Merge pull request #223 from kakkun61/hooks

Introducing hooks

Author: aravindgopall

hedis.cabal

@@ -108,7 +108,8 @@ library
                     Database.Redis.Commands,
                     Database.Redis.ManualCommands,
                     Database.Redis.URL,
-                    Database.Redis.ConnectionContext
+                    Database.Redis.ConnectionContext,
+                    Database.Redis.Hooks
   other-extensions: StrictData
 
 benchmark hedis-benchmark
@@ -203,3 +204,21 @@ test-suite hedis-test-cluster
       ghc-options: -Werror
     if flag(dev)
       ghc-prof-options: -auto-all
+
+test-suite hedis-test-hooks
+    default-language: Haskell2010
+    type: exitcode-stdio-1.0
+    hs-source-dirs: test
+    main-is: MainHooks.hs
+    build-depends:
+        base == 4.*,
+        hedis,
+        HUnit,
+        test-framework,
+        test-framework-hunit
+    -- We use -O0 here, since GHC takes *very* long to compile so many constants
+    ghc-options: -O0 -Wall -rtsopts -fno-warn-unused-do-bind -Wunused-packages
+    if flag(dev)
+      ghc-options: -Werror
+    if flag(dev)
+      ghc-prof-options: -auto-all

src/Database/Redis.hs

@@ -176,6 +176,9 @@ module Database.Redis (
     -- * Pub\/Sub
     module Database.Redis.PubSub,
 
+    -- * Hooks
+    Hooks(..), SendRequestHook, SendPubSubHook, CallbackHook, SendHook, ReceiveHook, defaultHooks,
+
     -- * Low-Level Command API
     sendRequest,
     Reply(..), Status(..), RedisArg(..), RedisResult(..), ConnectionLostException(..),

src/Database/Redis/Cluster.hs

@@ -15,6 +15,7 @@ module Database.Redis.Cluster
   , disconnect
   , requestPipelined
   , nodes
+  , hooks
 ) where
 
 import qualified Data.ByteString as B
@@ -36,6 +37,7 @@ import System.IO.Unsafe(unsafeInterleaveIO)
 
 import Database.Redis.Protocol(Reply(Error), renderRequest, reply)
 import qualified Database.Redis.Cluster.Command as CMD
+import Database.Redis.Hooks (Hooks)
 
 -- This module implements a clustered connection whilst maintaining
 -- compatibility with the original Hedis codebase. In particular it still
@@ -48,7 +50,7 @@ import qualified Database.Redis.Cluster.Command as CMD
 
 -- | A connection to a redis cluster, it is compoesed of a map from Node IDs to
 -- | 'NodeConnection's, a 'Pipeline', and a 'ShardMap'
-data Connection = Connection (HM.HashMap NodeID NodeConnection) (MVar Pipeline) (MVar ShardMap) CMD.InfoMap
+data Connection = Connection (HM.HashMap NodeID NodeConnection) (MVar Pipeline) (MVar ShardMap) CMD.InfoMap Hooks
 
 -- | A connection to a single node in the cluster, similar to 'ProtocolPipelining.Connection'
 data NodeConnection = NodeConnection CC.ConnectionContext (IOR.IORef (Maybe B.ByteString)) NodeID
@@ -100,13 +102,13 @@ instance Exception UnsupportedClusterCommandException
 newtype CrossSlotException = CrossSlotException [[B.ByteString]] deriving (Show, Typeable)
 instance Exception CrossSlotException
 
-connect :: [CMD.CommandInfo] -> MVar ShardMap -> Maybe Int -> IO Connection
-connect commandInfos shardMapVar timeoutOpt = do
+connect :: [CMD.CommandInfo] -> MVar ShardMap -> Maybe Int -> Hooks -> IO Connection
+connect commandInfos shardMapVar timeoutOpt hooks' = do
         shardMap <- readMVar shardMapVar
         stateVar <- newMVar $ Pending []
         pipelineVar <- newMVar $ Pipeline stateVar
         nodeConns <- nodeConnections shardMap
-        return $ Connection nodeConns pipelineVar shardMapVar (CMD.newInfoMap commandInfos) where
+        return $ Connection nodeConns pipelineVar shardMapVar (CMD.newInfoMap commandInfos) hooks' where
     nodeConnections :: ShardMap -> IO (HM.HashMap NodeID NodeConnection)
     nodeConnections shardMap = HM.fromList <$> mapM connectNode (nub $ nodes shardMap)
     connectNode :: Node -> IO (NodeID, NodeConnection)
@@ -116,14 +118,14 @@ connect commandInfos shardMapVar timeoutOpt = do
         return (n, NodeConnection ctx ref n)
 
 disconnect :: Connection -> IO ()
-disconnect (Connection nodeConnMap _ _ _) = mapM_ disconnectNode (HM.elems nodeConnMap) where
+disconnect (Connection nodeConnMap _ _ _ _) = mapM_ disconnectNode (HM.elems nodeConnMap) where
     disconnectNode (NodeConnection nodeCtx _ _) = CC.disconnect nodeCtx
 
