diff --git a/FediChord.asn1 b/FediChord.asn1 index f278f8f..79b894a 100644 --- a/FediChord.asn1 +++ b/FediChord.asn1 @@ -89,8 +89,8 @@ StabiliseResponsePayload ::= SEQUENCE { LeaveRequestPayload ::= SEQUENCE { successors SEQUENCE OF NodeState, - predecessors SEQUENCE OF NodeState - -- ToDo: transfer of own data to newly responsible node + predecessors SEQUENCE OF NodeState, + doMigration BOOLEAN } LeaveResponsePayload ::= NULL -- just a confirmation diff --git a/Hash2Pub.cabal b/Hash2Pub.cabal index ebc9c7e..376d675 100644 --- a/Hash2Pub.cabal +++ b/Hash2Pub.cabal @@ -46,8 +46,8 @@ category: Network extra-source-files: CHANGELOG.md common deps - build-depends: base ^>=4.12.0.0, containers ^>=0.6.0.1, bytestring, utf8-string ^>=1.0.1.1, network ^>=2.8.0.1, time ^>=1.8.0.2, cmdargs ^>= 0.10, cryptonite ^>= 0.25, memory, async, stm, asn1-encoding, asn1-types, asn1-parse, publicsuffix, network-byte-order, safe, iproute, mtl, random, servant, servant-server, servant-client, warp, text, unordered-containers - ghc-options: -Wall + build-depends: base >=4, containers ^>=0.6.0.1, bytestring, utf8-string ^>=1.0.1.1, network ^>=3.1, time, cmdargs ^>= 0.10, cryptonite, memory, async, stm, asn1-encoding, asn1-types, asn1-parse, publicsuffix, network-byte-order, safe, iproute, mtl, random, servant, servant-server, servant-client, warp, text, unordered-containers, hashable, unicode-transforms, http-client, http-types, unbounded-delays, dlist, formatting + ghc-options: -Wall -Wpartial-fields -O2 @@ -55,10 +55,10 @@ library import: deps -- Modules exported by the library. - exposed-modules: Hash2Pub.FediChord, Hash2Pub.FediChordTypes, Hash2Pub.DHTProtocol, Hash2Pub.ASN1Coding, Hash2Pub.ProtocolTypes, Hash2Pub.PostService, Hash2Pub.ServiceTypes, Hash2Pub.RingMap + exposed-modules: Hash2Pub.FediChord, Hash2Pub.FediChordTypes, Hash2Pub.DHTProtocol, Hash2Pub.ASN1Coding, Hash2Pub.ProtocolTypes, Hash2Pub.PostService, Hash2Pub.RingMap -- Modules included in this library but not exported. - other-modules: Hash2Pub.Utils + other-modules: Hash2Pub.Utils, Hash2Pub.PostService.API -- LANGUAGE extensions used by modules in this package. other-extensions: GeneralizedNewtypeDeriving, DataKinds, OverloadedStrings @@ -91,7 +91,21 @@ executable Hash2Pub -- Base language which the package is written in. default-language: Haskell2010 - ghc-options: -threaded + ghc-options: -threaded -rtsopts -with-rtsopts=-N + +executable Experiment + -- experiment runner + import: deps + + build-depends: Hash2Pub + + main-is: Experiment.hs + + hs-source-dirs: app + + default-language: Haskell2010 + + ghc-options: -threaded test-suite Hash2Pub-test diff --git a/Readme.md b/Readme.md index 3c7dbe5..e3cff3d 100644 --- a/Readme.md +++ b/Readme.md @@ -1,7 +1,7 @@ # Hash2Pub ***This is heavily WIP and does not provide any useful functionality yet***. -I aim for always having the master branch at a state where it builds and tests pass. +I aim for always having the `mainline` branch in a state where it builds and tests pass. A fully-decentralised relay for global hashtag federation in [ActivityPub](https://activitypub.rocks) based on a distributed hash table. It allows querying and subscribing to all posts of a certain hashtag and is implemented in Haskell. @@ -10,8 +10,13 @@ This is the practical implementation of the concept presented in the paper [Dece The ASN.1 module schema used for DHT messages can be found in `FediChord.asn1`. +For further questions and discussins, please refer to the **Hash2Pub topic in [SocialHub](https://socialhub.activitypub.rocks/c/software/hash2pub/48)**. + ## Building The project and its developent environment are built with [Nix](https://nixos.org/nix/). -The development environment can be entered with `nix-shell`. Then the project can be built with `cabal build` from within the environment, or using `nix-shell --command "cabal build"` to do both steps at once. +The development environment can be entered with `nix-shell shell-minimal.nix`. Then the project can be built with `cabal build` from within the environment, or using `nix-shell --command "cabal build" shell-minimal.nix` to do both steps at once. + +While the `shell-minimal.nix` environment contains everything necessary for building and testing this project, the `shell.nix` additionally contains the Haskell IDE engine *hie* and the documentation for all used Haskell packages for more convenient development. +Be aware that these need to be build from source and can take a very long time to build. diff --git a/app/Experiment.hs b/app/Experiment.hs new file mode 100644 index 0000000..f2fa586 --- /dev/null +++ b/app/Experiment.hs @@ -0,0 +1,51 @@ +{-# LANGUAGE OverloadedStrings #-} + +module Main where + +import Control.Concurrent +import Control.Monad (forM_) +import qualified Data.Text.Lazy as Txt +import qualified Data.Text.Lazy.IO as TxtI +import qualified Network.HTTP.Client as HTTP +import System.Environment (getArgs) + +import Hash2Pub.PostService (Hashtag, clientPublishPost) + +-- configuration constants +timelineFile = "../simulationData/inputs/generated/timeline_sample.csv" + +main :: IO () +main = do + -- read CLI parameters + speedupStr : _ <- getArgs + -- read and parse timeline schedule + -- relying on lazyness of HaskellIO, hoping it does not introduce too strong delays + postEvents <- parseSchedule <$> TxtI.readFile timelineFile + -- actually schedule and send the post events + executeSchedule (read speedupStr) postEvents + pure () + + + +parseSchedule :: Txt.Text + -> [(Int, Hashtag, (String, Int))] -- ^ [(delay in microseconds, hashtag, (hostname, port))] +parseSchedule = fmap (parseEntry . Txt.split (== ';')) . Txt.lines + where + parseEntry [delayT, contactT, tag] = + (read $ Txt.unpack delayT, tag, read $ Txt.unpack contactT) + parseEntry entry = error $ "invalid schedule input format: " <> show entry + +executeSchedule :: Int -- ^ speedup factor + -> [(Int, Hashtag, (String, Int))] -- ^ [(delay in microseconds, hashtag, (hostname, port))] + -> IO () +executeSchedule speedup events = do + -- initialise HTTP manager + httpMan <- HTTP.newManager $ HTTP.defaultManagerSettings { HTTP.managerResponseTimeout = HTTP.responseTimeoutMicro 60000000 } + forM_ events $ \(delay, tag, (pubHost, pubPort)) -> do + _ <- forkIO $ + clientPublishPost httpMan pubHost pubPort ("foobar #" <> tag) + >>= either putStrLn (const $ pure ()) + -- while threadDelay gives only minimum delay guarantees, let's hope the + -- additional delays are negligible + -- otherwise: evaluate usage of https://hackage.haskell.org/package/schedule-0.3.0.0/docs/Data-Schedule.html + threadDelay $ delay `div` speedup diff --git a/app/Main.hs b/app/Main.hs index 8887ee8..eac223d 100644 --- a/app/Main.hs +++ b/app/Main.hs @@ -10,15 +10,17 @@ import Data.IP (IPv6, toHostAddress6) import System.Environment import Hash2Pub.FediChord +import Hash2Pub.FediChordTypes +import Hash2Pub.PostService (PostService (..)) main :: IO () main = do -- ToDo: parse and pass config -- probably use `tomland` for that - conf <- readConfig + (fConf, sConf) <- readConfig -- TODO: first initialise 'RealNode', then the vservers -- ToDo: load persisted caches, bootstrapping nodes … - (serverSock, thisNode) <- fediChordInit conf + (serverSock, thisNode) <- fediChordInit fConf (runService sConf :: DHT d => d -> IO (PostService d)) -- currently no masking is necessary, as there is nothing to clean up nodeCacheWriterThread <- forkIO $ nodeCacheWriter thisNode -- try joining the DHT using one of the provided bootstrapping nodes @@ -41,15 +43,38 @@ main = do pure () -readConfig :: IO FediChordConf +readConfig :: IO (FediChordConf, ServiceConf) readConfig = do - confDomainString : ipString : portString : bootstrapHost : bootstrapPortString : _ <- getArgs - pure $ FediChordConf { - confDomain = confDomainString - , confIP = toHostAddress6 . read $ ipString - , confDhtPort = read portString - , confBootstrapNodes = [(bootstrapHost, read bootstrapPortString)] - --, confStabiliseInterval = 60 - , confBootstrapSamplingInterval = 180 - , confMaxLookupCacheAge = 300 - } + confDomainString : ipString : portString : servicePortString : speedupString : remainingArgs <- getArgs + -- allow starting the initial node without bootstrapping info to avoid + -- waiting for timeout + let + speedup = read speedupString + confBootstrapNodes' = case remainingArgs of + bootstrapHost : bootstrapPortString : _ -> + [(bootstrapHost, read bootstrapPortString)] + _ -> [] + fConf = FediChordConf + { confDomain = confDomainString + , confIP = toHostAddress6 . read $ ipString + , confDhtPort = read portString + , confBootstrapNodes = confBootstrapNodes' + , confStabiliseInterval = 80 * 10^6 + , confBootstrapSamplingInterval = 180 * 10^6 `div` speedup + , confMaxLookupCacheAge = 300 / fromIntegral speedup + , confJoinAttemptsInterval = 60 * 10^6 `div` speedup + , confMaxNodeCacheAge = 600 / fromIntegral speedup + , confResponsePurgeAge = 60 / fromIntegral speedup + , confRequestTimeout = 5 * 10^6 `div` speedup + , confRequestRetries = 3 + } + sConf = ServiceConf + { confSubscriptionExpiryTime = 24*3600 / fromIntegral speedup + , confServicePort = read servicePortString + , confServiceHost = confDomainString + , confLogfilePath = "../simulationData/logs/" <> confDomainString <> ".log" + , confSpeedupFactor = speedup + , confStatsEvalDelay = 120 * 10^6 `div` speedup + } + pure (fConf, sConf) + diff --git a/default.nix b/default.nix index eea5386..a3f7640 100644 --- a/default.nix +++ b/default.nix @@ -1,14 +1,19 @@ -{ pkgs ? import ( - builtins.fetchGit { - name = "nixpkgs-pinned"; - url = https://github.com/NixOS/nixpkgs/; - ref = "refs/heads/release-20.03"; - rev = "da7ddd822e32aeebea00e97ab5aeca9758250a40"; - }) {}, - compiler ? "ghc865" +{ + compiler ? "ghc884" }: let + pkgs = import ( + builtins.fetchGit { + name = "nixpkgs-pinned"; + url = https://github.com/NixOS/nixpkgs/; + ref = "refs/heads/release-20.09"; + rev = "e065200fc90175a8f6e50e76ef10a48786126e1c"; + }) { + # Pass no config for purity + config = {}; + overlays = []; + }; hp = pkgs.haskell.packages."${compiler}"; src = pkgs.nix-gitignore.gitignoreSource [] ./.; drv = hp.callCabal2nix "Hash2Pub" "${src}/Hash2Pub.cabal" {}; diff --git a/shell-minimal.nix b/shell-minimal.nix new file mode 100644 index 0000000..15cd4fb --- /dev/null +++ b/shell-minimal.nix @@ -0,0 +1 @@ +(import ./default.nix {withHIE = false;}).shell diff --git a/src/Hash2Pub/ASN1Coding.hs b/src/Hash2Pub/ASN1Coding.hs index 456dac6..10177ab 100644 --- a/src/Hash2Pub/ASN1Coding.hs +++ b/src/Hash2Pub/ASN1Coding.hs @@ -38,6 +38,7 @@ splitPayload numParts pl@LeaveRequestPayload{} = [ LeaveRequestPayload { leaveSuccessors = atDef [] (listInto numParts $ leaveSuccessors pl) (thisPart-1) , leavePredecessors = atDef [] (listInto numParts $ leavePredecessors pl) (thisPart-1) + , leaveDoMigration = leaveDoMigration pl } | thisPart <- [1..numParts] ] splitPayload numParts pl@StabiliseResponsePayload{} = [ StabiliseResponsePayload { @@ -134,9 +135,8 @@ encodePayload payload'@LeaveRequestPayload{} = <> [End Sequence , Start Sequence] <> concatMap encodeNodeState (leavePredecessors payload') - <> [End Sequence - , End Sequence] --- currently StabiliseResponsePayload and LeaveRequestPayload are equal + <> [End Sequence] + <> [Boolean (leaveDoMigration payload'), End Sequence] encodePayload payload'@StabiliseResponsePayload{} = Start Sequence : Start Sequence @@ -144,8 +144,7 @@ encodePayload payload'@StabiliseResponsePayload{} = <> [End Sequence , Start Sequence] <> concatMap encodeNodeState (stabilisePredecessors payload') - <> [End Sequence - , End Sequence] + <> [End Sequence, End Sequence] encodePayload payload'@StabiliseRequestPayload = [Null] encodePayload payload'@QueryIDResponsePayload{} = let @@ -415,9 +414,11 @@ parseLeaveRequest :: ParseASN1 ActionPayload parseLeaveRequest = onNextContainer Sequence $ do succ' <- onNextContainer Sequence (getMany parseNodeState) pred' <- onNextContainer Sequence (getMany parseNodeState) + doMigration <- parseBool pure $ LeaveRequestPayload { leaveSuccessors = succ' , leavePredecessors = pred' + , leaveDoMigration = doMigration } parseLeaveResponse :: ParseASN1 ActionPayload diff --git a/src/Hash2Pub/DHTProtocol.hs b/src/Hash2Pub/DHTProtocol.hs index d69d94c..c86c0f1 100644 --- a/src/Hash2Pub/DHTProtocol.hs +++ b/src/Hash2Pub/DHTProtocol.hs @@ -19,6 +19,7 @@ module Hash2Pub.DHTProtocol , sendQueryIdMessages , requestQueryID , requestJoin + , requestLeave , requestPing , requestStabilise , lookupMessage @@ -34,21 +35,25 @@ module Hash2Pub.DHTProtocol , ackRequest , isPossibleSuccessor , isPossiblePredecessor + , isInOwnResponsibilitySlice , isJoined , closestCachePredecessors ) where +import Control.Concurrent import Control.Concurrent.Async import Control.Concurrent.STM import Control.Concurrent.STM.TBQueue import Control.Concurrent.STM.TQueue import Control.Concurrent.STM.TVar import Control.Exception -import Control.Monad (foldM, forM, forM_) +import Control.Monad (foldM, forM, forM_, void, when) +import Control.Monad.Except (MonadError (..), runExceptT) +import Control.Monad.IO.Class (MonadIO (..)) import qualified Data.ByteString as BS import Data.Either (rights) -import Data.Foldable (foldl', foldr') +import Data.Foldable (foldl', foldr', foldrM) import Data.Functor.Identity import Data.IP (IPv6, fromHostAddress6, toHostAddress6) @@ -73,10 +78,11 @@ import Hash2Pub.FediChordTypes (CacheEntry (..), LocalNodeState (..), LocalNodeStateSTM, NodeCache, NodeID, NodeState (..), - RealNode (..), + RealNode (..), RealNodeSTM, RemoteNodeState (..), RingEntry (..), RingMap (..), - addRMapEntry, addRMapEntryWith, + Service (..), addRMapEntry, + addRMapEntryWith, cacheGetNodeStateUnvalidated, cacheLookup, cacheLookupPred, cacheLookupSucc, genNodeID, @@ -92,7 +98,7 @@ import Debug.Trace (trace) -- TODO: evaluate more fine-grained argument passing to allow granular locking -- | look up an ID to either claim responsibility for it or return the closest l nodes from the local cache -queryLocalCache :: LocalNodeState -> NodeCache -> Int -> NodeID -> QueryResponse +queryLocalCache :: LocalNodeState s -> NodeCache -> Int -> NodeID -> QueryResponse queryLocalCache ownState nCache lBestNodes targetID -- as target ID falls between own ID and first predecessor, it is handled by this node -- This only makes sense if the node is part of the DHT by having joined. @@ -102,9 +108,6 @@ queryLocalCache ownState nCache lBestNodes targetID -- the closest succeeding node (like with the p initiated parallel queries | otherwise = FORWARD $ closestSuccessor `Set.union` closestCachePredecessors (lBestNodes-1) targetID nCache where - ownID = getNid ownState - preds = predecessors ownState - closestSuccessor :: Set.Set RemoteCacheEntry closestSuccessor = maybe Set.empty (Set.singleton . toRemoteCacheEntry) $ cacheLookupSucc targetID nCache @@ -130,23 +133,25 @@ closestCachePredecessors remainingLookups lastID nCache -- Looks up the successor of the lookup key on a 'RingMap' representation of the -- predecessor list with the node itself added. If the result is the same as the node -- itself then it falls into the responsibility interval. -isInOwnResponsibilitySlice :: HasKeyID a NodeID => a -> LocalNodeState -> Bool -isInOwnResponsibilitySlice lookupTarget ownNs = (getKeyID <$> rMapLookupSucc (getKeyID lookupTarget :: NodeID) predecessorRMap) == pure (getNid ownNs) +isInOwnResponsibilitySlice :: HasKeyID NodeID a => a -> LocalNodeState s -> Bool +isInOwnResponsibilitySlice lookupTarget ownNs = (fst <$> rMapLookupSucc (getKeyID lookupTarget :: NodeID) predecessorRMap) == pure (getNid ownNs) where predecessorList = predecessors ownNs -- add node itself to RingMap representation, to distinguish between -- responsibility of own node and predecessor - predecessorRMap = addRMapEntry (toRemoteNodeState ownNs) $ rMapFromList predecessorList + predecessorRMap = addRMapEntry (getKeyID ownRemote) ownRemote $ rMapFromList (keyValuePair <$> predecessorList) :: RingMap NodeID RemoteNodeState + ownRemote = toRemoteNodeState ownNs closestPredecessor = headMay predecessorList -isPossiblePredecessor :: HasKeyID a NodeID => a -> LocalNodeState -> Bool +isPossiblePredecessor :: HasKeyID NodeID a => a -> LocalNodeState s -> Bool isPossiblePredecessor = isInOwnResponsibilitySlice -isPossibleSuccessor :: HasKeyID a NodeID => a -> LocalNodeState -> Bool -isPossibleSuccessor lookupTarget ownNs = (getKeyID <$> rMapLookupPred (getKeyID lookupTarget :: NodeID) successorRMap) == pure (getNid ownNs) +isPossibleSuccessor :: HasKeyID NodeID a => a -> LocalNodeState s -> Bool +isPossibleSuccessor lookupTarget ownNs = (fst <$> rMapLookupPred (getKeyID lookupTarget :: NodeID) successorRMap) == pure (getNid ownNs) where successorList = successors ownNs - successorRMap = addRMapEntry (toRemoteNodeState ownNs) $ rMapFromList successorList + successorRMap = addRMapEntry (getKeyID ownRemote) ownRemote $ rMapFromList (keyValuePair <$> successorList) + ownRemote = toRemoteNodeState ownNs closestSuccessor = headMay successorList -- cache operations @@ -169,7 +174,8 @@ addCacheEntryPure now (RemoteCacheEntry ns ts) cache = let -- TODO: