad (void, when)
import Control.Monad.IO.Class (MonadIO, liftIO)
import Control.Monad.State.Strict (MonadState, StateT, evalStateT, gets)
import qualified Control.Monad.State.Strict as StateT (get, put)
import Control.Monad.Reader (MonadReader, ReaderT, runReaderT, ask)
import Control.Exception (throwIO, SomeException, Exception, throwTo)
import qualified Control.Exception as Exception (catch)
import Control.Concurrent (forkIO)
import Control.Distributed.Process.Internal.StrictMVar
( newMVar
, withMVar
, modifyMVar
, modifyMVar_
, newEmptyMVar
, putMVar
, takeMVar
)
import Control.Concurrent.Chan (newChan, writeChan, readChan)
import Control.Concurrent.STM
( atomically
)
import Control.Distributed.Process.Internal.CQueue
( CQueue
, enqueue
, newCQueue
, mkWeakCQueue
)
import qualified Network.Transport as NT
( Transport
, EndPoint
, newEndPoint
, receive
, Event(..)
, EventErrorCode(..)
, TransportError(..)
, address
, closeEndPoint
, ConnectionId
, Connection
, close
, EndPointAddress
, Reliability(ReliableOrdered)
)
import Data.Accessor (Accessor, accessor, (^.), (^=), (^:))
import System.Random (randomIO)
import Control.Distributed.Static (RemoteTable, Closure)
import qualified Control.Distributed.Static as Static
( unclosure
, initRemoteTable
)
import Control.Distributed.Process.Internal.Types
( NodeId(..)
, LocalProcessId(..)
, ProcessId(..)
, LocalNode(..)
, Tracer
, LocalNodeState(..)
, LocalProcess(..)
, LocalProcessState(..)
, Process(..)
, DiedReason(..)
, NCMsg(..)
, ProcessSignal(..)
, localPidCounter
, localPidUnique
, localProcessWithId
, localConnections
, forever'
, MonitorRef(..)
, ProcessMonitorNotification(..)
, NodeMonitorNotification(..)
, PortMonitorNotification(..)
, ProcessExitException(..)
, ProcessLinkException(..)
, NodeLinkException(..)
, PortLinkException(..)
, DidUnmonitor(..)
, DidUnlinkProcess(..)
, DidUnlinkNode(..)
, DidUnlinkPort(..)
, SpawnRef
, DidSpawn(..)
, Message
, TypedChannel(..)
, Identifier(..)
, nodeOf
, ProcessInfo(..)
, ProcessInfoNone(..)
, SendPortId(..)
, typedChannelWithId
, RegisterReply(..)
, WhereIsReply(..)
, messageToPayload
, payloadToMessage
, createMessage
, runLocalProcess
, firstNonReservedProcessId
, ImplicitReconnect(WithImplicitReconnect, NoImplicitReconnect)
)
import Control.Distributed.Process.Internal.Trace
( trace
, traceFormat
, defaultTracer
, stopTracer
)
import Control.Distributed.Process.Serializable (Serializable)
import Control.Distributed.Process.Internal.Messaging
( sendBinary
, sendMessage
, sendPayload
, closeImplicitReconnections
, impliesDeathOf
)
import Control.Distributed.Process.Internal.Primitives
( register
, finally
, receiveWait
, match
, sendChan
)
import Control.Distributed.Process.Internal.Types (SendPort)
import qualified Control.Distributed.Process.Internal.Closure.BuiltIn as BuiltIn (remoteTable)
import Control.Distributed.Process.Internal.WeakTQueue (writeTQueue)
import qualified Control.Distributed.Process.Internal.StrictContainerAccessors as DAC
( mapMaybe
, mapDefault
)
--------------------------------------------------------------------------------
-- Initialization --
--------------------------------------------------------------------------------
initRemoteTable :: RemoteTable
initRemoteTable = BuiltIn.remoteTable Static.initRemoteTable
-- | Initialize a new local node.