 -- Add a request to the current pipeline for this connection. The pipeline will
 -- be executed implicitly as soon as any result returned from this function is
 -- evaluated.
 requestPipelined :: IO ShardMap -> Connection -> [B.ByteString] -> IO Reply
-requestPipelined refreshAction conn@(Connection _ pipelineVar shardMapVar _) nextRequest = modifyMVar pipelineVar $ \(Pipeline stateVar) -> do
+requestPipelined refreshAction conn@(Connection _ pipelineVar shardMapVar _ _) nextRequest = modifyMVar pipelineVar $ \(Pipeline stateVar) -> do
     (newStateVar, repliesIndex) <- hasLocked $ modifyMVar stateVar $ \case
         Pending requests | isMulti nextRequest -> do
             replies <- evaluatePipeline shardMapVar refreshAction conn requests
@@ -228,7 +230,7 @@ retryBatch shardMapVar refreshShardmapAction conn retryCount requests replies =
     -- there is one.
     case last replies of
         (Error errString) | B.isPrefixOf "MOVED" errString -> do
-            let (Connection _ _ _ infoMap) = conn
+            let (Connection _ _ _ infoMap _) = conn
             keys <- mconcat <$> mapM (requestKeys infoMap) requests
             hashSlot <- hashSlotForKeys (CrossSlotException requests) keys
             nodeConn <- nodeConnForHashSlot shardMapVar conn (MissingNodeException (head requests)) hashSlot
@@ -250,7 +252,7 @@ retryBatch shardMapVar refreshShardmapAction conn retryCount requests replies =
 evaluateTransactionPipeline :: MVar ShardMap -> IO ShardMap -> Connection -> [[B.ByteString]] -> IO [Reply]
 evaluateTransactionPipeline shardMapVar refreshShardmapAction conn requests' = do
     let requests = reverse requests'
-    let (Connection _ _ _ infoMap) = conn
+    let (Connection _ _ _ infoMap _) = conn
     keys <- mconcat <$> mapM (requestKeys infoMap) requests
     -- In cluster mode Redis expects commands in transactions to all work on the
     -- same hashslot. We find that hashslot here.
@@ -296,7 +298,7 @@ evaluateTransactionPipeline shardMapVar refreshShardmapAction conn requests' = d
 
 nodeConnForHashSlot :: Exception e => MVar ShardMap -> Connection -> e -> HashSlot -> IO NodeConnection
 nodeConnForHashSlot shardMapVar conn exception hashSlot = do
-    let (Connection nodeConns _ _ _) = conn
+    let (Connection nodeConns _ _ _ _) = conn
     (ShardMap shardMap) <- hasLocked $ readMVar shardMapVar
     node <-
         case IntMap.lookup (fromEnum hashSlot) shardMap of
@@ -339,12 +341,12 @@ moved _ = False
 
 
 nodeConnWithHostAndPort :: ShardMap -> Connection -> Host -> Port -> Maybe NodeConnection
-nodeConnWithHostAndPort shardMap (Connection nodeConns _ _ _) host port = do
+nodeConnWithHostAndPort shardMap (Connection nodeConns _ _ _ _) host port = do
     node <- nodeWithHostAndPort shardMap host port
     HM.lookup (nodeId node) nodeConns
 
 nodeConnectionForCommand :: Connection -> ShardMap -> [B.ByteString] -> IO [NodeConnection]
-nodeConnectionForCommand conn@(Connection nodeConns _ _ infoMap) (ShardMap shardMap) request =
+nodeConnectionForCommand conn@(Connection nodeConns _ _ infoMap _) (ShardMap shardMap) request =
     case request of
         ("FLUSHALL" : _) -> allNodes
         ("FLUSHDB" : _) -> allNodes
@@ -364,7 +366,7 @@ nodeConnectionForCommand conn@(Connection nodeConns _ _ infoMap) (ShardMap shard
                 Just allNodes' -> return allNodes'
 
 allMasterNodes :: Connection -> ShardMap -> Maybe [NodeConnection]
-allMasterNodes (Connection nodeConns _ _ _) (ShardMap shardMap) =
+allMasterNodes (Connection nodeConns _ _ _ _) (ShardMap shardMap) =
     mapM (flip HM.lookup nodeConns . nodeId) masterNodes
   where
     masterNodes = (\(Shard master _) -> master) <$> nub (IntMap.elems shardMap)
@@ -410,3 +412,6 @@ hasLocked action =
   action `catches`
   [ Handler $ \exc@BlockedIndefinitelyOnMVar -> throwIO exc
   ]
+
+hooks :: Connection -> Hooks
+hooks (Connection _ _ _ _ h) = h

