close #29: periodic cache maintenance
periodically delete expired cache entries, check unverified ones and potentially use them as neighbour
This commit is contained in:
parent
5e8cfb0ccd
commit
7f5dac55ea
|
|
@ -20,11 +20,16 @@ module Hash2Pub.DHTProtocol
|
|||
, requestPing
|
||||
, requestStabilise
|
||||
, queryIdLookupLoop
|
||||
, queueAddEntries
|
||||
, queueDeleteEntries
|
||||
, queueDeleteEntry
|
||||
, resolve
|
||||
, mkSendSocket
|
||||
, mkServerSocket
|
||||
, handleIncomingRequest
|
||||
, ackRequest
|
||||
, isPossibleSuccessor
|
||||
, isPossiblePredecessor
|
||||
)
|
||||
where
|
||||
|
||||
|
|
@ -81,7 +86,7 @@ import Debug.Trace (trace)
|
|||
queryLocalCache :: LocalNodeState -> 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
|
||||
| isInOwnResponsibilitySlice ownState targetID = FOUND . toRemoteNodeState $ ownState
|
||||
| targetID `isInOwnResponsibilitySlice` ownState = FOUND . toRemoteNodeState $ ownState
|
||||
-- my interpretation: the "l best next hops" are the l-1 closest preceding nodes and
|
||||
-- the closest succeeding node (like with the p initiated parallel queries
|
||||
| otherwise = FORWARD $ closestSuccessor `Set.union` closestPredecessors
|
||||
|
|
@ -110,8 +115,8 @@ queryLocalCache ownState nCache lBestNodes targetID
|
|||
-- 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 => LocalNodeState -> a -> Bool
|
||||
isInOwnResponsibilitySlice ownNs lookupTarget = (getKeyID <$> rMapLookupSucc (getKeyID lookupTarget) predecessorRMap) == pure (getNid ownNs)
|
||||
isInOwnResponsibilitySlice :: HasKeyID a => a -> LocalNodeState -> Bool
|
||||
isInOwnResponsibilitySlice lookupTarget ownNs = (getKeyID <$> rMapLookupSucc (getKeyID lookupTarget) predecessorRMap) == pure (getNid ownNs)
|
||||
where
|
||||
predecessorList = predecessors ownNs
|
||||
-- add node itself to RingMap representation, to distinguish between
|
||||
|
|
@ -119,6 +124,16 @@ isInOwnResponsibilitySlice ownNs lookupTarget = (getKeyID <$> rMapLookupSucc (ge
|
|||
predecessorRMap = addRMapEntry (toRemoteNodeState ownNs) $ rMapFromList predecessorList
|
||||
closestPredecessor = headMay predecessorList
|
||||
|
||||
isPossiblePredecessor :: HasKeyID a => a -> LocalNodeState -> Bool
|
||||
isPossiblePredecessor = isInOwnResponsibilitySlice
|
||||
|
||||
isPossibleSuccessor :: HasKeyID a => a -> LocalNodeState -> Bool
|
||||
isPossibleSuccessor lookupTarget ownNs = (getKeyID <$> rMapLookupPred (getKeyID lookupTarget) successorRMap) == pure (getNid ownNs)
|
||||
where
|
||||
successorList = successors ownNs
|
||||
successorRMap = addRMapEntry (toRemoteNodeState ownNs) $ rMapFromList successorList
|
||||
closestSuccessor = headMay successorList
|
||||
|
||||
-- cache operations
|
||||
|
||||
-- | update or insert a 'RemoteCacheEntry' into the cache,
|
||||
|
|
@ -662,6 +677,21 @@ queueAddEntries entries ns = do
|
|||
now <- getPOSIXTime
|
||||
forM_ entries $ \entry -> atomically $ writeTQueue (cacheWriteQueue ns) $ addCacheEntryPure now entry
|
||||
|
||||
|
||||
-- | enque a list of node IDs to be deleted from the global NodeCache
|
||||
queueDeleteEntries :: Foldable c
|
||||
=> c NodeID
|
||||
-> LocalNodeState
|
||||
-> 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
|
||||
-> IO ()
|
||||
queueDeleteEntry toDelete = queueDeleteEntries $ Identity toDelete
|
||||
|
||||
-- | 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
|
||||
|
|
|
|||
|
|
@ -63,6 +63,7 @@ import qualified Data.ByteString as BS
|
|||
import qualified Data.ByteString.UTF8 as BSU
|
||||
import Data.Either (rights)
|
||||
import Data.Foldable (foldr')
|
||||
import Data.Functor.Identity
|
||||
import Data.IP (IPv6, fromHostAddress6,
|
||||
toHostAddress6)
|
||||
import Data.List ((\\))
|
||||
|
|
@ -183,6 +184,58 @@ cacheWriter 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
|
||||
cacheVerifyThread :: LocalNodeStateSTM -> IO ()
|
||||
cacheVerifyThread nsSTM = forever $ do
|
||||
-- get cache
|
||||
(ns, cache) <- atomically $ do
|
||||
ns <- readTVar nsSTM
|
||||
cache <- readTVar $ nodeCacheSTM ns
|
||||
pure (ns, cache)
|
||||
-- iterate entries:
|
||||
-- for avoiding too many time syscalls, get current time before iterating.