newLocalNode :: NT.Transport -> RemoteTable -> IO LocalNode
newLocalNode transport rtable = do
mEndPoint <- NT.newEndPoint transport
case mEndPoint of
Left ex -> throwIO ex
Right endPoint -> do
localNode <- createBareLocalNode endPoint rtable
startServiceProcesses localNode
return localNode
-- | Create a new local node (without any service processes running)
createBareLocalNode :: NT.EndPoint -> RemoteTable -> IO LocalNode
createBareLocalNode endPoint rtable = do
unq <- randomIO
state <- newMVar LocalNodeState
{ _localProcesses = Map.empty
, _localPidCounter = firstNonReservedProcessId
, _localPidUnique = unq
, _localConnections = Map.empty
}
tracer <- defaultTracer
ctrlChan <- newChan
let node = LocalNode { localNodeId = NodeId $ NT.address endPoint
, localEndPoint = endPoint
, localState = state
, localCtrlChan = ctrlChan
, localTracer = tracer
, remoteTable = rtable
}
void . forkIO $ runNodeController node
void . forkIO $ handleIncomingMessages node
return node
-- | Start and register the service processes on a node
-- (for now, this is only the logger)
startServiceProcesses :: LocalNode -> IO ()
startServiceProcesses node = do
logger <- forkProcess node loop
runProcess node $ register "logger" logger
where
loop = do
receiveWait
[ match $ \((time, pid, string) ::(String, ProcessId, String)) -> do
liftIO . hPutStrLn stderr $ time ++ " " ++ show pid ++ ": " ++ string
loop
, match $ \(ch :: SendPort ()) -> -- a shutdown request
sendChan ch ()
]
-- | Force-close a local node
--
-- TODO: for now we just close the associated endpoint
closeLocalNode :: LocalNode -> IO ()
closeLocalNode node =
NT.closeEndPoint (localEndPoint node)
-- | Run a process on a local node and wait for it to finish
runProcess :: LocalNode -> Process () -> IO ()
runProcess node proc = do
done <- newEmptyMVar
void $ forkProcess node (proc `finally` liftIO (putMVar done ()))
takeMVar done
-- | Spawn a new process on a local node
forkProcess :: LocalNode -> Process () -> IO ProcessId
forkProcess node proc = modifyMVar (localState node) startProcess
where
startProcess :: LocalNodeState -> IO (LocalNodeState, ProcessId)
startProcess st = do
let lpid = LocalProcessId { lpidCounter = st ^. localPidCounter
, lpidUnique = st ^. localPidUnique
}
let pid = ProcessId { processNodeId = localNodeId node
, processLocalId = lpid
}
pst <- newMVar LocalProcessState { _monitorCounter = 0
, _spawnCounter = 0
, _channelCounter = 0
, _typedChannels = Map.empty
}
queue <- newCQueue
weakQueue <- mkWeakCQueue queue (return ())
(_, lproc) <- fixIO $ \ ~(tid, _) -> do
let lproc = LocalProcess { processQueue = queue
, processWeakQ = weakQueue
, processId = pid
, processState = pst
, processThread = tid
, processNode = node
}
tid' <- forkIO $ do
reason <- Exception.catch
(runLocalProcess lproc proc >> return DiedNormal)
(return . DiedException . (show :: SomeException -> String))
-- [Unified: Table 4, rules termination and exiting]
modifyMVar_ (localState node) (cleanupProcess pid)
writeChan (localCtrlChan node) NCMsg
{ ctrlMsgSender = ProcessIdentifier pid
, ctrlMsgSignal = Died (ProcessIdentifier pid) reason
}
return (tid', lproc)
if lpidCounter lpid == maxBound
then do
newUnique <- randomIO
return ( (localProcessWithId lpid ^= Just lproc)
. (localPidCounter ^= firstNonReservedProcessId)
. (localPidUnique ^= newUnique)
$ st
, pid
)
else
return ( (localProcessWithId lpid ^= Just lproc)
. (localPidCounter ^: (+ 1))
$ st
, pid
)
cleanupProcess :: ProcessId -> LocalNodeState -> IO LocalNodeState
cleanupProcess pid st = do
let pid' = ProcessIdentifier pid
let (affected, unaffected) = Map.partitionWithKey (\(fr, _to) !_v -> impliesDeathOf pid' fr) (st ^. localConnections)
mapM_ (NT.close . fst) (Map.elems affected)
return $ (localProcessWithId (processLocalId pid) ^= Nothing)
. (localConnections ^= unaffected)
$ st
--------------------------------------------------------------------------------
-- Handle incoming messages --
--------------------------------------------------------------------------------
type IncomingConnection = (NT.EndPointAddress, IncomingTarget)
data IncomingTarget =
Uninit
| ToProc (Weak (CQueue Message))
| ToChan TypedChannel
| ToNode
data ConnectionState = ConnectionState {
_incoming :: !(Map NT.ConnectionId IncomingConnection)