src/Database/Redis/Connection.hs

@@ -31,7 +31,7 @@ import qualified Network.Socket as NS
 import qualified Data.HashMap.Strict as HM
 
 import qualified Database.Redis.ProtocolPipelining as PP
-import Database.Redis.Core(Redis, runRedisInternal, runRedisClusteredInternal)
+import Database.Redis.Core(Redis, Hooks, runRedisInternal, runRedisClusteredInternal, defaultHooks)
 import Database.Redis.Protocol(Reply(..))
 import Database.Redis.Cluster(ShardMap(..), Node, Shard(..))
 import qualified Database.Redis.Cluster as Cluster
@@ -97,6 +97,7 @@ data ConnectInfo = ConnInfo
     --   get connected in this interval of time.
     , connectTLSParams      :: Maybe ClientParams
     -- ^ Optional TLS parameters. TLS will be enabled if this is provided.
+    , connectHooks          :: Hooks
     } deriving Show
 
 data ConnectError = ConnectAuthError Reply
@@ -117,6 +118,7 @@ instance Exception ConnectError
 --  connectMaxIdleTime    = 30              -- Keep open for 30 seconds
 --  connectTimeout        = Nothing         -- Don't add timeout logic
 --  connectTLSParams      = Nothing         -- Do not use TLS
+--  connectHooks          = defaultHooks    -- Do nothing
 -- @
 --
 defaultConnectInfo :: ConnectInfo
@@ -130,13 +132,14 @@ defaultConnectInfo = ConnInfo
     , connectMaxIdleTime    = 30
     , connectTimeout        = Nothing
     , connectTLSParams      = Nothing
+    , connectHooks          = defaultHooks
     }
 
 createConnection :: ConnectInfo -> IO PP.Connection
 createConnection ConnInfo{..} = do
     let timeoutOptUs =
           round . (1000000 *) <$> connectTimeout
-    conn <- PP.connect connectHost connectPort timeoutOptUs
+    conn <- PP.connectWithHooks connectHost connectPort timeoutOptUs connectHooks
     conn' <- case connectTLSParams of
                Nothing -> return conn
                Just tlsParams -> PP.enableTLS tlsParams conn
@@ -231,9 +234,9 @@ connectCluster bootstrapConnInfo = do
         Left e -> throwIO $ ClusterConnectError e
         Right infos -> do
 #if MIN_VERSION_resource_pool(0,3,0)
-            pool <- newPool (defaultPoolConfig (Cluster.connect infos shardMapVar Nothing) Cluster.disconnect (realToFrac $ connectMaxIdleTime bootstrapConnInfo) (connectMaxConnections bootstrapConnInfo))
+            pool <- newPool (defaultPoolConfig (Cluster.connect infos shardMapVar Nothing $ connectHooks bootstrapConnInfo) Cluster.disconnect (realToFrac $ connectMaxIdleTime bootstrapConnInfo) (connectMaxConnections bootstrapConnInfo))
 #else
-            pool <- createPool (Cluster.connect infos shardMapVar Nothing) Cluster.disconnect 1 (connectMaxIdleTime bootstrapConnInfo) (connectMaxConnections bootstrapConnInfo)
+            pool <- createPool (Cluster.connect infos shardMapVar Nothing $ connectHooks bootstrapConnInfo) Cluster.disconnect 1 (connectMaxIdleTime bootstrapConnInfo) (connectMaxConnections bootstrapConnInfo)
 #endif
             return $ ClusteredConnection shardMapVar pool
 
@@ -255,7 +258,7 @@ shardMapFromClusterSlotsResponse ClusterSlotsResponse{..} = ShardMap <$> foldr m
             Cluster.Node clusterSlotsNodeID role hostname (toEnum clusterSlotsNodePort)
 
 refreshShardMap :: Cluster.Connection -> IO ShardMap
-refreshShardMap (Cluster.Connection nodeConns _ _ _) = do
+refreshShardMap (Cluster.Connection nodeConns _ _ _ _) = do
     let (Cluster.NodeConnection ctx _ _) = head $ HM.elems nodeConns
     pipelineConn <- PP.fromCtx ctx
     _ <- PP.beginReceiving pipelineConn

src/Database/Redis/Core.hs

@@ -5,9 +5,11 @@
 module Database.Redis.Core (
     Redis(), unRedis, reRedis,
     RedisCtx(..), MonadRedis(..),
+    Hooks(..), SendRequestHook, SendPubSubHook, CallbackHook, SendHook, ReceiveHook, 
     send, recv, sendRequest,
     runRedisInternal,
     runRedisClusteredInternal,
+    defaultHooks,
     RedisEnv(..),
 ) where
 