limit diffSeconds to some maximum value to prevent malicious nodes from inserting entries valid nearly until eternity timestamp' = if ts <= now then ts else now - newCache = addRMapEntryWith insertCombineFunction (CacheEntry False ns timestamp') cache + newEntry = CacheEntry False ns timestamp' + newCache = addRMapEntryWith insertCombineFunction (getKeyID newEntry) newEntry cache insertCombineFunction newVal@(KeyEntry (CacheEntry newValidationState newNode newTimestamp)) oldVal = case oldVal of ProxyEntry n _ -> ProxyEntry n (Just newVal) @@ -202,7 +208,7 @@ addNodeAsVerifiedPure :: POSIXTime -> RemoteNodeState -> NodeCache -> NodeCache -addNodeAsVerifiedPure now node = addRMapEntry (CacheEntry True node now) +addNodeAsVerifiedPure now node = addRMapEntry (getKeyID node) (CacheEntry True node now) @@ -221,7 +227,7 @@ markCacheEntryAsVerified timestamp nid = RingMap . Map.adjust adjustFunc nid . g -- | uses the successor and predecessor list of a node as an indicator for whether a -- node has properly joined the DHT -isJoined :: LocalNodeState -> Bool +isJoined :: LocalNodeState s -> Bool isJoined ns = not . all null $ [successors ns, predecessors ns] -- | the size limit to be used when serialising messages for sending @@ -245,19 +251,20 @@ ackRequest _ _ = Map.empty -- | Dispatch incoming requests to the dedicated handling and response function, and enqueue -- the response to be sent. -handleIncomingRequest :: LocalNodeStateSTM -- ^ the handling node +handleIncomingRequest :: Service s (RealNodeSTM s) + => LocalNodeStateSTM s -- ^ the handling node -> TQueue (BS.ByteString, SockAddr) -- ^ send queue -> Set.Set FediChordMessage -- ^ all parts of the request to handle -> SockAddr -- ^ source address of the request -> IO () handleIncomingRequest nsSTM sendQ msgSet sourceAddr = do - putStrLn $ "handling incoming request: " <> show msgSet ns <- readTVarIO nsSTM -- add nodestate to cache now <- getPOSIXTime case headMay . Set.elems $ msgSet of Nothing -> pure () Just aPart -> do + let (SockAddrInet6 _ _ sourceIP _) = sourceAddr queueAddEntries (Identity $ RemoteCacheEntry (sender aPart) now) ns -- distinguish on whether and how to respond. If responding, pass message to response generating function and write responses to send queue maybe (pure ()) ( @@ -265,17 +272,36 @@ handleIncomingRequest nsSTM sendQ msgSet sourceAddr = do ) =<< (case action aPart of Ping -> Just <$> respondPing nsSTM msgSet - Join -> Just <$> respondJoin nsSTM msgSet + Join -> dropSpoofedIDs sourceIP nsSTM msgSet respondJoin -- ToDo: figure out what happens if not joined QueryID -> Just <$> respondQueryID nsSTM msgSet -- only when joined - Leave -> if isJoined ns then Just <$> respondLeave nsSTM msgSet else pure Nothing - Stabilise -> if isJoined ns then Just <$> respondStabilise nsSTM msgSet else pure Nothing + Leave -> if isJoined ns then dropSpoofedIDs sourceIP nsSTM msgSet respondLeave else pure Nothing + Stabilise -> if isJoined ns then dropSpoofedIDs sourceIP nsSTM msgSet respondStabilise else pure Nothing ) -- for single part request, response starts with part number 1. For multipart requests, response starts with part number n+1. -- TODO: determine request type only from first part, but catch RecSelError on each record access when folding, because otherwise different request type parts can make this crash -- TODO: test case: mixed message types of parts + where + -- | Filter out requests with spoofed node IDs by recomputing the ID using + -- the sender IP. + -- For valid (non-spoofed) sender IDs, the passed responder function is invoked. + dropSpoofedIDs :: HostAddress6 -- msg source address + -> LocalNodeStateSTM s + -> Set.Set FediChordMessage -- message parts of the request + -> (LocalNodeStateSTM s -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString)) -- reponder function to be invoked for valid requests + -> IO (Maybe (Map.Map Integer BS.ByteString)) + dropSpoofedIDs addr nsSTM' msgSet' responder = + let + aRequestPart = Set.elemAt 0 msgSet + senderNs = sender aRequestPart + givenSenderID = getNid senderNs + recomputedID = genNodeID addr (getDomain senderNs) (fromInteger $ getVServerID senderNs) + in + if recomputedID == givenSenderID + then Just <$> responder nsSTM' msgSet' + else pure Nothing -- ....... response sending ....... @@ -284,9 +310,8 @@ handleIncomingRequest nsSTM sendQ msgSet sourceAddr = do -- | execute a key ID lookup on local cache and respond with the result -respondQueryID :: LocalNodeStateSTM -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) +respondQueryID :: LocalNodeStateSTM s -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) respondQueryID nsSTM msgSet = do - putStrLn "responding to a QueryID request" -- this message cannot be split reasonably, so just -- consider the first payload let @@ -324,8 +349,7 @@ respondQueryID nsSTM msgSet = do -- | Respond to a Leave request by removing the leaving node from local data structures -- and confirming with response. --- TODO: copy over key data from leaver and confirm -respondLeave :: LocalNodeStateSTM -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) +respondLeave :: Service s (RealNodeSTM s) => LocalNodeStateSTM s -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) respondLeave nsSTM msgSet = do -- combine payload of all parts let (requestPreds, requestSuccs) = foldr' (\msg (predAcc, succAcc) -> @@ -334,16 +358,15 @@ respondLeave nsSTM msgSet = do ) ([],[]) msgSet aRequestPart = Set.elemAt 0 msgSet - senderID = getNid . sender $ aRequestPart + leaveSenderID = getNid . sender $ aRequestPart responseMsg <- atomically $ do nsSnap <- readTVar nsSTM -- remove leaving node from successors, predecessors and NodeCache - writeTQueue (cacheWriteQueue nsSnap) $ deleteCacheEntry senderID + writeTQueue (cacheWriteQueue nsSnap) $ deleteCacheEntry leaveSenderID writeTVar nsSTM $ -- add predecessors and successors of leaving node to own lists - setPredecessors (filter ((/=) senderID . getNid) $ requestPreds <> predecessors nsSnap) - . setSuccessors (filter ((/=) senderID . getNid) $ requestSuccs <> successors nsSnap) $ nsSnap - -- TODO: handle handover of key data + setPredecessors (filter ((/=) leaveSenderID . getNid) $ requestPreds <> predecessors nsSnap) + . setSuccessors (filter ((/=) leaveSenderID . getNid) $ requestSuccs <> successors nsSnap) $ nsSnap let leaveResponse = Response { requestID = requestID aRequestPart , senderID = getNid nsSnap @@ -353,10 +376,14 @@ respondLeave nsSTM msgSet = do , payload = Just LeaveResponsePayload } pure leaveResponse + -- if awaiting an incoming service data migration, collect the lock without blocking this thread + when (maybe False leaveDoMigration (payload aRequestPart)) $ do + ownService <- atomically $ nodeService <$> (readTVar nsSTM >>= (readTVar . parentRealNode)) + void (forkIO $ waitForMigrationFrom ownService leaveSenderID) pure $ serialiseMessage sendMessageSize responseMsg -- | respond to stabilise requests by returning successor and predecessor list -respondStabilise :: LocalNodeStateSTM -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) +respondStabilise :: LocalNodeStateSTM s -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) respondStabilise nsSTM msgSet = do nsSnap <- readTVarIO nsSTM let @@ -378,7 +405,7 @@ respondStabilise nsSTM msgSet = do -- | respond to Ping request by returning all active vserver NodeStates -respondPing :: LocalNodeStateSTM -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) +respondPing :: LocalNodeStateSTM s -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) respondPing nsSTM msgSet = do -- TODO: respond with all active VS when implementing k-choices nsSnap <- readTVarIO nsSTM @@ -395,18 +422,19 @@ respondPing nsSTM msgSet = do } pure $ serialiseMessage sendMessageSize pingResponse --- this modifies node state, so locking and IO seems to be necessary. --- Still try to keep as much code as possible pure -respondJoin :: LocalNodeStateSTM -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) + +respondJoin :: Service s (RealNodeSTM s) => LocalNodeStateSTM s -> Set.Set FediChordMessage -> IO (Map.Map Integer BS.ByteString) respondJoin nsSTM msgSet = do -- atomically read and modify the node state according to the parsed request - responseMsg <- atomically $ do + (dataMigration, responseMsg) <- atomically $ do nsSnap <- readTVar nsSTM cache <- readTVar $ nodeCacheSTM nsSnap let aRequestPart = Set.elemAt 0 msgSet senderNS = sender aRequestPart - responsibilityLookup = queryLocalCache nsSnap cache 1 (getNid senderNS) + -- if not joined yet, attract responsibility for + -- all keys to make bootstrapping possible + responsibilityLookup = if isJoined nsSnap then queryLocalCache nsSnap cache 1 (getNid senderNS) else FOUND (toRemoteNodeState nsSnap) thisNodeResponsible (FOUND _) = True thisNodeResponsible (FORWARD _) = False -- check whether the joining node falls into our responsibility @@ -430,33 +458,41 @@ respondJoin nsSTM msgSet = do , payload = Just responsePayload } writeTVar nsSTM joinedNS - pure joinResponse + ownService <- nodeService <$> readTVar (parentRealNode nsSnap) + let + serviceDataMigrator = migrateData ownService (getNid nsSnap) lowerKeyBound (getNid senderNS) (getDomain senderNS, fromIntegral $ getServicePort senderNS) + lowerKeyBound = maybe (getNid nsSnap) getNid $ headMay (predecessors nsSnap) + pure (Just serviceDataMigrator, joinResponse) -- otherwise respond with empty payload - else pure Response { + else pure (Nothing, Response { requestID = requestID aRequestPart , senderID = getNid nsSnap , part = if Set.size msgSet == 1 then 1 else fromIntegral $ Set.size msgSet + 1 , isFinalPart = False , action = Join , payload = Nothing - } + }) + -- as DHT response is required immediately, fork the service data migration push + -- into a new thread. That's kind of ugly but the best I can think of so far + when (isJust dataMigration) (forkIO (fromJust dataMigration >> pure ()) >> pure ()) pure $ serialiseMessage sendMessageSize responseMsg -- TODO: notify service layer to copy over data now handled by the new joined node -- ....... request sending ....... -- | send a join request and return the joined 'LocalNodeState' including neighbours -requestJoin :: NodeState a => a -- ^ currently responsible node to be contacted - -> LocalNodeStateSTM -- ^ joining NodeState - -> IO (Either String LocalNodeStateSTM) -- ^ node after join with all its new information +requestJoin :: (NodeState a, Service s (RealNodeSTM s)) => a -- ^ currently responsible node to be contacted + -> LocalNodeStateSTM s -- ^ joining NodeState + -> IO (Either String (LocalNodeStateSTM s)) -- ^ node after join with all its new information requestJoin toJoinOn ownStateSTM = do ownState <- readTVarIO ownStateSTM prn <- readTVarIO $ parentRealNode ownState - srcAddr <- confIP . nodeConfig <$> readTVarIO (parentRealNode ownState) + nodeConf <- nodeConfig <$> readTVarIO (parentRealNode ownState) + let srcAddr = confIP nodeConf bracket (mkSendSocket srcAddr (getDomain toJoinOn) (getDhtPort toJoinOn)) close (\sock -> do -- extract own state for getting request information - responses <- sendRequestTo 5000 3 (\rid -> Request rid (toRemoteNodeState ownState) 1 True Join (Just JoinRequestPayload)) sock + responses <- sendRequestTo (confRequestTimeout nodeConf) (confRequestRetries nodeConf) (\rid -> Request rid (toRemoteNodeState ownState) 1 True Join (Just JoinRequestPayload)) sock (cacheInsertQ, joinedState) <- atomically $ do stateSnap <- readTVar ownStateSTM let @@ -481,25 +517,28 @@ requestJoin toJoinOn ownStateSTM = do ([], Set.empty, Set.empty) responses -- sort, slice and set the accumulated successors and predecessors - newState = setSuccessors (Set.elems succAccSet) . setPredecessors (Set.elems predAccSet) $ stateSnap + -- the contacted node itself is a successor as well and, with few + -- nodes, can be a predecessor as well + newState = setSuccessors (toRemoteNodeState toJoinOn:Set.elems succAccSet) . setPredecessors (toRemoteNodeState toJoinOn:Set.elems predAccSet) $ stateSnap writeTVar ownStateSTM newState pure (cacheInsertQ, newState) -- execute the cache insertions mapM_ (\f -> f joinedState) cacheInsertQ - pure $ if responses == Set.empty - then Left $ "join error: got no response from " <> show (getNid toJoinOn) - else if null (predecessors joinedState) && null (successors joinedState) - then Left "join error: no predecessors or successors" - -- successful join - else Right ownStateSTM + if responses == Set.empty + then pure . Left $ "join error: got no response from " <> show (getNid toJoinOn) + else do + -- wait for migration data to be completely received + waitForMigrationFrom (nodeService prn) (getNid toJoinOn) + pure $ Right ownStateSTM ) `catch` (\e -> pure . Left $ displayException (e :: IOException)) -- | Send a 'QueryID' 'Request' for getting the node that handles a certain key ID. -requestQueryID :: LocalNodeState -- ^ NodeState of the querying node +requestQueryID :: (MonadIO m, MonadError String m) + => LocalNodeState s -- ^ NodeState of the querying node -> NodeID -- ^ target key ID to look up - -> IO RemoteNodeState -- ^ the node responsible for handling that key + -> m RemoteNodeState -- ^ the node responsible for handling that key -- 1. do a local lookup for the l closest nodes -- 2. create l sockets -- 3. send a message async concurrently to all l nodes @@ -507,23 +546,23 @@ requestQueryID :: LocalNodeState -- ^ NodeState of the querying node -- 5. repeat until FOUND (problem: new entries not necessarily already in cache, explicitly compare with closer results) -- TODO: deal with lookup failures requestQueryID ns targetID = do - firstCacheSnapshot <- readTVarIO . nodeCacheSTM $ ns + firstCacheSnapshot <- liftIO . readTVarIO . nodeCacheSTM $ ns -- TODO: make maxAttempts configurable queryIdLookupLoop firstCacheSnapshot ns 50 targetID -- | like 'requestQueryID, but allows passing of a custom cache, e.g. for joining -queryIdLookupLoop :: NodeCache -> LocalNodeState -> Int -> NodeID -> IO RemoteNodeState +queryIdLookupLoop :: (MonadIO m, MonadError String m) => NodeCache -> LocalNodeState s -> Int -> NodeID -> m RemoteNodeState -- return node itself as default fallback value against infinite recursion. -- TODO: consider using an Either instead of a default value -queryIdLookupLoop _ ns 0 _ = pure $ toRemoteNodeState ns +queryIdLookupLoop _ ns 0 _ = throwError "exhausted maximum lookup attempts" queryIdLookupLoop cacheSnapshot ns maxAttempts targetID = do let localResult = queryLocalCache ns cacheSnapshot (lNumBestNodes ns) targetID -- FOUND can only be returned if targetID is owned by local node case localResult of FOUND thisNode -> pure thisNode FORWARD nodeSet -> do - responseEntries <- sendQueryIdMessages targetID ns Nothing (remoteNode <$> Set.elems nodeSet) - now <- getPOSIXTime + responseEntries <- liftIO $ sendQueryIdMessages targetID ns Nothing (remoteNode <$> Set.elems nodeSet) + now <- liftIO getPOSIXTime -- check for a FOUND and return it case responseEntries of FOUND foundNode -> pure foundNode @@ -538,7 +577,7 @@ queryIdLookupLoop cacheSnapshot ns maxAttempts targetID = do sendQueryIdMessages :: (Integral i) => NodeID -- ^ target key ID to look up - -> LocalNodeState -- ^ node state of the node doing the query + -> LocalNodeState s -- ^ node state of the node doing the query -> Maybe i -- ^ optionally provide an explicit @l@ parameter of number of nodes to be returned -> [RemoteNodeState] -- ^ nodes to query -> IO QueryResponse -- ^ accumulated response @@ -546,10 +585,10 @@ sendQueryIdMessages targetID ns lParam targets = do -- create connected sockets to all query targets and use them for request handling - srcAddr <- confIP . nodeConfig <$> readTVarIO (parentRealNode ns) - -- ToDo: make attempts and timeout configurable + nodeConf <- nodeConfig <$> readTVarIO (parentRealNode ns) + let srcAddr = confIP nodeConf queryThreads <- mapM (\resultNode -> async $ bracket (mkSendSocket srcAddr (getDomain resultNode) (getDhtPort resultNode)) close ( - sendRequestTo 5000 3 (lookupMessage targetID ns Nothing) + sendRequestTo (confRequestTimeout nodeConf) (confRequestRetries nodeConf) (lookupMessage targetID ns Nothing) )) targets -- ToDo: process results immediately instead of waiting for the last one to finish, see https://stackoverflow.com/a/38815224/9198613 -- ToDo: exception handling, maybe log them @@ -557,8 +596,10 @@ sendQueryIdMessages targetID ns lParam targets = do -- insert new cache entries both into global cache as well as return accumulated QueryResponses for further processing now <- getPOSIXTime -- collect cache entries from all responses - foldM (\acc resp -> do - let entrySet = case queryResult <$> payload resp of + foldrM (\resp acc -> do + let + responseResult = queryResult <$> payload resp + entrySet = case responseResult of Just (FOUND result1) -> Set.singleton (RemoteCacheEntry result1 now) Just (FORWARD resultset) -> resultset _ -> Set.empty @@ -568,15 +609,20 @@ sendQueryIdMessages targetID ns lParam targets = do -- return accumulated QueryResult pure $ case acc of -- once a FOUND as been encountered, return this as a result - isFound@FOUND{} -> isFound - FORWARD accSet -> FORWARD $ entrySet `Set.union` accSet + FOUND{} -> acc + FORWARD accSet + | maybe False isFound responseResult -> fromJust responseResult + | otherwise -> FORWARD $ entrySet `Set.union` accSet ) (FORWARD Set.empty) responses + where + isFound FOUND{} = True + isFound _ = False -- | Create a QueryID message to be supplied to 'sendRequestTo' lookupMessage :: Integral i => NodeID -- ^ target ID - -> LocalNodeState -- ^ sender node state + -> LocalNodeState s -- ^ sender node state -> Maybe i -- ^ optionally provide a different l parameter -> (Integer -> FediChordMessage) lookupMessage targetID ns lParam = \rID -> Request rID (toRemoteNodeState ns) 1 True QueryID (Just $ pl ns targetID) @@ -586,12 +632,13 @@ lookupMessage targetID ns lParam = \rID -> Request rID (toRemoteNodeState ns) 1 -- | Send a stabilise request to provided 'RemoteNode' and, if successful, -- return parsed neighbour lists -requestStabilise :: LocalNodeState -- ^ sending node +requestStabilise :: LocalNodeState s -- ^ sending node -> RemoteNodeState -- ^ neighbour node to send to -> IO (Either String ([RemoteNodeState], [RemoteNodeState])) -- ^ (predecessors, successors) of responding node requestStabilise ns neighbour = do - srcAddr <- confIP . nodeConfig <$> readTVarIO (parentRealNode ns) - responses <- bracket (mkSendSocket srcAddr (getDomain neighbour) (getDhtPort neighbour)) close (fmap Right . sendRequestTo 5000 3 (\rid -> + nodeConf <- nodeConfig <$> readTVarIO (parentRealNode ns) + let srcAddr = confIP nodeConf + responses <- bracket (mkSendSocket srcAddr (getDomain neighbour) (getDhtPort neighbour)) close (fmap Right . sendRequestTo (confRequestTimeout nodeConf) (confRequestRetries nodeConf) (\rid -> Request { requestID = rid , sender = toRemoteNodeState ns @@ -613,22 +660,55 @@ requestStabilise ns neighbour = do ) ([],[]) respSet -- update successfully responded neighbour in cache - now <- getPOSIXTime - maybe (pure ()) (\p -> queueAddEntries (Identity $ RemoteCacheEntry (sender p) now) ns) $ headMay (Set.elems respSet) + maybe (pure ()) (\p -> queueUpdateVerifieds (Identity $ senderID p) ns) $ headMay (Set.elems respSet) pure $ if null responsePreds && null responseSuccs then Left "no neighbours returned" else Right (responsePreds, responseSuccs) ) responses -requestPing :: LocalNodeState -- ^ sending node +-- | Send a Leave request to the specified node. +-- Service data transfer needs to be done separately, as not all neighbours +-- that need to know about the leaving handle the new service data. +requestLeave :: LocalNodeState s + -> Bool -- whether to migrate service data + -> RemoteNodeState -- target node + -> IO (Either String ()) -- error or success +requestLeave ns doMigration target = do + nodeConf <- nodeConfig <$> readTVarIO (parentRealNode ns) + let srcAddr = confIP nodeConf + leavePayload = LeaveRequestPayload { + leaveSuccessors = successors ns + , leavePredecessors = predecessors ns + , leaveDoMigration = doMigration + } + responses <- bracket (mkSendSocket srcAddr (getDomain target) (getDhtPort target)) close (fmap Right . sendRequestTo (confRequestTimeout nodeConf) (confRequestRetries nodeConf) (\rid -> + Request { + requestID = rid + , sender = toRemoteNodeState ns + , part = 1 + , isFinalPart = False + , action = Leave + , payload = Just leavePayload + } + ) + ) `catch` (\e -> pure . Left $ displayException (e :: IOException)) + either + -- forward IO error messages + (pure . Left) + -- empty payload, so no processing required + (const . pure . Right $ ()) + responses + +requestPing :: LocalNodeState s -- ^ sending node -> RemoteNodeState -- ^ node to be PINGed -> IO (Either String [RemoteNodeState]) -- ^ all active vServers of the pinged node requestPing ns target = do - srcAddr <- confIP . nodeConfig <$> readTVarIO (parentRealNode ns) + nodeConf <- nodeConfig <$> readTVarIO (parentRealNode ns) + let srcAddr = confIP nodeConf responses <- bracket (mkSendSocket srcAddr (getDomain target) (getDhtPort target)) close (\sock -> do - resp <- sendRequestTo 5000 3 (\rid -> + resp <- sendRequestTo (confRequestTimeout nodeConf) (confRequestRetries nodeConf) (\rid -> Request { requestID = rid , sender = toRemoteNodeState ns @@ -664,10 +744,9 @@ requestPing ns target = do ) responses - -- | Generic function for sending a request over a connected socket and collecting the response. -- Serialises the message and tries to deliver its parts for a number of attempts within a specified timeout. -sendRequestTo :: Int -- ^ timeout in seconds +sendRequestTo :: Int -- ^ timeout in milliseconds -> Int -- ^ number of retries -> (Integer -> FediChordMessage) -- ^ the message to be sent, still needing a requestID -> Socket -- ^ connected socket to use for sending @@ -678,11 +757,10 @@ sendRequestTo timeoutMillis numAttempts msgIncomplete sock = do let msgComplete = msgIncomplete randomID requests = serialiseMessage sendMessageSize msgComplete - putStrLn $ "sending request message " <> show msgComplete -- create a queue for passing received response messages back, even after a timeout responseQ <- newTBQueueIO $ 2*maximumParts -- keep room for duplicate packets -- start sendAndAck with timeout - attempts numAttempts . timeout timeoutMillis $ sendAndAck responseQ sock requests + _ <- attempts numAttempts . timeout (timeoutMillis*1000) $ sendAndAck responseQ sock requests -- after timeout, check received responses, delete them from unacked message set/ map and rerun senAndAck with that if necessary. recvdParts <- atomically $ flushTBQueue responseQ pure $ Set.fromList recvdParts @@ -691,19 +769,20 @@ sendRequestTo timeoutMillis numAttempts msgIncomplete sock = do -> Socket -- ^ the socket used for sending and receiving for this particular remote node -> Map.Map Integer BS.ByteString -- ^ the remaining unacked request parts -> IO () - sendAndAck responseQueue sock remainingSends = do - sendMany sock $ Map.elems remainingSends + sendAndAck responseQueue sock' remainingSends = do + sendMany sock' $ Map.elems remainingSends -- if all requests have been acked/ responded to, return prematurely - recvLoop responseQueue remainingSends Set.empty Nothing - recvLoop :: TBQueue FediChordMessage -- ^ the queue for putting in the received responses + recvLoop sock' responseQueue remainingSends Set.empty Nothing + recvLoop :: Socket + -> TBQueue FediChordMessage -- ^ the queue for putting in the received responses -> Map.Map Integer BS.ByteString -- ^ the remaining unacked request parts -> Set.Set Integer -- ^ already received response part numbers - -> Maybe Integer -- ^ total number of response parts if already known + -> Maybe Integer -- ^ total number of response parts if already known -> IO () - recvLoop responseQueue remainingSends' receivedPartNums totalParts = do + recvLoop sock' responseQueue remainingSends' receivedPartNums totalParts = do -- 65535 is maximum length of UDP packets, as long as -- no IPv6 jumbograms are used - response <- deserialiseMessage <$> recv sock 65535 + response <- deserialiseMessage <$> recv sock' 65535 case response of Right msg@Response{} -> do atomically $ writeTBQueue responseQueue msg @@ -711,16 +790,17 @@ sendRequestTo timeoutMillis numAttempts msgIncomplete sock = do newTotalParts = if isFinalPart msg then Just (part msg) else totalParts newRemaining = Map.delete (part msg) remainingSends' newReceivedParts = Set.insert (part msg) receivedPartNums - if Map.null newRemaining && maybe False (\p -> Set.size receivedPartNums == fromIntegral p) newTotalParts + if Map.null newRemaining && maybe False (\p -> Set.size newReceivedParts == fromIntegral p) newTotalParts then pure () - else recvLoop responseQueue newRemaining receivedPartNums newTotalParts + else recvLoop sock' responseQueue newRemaining newReceivedParts newTotalParts -- drop errors and invalid messages - Left _ -> recvLoop responseQueue remainingSends' receivedPartNums totalParts + Right Request{} -> pure () -- expecting a response, not a request + Left _ -> recvLoop sock' responseQueue remainingSends' receivedPartNums totalParts -- | enqueue a list of RemoteCacheEntries to be added to the global NodeCache queueAddEntries :: Foldable c => c RemoteCacheEntry - -> LocalNodeState + -> LocalNodeState s -> IO () queueAddEntries entries ns = do now <- getPOSIXTime @@ -730,17 +810,29 @@ queueAddEntries entries ns = do -- | enque a list of node IDs to be deleted from the global NodeCache queueDeleteEntries :: Foldable c => c NodeID - -> LocalNodeState + -> LocalNodeState s -> IO () queueDeleteEntries ids ns = forM_ ids $ atomically . writeTQueue (cacheWriteQueue ns) . deleteCacheEntry -- | enque a single node ID to be deleted from the global NodeCache queueDeleteEntry :: NodeID - -> LocalNodeState + -> LocalNodeState s -> IO () queueDeleteEntry toDelete = queueDeleteEntries $ Identity toDelete + +-- | enqueue the timestamp update and verification marking of an entry in the +-- global 'NodeCache'. +queueUpdateVerifieds :: Foldable c + => c NodeID + -> LocalNodeState s + -> IO () +queueUpdateVerifieds nIds ns = do + now <- getPOSIXTime + forM_ nIds $ \nid' -> atomically $ writeTQueue (cacheWriteQueue ns) $ + markCacheEntryAsVerified (Just now) nid' + -- | retry an IO action at most *i* times until it delivers a result attempts :: Int -- ^ number of retries *i* -> IO (Maybe a) -- ^ action to retry @@ -773,7 +865,7 @@ mkServerSocket ip port = do sockAddr <- addrAddress <$> resolve (Just $ show . fromHostAddress6 $ ip) (Just port) sock <- socket AF_INET6 Datagram defaultProtocol setSocketOption sock IPv6Only 1 - bind sock sockAddr + bind sock sockAddr `catch` (\e -> putStrLn $ "Caught exception while bind " <> show sock <> " " <> show sockAddr <> ": " <> show (e :: SomeException)) pure sock -- | create a UDP datagram socket, connected to a destination. @@ -789,6 +881,6 @@ mkSendSocket srcIp dest destPort = do setSocketOption sendSock IPv6Only 1 -- bind to the configured local IP to make sure that outgoing packets are sent from -- this source address - bind sendSock srcAddr + bind sendSock srcAddr `catch` (\e -> putStrLn $ "Caught exception while mkSendSocket bind " <> show sendSock <> " " <> show srcAddr <> ": " <> show (e :: SomeException)) connect sendSock destAddr pure sendSock diff --git a/src/Hash2Pub/FediChord.hs b/src/Hash2Pub/FediChord.hs index 26a373c..9f14a1e 100644 --- a/src/Hash2Pub/FediChord.hs +++ b/src/Hash2Pub/FediChord.hs @@ -1,9 +1,8 @@ -{-# LANGUAGE DataKinds #-} -{-# LANGUAGE DerivingStrategies #-} -{-# LANGUAGE FlexibleContexts #-} -{-# LANGUAGE FlexibleInstances #-} -{-# LANGUAGE OverloadedStrings #-} -{-# LANGUAGE TypeSynonymInstances #-} +{-# LANGUAGE DataKinds #-} +{-# LANGUAGE DerivingStrategies #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE OverloadedStrings #-} {- | Module : FediChord Description : An opinionated implementation of the EpiChord DHT by Leong et al. @@ -40,7 +39,7 @@ module Hash2Pub.FediChord ( , bsAsIpAddr , FediChordConf(..) , fediChordInit - , fediChordJoin + , fediChordVserverJoin , fediChordBootstrapJoin , tryBootstrapJoining , fediMainThreads @@ -78,7 +77,6 @@ import Data.Maybe (catMaybes, fromJust, fromMaybe, isJust, isNothing, mapMaybe) import qualified Data.Set as Set import Data.Time.Clock.POSIX -import Data.Typeable (Typeable (..), typeOf) import Data.Word import qualified Network.ByteOrder as NetworkBytes import Network.Socket hiding (recv, recvFrom, send, @@ -95,24 +93,34 @@ import Debug.Trace (trace) -- | initialise data structures, compute own IDs and bind to listening socket -- ToDo: load persisted state, thus this function already operates in IO -fediChordInit :: FediChordConf -> IO (Socket, LocalNodeStateSTM) -fediChordInit initConf = do +fediChordInit :: (Service s (RealNodeSTM s)) + => FediChordConf + -> (RealNodeSTM s -> IO (s (RealNodeSTM s))) -- ^ runner function for service + -> IO (Socket, LocalNodeStateSTM s) +fediChordInit initConf serviceRunner = do emptyLookupCache <- newTVarIO Map.empty let realNode = RealNode { vservers = [] , nodeConfig = initConf , bootstrapNodes = confBootstrapNodes initConf , lookupCacheSTM = emptyLookupCache + , nodeService = undefined } realNodeSTM <- newTVarIO realNode + -- launch service and set the reference in the RealNode + serv <- serviceRunner realNodeSTM + atomically . modifyTVar' realNodeSTM $ \rn -> rn { nodeService = serv } + -- initialise a single vserver initialState <- nodeStateInit realNodeSTM initialStateSTM <- newTVarIO initialState + -- add vserver to list at RealNode + atomically . modifyTVar' realNodeSTM $ \rn -> rn { vservers = initialStateSTM:vservers rn } serverSock <- mkServerSocket (getIpAddr initialState) (getDhtPort initialState) pure (serverSock, initialStateSTM) -- | initialises the 'NodeState' for this local node. -- Separated from 'fediChordInit' to be usable in tests. -nodeStateInit :: RealNodeSTM -> IO LocalNodeState +nodeStateInit :: Service s (RealNodeSTM s) => RealNodeSTM s -> IO (LocalNodeState s) nodeStateInit realNodeSTM = do realNode <- readTVarIO realNodeSTM cacheSTM <- newTVarIO initCache @@ -125,7 +133,7 @@ nodeStateInit realNodeSTM = do , ipAddr = confIP conf , nid = genNodeID (confIP conf) (confDomain conf) $ fromInteger vsID , dhtPort = toEnum $ confDhtPort conf - , servicePort = 0 + , servicePort = getListeningPortFromService $ nodeService realNode , vServerID = vsID } initialState = LocalNodeState { @@ -144,9 +152,10 @@ nodeStateInit realNodeSTM = do -- | Join a new node into the DHT, using a provided bootstrap node as initial cache seed -- for resolving the new node's position. -fediChordBootstrapJoin :: LocalNodeStateSTM -- ^ the local 'NodeState' - -> (String, PortNumber) -- ^ domain and port of a bootstrapping node - -> IO (Either String LocalNodeStateSTM) -- ^ the joined 'NodeState' after a +fediChordBootstrapJoin :: Service s (RealNodeSTM s) + => LocalNodeStateSTM s -- ^ the local 'NodeState' + -> (String, PortNumber) -- ^ domain and port of a bootstrapping node + -> IO (Either String (LocalNodeStateSTM s)) -- ^ the joined 'NodeState' after a -- successful join, otherwise an error message fediChordBootstrapJoin nsSTM bootstrapNode = do -- can be invoked multiple times with all known bootstrapping nodes until successfully joined @@ -157,12 +166,13 @@ fediChordBootstrapJoin nsSTM bootstrapNode = do currentlyResponsible <- liftEither lookupResp liftIO . putStrLn $ "Trying to join on " <> show (getNid currentlyResponsible) -- 2. then send a join to the currently responsible node + liftIO $ putStrLn "send a bootstrap Join" joinResult <- liftIO $ requestJoin currentlyResponsible nsSTM liftEither joinResult -- Periodically lookup own ID through a random bootstrapping node to discover and merge separated DHT clusters. -- Unjoined try joining instead. -convergenceSampleThread :: LocalNodeStateSTM -> IO () +convergenceSampleThread :: Service s (RealNodeSTM s) => LocalNodeStateSTM s -> IO () convergenceSampleThread nsSTM = forever $ do nsSnap <- readTVarIO nsSTM parentNode <- readTVarIO $ parentRealNode nsSnap @@ -189,11 +199,11 @@ convergenceSampleThread nsSTM = forever $ do -- unjoined node: try joining through all bootstrapping nodes else tryBootstrapJoining nsSTM >> pure () let delaySecs = confBootstrapSamplingInterval . nodeConfig $ parentNode - threadDelay $ delaySecs * 10^6 + threadDelay delaySecs -- | Try joining the DHT through any of the bootstrapping nodes until it succeeds. -tryBootstrapJoining :: LocalNodeStateSTM -> IO (Either String LocalNodeStateSTM) +tryBootstrapJoining :: Service s (RealNodeSTM s) => LocalNodeStateSTM s -> IO (Either String (LocalNodeStateSTM s)) tryBootstrapJoining nsSTM = do bss <- atomically $ do nsSnap <- readTVar nsSTM @@ -210,13 +220,14 @@ tryBootstrapJoining nsSTM = do -- | Look up a key just based on the responses of a single bootstrapping node. -bootstrapQueryId :: LocalNodeStateSTM -> (String, PortNumber) -> NodeID -> IO (Either String RemoteNodeState) +bootstrapQueryId :: LocalNodeStateSTM s -> (String, PortNumber) -> NodeID -> IO (Either String RemoteNodeState) bootstrapQueryId nsSTM (bootstrapHost, bootstrapPort) targetID = do ns <- readTVarIO nsSTM - srcAddr <- confIP . nodeConfig <$> readTVarIO (parentRealNode ns) + nodeConf <- nodeConfig <$> readTVarIO (parentRealNode ns) + let srcAddr = confIP nodeConf bootstrapResponse <- bracket (mkSendSocket srcAddr bootstrapHost bootstrapPort) close ( -- Initialise an empty cache only with the responses from a bootstrapping node - fmap Right . sendRequestTo 5000 3 (lookupMessage targetID ns Nothing) + fmap Right . sendRequestTo (confRequestTimeout nodeConf) (confRequestRetries nodeConf) (lookupMessage targetID ns Nothing) ) `catch` (\e -> pure . Left $ "Error at bootstrap QueryId: " <> displayException (e :: IOException)) @@ -235,60 +246,95 @@ bootstrapQueryId nsSTM (bootstrapHost, bootstrapPort) targetID = do Just (FORWARD resultset) -> foldr' (addCacheEntryPure now) cacheAcc resultset ) initCache resp - currentlyResponsible <- queryIdLookupLoop bootstrapCache ns 50 $ getNid ns - pure $ Right currentlyResponsible + currentlyResponsible <- runExceptT $ queryIdLookupLoop bootstrapCache ns 50 $ getNid ns + pure currentlyResponsible -- | join a node to the DHT using the