, _incomingFrom :: !(Map NT.EndPointAddress (Set NT.ConnectionId))
}
initConnectionState :: ConnectionState
initConnectionState = ConnectionState {
_incoming = Map.empty
, _incomingFrom = Map.empty
}
incoming :: Accessor ConnectionState (Map NT.ConnectionId IncomingConnection)
incoming = accessor _incoming (\conns st -> st { _incoming = conns })
incomingAt :: NT.ConnectionId -> Accessor ConnectionState (Maybe IncomingConnection)
incomingAt cid = incoming >>> DAC.mapMaybe cid
incomingFrom :: NT.EndPointAddress -> Accessor ConnectionState (Set NT.ConnectionId)
incomingFrom addr = aux >>> DAC.mapDefault Set.empty addr
where
aux = accessor _incomingFrom (\fr st -> st { _incomingFrom = fr })
handleIncomingMessages :: LocalNode -> IO ()
handleIncomingMessages node = go initConnectionState
where
go :: ConnectionState -> IO ()
go !st = do
event <- NT.receive endpoint
case event of
NT.ConnectionOpened cid rel theirAddr ->
if rel == NT.ReliableOrdered
then go ( (incomingAt cid ^= Just (theirAddr, Uninit))
. (incomingFrom theirAddr ^: Set.insert cid)
$ st
)
else invalidRequest cid st
NT.Received cid payload ->
case st ^. incomingAt cid of
Just (_, ToProc weakQueue) -> do
mQueue <- deRefWeak weakQueue
forM_ mQueue $ \queue -> do
-- TODO: if we find that the queue is Nothing, should we remove
-- it from the NC state? (and same for channels, below)
let msg = payloadToMessage payload
enqueue queue msg -- 'enqueue' is strict
go st
Just (_, ToChan (TypedChannel chan')) -> do
mChan <- deRefWeak chan'
-- If mChan is Nothing, the process has given up the read end of
-- the channel and we simply ignore the incoming message
forM_ mChan $ \chan -> atomically $
-- We make sure the message is fully decoded when it is enqueued
writeTQueue chan $! decode (BSL.fromChunks payload)
go st
Just (_, ToNode) -> do
let ctrlMsg = decode . BSL.fromChunks $ payload
writeChan ctrlChan $! ctrlMsg
go st
Just (src, Uninit) ->
case decode (BSL.fromChunks payload) of
ProcessIdentifier pid -> do
let lpid = processLocalId pid
mProc <- withMVar state $ return . (^. localProcessWithId lpid)
case mProc of
Just proc ->
go (incomingAt cid ^= Just (src, ToProc (processWeakQ proc)) $ st)
Nothing ->
invalidRequest cid st
SendPortIdentifier chId -> do
let lcid = sendPortLocalId chId
lpid = processLocalId (sendPortProcessId chId)
mProc <- withMVar state $ return . (^. localProcessWithId lpid)
case mProc of
Just proc -> do
mChannel <- withMVar (processState proc) $ return . (^. typedChannelWithId lcid)
case mChannel of
Just channel ->
go (incomingAt cid ^= Just (src, ToChan channel) $ st)
Nothing ->
invalidRequest cid st
Nothing ->
invalidRequest cid st
NodeIdentifier nid ->
if nid == localNodeId node
then go (incomingAt cid ^= Just (src, ToNode) $ st)
else invalidRequest cid st
Nothing ->
invalidRequest cid st
NT.ConnectionClosed cid ->
case st ^. incomingAt cid of
Nothing ->
invalidRequest cid st
Just (src, _) ->
go ( (incomingAt cid ^= Nothing)
. (incomingFrom src ^: Set.delete cid)
$ st
)
NT.ErrorEvent (NT.TransportError (NT.EventConnectionLost theirAddr) _) -> do
-- [Unified table 9, rule node_disconnect]
let nid = NodeIdentifier $ NodeId theirAddr
writeChan ctrlChan NCMsg
{ ctrlMsgSender = nid
, ctrlMsgSignal = Died nid DiedDisconnect
}
let notLost k = not (k `Set.member` (st ^. incomingFrom theirAddr))
closeImplicitReconnections node nid
go ( (incomingFrom theirAddr ^= Set.empty)
. (incoming ^: Map.filterWithKey (const . notLost))
$ st
)
NT.ErrorEvent (NT.TransportError NT.EventEndPointFailed str) ->
fail $ "Cloud Haskell fatal error: end point failed: " ++ str
NT.ErrorEvent (NT.TransportError NT.EventTransportFailed str) ->
fail $ "Cloud Haskell fatal error: transport failed: " ++ str
NT.EndPointClosed ->
return ()
NT.ReceivedMulticast _ _ ->
-- If we received a multicast message, something went horribly wrong
-- and we just give up
fail "Cloud Haskell fatal error: received unexpected multicast"
invalidRequest :: NT.ConnectionId -> ConnectionState -> IO ()
invalidRequest cid st = do
-- TODO: We should treat this as a fatal error on the part of the remote
-- node. That is, we should report the remote node as having died, and we
-- should close incoming connections (this requires a Transport layer
-- extension).
