Skeleton implementation of Ames with galaxy lookup.

Needs to be moved to RIO so that I can get logging data about this.

pkg/king/lib/Vere/Ames.hs

@@ -7,25 +7,28 @@ import Network.Socket            hiding (recvFrom, sendTo)
 import Network.Socket.ByteString
 import Vere.Pier.Types
 
+import qualified Data.Map   as M
+import qualified Urbit.Ob   as Ob
 import qualified Urbit.Time as Time
 
-
 -- Types -----------------------------------------------------------------------
 
 data AmesDrv = AmesDrv
   { aIsLive        :: IORef Bool
+  , aTurfs         :: TVar [Turf]
+  , aGalaxies      :: IORef (M.Map Galaxy (Async (), TQueue ByteString))
   , aSocket        :: Socket
   , aWakeTimer     :: Async ()
   , aListener      :: Async ()
+  , aSendingQueue  :: TQueue (SockAddr, ByteString)
+  , aSendingThread :: Async ()
   }
 
 data NetworkMode = Fake | Real
   deriving (Eq, Ord, Show)
 
-{-
-data GalaxyInfo = GalaxyInfo { ip :: Ipv4, age :: Time.Unix }
-  deriving (Eq, Ord, Show)
--}
+-- data GalaxyInfo = GalaxyInfo { ip :: Ipv4, age :: Time.Unix }
+--   deriving (Eq, Ord, Show)
 
 
 -- Utils -----------------------------------------------------------------------
@@ -105,16 +108,24 @@ ames inst who mPort enqueueEv =
     start :: IO AmesDrv
     start = do
         vLiv      <- newIORef False
+        vTurf     <- newTVarIO []
+        vGalaxies <- newIORef mempty
         time      <- async runTimer
         sock      <- bindSock
         hear      <- async (waitPacket sock)
-        pure $ AmesDrv vLiv sock time hear
+        sendQueue <- newTQueueIO
+        sending   <- async (sendingThread sendQueue sock)
+        pure       $ AmesDrv vLiv vTurf vGalaxies sock time hear sendQueue sending
 
     netMode :: NetworkMode
     netMode = Fake
 
     stop :: AmesDrv -> IO ()
     stop (AmesDrv{..}) = do
+        galaxies <- readIORef aGalaxies
+        mapM_ (cancel . fst) galaxies
+
+        cancel aSendingThread
         cancel aWakeTimer
         cancel aListener
         close' aSocket
@@ -140,12 +151,101 @@ ames inst who mPort enqueueEv =
             _                -> pure ()
 
     handleEffect :: AmesDrv -> NewtEf -> IO ()
-    handleEffect AmesDrv{..} = \case
+    handleEffect drv@AmesDrv{..} = \case
       NewtEfTurf (_id, ()) turfs -> do
           writeIORef aIsLive True
+          atomically $ writeTVar aTurfs turfs
 
       NewtEfSend (_id, ()) dest (MkBytes bs) -> do
-          live <- readIORef aIsLive
-          when live $ do
-              when (netMode == Real || okayFakeAddr dest) $ do
-                  void $ sendTo aSocket bs $ destSockAddr netMode dest
+          whenM (readIORef aIsLive) (sendPacket drv netMode dest bs)
+
+    sendPacket :: AmesDrv -> NetworkMode -> AmesDest -> ByteString -> IO ()
+
+    sendPacket AmesDrv{..} Fake dest bs =
+      when (okayFakeAddr dest) $ do
+        atomically $ writeTQueue aSendingQueue ((destSockAddr Fake dest), bs)
+
+    sendPacket AmesDrv{..} Real (ADGala wen galaxy) bs = do
+      galaxies <- readIORef aGalaxies
+      queue <- case M.lookup galaxy galaxies of
+        Just (_, queue) -> pure queue
+        Nothing -> do
+          inQueue <- newTQueueIO
+          thread <- galaxyResolver galaxy aTurfs inQueue aSendingQueue
+          modifyIORef (aGalaxies) (M.insert galaxy (thread, inQueue))
+          pure inQueue
+
+      atomically $ writeTQueue queue bs
+
+    sendPacket AmesDrv{..} Real ip@(ADIpv4 _ _ _) bs =
+      atomically $ writeTQueue aSendingQueue ((destSockAddr Real ip), bs)
+
+    -- An outbound queue of messages. We can only write to a socket from one
+    -- thread, so coalesce those writes here.
+    sendingThread :: TQueue (SockAddr, ByteString) -> Socket -> IO ()
+    sendingThread queue socket = forever $ do
+      (dest, bs) <- atomically $ readTQueue queue
+      void $ sendTo socket bs dest
+
+    -- Asynchronous thread per galaxy which handles domain resolution, and can
+    -- block its own queue of ByteStrings to send.
+    --
+    -- Maybe perform the resolution asynchronously, injecting into the resolver
+    -- queue as a message.
+    --
+    -- TODO: Figure out how the real haskell time library works.
+    galaxyResolver :: Galaxy -> TVar [Turf] -> TQueue ByteString
+                   -> TQueue (SockAddr, ByteString)
+                   -> IO (Async ())
+    galaxyResolver galaxy turfVar incoming outgoing =
+      async $ loop Nothing Time.unixEpoch
+      where
+        loop :: Maybe SockAddr -> Time.Wen -> IO ()
+        loop lastGalaxyIP lastLookupTime = do
+          packet <- atomically $ readTQueue incoming
+
+          i <- checkIP lastGalaxyIP lastLookupTime
+          case i of
+            (Nothing, t) -> do
+              -- We've failed to lookup the IP. Drop the outbound packet
+              -- because we have no IP for our galaxy, including possible
+              -- previous IPs.
+              loop Nothing t
+            (Just ip, t) -> do
+              queueSendToGalaxy ip packet
+              loop (Just ip) t
+
+        checkIP :: Maybe SockAddr -> Time.Wen -> IO (Maybe SockAddr, Time.Wen)
+        checkIP lastIP lastLookupTime = do
+          current <- Time.now
+          if (Time.gap current lastLookupTime ^. Time.secs) < 300
+          then pure (lastIP, lastLookupTime)
+          else do
+            toCheck <- atomically $ readTVar turfVar
+            ip <- resolveFirstIP lastIP toCheck
+            timeAfterResolution <- Time.now
+            pure (ip, timeAfterResolution)
+
+        resolveFirstIP :: Maybe SockAddr -> [Turf] -> IO (Maybe SockAddr)
+        resolveFirstIP prevIP [] = do
+          -- print ("ames: czar at %s: not found (b)\n")
+          pure prevIP
+
+        resolveFirstIP prevIP (x:xs) = do
+          let hostname = buildDNS galaxy x
+          listIPs <- getAddrInfo Nothing (Just hostname) Nothing
+          case listIPs of
+            []     -> resolveFirstIP prevIP xs
+            (y:ys) -> pure $ Just $ addrAddress y
+
+        buildDNS :: Galaxy -> Turf -> String
+        buildDNS (Galaxy g) turf = name ++ "." ++ (unpack $ _turfText turf)
+          where
+            nameWithSig = Ob.renderPatp $ Ob.patp $ fromIntegral g
+            name = case stripPrefix "~" nameWithSig of
+              Nothing -> error "Urbit.ob didn't produce string with ~"
+              Just x  -> (unpack x)
+
+        queueSendToGalaxy :: SockAddr -> ByteString -> IO ()
+        queueSendToGalaxy inet packet =
+          atomically $ writeTQueue outgoing (inet, packet)