global node cache -- node's position. -fediChordJoin :: LocalNodeStateSTM -- ^ the local 'NodeState' - -> IO (Either String LocalNodeStateSTM) -- ^ the joined 'NodeState' after a +fediChordVserverJoin :: (MonadError String m, MonadIO m, Service s (RealNodeSTM s)) + => LocalNodeStateSTM s -- ^ the local 'NodeState' + -> m (LocalNodeStateSTM s) -- ^ the joined 'NodeState' after a -- successful join, otherwise an error message -fediChordJoin nsSTM = do - ns <- readTVarIO nsSTM +fediChordVserverJoin nsSTM = do + ns <- liftIO $ readTVarIO nsSTM -- 1. get routed to the currently responsible node currentlyResponsible <- requestQueryID ns $ getNid ns - putStrLn $ "Trying to join on " <> show (getNid currentlyResponsible) + liftIO . putStrLn $ "Trying to join on " <> show (getNid currentlyResponsible) -- 2. then send a join to the currently responsible node - joinResult <- requestJoin currentlyResponsible nsSTM - case joinResult of - Left err -> pure . Left $ "Error joining on " <> err - Right joinedNS -> pure . Right $ joinedNS + joinResult <- liftIO $ requestJoin currentlyResponsible nsSTM + liftEither joinResult + +fediChordVserverLeave :: (MonadError String m, MonadIO m, Service s (RealNodeSTM s)) => LocalNodeState s -> m () +fediChordVserverLeave ns = do + -- TODO: deal with failure of all successors, e.g. by invoking a stabilise + -- and looking up further successors. So far we just fail here. + _ <- migrateSuccessor + -- then send leave messages to all other neighbours + -- TODO: distinguish between sending error causes on our side and on the + -- network/ target side. The latter cannot be fixed anyways while the + -- former could be worked around + + -- send a leave message to all neighbours + forM_ (predecessors ns <> successors ns) $ liftIO . requestLeave ns False + where + sendUntilSuccess i = maybe + (pure $ Left "Exhausted all successors") + (\neighb -> do + leaveResponse <- requestLeave ns True neighb + case leaveResponse of + Left _ -> sendUntilSuccess (i+1) + -- return first successfully contacted neighbour, + -- so it can be contacted by the service layer for migration + Right _ -> pure $ Right neighb + ) + $ atMay (successors ns) i + migrateSuccessor :: (MonadError String m, MonadIO m) => m () + migrateSuccessor = do + -- send leave message to first responding successor + successorLeave <- liftIO $ sendUntilSuccess 0 + -- trigger service data transfer for abandoned key space + migrateToNode <- liftEither successorLeave + let lowerKeyBound = maybe (getNid ns) getNid $ headMay (predecessors ns) + ownService <- nodeService <$> (liftIO . readTVarIO $ parentRealNode ns) + -- previously held data is the one between the immediate predecessor and + -- the own ID + migrationResult <- liftIO $ migrateData ownService (getNid ns) lowerKeyBound (getNid ns) (getDomain migrateToNode, fromIntegral $ getServicePort migrateToNode) + liftEither migrationResult + -- | Wait for new cache entries to appear and then try joining on them. -- Exits after successful joining. -joinOnNewEntriesThread :: LocalNodeStateSTM -> IO () +joinOnNewEntriesThread :: Service s (RealNodeSTM s) => LocalNodeStateSTM s -> IO () joinOnNewEntriesThread nsSTM = loop where loop = do nsSnap <- readTVarIO nsSTM - (lookupResult, cache) <- atomically $ do + (lookupResult, parentNode) <- atomically $ do cache <- readTVar $ nodeCacheSTM nsSnap + parentNode <- readTVar $ parentRealNode nsSnap case queryLocalCache nsSnap cache 1 (getNid nsSnap) of -- empty cache, block until cache changes and then retry (FORWARD s) | Set.null s -> retry - result -> pure (result, cache) + result -> pure (result, parentNode) case lookupResult of -- already joined - FOUND _ -> do - print =<< readTVarIO nsSTM + FOUND _ -> pure () -- otherwise try joining FORWARD _ -> do - joinResult <- fediChordJoin nsSTM + joinResult <- runExceptT $ fediChordVserverJoin nsSTM either -- on join failure, sleep and retry - -- TODO: make delay configurable - (const $ threadDelay (30 * 10^6) >> loop) + (const $ threadDelay (confJoinAttemptsInterval . nodeConfig $ parentNode) >> loop) (const $ pure ()) joinResult - emptyset = Set.empty -- because pattern matches don't accept qualified names -- | cache updater thread that waits for incoming NodeCache update instructions on -- the node's cacheWriteQueue and then modifies the NodeCache as the single writer. -nodeCacheWriter :: LocalNodeStateSTM -> IO () +nodeCacheWriter :: LocalNodeStateSTM s -> IO () nodeCacheWriter nsSTM = forever $ atomically $ do ns <- readTVar nsSTM @@ -296,20 +342,15 @@ nodeCacheWriter nsSTM = modifyTVar' (nodeCacheSTM ns) cacheModifier --- TODO: make max entry age configurable -maxEntryAge :: POSIXTime -maxEntryAge = 600 - - -- | Periodically iterate through cache, clean up expired entries and verify unverified ones -nodeCacheVerifyThread :: LocalNodeStateSTM -> IO () +nodeCacheVerifyThread :: LocalNodeStateSTM s -> IO () nodeCacheVerifyThread nsSTM = forever $ do - putStrLn "cache verify run: begin" -- get cache - (ns, cache) <- atomically $ do + (ns, cache, maxEntryAge) <- atomically $ do ns <- readTVar nsSTM cache <- readTVar $ nodeCacheSTM ns - pure (ns, cache) + maxEntryAge <- confMaxNodeCacheAge . nodeConfig <$> readTVar (parentRealNode ns) + pure (ns, cache, maxEntryAge) -- iterate entries: -- for avoiding too many time syscalls, get current time before iterating. now <- getPOSIXTime @@ -356,14 +397,13 @@ nodeCacheVerifyThread nsSTM = forever $ do forkIO $ sendQueryIdMessages targetID latestNs (Just (1 + jEntriesPerSlice latestNs)) (nodesToQuery targetID) >> pure () -- ask for 1 entry more than j because of querying the middle ) - putStrLn "cache verify run: end" - threadDelay $ 10^6 * round maxEntryAge `div` 20 + threadDelay $ fromEnum (maxEntryAge / 20) `div` 10^6 -- convert from pico to milliseconds -- | Checks the invariant of at least @jEntries@ per cache slice. -- If this invariant does not hold, the middle of the slice is returned for -- making lookups to that ID -checkCacheSliceInvariants :: LocalNodeState +checkCacheSliceInvariants :: LocalNodeState s -> NodeCache -> [NodeID] -- ^ list of middle IDs of slices not -- ^ fulfilling the invariant @@ -419,12 +459,10 @@ checkCacheSliceInvariants ns -- | Periodically send @StabiliseRequest' s to the closest neighbour nodes, until -- one responds, and get their neighbours for maintaining the own neighbour lists. -- If necessary, request new neighbours. -stabiliseThread :: LocalNodeStateSTM -> IO () +stabiliseThread :: Service s (RealNodeSTM s) => LocalNodeStateSTM s -> IO () stabiliseThread nsSTM = forever $ do - ns <- readTVarIO nsSTM + oldNs <- readTVarIO nsSTM - putStrLn "stabilise run: begin" - print ns -- iterate through the same snapshot, collect potential new neighbours -- and nodes to be deleted, and modify these changes only at the end of @@ -433,8 +471,8 @@ stabiliseThread nsSTM = forever $ do -- don't contact all neighbours unless the previous one failed/ Left ed - predStabilise <- stabiliseClosestResponder ns predecessors 1 [] - succStabilise <- stabiliseClosestResponder ns predecessors 1 [] + predStabilise <- stabiliseClosestResponder oldNs predecessors 1 [] + succStabilise <- stabiliseClosestResponder oldNs predecessors 1 [] let (predDeletes, predNeighbours) = either (const ([], [])) id predStabilise @@ -459,31 +497,60 @@ stabiliseThread nsSTM = forever $ do -- try looking up additional neighbours if list too short forM_ [(length $ predecessors updatedNs)..(kNeighbours updatedNs)] (\_ -> do ns' <- readTVarIO nsSTM - nextEntry <- requestQueryID ns' $ pred . getNid $ lastDef (toRemoteNodeState ns') (predecessors ns') - atomically $ do - latestNs <- readTVar nsSTM - writeTVar nsSTM $ addPredecessors [nextEntry] latestNs + nextEntry <- runExceptT . requestQueryID ns' $ pred . getNid $ lastDef (toRemoteNodeState ns') (predecessors ns') + either + (const $ pure ()) + (\entry -> atomically $ do + latestNs <- readTVar nsSTM + writeTVar nsSTM $ addPredecessors [entry] latestNs + ) + nextEntry ) forM_ [(length $ successors updatedNs)..(kNeighbours updatedNs)] (\_ -> do ns' <- readTVarIO nsSTM - nextEntry <- requestQueryID ns' $ succ . getNid $ lastDef (toRemoteNodeState ns') (successors ns') - atomically $ do - latestNs <- readTVar nsSTM - writeTVar nsSTM $ addSuccessors [nextEntry] latestNs + nextEntry <- runExceptT . requestQueryID ns' $ succ . getNid $ lastDef (toRemoteNodeState ns') (successors ns') + either + (const $ pure ()) + (\entry -> atomically $ do + latestNs <- readTVar nsSTM + writeTVar nsSTM $ addSuccessors [entry] latestNs + ) + nextEntry ) - putStrLn "stabilise run: end" - -- TODO: make delay configurable - threadDelay (60 * 10^6) + newNs <- readTVarIO nsSTM + + let + oldPredecessor = headDef (toRemoteNodeState oldNs) $ predecessors oldNs + newPredecessor = headMay $ predecessors newNs + -- manage need for service data migration: + maybe (pure ()) (\newPredecessor' -> + when ( + isJust newPredecessor + && oldPredecessor /= newPredecessor' + -- case: predecessor has changed in some way => own responsibility has changed in some way + -- case 1: new predecessor is further away => broader responsibility, but new pred needs to push the data + -- If this is due to a node leaving without transfering its data, try getting it from a redundant copy + -- case 2: new predecessor is closer, it takes some of our data but somehow didn't join on us => push data to it + && isInOwnResponsibilitySlice newPredecessor' oldNs) $ do + ownService <- nodeService <$> (liftIO . readTVarIO $ parentRealNode newNs) + migrationResult <- migrateData ownService (getNid newNs) (getNid oldPredecessor) (getNid newPredecessor') (getDomain newPredecessor', fromIntegral $ getServicePort newPredecessor') + -- TODO: deal with migration failure, e.g retry + pure () + ) + newPredecessor + + stabiliseDelay <- confStabiliseInterval . nodeConfig <$> readTVarIO (parentRealNode newNs) + threadDelay stabiliseDelay where -- | send a stabilise request to the n-th neighbour - -- (specified by the provided getter function) and on failure retr + -- (specified by the provided getter function) and on failure retry -- with the n+1-th neighbour. -- On success, return 2 lists: The failed nodes and the potential neighbours -- returned by the queried node. - stabiliseClosestResponder :: LocalNodeState -- ^ own node - -> (LocalNodeState -> [RemoteNodeState]) -- ^ getter function for either predecessors or successors + stabiliseClosestResponder :: LocalNodeState s -- ^ own node + -> (LocalNodeState s -> [RemoteNodeState]) -- ^ getter function for either predecessors or successors -> Int -- ^ index of neighbour to query -> [RemoteNodeState] -- ^ delete accumulator -> IO (Either String ([RemoteNodeState], [RemoteNodeState])) -- ^ (nodes to be deleted, successfully pinged potential neighbours) @@ -507,7 +574,7 @@ stabiliseThread nsSTM = forever $ do currentNeighbour ns neighbourGetter = atMay $ neighbourGetter ns - checkReachability :: LocalNodeState -- ^ this node + checkReachability :: LocalNodeState s -- ^ this node -> RemoteNodeState -- ^ node to Ping for reachability -> IO (Maybe RemoteNodeState) -- ^ if the Pinged node handles the requested node state then that one checkReachability ns toCheck = do @@ -536,10 +603,10 @@ sendThread sock sendQ = forever $ do sendAllTo sock packet addr -- | Sets up and manages the main server threads of FediChord -fediMainThreads :: Socket -> LocalNodeStateSTM -> IO () +fediMainThreads :: Service s (RealNodeSTM s) => Socket -> LocalNodeStateSTM s -> IO () fediMainThreads sock nsSTM = do ns <- readTVarIO nsSTM - putStrLn $ "launching threads, ns: " <> show ns + putStrLn "launching threads" sendQ <- newTQueueIO recvQ <- newTQueueIO -- concurrently launch all handler threads, if one of them throws an exception @@ -562,38 +629,36 @@ type RequestMap = Map.Map (SockAddr, Integer) RequestMapEntry data RequestMapEntry = RequestMapEntry (Set.Set FediChordMessage) (Maybe Integer) POSIXTime --- TODO: make purge age configurable --- | periodically clean up old request parts -responsePurgeAge :: POSIXTime -responsePurgeAge = 60 -- seconds -requestMapPurge :: MVar RequestMap -> IO () -requestMapPurge mapVar = forever $ do +requestMapPurge :: POSIXTime -> MVar RequestMap -> IO () +requestMapPurge purgeAge mapVar = forever $ do rMapState <- takeMVar mapVar now <- getPOSIXTime - putMVar mapVar $ Map.filter (\entry@(RequestMapEntry _ _ ts) -> - now - ts < responsePurgeAge + putMVar mapVar $ Map.filter (\(RequestMapEntry _ _ ts) -> + now - ts < purgeAge ) rMapState - threadDelay $ round responsePurgeAge * 2 * 10^6 + threadDelay $ (fromEnum purgeAge * 2) `div` 10^6 -- | Wait for messages, deserialise them, manage parts and acknowledgement status, -- and pass them to their specific handling function. -fediMessageHandler :: TQueue (BS.ByteString, SockAddr) -- ^ send queue +fediMessageHandler :: Service s (RealNodeSTM s) + => TQueue (BS.ByteString, SockAddr) -- ^ send queue -> TQueue (BS.ByteString, SockAddr) -- ^ receive queue - -> LocalNodeStateSTM -- ^ acting NodeState + -> LocalNodeStateSTM s -- ^ acting NodeState -> IO () fediMessageHandler sendQ recvQ nsSTM = do -- Read node state just once, assuming that all relevant data for this function does -- not change. -- Other functions are passed the nsSTM reference and thus can get the latest state. nsSnap <- readTVarIO nsSTM + nodeConf <- nodeConfig <$> readTVarIO (parentRealNode nsSnap) -- handling multipart messages: -- Request parts can be insert into a map (key: (sender IP against spoofing, request ID), value: timestamp + set of message parts, handle all of them when size of set == parts) before being handled. This map needs to be purged periodically by a separate thread and can be protected by an MVar for fairness. requestMap <- newMVar (Map.empty :: RequestMap) -- run receive loop and requestMapPurge concurrently, so that an exception makes -- both of them fail - concurrently_ (requestMapPurge requestMap) $ forever $ do + concurrently_ (requestMapPurge (confResponsePurgeAge nodeConf) requestMap) $ forever $ do -- wait for incoming messages (rawMsg, sourceAddr) <- atomically $ readTQueue recvQ let aMsg = deserialiseMessage rawMsg @@ -646,14 +711,33 @@ fediMessageHandler sendQ recvQ nsSTM = do -- ==== interface to service layer ==== -instance DHT RealNodeSTM where +instance DHT (RealNodeSTM s) where lookupKey nodeSTM keystring = getKeyResponsibility nodeSTM $ genKeyID keystring - forceLookupKey nodeSTM keystring = updateLookupCache nodeSTM $ genKeyID keystring + forceLookupKey nodeSTM keystring = (putStrLn $ "forced responsibility lookup of #" <> keystring) >> (updateLookupCache nodeSTM $ genKeyID keystring) + -- potential better implementation: put all neighbours of all vservers and the vservers on a ringMap, look the key up and see whether it results in a LocalNodeState + isResponsibleFor nodeSTM key = do + node <- readTVarIO nodeSTM + foldM (\responsible vsSTM -> do + vs <- readTVarIO vsSTM + pure $ responsible || isInOwnResponsibilitySlice key vs + ) + False + $ vservers node + isResponsibleForSTM nodeSTM key = do + node <- readTVar nodeSTM + foldM (\responsible vsSTM -> do + vs <- readTVar vsSTM + pure $ responsible || isInOwnResponsibilitySlice key vs + ) + False + $ vservers node + + -- | Returns the hostname and port of the host responsible for a key. -- Information is provided from a cache, only on a cache miss a new DHT lookup -- is triggered. -getKeyResponsibility :: RealNodeSTM -> NodeID -> IO (Maybe (String, PortNumber)) +getKeyResponsibility :: RealNodeSTM s -> NodeID -> IO (Maybe (String, PortNumber)) getKeyResponsibility nodeSTM lookupKey = do node <- readTVarIO nodeSTM cache <- readTVarIO $ lookupCacheSTM node @@ -669,8 +753,8 @@ getKeyResponsibility nodeSTM lookupKey = do -- | Triggers a new DHT lookup for a key, updates the lookup cache and returns the -- new entry. -- If no vserver is active in the DHT, 'Nothing' is returned. -updateLookupCache :: RealNodeSTM -> NodeID -> IO (Maybe (String, PortNumber)) -updateLookupCache nodeSTM lookupKey = do +updateLookupCache :: RealNodeSTM s -> NodeID -> IO (Maybe (String, PortNumber)) +updateLookupCache nodeSTM keyToLookup = do (node, lookupSource) <- atomically $ do node <- readTVar nodeSTM let firstVs = headMay (vservers node) @@ -680,23 +764,30 @@ updateLookupCache nodeSTM lookupKey = do pure (node, lookupSource) maybe (do -- if no local node available, delete cache entry and return Nothing - atomically $ modifyTVar' (lookupCacheSTM node) $ Map.delete lookupKey + atomically $ modifyTVar' (lookupCacheSTM node) $ Map.delete keyToLookup pure Nothing ) (\n -> do -- start a lookup from the node, update the cache with the lookup result and return it - newResponsible <- requestQueryID n lookupKey - let newEntry = (getDomain newResponsible, getServicePort newResponsible) - now <- getPOSIXTime - -- atomic update against lost updates - atomically $ modifyTVar' (lookupCacheSTM node) $ - Map.insert lookupKey (CacheEntry False newEntry now) - pure $ Just newEntry + -- TODO: better retry management, because having no vserver joined yet should + -- be treated differently than other reasons for not getting a result. + newResponsible <- runExceptT $ requestQueryID n keyToLookup + either + (const $ pure Nothing) + (\result -> do + let newEntry = (getDomain result, getServicePort result) + now <- getPOSIXTime + -- atomic update against lost updates + atomically $ modifyTVar' (lookupCacheSTM node) $ + Map.insert keyToLookup (CacheEntry False newEntry now) + pure $ Just newEntry + ) + newResponsible ) lookupSource -- | Periodically clean the lookup cache from expired entries. -lookupCacheCleanup :: RealNodeSTM -> IO () +lookupCacheCleanup :: RealNodeSTM s -> IO () lookupCacheCleanup nodeSTM = do node <- readTVarIO nodeSTM forever $ do @@ -706,4 +797,4 @@ lookupCacheCleanup nodeSTM = do now - ts < confMaxLookupCacheAge (nodeConfig node) ) ) - threadDelay $ round (confMaxLookupCacheAge $ nodeConfig node) * (10^5) + threadDelay $ fromEnum (2 * confMaxLookupCacheAge (nodeConfig node)) `div` 10^6 diff --git a/src/Hash2Pub/FediChordTypes.hs b/src/Hash2Pub/FediChordTypes.hs index 7652f4f..4ce20a7 100644 --- a/src/Hash2Pub/FediChordTypes.hs +++ b/src/Hash2Pub/FediChordTypes.hs @@ -1,5 +1,6 @@ {-# LANGUAGE DataKinds #-} {-# LANGUAGE DerivingStrategies #-} +{-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} {-# LANGUAGE MultiParamTypeClasses #-} @@ -26,8 +27,7 @@ module Hash2Pub.FediChordTypes ( , CacheEntry(..) , RingEntry(..) , RingMap(..) - , HasKeyID - , getKeyID + , HasKeyID(..) , rMapSize , rMapLookup , rMapLookupPred @@ -58,11 +58,14 @@ module Hash2Pub.FediChordTypes ( , bsAsIpAddr , FediChordConf(..) , DHT(..) + , Service(..) + , ServiceConf(..) ) where import Control.Exception import Data.Foldable (foldr') import Data.Function (on) +import qualified Data.Hashable as Hashable import Data.List (delete, nub, sortBy) import qualified Data.Map.Strict as Map import Data.Maybe (fromJust, fromMaybe, isJust, @@ -144,8 +147,8 @@ a `localCompare` b -- | Data for managing the virtual server nodes of this real node. -- Also contains shared data and config values. -- TODO: more data structures for k-choices bookkeeping -data RealNode = RealNode - { vservers :: [LocalNodeStateSTM] +data RealNode s = RealNode + { vservers :: [LocalNodeStateSTM s] -- ^ references to all active versers , nodeConfig :: FediChordConf -- ^ holds the initial configuration read at program start @@ -153,9 +156,10 @@ data RealNode = RealNode -- ^ nodes to be used as bootstrapping points, new ones learned during operation , lookupCacheSTM :: TVar LookupCache -- ^ a global cache of looked up keys and their associated nodes + , nodeService :: s (RealNodeSTM s) } -type RealNodeSTM = TVar RealNode +type RealNodeSTM s = TVar (RealNode s) -- | represents a node and all its important state data RemoteNodeState = RemoteNodeState @@ -177,7 +181,7 @@ instance Ord RemoteNodeState where a `compare` b = nid a `compare` nid b -- | represents a node and encapsulates all data and parameters that are not present for remote nodes -data LocalNodeState = LocalNodeState +data LocalNodeState s = LocalNodeState { nodeState :: RemoteNodeState -- ^ represents common data present both in remote and local node representations , nodeCacheSTM :: TVar NodeCache @@ -196,13 +200,13 @@ data LocalNodeState = LocalNodeState -- ^ number of parallel sent queries , jEntriesPerSlice :: Int -- ^ number of desired entries per cache slice - , parentRealNode :: RealNodeSTM + , parentRealNode :: RealNodeSTM s -- ^ the parent node managing this vserver instance } deriving (Show, Eq) -- | for concurrent access, LocalNodeState is wrapped in a TVar -type LocalNodeStateSTM = TVar LocalNodeState +type LocalNodeStateSTM s = TVar (LocalNodeState s) -- | class for various NodeState representations, providing -- getters and setters for common values @@ -239,14 +243,14 @@ instance NodeState RemoteNodeState where toRemoteNodeState = id -- | helper function for setting values on the 'RemoteNodeState' contained in the 'LocalNodeState' -propagateNodeStateSet_ :: (RemoteNodeState -> RemoteNodeState) -> LocalNodeState -> LocalNodeState +propagateNodeStateSet_ :: (RemoteNodeState -> RemoteNodeState) -> LocalNodeState s -> LocalNodeState s propagateNodeStateSet_ func ns = let newNs = func $ nodeState ns in ns {nodeState = newNs} -instance NodeState LocalNodeState where +instance NodeState (LocalNodeState s) where getNid = getNid . nodeState getDomain = getDomain . nodeState getIpAddr = getIpAddr . nodeState @@ -268,34 +272,37 @@ instance Typeable a => Show (TVar a) where instance Typeable a => Show (TQueue a) where show x = show (typeOf x) +instance Typeable a => Show (TChan a) where + show x = show (typeOf x) + -- | convenience function that replaces the predecessors of a 'LocalNodeState' with the k closest nodes from the provided list -setPredecessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState -setPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . rMapFromList . filter ((/=) (getNid ns) . getNid) $ preds} +setPredecessors :: [RemoteNodeState] -> LocalNodeState s -> LocalNodeState s +setPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . rMapFromList . fmap keyValuePair . filter ((/=) (getNid ns) . getNid) $ preds} -- | convenience function that replaces the successors of a 'LocalNodeState' with the k closest nodes from the provided list -setSuccessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState -setSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . rMapFromList . filter ((/=) (getNid ns) . getNid) $ succs} +setSuccessors :: [RemoteNodeState] -> LocalNodeState s -> LocalNodeState s +setSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . rMapFromList . fmap keyValuePair . filter ((/=) (getNid ns) . getNid) $ succs} -- | sets the predecessors of a 'LocalNodeState' to the closest k nodes of the current predecessors and the provided list, combined -addPredecessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState -addPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . addRMapEntries (filter ((/=) (getNid ns) . getNid) preds) . rMapFromList $ predecessors ns} +addPredecessors :: [RemoteNodeState] -> LocalNodeState s -> LocalNodeState s +addPredecessors preds ns = ns {predecessors = takeRMapPredecessors (getNid ns) (kNeighbours ns) . addRMapEntries (keyValuePair <$> filter ((/=) (getNid ns) . getNid) preds) . rMapFromList . fmap keyValuePair $ predecessors ns} -- | sets the successors of a 'LocalNodeState' to the closest k nodes of the current successors and the provided list, combined -addSuccessors :: [RemoteNodeState] -> LocalNodeState -> LocalNodeState -addSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . addRMapEntries (filter ((/=) (getNid ns) . getNid) succs) . rMapFromList $ successors ns} +addSuccessors :: [RemoteNodeState] -> LocalNodeState s -> LocalNodeState s +addSuccessors succs ns = ns {successors = takeRMapSuccessors (getNid ns) (kNeighbours ns) . addRMapEntries (keyValuePair <$> filter ((/=) (getNid ns) . getNid) succs) . rMapFromList . fmap keyValuePair $ successors ns} -instance HasKeyID RemoteNodeState NodeID where +instance HasKeyID NodeID RemoteNodeState where getKeyID = getNid -instance HasKeyID a k => HasKeyID (CacheEntry a) k where +instance HasKeyID k a => HasKeyID k (CacheEntry a) where getKeyID (CacheEntry _ obj _) = getKeyID obj instance HasKeyID NodeID NodeID where getKeyID = id type NodeCacheEntry = CacheEntry RemoteNodeState -type NodeCache = RingMap NodeCacheEntry NodeID +type NodeCache = RingMap NodeID NodeCacheEntry type LookupCacheEntry = CacheEntry (String, PortNumber) type LookupCache = Map.Map NodeID LookupCacheEntry @@ -319,12 +326,15 @@ cacheLookup = rMapLookup cacheLookupSucc :: NodeID -- ^lookup key -> NodeCache -- ^ring cache -> Maybe NodeCacheEntry -cacheLookupSucc = rMapLookupSucc +cacheLookupSucc key cache = snd <$> rMapLookupSucc key cache cacheLookupPred :: NodeID -- ^lookup key -> NodeCache -- ^ring cache -> Maybe NodeCacheEntry -cacheLookupPred = rMapLookupPred +cacheLookupPred key cache = snd <$> rMapLookupPred key cache + +-- clean up cache entries: once now - entry > maxAge +-- transfer difference now - entry to other node -- | return the @NodeState@ data from a cache entry without checking its validation status cacheGetNodeStateUnvalidated :: CacheEntry RemoteNodeState -> RemoteNodeState @@ -401,18 +411,67 @@ data FediChordConf = FediChordConf -- ^ listening port for the FediChord DHT , confBootstrapNodes :: [(String, PortNumber)] -- ^ list of potential bootstrapping nodes + , confStabiliseInterval :: Int + -- ^ pause between stabilise runs, in milliseconds , confBootstrapSamplingInterval :: Int - -- ^ pause between sampling the own ID through bootstrap nodes, in seconds + -- ^ pause between sampling the own ID through bootstrap nodes, in milliseconds , confMaxLookupCacheAge :: POSIXTime - -- ^ maximum age of lookup cache entries in seconds + -- ^ maximum age of key lookup cache entries in seconds + , confJoinAttemptsInterval :: Int + -- ^ interval between join attempts on newly learned nodes, in milliseconds + , confMaxNodeCacheAge :: POSIXTime + -- ^ maximum age of entries in the node cache, in milliseconds + , confResponsePurgeAge :: POSIXTime + -- ^ maximum age of message parts in response part cache, in seconds + , confRequestTimeout :: Int + -- ^ how long to wait until response has arrived, in milliseconds + , confRequestRetries :: Int + -- ^ how often re-sending a timed-out request can be retried } deriving (Show, Eq) +-- ====== Service Types ============ + +class Service s d where + -- | run the service + runService :: ServiceConf -> d -> IO (s d) + getListeningPortFromService :: (Integral i) => s d -> i + -- | trigger a service data migration of data between the two given keys + migrateData :: s d + -> NodeID -- ^ source/ sender node ID + -> NodeID -- ^ start key + -> NodeID -- ^ end key + -> (String, Int) -- ^ hostname and port of target service + -> IO (Either String ()) -- ^ success or failure + -- | Wait for an incoming migration from a given node to succeed, may block forever + waitForMigrationFrom :: s d -> NodeID -> IO () + +instance Hashable.Hashable NodeID where + hashWithSalt salt = Hashable.hashWithSalt salt . getNodeID + hash = Hashable.hash . getNodeID + +data ServiceConf = ServiceConf + { confSubscriptionExpiryTime :: POSIXTime + -- ^ subscription lease expiration in seconds + , confServicePort :: Int + -- ^ listening port for service + , confServiceHost :: String + -- ^ hostname of service + , confLogfilePath :: String + -- ^ where to store the (measurement) log file + , confStatsEvalDelay :: Int + -- ^ delay between statistic rate measurement samplings, in microseconds + , confSpeedupFactor :: Int + -- While the speedup factor needs to be already included in all + } + class DHT d where -- | lookup the responsible host handling a given key string, - -- possibly from a lookup cache + -- possiblggy from a lookup cache lookupKey :: d -> String -> IO (Maybe (String, PortNumber)) -- | lookup the responsible host handling a given key string, -- but force the DHT to do a fresh lookup instead of returning a cached result. -- Also invalidates old cache entries. forceLookupKey :: d -> String -> IO (Maybe (String, PortNumber)) + isResponsibleFor :: d -> NodeID -> IO Bool + isResponsibleForSTM :: d -> NodeID -> STM Bool diff --git a/src/Hash2Pub/PostService.hs b/src/Hash2Pub/PostService.hs index e8b325b..ffeef17 100644 --- a/src/Hash2Pub/PostService.hs +++ b/src/Hash2Pub/PostService.hs @@ -1,117 +1,884 @@ {-# LANGUAGE DataKinds #-} {-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE InstanceSigs #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE TypeOperators #-} -{-# LANGUAGE InstanceSigs #-} module Hash2Pub.PostService where import Control.Concurrent -import qualified Data.ByteString.Lazy.UTF8 as BSU -import Data.Maybe (fromMaybe) +import Control.Concurrent.Async +import Control.Concurrent.STM +import Control.Exception (Exception (..), try) +import Control.Monad (foldM, forM, forM_, forever, unless, + void, when) +import Control.Monad.IO.Class (liftIO) +import Data.Bifunctor +import qualified Data.ByteString.Lazy.UTF8 as BSUL +import qualified Data.ByteString.UTF8 as BSU +import qualified Data.DList as D +import Data.Either (lefts, rights) +import qualified Data.HashMap.Strict as HMap +import qualified Data.HashSet as HSet +import Data.Maybe (fromJust, isJust) import Data.String (fromString) -import qualified Data.Text as Txt +import Data.Text.Lazy (Text) +import qualified Data.Text.Lazy as Txt +import qualified Data.Text.Lazy.IO as TxtI +import Data.Text.Normalize (NormalizationMode (NFC), normalize) +import Data.Time.Clock.POSIX +import Data.Typeable (Typeable) +import qualified Network.HTTP.Client as HTTP +import qualified Network.HTTP.Types as HTTPT +import System.IO +import System.Random +import Text.Read (readEither) +import Formatting (fixed, format, int, (%)) import qualified Network.Wai.Handler.Warp as Warp import Servant +import Servant.Client -import Hash2Pub.FediChord -import Hash2Pub.ServiceTypes +import Hash2Pub.FediChordTypes +import Hash2Pub.PostService.API +import Hash2Pub.RingMap +import Hash2Pub.Utils +import Debug.Trace data PostService d = PostService - { psPort :: Warp.Port - , psHost :: String + { serviceConf :: ServiceConf -- queues, other data structures - , baseDHT :: (DHT d) => d - , serviceThread :: ThreadId + , baseDHT :: (DHT d) => d + , serviceThread :: TVar ThreadId + , subscribers :: TVar RelayTags + -- ^ for each tag store the subscribers + their queue + , ownSubscriptions :: TVar (HMap.HashMap NodeID POSIXTime) + -- ^ tags subscribed by the own node have an assigned lease time + , relayInQueue :: TQueue (Hashtag, PostID, PostContent) + -- ^ Queue for processing incoming posts of own instance asynchronously + , postFetchQueue :: TQueue PostID + -- ^ queue of posts to be fetched + , migrationsInProgress :: TVar (HMap.HashMap NodeID (MVar ())) + , httpMan :: HTTP.Manager + , statsQueue :: TQueue StatsEvent + , loadStats :: TVar RelayStats + -- ^ current load stats, replaced periodically + , logFileHandle :: Handle } + deriving (Typeable) + +type Hashtag = Text +type PostID = Text +type PostContent = Text +-- | For each handled tag, store its subscribers and provide a +-- broadcast 'TChan' for enqueuing posts +type RelayTags = RingMap NodeID (TagSubscribersSTM, TChan PostID, Hashtag) +type TagSubscribersSTM = TVar TagSubscribers +-- | each subscriber is identified by its contact data "hostname" "port" +-- and holds a TChan duplicated from the broadcast TChan of the tag +-- + an expiration timestamp +type TagSubscribers = (HMap.HashMap (String, Int) (TChan PostID, POSIXTime)) + instance DHT d => Service PostService d where - runService dht host port = do + -- | initialise 'PostService' data structures and run server + runService conf dht = do + -- create necessary TVars + threadVar <- newTVarIO =<< myThreadId -- own thread ID as placeholder + subscriberVar <- newTVarIO emptyRMap + ownSubsVar <- newTVarIO HMap.empty + --ownPostVar <- newTVarIO HSet.empty + relayInQueue' <- newTQueueIO + postFetchQueue' <- newTQueueIO + migrationsInProgress' <- newTVarIO HMap.empty + httpMan' <- HTTP.newManager HTTP.defaultManagerSettings + statsQueue' <- newTQueueIO + loadStats' <- newTVarIO emptyStats + loggingFile <- openFile (confLogfilePath conf) WriteMode + hSetBuffering loggingFile LineBuffering let - port' = fromIntegral port - warpSettings = Warp.setPort port' . Warp.setHost (fromString host) $ Warp.defaultSettings - servThread <- forkIO $ Warp.runSettings warpSettings postServiceApplication - pure $ PostService { - psPort = port' - , psHost = host - , baseDHT = dht - , serviceThread = servThread - } - getServicePort s = fromIntegral $ psPort s + thisService = PostService + { serviceConf = conf + , baseDHT = dht + , serviceThread = threadVar + , subscribers = subscriberVar + , ownSubscriptions = ownSubsVar + --, ownPosts = ownPostVar + , relayInQueue = relayInQueue' + , postFetchQueue = postFetchQueue' + , migrationsInProgress = migrationsInProgress' + , httpMan = httpMan' + , statsQueue = statsQueue' + , loadStats = loadStats' + , logFileHandle = loggingFile + } + port' = fromIntegral (confServicePort conf) + warpSettings = Warp.setPort port' . Warp.setHost (fromString . confServiceHost $ conf) $ Warp.defaultSettings + -- log a start message, this also truncates existing files + TxtI.hPutStrLn loggingFile $ Txt.unlines + [ "# Starting mock relay implementation" + , "#time stamp ; relay receive rate ;relay delivery rate ;instance publish rate ;instance fetch rate ;total subscriptions" + ] + -- Run 'concurrently_' from another thread to be able to return the + -- 'PostService'. + -- Terminating that parent thread will make all child threads terminate as well. + servThreadID <- forkIO $ + concurrently_ + -- web server + (Warp.runSettings warpSettings $ postServiceApplication thisService) + $ concurrently + -- background processing workers + (launchWorkerThreads thisService) + -- statistics/ measurements + (launchStatsThreads thisService) + -- update thread ID after fork + atomically $ writeTVar threadVar servThreadID + pure thisService + + getListeningPortFromService = fromIntegral . confServicePort . serviceConf + + migrateData = clientDeliverSubscriptions + + waitForMigrationFrom serv fromID = do + migrationSynchroniser <- atomically $ do + syncPoint <- HMap.lookup fromID <$> readTVar (migrationsInProgress serv) + maybe + -- decision: this function blocks until it gets an incoming migration from given ID + retry + pure + syncPoint + -- block until migration finished + takeMVar migrationSynchroniser -- | return a WAI application -postServiceApplication :: Application -postServiceApplication = serve exposedPostServiceAPI postServer - -servicePort = 8081 - --- | needed for guiding type inference -exposedPostServiceAPI :: Proxy PostServiceAPI -exposedPostServiceAPI = Proxy +postServiceApplication :: DHT d => PostService d -> Application +postServiceApplication serv = serve exposedPostServiceAPI $ postServer serv +-- ========= constants =========== + +placeholderPost :: Text +placeholderPost = Txt.take 5120 . Txt.repeat $ 'O' -- size 5KiB -- ========= HTTP API and handlers ============= -type PostServiceAPI = "relay" :> "inbox" :> ReqBody '[PlainText] Txt.Text :> PostCreated '[PlainText] Txt.Text - -- ^ delivery endpoint of newly published posts of the relay's instance - :<|> "relay" :> "subscribers" :> ReqBody '[PlainText] Txt.Text :> Post '[PlainText] Txt.Text - -- ^ endpoint for delivering the subscriptions and outstanding queue - :<|> "post" :> Capture "postid" Txt.Text :> Get '[PlainText] Txt.Text - -- ^ fetch endpoint for posts, full post ID is http://$domain/post/$postid - :<|> "posts" :> ReqBody '[PlainText] Txt.Text :> Post '[PlainText] Txt.Text - -- ^ endpoint for fetching multiple posts at once - :<|> "tags" :> Capture "hashtag" Txt.Text :> ReqBody '[PlainText] Txt.Text :> PostCreated '[PlainText] Txt.Text - -- ^ delivery endpoint for posts of $tag at subscribing instance - :<|> "tags" :> Capture "hashtag" Txt.Text :> "subscribe" :> Header "Origin" Txt.Text :> Get '[PlainText] Integer - -- ^ endpoint for subscribing the instance specified in - -- the Origin header to $hashtag. - -- Returns subscription lease time in seconds. - :<|> "tags" :> Capture "hashtag" Txt.Text :> "unsubscribe" :> Header "Origin" Txt.Text :> Get '[PlainText] Txt.Text - -- ^ endpoint for unsubscribing the instance specified in - -- the Origin header to $hashtag +postServer :: DHT d => PostService d -> Server PostServiceAPI +postServer service = relayInbox service + :<|> subscriptionDelivery service + :<|> postFetch service + :<|> postMultiFetch service + :<|> postInbox service + :<|> tagDelivery service + :<|> tagSubscribe service + :<|> tagUnsubscribe service -postServer :: Server PostServiceAPI -postServer = relayInbox - :<|> subscriptionDelivery - :<|> postFetch - :<|> postMultiFetch - :<|> tagDelivery - :<|> tagSubscribe - :<|> tagUnsubscribe +-- | delivery endpoint: receive posts of a handled tag and enqueue them for relaying +relayInbox :: DHT d => PostService d -> Hashtag -> Text -> Handler NoContent +relayInbox serv tag posts = do + let + -- skip checking whether the post actually contains the tag, just drop full post + postIDs = head . Txt.splitOn "," <$> Txt.lines posts + -- if tag is not in own responsibility, return a 410 Gone + responsible <- liftIO $ isResponsibleFor (baseDHT serv) (hashtagToId tag) + if responsible + then pure () + else + throwError $ err410 { errBody = "Relay is not responsible for this tag"} + broadcastChan <- liftIO $ atomically $ getTagBroadcastChannel serv tag + maybe + -- if noone subscribed to the tag, nothing needs to be done + (pure ()) + -- otherwise enqueue posts into broadcast queue of the tag + (\queue -> do + liftIO $ forM_ postIDs (atomically . writeTChan queue) + -- report the received post for statistic purposes + liftIO . atomically . writeTQueue (statsQueue serv) $ StatsEvent RelayReceiveEvent (length postIDs) (hashtagToId tag) + ) + broadcastChan + pure NoContent + +-- exception to be thrown when a tag is not in the responsibility of a relay +newtype UnhandledTagException = UnhandledTagException String + deriving (Show, Typeable) + +instance Exception UnhandledTagException + +-- | delivery endpoint: receives a list of subscribers of tags and their outstanding queues for migration +subscriptionDelivery :: DHT d => PostService d -> Integer -> Text -> Handler Text +subscriptionDelivery serv senderID subList = do + let + tagSubs = Txt.lines subList + -- signal that the migration is in progress + syncMVar <- liftIO newEmptyMVar + liftIO . atomically $ modifyTVar' (migrationsInProgress serv) $ + HMap.insert (fromInteger senderID) syncMVar + -- In favor of having the convenience of rolling back the transaction once a + -- not-handled tag occurs, this results in a single large transaction. + -- Hopefully the performance isn't too bad. + res <- liftIO . atomically $ (foldM (\_ tag' -> do + responsible <- isResponsibleForSTM (baseDHT serv) (hashtagToId tag') + if responsible + then processTag (subscribers serv) tag' + else throwSTM $ UnhandledTagException (Txt.unpack tag' <> " not handled by this relay") + pure $ Right () + ) (pure ()) tagSubs + `catchSTM` (\e -> pure . Left $ show (e :: UnhandledTagException)) + -- TODO: potentially log this + :: STM (Either String ())) + -- TODO: should this always signal migration finished to avoid deadlocksP + liftIO $ putMVar syncMVar () -- wakes up waiting thread + -- allow response to be completed independently from waiting thread + _ <- liftIO . forkIO $ do + putMVar syncMVar () -- blocks until waiting thread has resumed + -- delete this migration from ongoing ones + liftIO . atomically $ modifyTVar' (migrationsInProgress serv) $ + HMap.delete (fromInteger senderID) + case res of + Left err -> throwError err410 {errBody = BSUL.fromString err} + Right _ -> pure "" + -- TODO: check and only accept tags in own (future?) responsibility + where + processTag :: TVar RelayTags -> Text -> STM () + processTag subscriberSTM tagData = do + let + tag:subText:lease:posts:_ = Txt.splitOn "," tagData + -- ignore checking of lease time + leaseTime = fromIntegral (read . Txt.unpack $ lease :: Integer) + sub = read . Txt.unpack $ subText :: (String, Int) + postList = Txt.words posts + enqueueSubscription subscriberSTM (normaliseTag tag) sub postList leaseTime -relayInbox :: Txt.Text -> Handler Txt.Text -relayInbox post = pure $ "Here be InboxDragons with " <> post +-- | endpoint for fetching a post by its ID +postFetch :: PostService d -> Text -> Handler Text +postFetch serv _ = do + -- decision: for saving memory do not store published posts, just + -- pretend there is a post for each requested ID + liftIO . atomically . writeTQueue (statsQueue serv) $ StatsEvent IncomingPostFetchEvent 1 0 -- tag fetched for is irrelevant + pure placeholderPost -subscriptionDelivery :: Txt.Text -> Handler Txt.Text -subscriptionDelivery subList = pure $ "Here be Subscription List dragons: " <> subList -postFetch :: Txt.Text -> Handler Txt.Text -postFetch postID = pure $ "Here be a post with dragon ID " <> postID +-- | endpoint for fetching multiple posts of this instance by their IDs +postMultiFetch :: PostService d -> Text -> Handler Text +postMultiFetch serv postIDs = do + let + idList = Txt.lines postIDs + -- decision: for saving memory do not store published posts, just + -- pretend there is a post for each requested ID + response = foldl (\response' _ -> + placeholderPost <> "\n" <> response' + ) "" idList + liftIO . atomically . writeTQueue (statsQueue serv) $ StatsEvent IncomingPostFetchEvent (length idList) 0 -- tag fetched for is irrelevant + pure response -postMultiFetch :: Txt.Text -> Handler Txt.Text -postMultiFetch postIDs = pure $ "Here be multiple post dragons: " - <> (Txt.unwords . Txt.lines $ postIDs) -tagDelivery :: Txt.Text -> Txt.Text -> Handler Txt.Text -tagDelivery hashtag posts = pure $ "Here be #" <> hashtag <> " dragons with " <> posts +-- | delivery endpoint: inbox for initially publishing a post at an instance +postInbox :: PostService d -> Text -> Handler NoContent +postInbox serv post = do + -- extract contained hashtags + let + containedTags = fmap (normaliseTag . Txt.tail) . filter ((==) '#' . Txt.head) . Txt.words $ post + -- generate post ID + postId <- liftIO $ Txt.pack . show <$> (randomRIO (0, 2^(128::Integer)-1) :: IO Integer) + -- decision: for saving memory do not store published post IDs, just deliver a post for any requested ID + -- enqueue a relay job for each tag + liftIO $ forM_ (containedTags :: [Text]) (\tag -> + atomically $ writeTQueue (relayInQueue serv) (tag, postId, post) + ) + pure NoContent -tagSubscribe :: Txt.Text -> Maybe Txt.Text -> Handler Integer -tagSubscribe hashtag origin = pure 42 -tagUnsubscribe :: Txt.Text -> Maybe Txt.Text -> Handler Txt.Text -tagUnsubscribe hashtag origin = pure $ "Here be a dragon unsubscription from " <> fromMaybe "Nothing" origin <> " to " <> hashtag +-- | delivery endpoint: receive postIDs of a certain subscribed hashtag +tagDelivery :: PostService d -> Text -> Text -> Handler Text +tagDelivery serv hashtag posts = do + let postIDs = Txt.lines posts + subscriptions <- liftIO . readTVarIO . ownSubscriptions $ serv + if isJust (HMap.lookup (hashtagToId hashtag) subscriptions) + then -- TODO: increase a counter/ statistics for received posts of this tag + liftIO $ forM_ postIDs $ atomically . writeTQueue (postFetchQueue serv) + else -- silently drop posts from unsubscribed tags + pure () + pure $ "Received a postID for tag " <> hashtag +-- | receive subscription requests to a handled hashtag +tagSubscribe :: DHT d => PostService d -> Text -> Maybe Text -> Handler Integer +tagSubscribe serv hashtag origin = do + responsible <- liftIO $ isResponsibleFor (baseDHT serv) (hashtagToId hashtag) + if not responsible + -- GONE if not responsible + then throwError err410 { errBody = "not responsible for this tag" } + else pure () + originURL <- maybe + (throwError $ err400 { errBody = "Missing Origin header" }) + pure + origin + req <- HTTP.parseUrlThrow (Txt.unpack originURL) + now <- liftIO getPOSIXTime + let leaseTime = now + confSubscriptionExpiryTime (serviceConf serv) + -- setup subscription entry + _ <- liftIO . atomically $ setupSubscriberChannel (subscribers serv) hashtag (BSU.toString $ HTTP.host req, HTTP.port req) leaseTime + --liftIO . putStrLn $ "just got a subscription to " <> Txt.unpack hashtag + pure $ round leaseTime + + +-- | receive and handle unsubscription requests regarding a handled tag +tagUnsubscribe :: DHT d => PostService d -> Text -> Maybe Text -> Handler Text +tagUnsubscribe serv hashtag origin = do + responsible <- liftIO $ isResponsibleFor (baseDHT serv) (hashtagToId hashtag) + if not responsible + -- GONE if not responsible + then throwError err410 { errBody = "not responsible for this tag" } + else pure () + originURL <- maybe + (throwError $ err400 { errBody = "Missing Origin header" }) + pure + origin + req <- HTTP.parseUrlThrow (Txt.unpack originURL) + liftIO . atomically $ deleteSubscription (subscribers serv) hashtag (BSU.toString $ HTTP.host req, HTTP.port req) + pure "bye bye" + +-- client/ request functions + +clientAPI :: Proxy PostServiceAPI +clientAPI = Proxy + +relayInboxClient + :<|> subscriptionDeliveryClient + :<|> postFetchClient + :<|> postMultiFetchClient + :<|> postInboxClient + :<|> tagDeliveryClient + :<|> tagSubscribeClient + :<|> tagUnsubscribeClient + = client clientAPI + + +-- | Deliver the subscriber list of all hashtags in the interval [fromTag, toTag] +-- and their outstanding delivery queue to another instance. +-- If the transfer succeeds, the transfered subscribers are removed from the local list. +clientDeliverSubscriptions :: PostService d + -> NodeID -- ^ sender node ID + -> NodeID -- ^ fromTag + -> NodeID -- ^ toTag + -> (String, Int) -- ^ hostname and port of instance to deliver to + -> IO (Either String ()) -- Either signals success or failure +clientDeliverSubscriptions serv fromNode fromKey toKey (toHost, toPort) = do + -- collect tag interval + intervalTags <- takeRMapSuccessorsFromTo fromKey toKey <$> readTVarIO (subscribers serv) + -- returns a [ (TagSubscribersSTM, TChan PostID, Hashtag) ] + -- extract subscribers and posts + -- no need for extracting as a single atomic operation, as newly incoming posts are supposed to be rejected because of already having re-positioned on the DHT + subscriberData <- foldM (\response (subSTM, _, tag) -> do + subMap <- readTVarIO subSTM + thisTagsData <- foldM (\tagResponse (subscriber, (subChan, lease)) -> do + -- duplicate the pending queue to work on a copy, in case of a delivery error + pending <- atomically $ do + queueCopy <- cloneTChan subChan + channelGetAll queueCopy + if null pending + then pure tagResponse + else pure $ tag <> "," <> Txt.pack (show subscriber) <> "," <> Txt.pack (show lease) <> "," <> Txt.unwords pending <> "\n" + ) + "" + (HMap.toList subMap) + pure $ thisTagsData <> response + ) + "" + intervalTags + -- send subscribers + resp <- runClientM (subscriptionDeliveryClient (getNodeID fromNode) subscriberData) (mkClientEnv (httpMan serv) (BaseUrl Http toHost (fromIntegral toPort) "")) + -- on failure return a Left, otherwise delete subscription entry + case resp of + Left err -> pure . Left . show $ err + Right _ -> do + atomically $ + modifyTVar' (subscribers serv) $ \tagMap -> + foldr deleteRMapEntry tagMap ((\(_, _, t) -> hashtagToId t) <$> intervalTags) + pure . Right $ () + where + channelGetAll :: TChan a -> STM [a] + channelGetAll chan = channelGetAll' chan [] + channelGetAll' :: TChan a -> [a] -> STM [a] + channelGetAll' chan acc = do + haveRead <- tryReadTChan chan + maybe (pure acc) (\x -> channelGetAll' chan (x:acc)) haveRead + + +-- | Subscribe the client to the given hashtag. On success it returns the given lease time, +-- but also records the subscription in its own data structure. +clientSubscribeTo :: DHT d => PostService d -> Hashtag -> IO (Either String Integer) +clientSubscribeTo serv tag = do + lookupRes <- lookupKey (baseDHT serv) (Txt.unpack tag) + doSubscribe lookupRes True + where + doSubscribe lookupResponse allowRetry = maybe + (pure . Left $ "No node found") + (\(foundHost, foundPort) -> do + let origin = "http://" <> Txt.pack (confServiceHost $ serviceConf serv) <> ":" <> Txt.pack (show (getListeningPortFromService serv :: Integer)) + resp <- runClientM (tagSubscribeClient tag (Just origin)) (mkClientEnv (httpMan serv) (BaseUrl Http foundHost (fromIntegral foundPort) "")) + case resp of + Left (FailureResponse _ fresp) + |(HTTPT.statusCode . responseStatusCode $ fresp) == 410 && allowRetry -> do -- responsibility gone, force new lookup + newRes <- forceLookupKey (baseDHT serv) (Txt.unpack tag) + --putStrLn $ "failed subscribing to " <> Txt.unpack tag <> " on " <> foundHost + doSubscribe newRes False + Left err -> pure . Left . show $ err + Right lease -> do + atomically . modifyTVar' (ownSubscriptions serv) $ HMap.insert (hashtagToId tag) (fromInteger lease) + --putStrLn $ "just subscribed to " <> Txt.unpack tag <> " on " <> foundHost + pure . Right $ lease + ) + lookupResponse + + +-- | Unsubscribe the client from the given hashtag. +clientUnsubscribeFrom :: DHT d => PostService d -> Hashtag -> IO (Either String ()) +clientUnsubscribeFrom serv tag = do + lookupRes <- lookupKey (baseDHT serv) (Txt.unpack tag) + doUnsubscribe lookupRes True + where + doUnsubscribe lookupResponse allowRetry = maybe + (pure . Left $ "No node found") + (\(foundHost, foundPort) -> do + let origin = "http://" <> Txt.pack (confServiceHost $ serviceConf serv) <> ":" <> Txt.pack (show (getListeningPortFromService serv :: Integer)) + resp <- runClientM (tagUnsubscribeClient tag (Just origin)) (mkClientEnv (httpMan serv) (BaseUrl Http foundHost (fromIntegral foundPort) "")) + case resp of + Left (FailureResponse _ fresp) + |(HTTPT.statusCode . responseStatusCode $ fresp) == 410 && allowRetry -> do -- responsibility gone, force new lookup + newRes <- forceLookupKey (baseDHT serv) (Txt.unpack tag) + doUnsubscribe newRes False + Left err -> pure . Left . show $ err + Right _ -> do + atomically . modifyTVar' (ownSubscriptions serv) $ HMap.delete (hashtagToId tag) + pure . Right $ () + ) + lookupResponse + + +-- | publish a new post to the inbox of a specified relay instance. This +-- instance will then be the originating instance of the post and will forward +-- the post to the responsible relays. +-- As the initial publishing isn't done by a specific relay (but *to* a specific relay +-- instead), the function does *not* take a PostService as argument. +clientPublishPost :: HTTP.Manager -- ^ for better performance, a shared HTTP manager has to be provided + -> String -- ^ hostname + -> Int -- ^ port + -> PostContent -- ^ post content + -> IO (Either String ()) -- ^ error or success +clientPublishPost httpman hostname port postC = do + resp <- runClientM (postInboxClient postC) (mkClientEnv httpman (BaseUrl Http hostname port "")) + pure . bimap show (const ()) $ resp + +-- currently this is unused code +getClients :: String -> Int -> HTTP.Manager -> Client IO PostServiceAPI +getClients hostname' port' httpMan = hoistClient clientAPI + (fmap (either (error . show) id) + . flip runClientM clientEnv + ) + (client clientAPI) + where + clientEnv = mkClientEnv httpMan (BaseUrl Http hostname' port' "") + +-- ======= data structure manipulations ========= + +-- | Write all pending posts of a subscriber-tag-combination to its queue. +-- Sets up all necessary data structures if they are still missing. +enqueueSubscription :: TVar RelayTags -- tag-subscriber map + -> Hashtag -- hashtag of pending posts + -> (String, Int) -- subscriber's connection information + -> [PostID] -- pending posts + -> POSIXTime -- lease expiry time + -> STM () +enqueueSubscription tagMapSTM tag subscriber posts leaseTime = do + -- get the tag output queue and, if necessary, create it + subChan <- setupSubscriberChannel tagMapSTM tag subscriber leaseTime + forM_ posts (writeTChan subChan) + + +-- | STM operation to return the outgoing post queue of a tag to a specified subscriber. +-- If the queue doesn't exist yet, all necessary data structures are set up accordingly. +setupSubscriberChannel :: TVar RelayTags -> Hashtag -> (String, Int) -> POSIXTime -> STM (TChan PostID) +setupSubscriberChannel tagMapSTM tag subscriber leaseTime = do + tagMap <- readTVar tagMapSTM + case lookupTagSubscriptions tag tagMap of + Nothing -> do + -- if no collision/ tag doesn't exist yet, just initialize a + -- new subscriber map + broadcastChan <- newBroadcastTChan + tagOutChan <- dupTChan broadcastChan + newSubMapSTM <- newTVar $ HMap.singleton subscriber (tagOutChan, leaseTime) + writeTVar tagMapSTM $ addRMapEntry (hashtagToId tag) (newSubMapSTM, broadcastChan, tag) tagMap + pure tagOutChan + Just (foundSubMapSTM, broadcastChan, _) -> do + -- otherwise use the existing subscriber map + foundSubMap <- readTVar foundSubMapSTM + case HMap.lookup subscriber foundSubMap of + Nothing -> do + -- for new subscribers, create new output channel + tagOutChan <- dupTChan broadcastChan + writeTVar foundSubMapSTM $ HMap.insert subscriber (tagOutChan, leaseTime) foundSubMap + pure tagOutChan + -- existing subscriber's channels are just returned + Just (tagOutChan, _) -> pure tagOutChan + + +-- | deletes a subscription from the passed subscriber map +deleteSubscription :: TVar RelayTags -> Hashtag -> (String, Int) -> STM () +deleteSubscription tagMapSTM tag subscriber = do + tagMap <- readTVar tagMapSTM + case lookupTagSubscriptions tag tagMap of + -- no subscribers to that tag, just return + Nothing -> pure () + Just (foundSubMapSTM, _, _) -> do + foundSubMap <- readTVar foundSubMapSTM + let newSubMap = HMap.delete subscriber foundSubMap + -- if there are no subscriptions for the tag anymore, remove its + -- data sttructure altogether + if HMap.null newSubMap + then writeTVar tagMapSTM $ deleteRMapEntry (hashtagToId tag) tagMap + -- otherwise just remove the subscription of that node + else writeTVar foundSubMapSTM newSubMap + + + +-- | returns the broadcast channel of a hashtag if there are any subscribers to it +getTagBroadcastChannel :: PostService d -> Hashtag -> STM (Maybe (TChan PostID)) +getTagBroadcastChannel serv tag = do + tagMap <- readTVar $ subscribers serv + case lookupTagSubscriptions tag tagMap of + Nothing -> pure Nothing + Just (subscriberSTM, broadcastChan, _) -> do + subscriberMap <- readTVar subscriberSTM + if HMap.null subscriberMap + then pure Nothing + else pure (Just broadcastChan) + + +-- | look up the subscription data of a tag +lookupTagSubscriptions :: Hashtag -> RingMap NodeID a -> Maybe a +lookupTagSubscriptions tag = rMapLookup (hashtagToId tag) + + +-- normalise the unicode representation of a string to NFC and convert to lower case +normaliseTag :: Text -> Text +normaliseTag = Txt.toLower . Txt.fromStrict . normalize NFC . Txt.toStrict + + +-- | convert a hashtag to its representation on the DHT +hashtagToId :: Hashtag -> NodeID +hashtagToId = genKeyID . Txt.unpack + + +readUpToTChan :: Int -> TChan a -> STM [a] +readUpToTChan 0 _ = pure [] +readUpToTChan n chan = do + readFromChan <- tryReadTChan chan + case readFromChan of + Nothing -> pure [] + Just val -> do + moreReads <- readUpToTChan (pred n) chan + pure (val:moreReads) + + +readUpToTQueue :: Int -> TQueue a -> STM [a] +readUpToTQueue 0 _ = pure [] +readUpToTQueue n q = do + readFromQueue <- tryReadTQueue q + case readFromQueue of + Nothing -> pure [] + Just val -> do + moreReads <- readUpToTQueue (pred n) q + pure (val:moreReads) + -- | define how to convert all showable types to PlainText -- No idea what I'm doing with these overlappable instances though ¯\_(ツ)_/¯ -- TODO: figure out how this overlapping stuff actually works https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html#instance-overlap instance {-# OVERLAPPABLE #-} Show a => MimeRender PlainText a where - mimeRender _ = BSU.fromString . show + mimeRender _ = BSUL.fromString . show + +instance {-# OVERLAPPABLE #-} Read a => MimeUnrender PlainText a where + mimeUnrender _ = readEither . BSUL.toString + +-- ====== worker threads ====== + +-- TODO: make configurable +numParallelDeliveries = 10 + +launchWorkerThreads :: DHT d => PostService d -> IO () +launchWorkerThreads serv = concurrently_ + (processIncomingPosts serv) + $ concurrently_ + (purgeSubscriptionsThread serv) + $ concurrently_ + (fetchTagPosts serv) + (relayWorker serv) + + +-- | periodically remove expired subscription entries from relay subscribers +purgeSubscriptionsThread :: PostService d -> IO () +purgeSubscriptionsThread serv = forever $ do + -- read config + now <- getPOSIXTime + let + purgeInterval = confSubscriptionExpiryTime (serviceConf serv) / 10 + -- no need to atomically lock this, as newly incoming subscriptions do not + -- need to be purged + tagMap <- readTVarIO $ subscribers serv + forM_ tagMap $ \(subscriberMapSTM, _, _) -> + -- but each subscriberMap needs to be modified atomically + atomically . modifyTVar' subscriberMapSTM $ HMap.filter (\(_, ts) -> ts > now) + threadDelay $ fromEnum purgeInterval `div` 10^6 + + +-- | process the pending relay inbox of incoming posts from the internal queue: +-- Look up responsible relay node for given hashtag and forward post to it +processIncomingPosts :: DHT d => PostService d -> IO () +processIncomingPosts serv = forever $ do + -- blocks until available + deliveriesToProcess <- atomically $ do + readResult <- readUpToTQueue numParallelDeliveries $ relayInQueue serv + if null readResult + then retry + else pure readResult + runningJobs <- forM deliveriesToProcess $ \(tag, pID, pContent) -> async $ do + let pIdUri = "http://" <> (Txt.pack . confServiceHost . serviceConf $ serv) <> ":" <> (fromString . show . confServicePort . serviceConf $ serv) <> "/post/" <> pID + lookupRes <- lookupKey (baseDHT serv) (Txt.unpack tag) + case lookupRes of + -- no vserver active => wait and retry + Nothing -> threadDelay (10 * 10^6) >> pure (Left "no vserver active") + Just (responsibleHost, responsiblePort) -> do + resp <- runClientM (relayInboxClient tag $ pIdUri <> "," <> pContent) (mkClientEnv (httpMan serv) (BaseUrl Http responsibleHost (fromIntegral responsiblePort) "")) + case resp of + Left err -> do + -- 410 error indicates outdated responsibility mapping + -- Simplification: just invalidate the mapping entry on all errors, force a re-lookup and re-queue the post + -- TODO: keep track of maximum retries + _ <- forceLookupKey (baseDHT serv) (Txt.unpack tag) + atomically . writeTQueue (relayInQueue serv) $ (tag, pID, pContent) + pure . Left $ "Error: " <> show err + Right _ -> do + -- idea for the experiment: each post publication makes the initial posting instance subscribe to all contained tags + now <- getPOSIXTime + subscriptionStatus <- HMap.lookup (hashtagToId tag) <$> readTVarIO (ownSubscriptions serv) + -- if not yet subscribed or subscription expires within 5 minutes, (re)subscribe to tag + when (maybe True (\subLease -> now - subLease < 300) subscriptionStatus) $ + void $ clientSubscribeTo serv tag + + -- for evaluation, return the tag of the successfully forwarded post + pure $ Right tag + + -- collect async results + results <- mapM waitCatch runningJobs + -- report the count of published posts for statistics + atomically . writeTQueue (statsQueue serv) $ StatsEvent PostPublishEvent (length . rights $ results) 0 -- hashtag published to doesn't matter + pure () + + + +-- | process the pending fetch jobs of delivered post IDs: Delivered posts are tried to be fetched from their URI-ID +fetchTagPosts :: DHT d => PostService d -> IO () +fetchTagPosts serv = forever $ do + -- blocks until available + -- TODO: batching, retry + -- TODO: process multiple in parallel + pIdUri <- atomically . readTQueue $ postFetchQueue serv + fetchReq <- HTTP.parseRequest . Txt.unpack $ pIdUri + resp <- try $ HTTP.httpLbs fetchReq (httpMan serv) :: IO (Either HTTP.HttpException (HTTP.Response BSUL.ByteString)) + case resp of + Right response -> + -- TODO error handling, retry + --if HTTPT.statusCode (HTTP.responseStatus response) == 200 + -- then + -- -- success, TODO: statistics + -- else + pure () + Left _ -> + -- TODO error handling, retry + pure () + + +relayWorker :: PostService d -> IO () +relayWorker serv = forever $ do + -- atomically (to be able to retry) fold a list of due delivery actions + jobsToProcess <- atomically $ do + subscriptionMap <- readTVar $ subscribers serv + jobList <- D.toList <$> foldM (\jobAcc (subscriberMapSTM, _, tag) -> do + subscriberMap <- readTVar subscriberMapSTM + foldM (\jobAcc' ((subHost, subPort), (postChan, _)) -> do + postsToDeliver <- readUpToTChan 500 postChan + let postDeliveryAction = runClientM (tagDeliveryClient tag (Txt.unlines postsToDeliver)) (mkClientEnv (httpMan serv) (BaseUrl Http subHost (fromIntegral subPort) "")) + -- append relay push job to job list + pure $ if not (null postsToDeliver) + then jobAcc' `D.snoc` (do + deliveryResult <- postDeliveryAction + either + (const $ pure ()) + -- on successful push, record that event for statistics + (const . atomically . writeTQueue (statsQueue serv) $ StatsEvent RelayDeliveryEvent (length postsToDeliver) (hashtagToId tag)) + deliveryResult + pure deliveryResult + ) + else jobAcc' + ) jobAcc $ HMap.toList subscriberMap + ) D.empty subscriptionMap + -- if no relay jobs, then retry + if null jobList + then retry + else pure jobList + + -- when processing the list, send several deliveries in parallel + forM_ (chunksOf numParallelDeliveries jobsToProcess) $ \jobset -> do + runningJobs <- mapM async jobset + -- so far just dropping failed attempts, TODO: retry mechanism + results <- mapM waitCatch runningJobs + let + successfulResults = rights results + unsuccessfulResults = lefts results + unless (null unsuccessfulResults) $ putStrLn ("ERR: " <> show (length unsuccessfulResults) <> " failed deliveries!") + putStrLn $ "successfully relayed " <> show (length successfulResults) + pure () + + +-- ======= statistics/measurement and logging ======= + +data StatsEventType = PostPublishEvent + | RelayReceiveEvent + | RelayDeliveryEvent + | IncomingPostFetchEvent + deriving (Enum, Show, Eq) + +-- | Represents measurement event of a 'StatsEventType' with a count relevant for a certain key +data StatsEvent = StatsEvent StatsEventType Int NodeID + deriving (Show, Eq) + + +-- | measured rates of relay performance +-- TODO: maybe include other metrics in here as well, like number of subscribers? +data RelayStats = RelayStats + { relayReceiveRates :: RingMap NodeID Double + -- ^ rate of incoming posts in the responsibility of this relay + , relayDeliveryRates :: RingMap NodeID Double + -- ^ rate of relayed outgoing posts + , postFetchRate :: Double -- no need to differentiate between tags + -- ^ number of post-fetches delivered + , postPublishRate :: Double + -- ^ rate of initially publishing posts through this instance + } + deriving (Show, Eq) + + + +launchStatsThreads :: PostService d -> IO () +launchStatsThreads serv = do + -- create shared accumulator + sharedAccum <- newTVarIO emptyStats + concurrently_ + (accumulateStatsThread sharedAccum $ statsQueue serv) + (evaluateStatsThread serv sharedAccum) + + +-- | Read stats events from queue and add them to a shared accumulator. +-- Instead of letting the events accumulate in the queue and allocate linear memory, immediately fold the result. +accumulateStatsThread :: TVar RelayStats -> TQueue StatsEvent -> IO () +accumulateStatsThread statsAccumulator statsQ = forever $ do + -- blocks until stats event arrives + event <- atomically $ readTQueue statsQ + -- add the event number to current accumulator + atomically $ modifyTVar' statsAccumulator $ statsAdder event + + +-- | add incoming stats events to accumulator value +statsAdder :: StatsEvent -> RelayStats -> RelayStats +statsAdder event stats = case event of + StatsEvent PostPublishEvent num _ -> + stats {postPublishRate = fromIntegral num + postPublishRate stats} + StatsEvent RelayReceiveEvent num key -> + stats {relayReceiveRates = sumIfEntryExists key (fromIntegral num) (relayReceiveRates stats)} + StatsEvent RelayDeliveryEvent num key -> + stats {relayDeliveryRates = sumIfEntryExists key (fromIntegral num) (relayDeliveryRates stats)} + StatsEvent IncomingPostFetchEvent num _ -> + stats {postFetchRate = fromIntegral num + postFetchRate stats} + where + sumIfEntryExists = addRMapEntryWith (\newVal oldVal -> + let toInsert = fromJust $ extractRingEntry newVal + in + case oldVal of + KeyEntry n -> KeyEntry (n + toInsert) + ProxyEntry pointer (Just (KeyEntry n)) -> ProxyEntry pointer (Just (KeyEntry $ n + toInsert)) + ProxyEntry pointer Nothing -> ProxyEntry pointer (Just newVal) + _ -> error "RingMap nested too deeply" + ) + + +-- Periodically exchange the accumulated statistics with empty ones, evaluate them +-- and make them the current statistics of the service. +evaluateStatsThread :: PostService d -> TVar RelayStats -> IO () +evaluateStatsThread serv statsAcc = getPOSIXTime >>= loop + where + loop previousTs = do + threadDelay $ confStatsEvalDelay (serviceConf serv) + -- get and reset the stats accumulator + summedStats <- atomically $ do + stats <- readTVar statsAcc + writeTVar statsAcc emptyStats + pure stats + -- as the transaction might retry several times, current time needs to + -- be read afterwards + now <- getPOSIXTime + -- evaluate stats rate and replace server stats + -- persistently store in a TVar so it can be retrieved later by the DHT + let timePassed = (now - previousTs) * fromIntegral (confSpeedupFactor $ serviceConf serv) + rateStats = evaluateStats timePassed summedStats + atomically $ writeTVar (loadStats serv) rateStats + -- and now what? write a log to file + -- format: total relayReceiveRates;total relayDeliveryRates;postFetchRate;postPublishRate; subscriberSum + -- later: current (reported) load, target load + subscriberSum <- sumSubscribers + TxtI.hPutStrLn (logFileHandle serv) $ + format (fixed 9 % ";" % fixed 20 % ";" % fixed 20 % ";" % fixed 20 % ";" % fixed 20 % ";" % int ) + (realToFrac now :: Double) + (sum . relayReceiveRates $ rateStats) + (sum . relayDeliveryRates $ rateStats) + (postPublishRate rateStats) + (postFetchRate rateStats) + subscriberSum + loop now + + sumSubscribers = do + tagMap <- readTVarIO $ subscribers serv + foldM (\subscriberSum (subscriberMapSTM, _, _) -> do + subscriberMap <- readTVarIO subscriberMapSTM + pure $ subscriberSum + HMap.size subscriberMap + ) + 0 tagMap + + +-- | Evaluate the accumulated statistic events: Currently mostly calculates the event +-- rates by dividing through the collection time frame +evaluateStats :: POSIXTime -> RelayStats -> RelayStats +evaluateStats timeInterval summedStats = + -- first sum all event numbers, then divide through number of seconds passed to + -- get rate per second + RelayStats + { relayReceiveRates = (/ intervalSeconds) <$> relayReceiveRates summedStats + , relayDeliveryRates = (/ intervalSeconds) <$> relayDeliveryRates summedStats + , postPublishRate = postPublishRate summedStats / intervalSeconds + , postFetchRate = postFetchRate summedStats / intervalSeconds + } + where + intervalSeconds = realToFrac timeInterval + + +emptyStats :: RelayStats +emptyStats = RelayStats + { relayReceiveRates = emptyRMap + , relayDeliveryRates = emptyRMap + , postFetchRate = 0 + , postPublishRate = 0 + } diff --git a/src/Hash2Pub/PostService/API.hs b/src/Hash2Pub/PostService/API.hs new file mode 100644 index 0000000..1484631 --- /dev/null +++ b/src/Hash2Pub/PostService/API.hs @@ -0,0 +1,37 @@ +{-# LANGUAGE DataKinds #-} +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE InstanceSigs #-} +{-# LANGUAGE MultiParamTypeClasses #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE TypeOperators #-} +module Hash2Pub.PostService.API where + +import Data.Text.Lazy (Text) + +import Servant + +type PostServiceAPI = "relay" :> "inbox" :> Capture "hashtag" Text :> ReqBody '[PlainText] Text :> PutCreated '[PlainText] NoContent + -- delivery endpoint at responsible relay for delivering posts of $tag for distribution + :<|> "relay" :> "subscribers" :> Capture "senderID" Integer :> ReqBody '[PlainText] Text :> PostNoContent '[PlainText] Text + -- endpoint for delivering the subscriptions and outstanding queue + :<|> "post" :> Capture "postid" Text :> Get '[PlainText] Text + -- fetch endpoint for posts, full post ID is http://$domain/post/$postid + :<|> "posts" :> ReqBody '[PlainText] Text :> Post '[PlainText] Text + -- endpoint for fetching multiple posts at once + :<|> "posts" :> "inbox" :> ReqBody '[PlainText] Text :> PutCreated '[PlainText] NoContent + -- delivery endpoint of newly published posts of the relay's instance + :<|> "tags" :> Capture "hashtag" Text :> ReqBody '[PlainText] Text :> PostCreated '[PlainText] Text + -- delivery endpoint for posts of $tag at subscribing instance + :<|> "tags" :> Capture "hashtag" Text :> "subscribe" :> Header "Origin" Text :> Get '[PlainText] Integer + -- endpoint for subscribing the instance specified in + -- the Origin header to $hashtag. + -- Returns subscription lease time in seconds. + :<|> "tags" :> Capture "hashtag" Text :> "unsubscribe" :> Header "Origin" Text :> Get '[PlainText] Text + -- endpoint for unsubscribing the instance specified in + -- the Origin header to $hashtag + +-- | needed for guiding type inference +exposedPostServiceAPI :: Proxy PostServiceAPI +exposedPostServiceAPI = Proxy + diff --git a/src/Hash2Pub/ProtocolTypes.hs b/src/Hash2Pub/ProtocolTypes.hs index 37c00e9..a5af10c 100644 --- a/src/Hash2Pub/ProtocolTypes.hs +++ b/src/Hash2Pub/ProtocolTypes.hs @@ -1,7 +1,5 @@ module Hash2Pub.ProtocolTypes where -import qualified Data.Map as Map -import Data.Maybe (mapMaybe) import qualified Data.Set as Set import Data.Time.Clock.POSIX (POSIXTime) @@ -55,6 +53,7 @@ data ActionPayload = QueryIDRequestPayload | LeaveRequestPayload { leaveSuccessors :: [RemoteNodeState] , leavePredecessors :: [RemoteNodeState] + , leaveDoMigration :: Bool } | StabiliseRequestPayload | PingRequestPayload diff --git a/src/Hash2Pub/RingMap.hs b/src/Hash2Pub/RingMap.hs index 529a68b..a2fe3ae 100644 --- a/src/Hash2Pub/RingMap.hs +++ b/src/Hash2Pub/RingMap.hs @@ -5,36 +5,61 @@ module Hash2Pub.RingMap where import Data.Foldable (foldr') import qualified Data.Map.Strict as Map -import Data.Maybe (fromJust, isJust, isNothing, mapMaybe) +import Data.Maybe (isJust, isNothing, mapMaybe) -- | Class for all types that can be identified via a EpiChord key. -- Used for restricting the types a 'RingMap' can store -class (Eq a, Show a, Bounded k, Ord k) => HasKeyID a k where +class (Eq a, Show a, Bounded k, Ord k) => HasKeyID k a where getKeyID :: a -> k + keyValuePair :: a -> (k, a) + keyValuePair val = (getKeyID val, val) -- | generic data structure for holding elements with a key and modular lookup -newtype RingMap a k = RingMap { getRingMap :: (HasKeyID a k, Bounded k, Ord k) => Map.Map k (RingEntry a k) } +newtype RingMap k a = RingMap { getRingMap :: (Bounded k, Ord k) => Map.Map k (RingEntry k a) } -instance (HasKeyID a k, Bounded k, Ord k) => Eq (RingMap a k) where +instance (Bounded k, Ord k, Eq a) => Eq (RingMap k a) where a == b = getRingMap a == getRingMap b -instance (HasKeyID a k, Bounded k, Ord k, Show k) => Show (RingMap a k) where - show rmap = shows "RingMap " (show $ getRingMap rmap) +instance (Bounded k, Ord k, Show k, Show a) => Show (RingMap k a) where + show rmap = shows ("RingMap " :: String) (show $ getRingMap rmap) + + +instance (Bounded k, Ord k) => Functor (RingMap k) where + -- | map a function over all payload values of a 'RingMap' + fmap f = RingMap . Map.map traversingF . getRingMap + where + traversingF (KeyEntry a) = KeyEntry (f a) + traversingF (ProxyEntry pointer (Just entry)) = ProxyEntry pointer (Just $ traversingF entry) + traversingF (ProxyEntry pointer Nothing) = ProxyEntry pointer Nothing + + +instance (Bounded k, Ord k) => Foldable (RingMap k) where + foldr f initVal = Map.foldr traversingFR initVal . getRingMap + where + traversingFR (KeyEntry a) acc = f a acc + traversingFR (ProxyEntry _ Nothing) acc = acc + traversingFR (ProxyEntry _ (Just entry)) acc = traversingFR entry acc + foldl f initVal = Map.foldl traversingFL initVal . getRingMap + where + traversingFL acc (KeyEntry a) = f acc a + traversingFL acc (ProxyEntry _ Nothing) = acc + traversingFL acc (ProxyEntry _ (Just entry)) = traversingFL acc entry + -- | entry of a 'RingMap' that holds a value and can also -- wrap around the lookup direction at the edges of the name space. -data RingEntry a k = KeyEntry a - | ProxyEntry (k, ProxyDirection) (Maybe (RingEntry a k)) +data RingEntry k a = KeyEntry a + | ProxyEntry (k, ProxyDirection) (Maybe (RingEntry k a)) deriving (Show, Eq) -- | as a compromise, only KeyEntry components are ordered by their key -- while ProxyEntry components should never be tried to be ordered. -instance (HasKeyID a k, Eq k, Ord a, Bounded k, Ord k) => Ord (RingEntry a k) where +instance (HasKeyID k a, Eq k, Ord a, Bounded k, Ord k) => Ord (RingEntry k a) where a `compare` b = compare (extractID a) (extractID b) where - extractID :: (HasKeyID a k, Ord a, Bounded k, Ord k) => RingEntry a k -> k + extractID :: (HasKeyID k a, Ord a, Bounded k, Ord k) => RingEntry k a -> k extractID (KeyEntry e) = getKeyID e extractID ProxyEntry{} = error "proxy entries should never appear outside of the RingMap" @@ -49,51 +74,51 @@ instance Enum ProxyDirection where fromEnum Backwards = - 1 fromEnum Forwards = 1 --- | helper function for getting the a from a RingEntry a k -extractRingEntry :: (HasKeyID a k, Bounded k, Ord k) => RingEntry a k -> Maybe a +-- | helper function for getting the a from a RingEntry k a +extractRingEntry :: (Bounded k, Ord k) => RingEntry k a -> Maybe a extractRingEntry (KeyEntry entry) = Just entry extractRingEntry (ProxyEntry _ (Just (KeyEntry entry))) = Just entry extractRingEntry _ = Nothing -- | An empty 'RingMap' needs to be initialised with 2 proxy entries, -- linking the modular name space together by connecting @minBound@ and @maxBound@ -emptyRMap :: (HasKeyID a k, Bounded k, Ord k) => RingMap a k +emptyRMap :: (Bounded k, Ord k) => RingMap k a emptyRMap = RingMap . Map.fromList $ proxyEntry <$> [(maxBound, (minBound, Forwards)), (minBound, (maxBound, Backwards))] where proxyEntry (from,to) = (from, ProxyEntry to Nothing) -- | Maybe returns the entry stored at given key -rMapLookup :: (HasKeyID a k, Bounded k, Ord k) +rMapLookup :: (Bounded k, Ord k) => k -- ^lookup key - -> RingMap a k -- ^lookup cache + -> RingMap k a -- ^lookup cache -> Maybe a rMapLookup key rmap = extractRingEntry =<< Map.lookup key (getRingMap rmap) -- | returns number of present 'KeyEntry' in a properly initialised 'RingMap' -rMapSize :: (HasKeyID a k, Integral i, Bounded k, Ord k) - => RingMap a k +rMapSize :: (Integral i, Bounded k, Ord k) + => RingMap k a -> i rMapSize rmap = fromIntegral $ Map.size innerMap - oneIfEntry rmap minBound - oneIfEntry rmap maxBound where innerMap = getRingMap rmap - oneIfEntry :: (HasKeyID a k, Integral i, Bounded k, Ord k) => RingMap a k -> k -> i + oneIfEntry :: (Integral i, Bounded k, Ord k) => RingMap k a -> k -> i oneIfEntry rmap' nid | isNothing (rMapLookup nid rmap') = 1 | otherwise = 0 -- | a wrapper around lookup functions, making the lookup redirectable by a @ProxyEntry@ -- to simulate a modular ring -lookupWrapper :: (HasKeyID a k, Bounded k, Ord k, Num k) - => (k -> Map.Map k (RingEntry a k) -> Maybe (k, RingEntry a k)) - -> (k -> Map.Map k (RingEntry a k) -> Maybe (k, RingEntry a k)) +lookupWrapper :: (Bounded k, Ord k, Num k) + => (k -> Map.Map k (RingEntry k a) -> Maybe (k, RingEntry k a)) + -> (k -> Map.Map k (RingEntry k a) -> Maybe (k, RingEntry k a)) -> ProxyDirection -> k - -> RingMap a k - -> Maybe a + -> RingMap k a + -> Maybe (k, a) lookupWrapper f fRepeat direction key rmap = case f key $ getRingMap rmap of -- the proxy entry found holds a - Just (_, ProxyEntry _ (Just (KeyEntry entry))) -> Just entry + Just (foundKey, ProxyEntry _ (Just (KeyEntry entry))) -> Just (foundKey, entry) -- proxy entry holds another proxy entry, this should not happen Just (_, ProxyEntry _ (Just (ProxyEntry _ _))) -> Nothing -- proxy entry without own entry is a pointer on where to continue @@ -106,10 +131,10 @@ lookupWrapper f fRepeat direction key rmap = then lookupWrapper fRepeat fRepeat direction newKey rmap else Nothing -- normal entries are returned - Just (_, KeyEntry entry) -> Just entry + Just (foundKey, KeyEntry entry) -> Just (foundKey, entry) Nothing -> Nothing where - rMapNotEmpty :: (HasKeyID a k, Bounded k, Ord k) => RingMap a k -> Bool + rMapNotEmpty :: (Bounded k, Ord k) => RingMap k a -> Bool rMapNotEmpty rmap' = (Map.size (getRingMap rmap') > 2) -- there are more than the 2 ProxyEntries || isJust (rMapLookup minBound rmap') -- or one of the ProxyEntries holds a node || isJust (rMapLookup maxBound rmap') @@ -117,32 +142,34 @@ lookupWrapper f fRepeat direction key rmap = -- | find the successor node to a given key on a modular EpiChord ring. -- Note: The EpiChord definition of "successor" includes the node at the key itself, -- if existing. -rMapLookupSucc :: (HasKeyID a k, Bounded k, Ord k, Num k) +rMapLookupSucc :: (Bounded k, Ord k, Num k) => k -- ^lookup key - -> RingMap a k -- ^ring cache - -> Maybe a + -> RingMap k a -- ^ring cache + -> Maybe (k, a) rMapLookupSucc = lookupWrapper Map.lookupGE Map.lookupGE Forwards -- | find the predecessor node to a given key on a modular EpiChord ring. -rMapLookupPred :: (HasKeyID a k, Bounded k, Ord k, Num k) +rMapLookupPred :: (Bounded k, Ord k, Num k) => k -- ^lookup key - -> RingMap a k -- ^ring cache - -> Maybe a + -> RingMap k a -- ^ring cache + -> Maybe (k, a) rMapLookupPred = lookupWrapper Map.lookupLT Map.lookupLE Backwards -addRMapEntryWith :: (HasKeyID a k, Bounded k, Ord k) - => (RingEntry a k -> RingEntry a k -> RingEntry a k) - -> a - -> RingMap a k - -> RingMap a k -addRMapEntryWith combineFunc entry = RingMap - . Map.insertWith combineFunc (getKeyID entry) (KeyEntry entry) +addRMapEntryWith :: (Bounded k, Ord k) + => (RingEntry k a -> RingEntry k a -> RingEntry k a) -- ^ f new_value mold_value + -> k -- ^ key + -> a -- ^ value + -> RingMap k a + -> RingMap k a +addRMapEntryWith combineFunc key entry = RingMap + . Map.insertWith combineFunc key (KeyEntry entry) . getRingMap -addRMapEntry :: (HasKeyID a k, Bounded k, Ord k) - => a - -> RingMap a k - -> RingMap a k +addRMapEntry :: (Bounded k, Ord k) + => k -- ^ key + -> a -- ^ value + -> RingMap k a + -> RingMap k a addRMapEntry = addRMapEntryWith insertCombineFunction where insertCombineFunction newVal oldVal = @@ -151,30 +178,30 @@ addRMapEntry = addRMapEntryWith insertCombineFunction KeyEntry _ -> newVal -addRMapEntries :: (Foldable t, HasKeyID a k, Bounded k, Ord k) - => t a - -> RingMap a k - -> RingMap a k -addRMapEntries entries rmap = foldr' addRMapEntry rmap entries +addRMapEntries :: (Foldable t, Bounded k, Ord k) + => t (k, a) + -> RingMap k a + -> RingMap k a +addRMapEntries entries rmap = foldr' (\(k, v) rmap' -> addRMapEntry k v rmap') rmap entries -setRMapEntries :: (Foldable t, HasKeyID a k, Bounded k, Ord k) - => t a - -> RingMap a k +setRMapEntries :: (Foldable t, Bounded k, Ord k) + => t (k, a) + -> RingMap k a setRMapEntries entries = addRMapEntries entries emptyRMap -deleteRMapEntry :: (HasKeyID a k, Bounded k, Ord k) +deleteRMapEntry :: (Bounded k, Ord k) => k - -> RingMap a k - -> RingMap a k + -> RingMap k a + -> RingMap k a deleteRMapEntry nid = RingMap . Map.update modifier nid . getRingMap where modifier (ProxyEntry idPointer _) = Just (ProxyEntry idPointer Nothing) modifier KeyEntry {} = Nothing -rMapToList :: (HasKeyID a k, Bounded k, Ord k) => RingMap a k -> [a] +rMapToList :: (Bounded k, Ord k) => RingMap k a -> [a] rMapToList = mapMaybe extractRingEntry . Map.elems . getRingMap -rMapFromList :: (HasKeyID a k, Bounded k, Ord k) => [a] -> RingMap a k +rMapFromList :: (Bounded k, Ord k) => [(k, a)] -> RingMap k a rMapFromList = setRMapEntries -- | takes up to i entries from a 'RingMap' by calling a getter function on a @@ -182,49 +209,64 @@ rMapFromList = setRMapEntries -- Stops once i entries have been taken or an entry has been encountered twice -- (meaning the ring has been traversed completely). -- Forms the basis for 'takeRMapSuccessors' and 'takeRMapPredecessors'. -takeRMapEntries_ :: (HasKeyID a k, Integral i, Bounded k, Ord k) - => (k -> RingMap a k -> Maybe a) - -> k - -> i - -> RingMap a k - -> [a] +takeRMapEntries_ :: (Integral i, Bounded k, Ord k) + => (k -> RingMap k a -> Maybe (k, a)) -- ^ parameterisable getter function to determine lookup direction + -> k -- ^ starting key + -> i -- ^ number of maximum values to take + -> RingMap k a + -> [a] -- ^ values taken -- TODO: might be more efficient with dlists takeRMapEntries_ getterFunc startAt num rmap = reverse $ case getterFunc startAt rmap of Nothing -> [] - Just anEntry -> takeEntriesUntil rmap getterFunc (getKeyID anEntry) (getKeyID anEntry) (num-1) [anEntry] - where - -- for some reason, just reusing the already-bound @rmap@ and @getterFunc@ - -- variables leads to a type error, these need to be passed explicitly - takeEntriesUntil :: (HasKeyID a k, Integral i, Bounded k, Ord k) - => RingMap a k - -> (k -> RingMap a k -> Maybe a) -- getter function - -> k - -> k - -> i - -> [a] - -> [a] - takeEntriesUntil rmap' getterFunc' havingReached previousEntry remaining takeAcc - | remaining <= 0 = takeAcc - | getKeyID (fromJust $ getterFunc' previousEntry rmap') == havingReached = takeAcc - | otherwise = let (Just gotEntry) = getterFunc' previousEntry rmap' - in takeEntriesUntil rmap' getterFunc' havingReached (getKeyID gotEntry) (remaining-1) (gotEntry:takeAcc) + Just (foundKey, anEntry) -> takeEntriesUntil_ rmap getterFunc foundKey foundKey (Just $ num-1) [anEntry] -takeRMapPredecessors :: (HasKeyID a k, Integral i, Bounded k, Ord k, Num k) + +takeEntriesUntil_ :: (Integral i, Bounded k, Ord k) + => RingMap k a + -> (k -> RingMap k a -> Maybe (k, a)) -- getter function + -> k -- limit value + -> k -- start value + -> Maybe i -- possible number limit + -> [a] + -> [a] +takeEntriesUntil_ _rmap' _getterFunc' _havingReached _previousEntry (Just remaining) takeAcc + -- length limit reached + | remaining <= 0 = takeAcc +takeEntriesUntil_ rmap' getterFunc' havingReached previousEntry numLimit takeAcc = + case nextEntry of + Just (fKey, gotEntry) + | fKey == havingReached -> takeAcc + | otherwise -> takeEntriesUntil_ rmap' getterFunc' havingReached fKey (fmap pred numLimit) (gotEntry:takeAcc) + Nothing -> takeAcc + where + nextEntry = getterFunc' previousEntry rmap' + + +takeRMapPredecessors :: (Integral i, Bounded k, Ord k, Num k) => k -> i - -> RingMap a k + -> RingMap k a -> [a] takeRMapPredecessors = takeRMapEntries_ rMapLookupPred -takeRMapSuccessors :: (HasKeyID a k, Integral i, Bounded k, Ord k, Num k) +takeRMapSuccessors :: (Integral i, Bounded k, Ord k, Num k) => k -> i - -> RingMap a k + -> RingMap k a -> [a] takeRMapSuccessors = takeRMapEntries_ rMapLookupSucc --- clean up cache entries: once now - entry > maxAge --- transfer difference now - entry to other node - +takeRMapPredecessorsFromTo :: (Bounded k, Ord k, Num k) + => k -- start value for taking + -> k -- stop value for taking + -> RingMap k a + -> [a] +takeRMapPredecessorsFromTo fromVal toVal rmap = takeEntriesUntil_ rmap rMapLookupPred toVal fromVal Nothing [] +takeRMapSuccessorsFromTo :: (Bounded k, Ord k, Num k) + => k -- start value for taking + -> k -- stop value for taking + -> RingMap k a + -> [a] +takeRMapSuccessorsFromTo fromVal toVal rmap = takeEntriesUntil_ rmap rMapLookupSucc toVal fromVal Nothing [] diff --git a/src/Hash2Pub/ServiceTypes.hs b/src/Hash2Pub/ServiceTypes.hs deleted file mode 100644 index ab06052..0000000 --- a/src/Hash2Pub/ServiceTypes.hs +++ /dev/null @@ -1,9 +0,0 @@ -{-# LANGUAGE MultiParamTypeClasses #-} -module Hash2Pub.ServiceTypes where - -import Hash2Pub.FediChord (DHT (..)) - -class Service s d where - -- | run the service - runService :: (Integral i) => d -> String -> i -> IO (s d) - getServicePort :: (Integral i) => s d -> i diff --git a/test/FediChordSpec.hs b/test/FediChordSpec.hs index 1cace7a..6a3ca5d 100644 --- a/test/FediChordSpec.hs +++ b/test/FediChordSpec.hs @@ -1,4 +1,6 @@ -{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE MultiParamTypeClasses #-} +{-# LANGUAGE OverloadedStrings #-} module FediChordSpec where import Control.Concurrent.STM.TVar @@ -187,6 +189,7 @@ spec = do lReqPayload = LeaveRequestPayload { leaveSuccessors = someNodes , leavePredecessors = someNodes + , leaveDoMigration = True } stabReqPayload = StabiliseRequestPayload pingReqPayload = PingRequestPayload @@ -292,12 +295,15 @@ exampleNodeState = RemoteNodeState { , vServerID = 0 } -exampleLocalNode :: IO LocalNodeState -exampleLocalNode = nodeStateInit =<< (newTVarIO $ RealNode { +exampleLocalNode :: IO (LocalNodeState MockService) +exampleLocalNode = do + realNode <- newTVarIO $ RealNode { vservers = [] , nodeConfig = exampleFediConf , bootstrapNodes = confBootstrapNodes exampleFediConf - }) + , nodeService = MockService + } + nodeStateInit realNode exampleFediConf :: FediChordConf @@ -313,3 +319,9 @@ exampleVs :: (Integral i) => i exampleVs = 4 exampleIp :: HostAddress6 exampleIp = tupleToHostAddress6 (0x2001, 0x16b8, 0x755a, 0xb110, 0x7d6a, 0x12ab, 0xf0c5, 0x386e) + +data MockService d = MockService + +instance DHT d => Service MockService d where + runService _ _ = pure MockService + getListeningPortFromService = const 1337