traceEventFmtIO node "" ["[network] invalid request: ", (show cid)]
go ( incomingAt cid ^= Nothing
$ st
)
state = localState node
endpoint = localEndPoint node
ctrlChan = localCtrlChan node
--------------------------------------------------------------------------------
-- Top-level access to the node controller --
--------------------------------------------------------------------------------
runNodeController :: LocalNode -> IO ()
runNodeController =
runReaderT (evalStateT (unNC nodeController) initNCState)
--------------------------------------------------------------------------------
-- Internal data types --
--------------------------------------------------------------------------------
data NCState = NCState
{ -- Mapping from remote processes to linked local processes
_links :: !(Map Identifier (Set ProcessId))
-- Mapping from remote processes to monitoring local processes
, _monitors :: !(Map Identifier (Set (ProcessId, MonitorRef)))
-- Process registry: names and where they live, mapped to the PIDs
, _registeredHere :: !(Map String ProcessId)
, _registeredOnNodes :: !(Map ProcessId [(NodeId,Int)])
}
newtype NC a = NC { unNC :: StateT NCState (ReaderT LocalNode IO) a }
deriving (Functor, Monad, MonadIO, MonadState NCState, MonadReader LocalNode)
initNCState :: NCState
initNCState = NCState { _links = Map.empty
, _monitors = Map.empty
, _registeredHere = Map.empty
, _registeredOnNodes = Map.empty
}
-- | Thrown in response to the user invoking 'kill' (see Primitives.hs). This
-- type is deliberately not exported so it cannot be caught explicitly.
data ProcessKillException =
ProcessKillException !ProcessId !String
deriving (Typeable)
instance Exception ProcessKillException
instance Show ProcessKillException where
show (ProcessKillException pid reason) =
"killed-by=" ++ show pid ++ ",reason=" ++ reason
--------------------------------------------------------------------------------
-- Tracing/Debugging --
--------------------------------------------------------------------------------
-- [Issue #104]
traceNotifyDied :: LocalNode -> Identifier -> DiedReason -> NC ()
traceNotifyDied node ident reason =
traceNcEventFmt node " " ["[node-controller]", (show ident), (show reason)]
traceNcEvent :: LocalNode -> String -> NC ()
traceNcEvent node msg = liftIO $ traceEventIO node msg
traceNcEventFmt :: LocalNode -> String -> [String] -> NC ()
traceNcEventFmt node fmt args =
liftIO $ traceEventFmtIO node fmt args
traceEventIO :: LocalNode -> String -> IO ()
traceEventIO node msg = withLocalTracer node $ \t -> trace t msg
traceEventFmtIO :: LocalNode
-> String
-> [String]
-> IO ()
traceEventFmtIO node fmt args =
withLocalTracer node $ \t -> traceFormat t fmt args
withLocalTracer :: LocalNode -> (Tracer -> IO ()) -> IO ()
withLocalTracer node act = act (localTracer node)
--------------------------------------------------------------------------------
-- Core functionality --
--------------------------------------------------------------------------------
-- [Unified: Table 7]
nodeController :: NC ()
nodeController = do
node <- ask
forever' $ do
msg <- liftIO $ readChan (localCtrlChan node)
-- [Unified: Table 7, rule nc_forward]
case destNid (ctrlMsgSignal msg) of
Just nid' | nid' /= localNodeId node ->
liftIO $ sendBinary node
(ctrlMsgSender msg)
(NodeIdentifier nid')
WithImplicitReconnect
msg
_ ->
return ()
case msg of
NCMsg (ProcessIdentifier from) (Link them) ->
ncEffectMonitor from them Nothing
NCMsg (ProcessIdentifier from) (Monitor ref) ->
ncEffectMonitor from (monitorRefIdent ref) (Just ref)
NCMsg (ProcessIdentifier from) (Unlink them) ->
ncEffectUnlink from them
NCMsg (ProcessIdentifier from) (Unmonitor ref) ->
ncEffectUnmonitor from ref
NCMsg _from (Died ident reason) ->
ncEffectDied ident reason
NCMsg (ProcessIdentifier from) (Spawn proc ref) ->
ncEffectSpawn from proc ref
NCMsg (ProcessIdentifier from) (Register label atnode pid force) ->
ncEffectRegister from label atnode pid force
NCMsg (ProcessIdentifier from) (WhereIs label) ->
ncEffectWhereIs from label
NCMsg from (NamedSend label msg') ->
ncEffectNamedSend from label msg'
NCMsg (ProcessIdentifier from) (Kill to reason) ->
ncEffectKill from to reason
NCMsg (ProcessIdentifier from) (Exit to reason) ->
ncEffectExit from to reason
NCMsg (ProcessIdentifier from) (GetInfo pid) ->
ncEffectGetInfo from pid
unexpected ->
error $ "nodeController: unexpected message " ++ show unexpected
-- [Unified: Table 10]
ncEffectMonitor :: ProcessId -- ^ Who's watching?