|
||||
now <- getPOSIXTime
|
||||
forM_ (cacheEntries cache) (\(CacheEntry validated node ts) ->
|
||||
-- case too old: delete (future work: decide whether pinging and resetting timestamp is better)
|
||||
if (now - ts) > maxEntryAge
|
||||
then
|
||||
queueDeleteEntry (getNid node) ns
|
||||
-- case unverified: try verifying, otherwise delete
|
||||
else if not validated
|
||||
then do
|
||||
-- marking as verified is done by 'requestPing' as well
|
||||
pong <- requestPing ns node
|
||||
either (\_->
|
||||
queueDeleteEntry (getNid node) ns
|
||||
)
|
||||
(\vss ->
|
||||
if node `notElem` vss
|
||||
then queueDeleteEntry (getNid node) ns
|
||||
-- after verifying a node, check whether it can be a closer neighbour
|
||||
else do
|
||||
if node `isPossiblePredecessor` ns
|
||||
then atomically $ do
|
||||
ns' <- readTVar nsSTM
|
||||
writeTVar nsSTM $ addPredecessors [node] ns'
|
||||
else pure ()
|
||||
if node `isPossibleSuccessor` ns
|
||||
then atomically $ do
|
||||
ns' <- readTVar nsSTM
|
||||
writeTVar nsSTM $ addSuccessors [node] ns'
|
||||
else pure ()
|
||||
) pong
|
||||
else pure ()
|
||||
)
|
||||
|
||||
threadDelay $ toEnum (fromEnum maxEntryAge `div` 20)
|
||||
|
||||
|
||||
|
||||
-- | 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.
|
||||
|
|
@ -308,9 +361,10 @@ fediMainThreads sock nsSTM = do
|
|||
concurrently_
|
||||
(fediMessageHandler sendQ recvQ nsSTM) $
|
||||
concurrently_ (stabiliseThread nsSTM) $
|
||||
concurrently_
|
||||
(sendThread sock sendQ)
|
||||
(recvThread sock recvQ)
|
||||
concurrently_ (cacheVerifyThread nsSTM) $
|
||||
concurrently_
|
||||
(sendThread sock sendQ)
|
||||
(recvThread sock recvQ)
|
||||
|
||||
|
||||
-- defining this here as, for now, the RequestMap is only used by fediMessageHandler.
|
||||
|
|
@ -322,17 +376,17 @@ data RequestMapEntry = RequestMapEntry (Set.Set FediChordMessage) (Maybe Integer
|
|||
|
||||
-- TODO: make purge age configurable
|
||||
-- | periodically clean up old request parts
|
||||
purgeAge :: POSIXTime
|
||||
purgeAge = 60 -- seconds
|
||||
responsePurgeAge :: POSIXTime
|
||||
responsePurgeAge = 60 -- seconds
|
||||
|
||||
requestMapPurge :: MVar RequestMap -> IO ()
|
||||
requestMapPurge mapVar = forever $ do
|
||||
rMapState <- takeMVar mapVar
|
||||
now <- getPOSIXTime
|
||||
putMVar mapVar $ Map.filter (\entry@(RequestMapEntry _ _ ts) ->
|
||||
now - ts < purgeAge
|
||||
now - ts < responsePurgeAge
|
||||
) rMapState
|
||||
threadDelay $ fromEnum purgeAge * 2000
|
||||
threadDelay $ fromEnum responsePurgeAge * 2000
|
||||
|
||||
|
||||
-- | Wait for messages, deserialise them, manage parts and acknowledgement status,
|
||||
|
|
|
|||
Loading…
Reference in a new issue