periodically purge request parts

src/Hash2Pub/FediChord.hs

@@ -216,9 +216,21 @@ 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
+purgeAge :: POSIXTime
+purgeAge = 60 -- seconds
+
 requestMapPurge :: MVar RequestMap -> IO ()
--- PLACEHOLDER
-requestMapPurge mapVar = pure ()
+requestMapPurge mapVar = forever $ do
+    rMapState <- takeMVar mapVar
+    now <- getPOSIXTime
+    putMVar mapVar $ Map.filter (\entry@(RequestMapEntry _ _ ts)  ->
+        now - ts < purgeAge
+                                ) rMapState
+    threadDelay $ fromEnum purgeAge * 2000
+
+
 
 -- | Wait for messages, deserialise them, manage parts and acknowledgement status,
 -- and pass them to their specific handling function.
@@ -230,7 +242,9 @@ fediMessageHandler sendQ recvQ ns = do
     -- 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)
-    forever $ do
+    -- run receive loop and requestMapPurge concurrently, so that an exception makes
+    -- both of them fail
+    concurrently_ (requestMapPurge requestMap) $ forever $ do
         -- wait for incoming messages
         (rawMsg, sourceAddr) <- atomically $ readTQueue recvQ
         let aMsg = deserialiseMessage rawMsg

src/Hash2Pub/Main.hs

@@ -42,8 +42,6 @@ main = do
         wait =<< async (fediMainThreads serverSock thisNode)
            )
         joinedState
-    -- stop main thread from terminating during development
-    getChar
     pure ()