-> Identifier -- ^ Who's being watched?
-> Maybe MonitorRef -- ^ 'Nothing' to link
-> NC ()
ncEffectMonitor from them mRef = do
node <- ask
shouldLink <-
if not (isLocal node them)
then return True
else isValidLocalIdentifier them
case (shouldLink, isLocal node (ProcessIdentifier from)) of
(True, _) -> -- [Unified: first rule]
case mRef of
Just ref -> modify' $ monitorsFor them ^: Set.insert (from, ref)
Nothing -> modify' $ linksFor them ^: Set.insert from
(False, True) -> -- [Unified: second rule]
notifyDied from them DiedUnknownId mRef
(False, False) -> -- [Unified: third rule]
-- TODO: this is the right sender according to the Unified semantics,
-- but perhaps having 'them' as the sender would make more sense
-- (see also: notifyDied)
liftIO $ sendBinary node
(NodeIdentifier $ localNodeId node)
(NodeIdentifier $ processNodeId from)
WithImplicitReconnect
NCMsg
{ ctrlMsgSender = NodeIdentifier (localNodeId node)
, ctrlMsgSignal = Died them DiedUnknownId
}
-- [Unified: Table 11]
ncEffectUnlink :: ProcessId -> Identifier -> NC ()
ncEffectUnlink from them = do
node <- ask
when (isLocal node (ProcessIdentifier from)) $
case them of
ProcessIdentifier pid ->
postAsMessage from $ DidUnlinkProcess pid
NodeIdentifier nid ->
postAsMessage from $ DidUnlinkNode nid
SendPortIdentifier cid ->
postAsMessage from $ DidUnlinkPort cid
modify' $ linksFor them ^: Set.delete from
-- [Unified: Table 11]
ncEffectUnmonitor :: ProcessId -> MonitorRef -> NC ()
ncEffectUnmonitor from ref = do
node <- ask
when (isLocal node (ProcessIdentifier from)) $
postAsMessage from $ DidUnmonitor ref
modify' $ monitorsFor (monitorRefIdent ref) ^: Set.delete (from, ref)
-- [Unified: Table 12]
ncEffectDied :: Identifier -> DiedReason -> NC ()
ncEffectDied ident reason = do
node <- ask
traceNotifyDied node ident reason
(affectedLinks, unaffectedLinks) <- gets (splitNotif ident . (^. links))
(affectedMons, unaffectedMons) <- gets (splitNotif ident . (^. monitors))
-- _registry :: !(Map (String,NodeId) ProcessId)
let localOnly = case ident of NodeIdentifier _ -> True ; _ -> False
forM_ (Map.toList affectedLinks) $ \(them, uss) ->
forM_ uss $ \us ->
when (localOnly <= isLocal node (ProcessIdentifier us)) $
notifyDied us them reason Nothing
forM_ (Map.toList affectedMons) $ \(them, refs) ->
forM_ refs $ \(us, ref) ->
when (localOnly <= isLocal node (ProcessIdentifier us)) $
notifyDied us them reason (Just ref)
modify' $ (links ^= unaffectedLinks) . (monitors ^= unaffectedMons)
modify' $ registeredHere ^: Map.filter (\pid -> not $ ident `impliesDeathOf` ProcessIdentifier pid)
remaining <- fmap Map.toList (gets (^. registeredOnNodes)) >>=
mapM (\(pid,nidlist) ->
case ident `impliesDeathOf` ProcessIdentifier pid of
True ->
do forM_ nidlist $ \(nid,_) ->
when (not $ isLocal node (NodeIdentifier nid))
(forwardNameDeath node nid)
return Nothing
False -> return $ Just (pid,nidlist) )
modify' $ registeredOnNodes ^= (Map.fromList (catMaybes remaining))
where
forwardNameDeath node nid =
liftIO $ sendBinary node
(NodeIdentifier $ localNodeId node)
(NodeIdentifier $ nid)
WithImplicitReconnect
NCMsg
{ ctrlMsgSender = NodeIdentifier (localNodeId node)
, ctrlMsgSignal = Died ident reason
}
-- [Unified: Table 13]
ncEffectSpawn :: ProcessId -> Closure (Process ()) -> SpawnRef -> NC ()
ncEffectSpawn pid cProc ref = do
mProc <- unClosure cProc
-- If the closure does not exist, we spawn a process that throws an exception
-- This allows the remote node to find out what's happening
let proc = case mProc of
Left err -> fail $ "Error: Could not resolve closure: " ++ err
Right p -> p
node <- ask
pid' <- liftIO $ forkProcess node proc
liftIO $ sendMessage node
(NodeIdentifier (localNodeId node))
(ProcessIdentifier pid)
WithImplicitReconnect
(DidSpawn ref pid')
-- Unified semantics does not explicitly describe how to implement 'register',
-- but mentions it's "very similar to nsend" (Table 14)
-- We send a response indicated if the operation is invalid
ncEffectRegister :: ProcessId -> String -> NodeId -> Maybe ProcessId -> Bool -> NC ()
ncEffectRegister from label atnode mPid reregistration = do
node <- ask
currentVal <- gets (^. registeredHereFor label)
isOk <-
case mPid of
Nothing -> -- unregister request
return $ isJust currentVal
Just thepid -> -- register request
do isvalidlocal <- isValidLocalIdentifier (ProcessIdentifier thepid)
return $ (isNothing currentVal /= reregistration) &&
(not (isLocal node (ProcessIdentifier thepid) ) || isvalidlocal )
if isLocal node (NodeIdentifier atnode)
then do when (isOk) $
do modify' $ registeredHereFor label ^= mPid
updateRemote node currentVal mPid
liftIO $ sendMessage node
(NodeIdentifier (localNodeId node))
(ProcessIdentifier from)
WithImplicitReconnect
(RegisterReply label isOk)
else let operation =
case reregistration of
True -> flip decList
False -> flip incList
in case mPid of
Nothing -> return ()
Just pid -> modify' $ registeredOnNodesFor pid ^: (maybeify $ operation atnode)
where updateRemote node (Just oldval) (Just newval) | processNodeId oldval /= processNodeId newval =
do forward node (processNodeId oldval) (Register label atnode (Just oldval) True)
forward node (processNodeId newval) (Register label atnode (Just newval) False)
updateRemote node Nothing (Just newval) =
forward node (processNodeId newval) (Register label atnode (Just newval) False)
updateRemote node (Just oldval) Nothing =
forward node (processNodeId oldval) (Register label atnode (Just oldval) True)
updateRemote _ _ _ = return ()
maybeify f Nothing = unmaybeify $ f []
maybeify f (Just x) = unmaybeify $ f x
unmaybeify [] = Nothing
unmaybeify x = Just x
incList [] tag = [(tag,1)]
incList ((atag,acount):xs) tag | tag==atag = (atag,acount+1) : xs
incList (x:xs) tag = x : incList xs tag
decList [] _ = []
decList ((atag,1):xs) tag | atag == tag = xs
decList ((atag,n):xs) tag | atag == tag = (atag,n-1):xs
decList (x:xs) tag = x:decList xs tag
forward node to reg =
when (not $ isLocal node (NodeIdentifier to)) $
liftIO $ sendBinary node
(ProcessIdentifier from)
(NodeIdentifier to)
WithImplicitReconnect
NCMsg
{ ctrlMsgSender = ProcessIdentifier from
, ctrlMsgSignal = reg
}
-- Unified semantics does not explicitly describe 'whereis'
ncEffectWhereIs :: ProcessId -> String -> NC ()
ncEffectWhereIs from label = do
node <- ask
mPid <- gets (^. registeredHereFor label)
liftIO $ sendMessage node
(NodeIdentifier (localNodeId node))
(ProcessIdentifier from)
WithImplicitReconnect
(WhereIsReply label mPid)
-- [Unified: Table 14]
ncEffectNamedSend :: Identifier -> String -> Message -> NC ()
ncEffectNamedSend from label msg = do
node <- ask
mPid <- gets (^. registeredHereFor label)
-- If mPid is Nothing, we just ignore the named send (as per Table 14)
forM_ mPid $ \pid ->
liftIO $ sendPayload node
from
(ProcessIdentifier pid)
NoImplicitReconnect
(messageToPayload msg)
-- [Issue #69]
ncEffectKill :: ProcessId -> ProcessId -> String -> NC ()
ncEffectKill from to reason = do
node <- ask
when (isLocal node (ProcessIdentifier to)) $
throwException to $ ProcessKillException from reason
-- [Issue #69]
ncEffectExit :: ProcessId -> ProcessId -> Message -> NC ()
ncEffectExit from to reason = do
node <- ask
when (isLocal node (ProcessIdentifier to)) $
throwException to $ ProcessExitException from reason
-- [Issue #89]
ncEffectGetInfo :: ProcessId -> ProcessId -> NC ()
ncEffectGetInfo from pid =
let lpid = processLocalId pid
them = (ProcessIdentifier pid)
in do
node <- ask
mProc <- liftIO $
withMVar (localState node) $ return . (^. localProcessWithId lpid)
case mProc of
Nothing -> dispatch (isLocal node (ProcessIdentifier from))
from node (ProcessInfoNone DiedUnknownId)
Just _ -> do
itsLinks <- gets (^. linksFor them)
itsMons <- gets (^. monitorsFor them)
registered <- gets (^. registeredHere)
let reg = registeredNames registered
dispatch (isLocal node (ProcessIdentifier from))
from
node
ProcessInfo {
infoNode = (processNodeId pid)
, infoRegisteredNames = reg
-- we cannot populate this field
, infoMessageQueueLength = Nothing
, infoMonitors = Set.toList itsMons
, infoLinks = Set.toList itsLinks
}
where dispatch :: (Serializable a, Show a)
=> Bool
-> ProcessId
-> LocalNode
-> a
-> NC ()
dispatch True dest _ pInfo = postAsMessage dest $ pInfo
dispatch False dest node pInfo = do
liftIO $ sendMessage node
(NodeIdentifier (localNodeId node))
(ProcessIdentifier dest)
WithImplicitReconnect
pInfo
registeredNames = Map.foldlWithKey (\ks k v -> if v == pid
then (k:ks)
else ks) []
--------------------------------------------------------------------------------
-- Auxiliary --
--------------------------------------------------------------------------------
notifyDied :: ProcessId -- ^ Who to notify?
-> Identifier -- ^ Who died?
-> DiedReason -- ^ How did they die?
-> Maybe MonitorRef -- ^ 'Nothing' for linking
-> NC ()
notifyDied dest src reason mRef = do
node <- ask
case (isLocal node (ProcessIdentifier dest), mRef, src) of
(True, Just ref, ProcessIdentifier pid) ->
postAsMessage dest $ ProcessMonitorNotification ref pid reason
(True, Just ref, NodeIdentifier nid) ->
postAsMessage dest $ NodeMonitorNotification ref nid reason
(True, Just ref, SendPortIdentifier cid) ->
postAsMessage dest $ PortMonitorNotification ref cid reason
(True, Nothing, ProcessIdentifier pid) ->
throwException dest $ ProcessLinkException pid reason
(True, Nothing, NodeIdentifier pid) ->
throwException dest $ NodeLinkException pid reason
(True, Nothing, SendPortIdentifier pid) ->
throwException dest $ PortLinkException pid reason
(False, _, _) ->
-- The change in sender comes from [Unified: Table 10]
liftIO $ sendBinary node
(NodeIdentifier $ localNodeId node)
(NodeIdentifier $ processNodeId dest)
WithImplicitReconnect
NCMsg
{ ctrlMsgSender = NodeIdentifier (localNodeId node)
, ctrlMsgSignal = Died src reason
}
-- | [Unified: Table 8]
destNid :: ProcessSignal -> Maybe NodeId
destNid (Link ident) = Just $ nodeOf ident
destNid (Unlink ident) = Just $ nodeOf ident
destNid (Monitor ref) = Just $ nodeOf (monitorRefIdent ref)
destNid (Unmonitor ref) = Just $ nodeOf (monitorRefIdent ref)
destNid (Spawn _ _) = Nothing
destNid (Register _ _ _ _) = Nothing
destNid (WhereIs _) = Nothing
destNid (NamedSend _ _) = Nothing
-- We don't need to forward 'Died' signals; if monitoring/linking is setup,
-- then when a local process dies the monitoring/linking machinery will take
-- care of notifying remote nodes
destNid (Died _ _) = Nothing
destNid (Kill pid _) = Just $ processNodeId pid
destNid (Exit pid _) = Just $ processNodeId pid
destNid (GetInfo pid) = Just $ processNodeId pid
-- | Check if a process is local to our own node
isLocal :: LocalNode -> Identifier -> Bool
isLocal nid ident = nodeOf ident == localNodeId nid
-- | Lookup a local closure
unClosure :: Typeable a => Closure a -> NC (Either String a)
unClosure closure = do
rtable <- remoteTable <$> ask
return (Static.unclosure rtable closure)
-- | Check if an identifier refers to a valid local object
isValidLocalIdentifier :: Identifier -> NC Bool
isValidLocalIdentifier ident = do
node <- ask
liftIO . withMVar (localState node) $ \nSt ->
case ident of
NodeIdentifier nid ->
return $ nid == localNodeId node
ProcessIdentifier pid -> do
let mProc = nSt ^. localProcessWithId (processLocalId pid)
return $ isJust mProc
SendPortIdentifier cid -> do
let pid = sendPortProcessId cid
mProc = nSt ^. localProcessWithId (processLocalId pid)
case mProc of
Nothing -> return False
Just proc -> withMVar (processState proc) $ \pSt -> do
let mCh = pSt ^. typedChannelWithId (sendPortLocalId cid)
return $ isJust mCh
--------------------------------------------------------------------------------
-- Messages to local processes --
--------------------------------------------------------------------------------
postAsMessage :: Serializable a => ProcessId -> a -> NC ()
postAsMessage pid = postMessage pid . createMessage
postMessage :: ProcessId -> Message -> NC ()
postMessage pid msg = do
withLocalProc pid $ \p -> enqueue (processQueue p) msg
throwException :: Exception e => ProcessId -> e -> NC ()
throwException pid e = withLocalProc pid $ \p ->
throwTo (processThread p) e
withLocalProc :: ProcessId -> (LocalProcess -> IO ()) -> NC ()
withLocalProc pid p = do
node <- ask
liftIO $ do
-- By [Unified: table 6, rule missing_process] messages to dead processes
-- can silently be dropped
let lpid = processLocalId pid
mProc <- withMVar (localState node) $ return . (^. localProcessWithId lpid)
forM_ mProc p
--------------------------------------------------------------------------------
-- Accessors --
--------------------------------------------------------------------------------
links :: Accessor NCState (Map Identifier (Set ProcessId))
links = accessor _links (\ls st -> st { _links = ls })
monitors :: Accessor NCState (Map Identifier (Set (ProcessId, MonitorRef)))
monitors = accessor _monitors (\ms st -> st { _monitors = ms })
registeredHere :: Accessor NCState (Map String ProcessId)
registeredHere = accessor _registeredHere (\ry st -> st { _registeredHere = ry })
registeredOnNodes :: Accessor NCState (Map ProcessId [(NodeId, Int)])
registeredOnNodes = accessor _registeredOnNodes (\ry st -> st { _registeredOnNodes = ry })
linksFor :: Identifier -> Accessor NCState (Set ProcessId)
linksFor ident = links >>> DAC.mapDefault Set.empty ident
monitorsFor :: Identifier -> Accessor NCState (Set (ProcessId, MonitorRef))
monitorsFor ident = monitors >>> DAC.mapDefault Set.empty ident
registeredHereFor :: String -> Accessor NCState (Maybe ProcessId)
registeredHereFor ident = registeredHere >>> DAC.mapMaybe ident
registeredOnNodesFor :: ProcessId -> Accessor NCState (Maybe [(NodeId,Int)])
registeredOnNodesFor ident = registeredOnNodes >>> DAC.mapMaybe ident
-- | @splitNotif ident@ splits a notifications map into those
-- notifications that should trigger when 'ident' fails and those links that
-- should not.
--
-- There is a hierarchy between identifiers: failure of a node implies failure
-- of all processes on that node, and failure of a process implies failure of
-- all typed channels to that process. In other words, if 'ident' refers to a
-- node, then the /should trigger/ set will include
--
-- * the notifications for the node specifically
-- * the notifications for processes on that node, and
-- * the notifications for typed channels to processes on that node.
--
-- Similarly, if 'ident' refers to a process, the /should trigger/ set will
-- include
--
-- * the notifications for that process specifically and
-- * the notifications for typed channels to that process.
--
-- See https://github.com/haskell/containers/issues/14 for the bang on _v.
splitNotif :: Identifier
-> Map Identifier a
-> (Map Identifier a, Map Identifier a)
splitNotif ident = Map.partitionWithKey (\k !_v -> ident `impliesDeathOf` k)
--------------------------------------------------------------------------------
-- Auxiliary --
--------------------------------------------------------------------------------
-- | Modify and evaluate the state
modify' :: MonadState s m => (s -> s) -> m ()
modify' f = StateT.get >>= \s -> StateT.put $! f s
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