@@ -24,6 +26,7 @@ import qualified Database.Redis.ProtocolPipelining as PP
 import Database.Redis.Types
 import Database.Redis.Cluster(ShardMap)
 import qualified Database.Redis.Cluster as Cluster
+import Database.Redis.Hooks
 
 --------------------------------------------------------------------------------
 -- The Redis Monad
@@ -118,8 +121,8 @@ sendRequest req = do
         env <- ask
         case env of
             NonClusteredEnv{..} -> do
-                r <- liftIO $ PP.request envConn (renderRequest req)
+                r <- liftIO $ sendRequestHook (PP.hooks envConn) (PP.request envConn . renderRequest) req
                 setLastReply r
                 return r
-            ClusteredEnv{..} -> liftIO $ Cluster.requestPipelined refreshAction connection req
+            ClusteredEnv{..} -> liftIO $ sendRequestHook (Cluster.hooks connection) (Cluster.requestPipelined refreshAction connection) req
     returnDecode r'

src/Database/Redis/Hooks.hs

@@ -0,0 +1,44 @@
+module Database.Redis.Hooks where
+
+import Data.ByteString (ByteString)
+import Database.Redis.Protocol (Reply)
+import {-# SOURCE #-} Database.Redis.PubSub (Message, PubSub)
+
+data Hooks =
+  Hooks
+    { sendRequestHook :: SendRequestHook
+    , sendPubSubHook :: SendPubSubHook
+    , callbackHook :: CallbackHook
+    , sendHook :: SendHook
+    , receiveHook :: ReceiveHook
+    }
+
+-- | A hook for sending commands to the server and receiving replys from the server.
+type SendRequestHook = ([ByteString] -> IO Reply) -> [ByteString] -> IO Reply
+
+-- | A hook for sending pub/sub messages to the server.
+type SendPubSubHook = ([ByteString] -> IO ()) -> [ByteString] -> IO ()
+
+-- | A hook for invoking callbacks with pub/sub messages.
+type CallbackHook = (Message -> IO PubSub) -> Message -> IO PubSub
+
+-- | A hook for just sending raw data to the server.
+type SendHook = (ByteString -> IO ()) -> ByteString -> IO ()
+
+-- | A hook for receiving raw data from the server.
+type ReceiveHook = IO Reply -> IO Reply
+
+-- | The default hooks.
+-- Every hook is the identity function.
+defaultHooks :: Hooks
+defaultHooks =
+  Hooks
+    { sendRequestHook = id
+    , sendPubSubHook = id
+    , callbackHook = id
+    , sendHook = id
+    , receiveHook = id
+    }
+
+instance Show Hooks where
+  show _ = "Hooks {sendRequestHook = _, sendPubSubHook = _, callbackHook = _, sendHook = _, receiveHook = _}"

src/Database/Redis/ProtocolPipelining.hs

@@ -17,7 +17,7 @@
 --
 module Database.Redis.ProtocolPipelining (
   Connection,
-  connect, enableTLS, beginReceiving, disconnect, request, send, recv, flush, fromCtx
+  connect, connectWithHooks, enableTLS, beginReceiving, disconnect, request, send, recv, flush, fromCtx, hooks
 ) where
 
 import           Prelude
@@ -31,6 +31,7 @@ import           System.IO.Unsafe
 
 import           Database.Redis.Protocol
 import qualified Database.Redis.ConnectionContext as CC
+import           Database.Redis.Hooks
 
 data Connection = Conn
   { connCtx        :: CC.ConnectionContext -- ^ Connection socket-handle.
@@ -42,14 +43,18 @@ data Connection = Conn
     -- ^ Number of pending replies and thus the difference length between
     --   'connReplies' and 'connPending'.
     --   length connPending  - pendingCount = length connReplies
+  , hooks         :: Hooks
   }
 
 
 fromCtx :: CC.ConnectionContext -> IO Connection
-fromCtx ctx = Conn ctx <$> newIORef [] <*> newIORef [] <*> newIORef 0
+fromCtx ctx = Conn ctx <$> newIORef [] <*> newIORef [] <*> newIORef 0 <*> pure defaultHooks
 
 connect :: NS.HostName -> CC.PortID -> Maybe Int -> IO Connection
-connect hostName portId timeoutOpt = do
+connect hostName portId timeoutOpt = connectWithHooks hostName portId timeoutOpt defaultHooks
+
+connectWithHooks :: NS.HostName -> CC.PortID -> Maybe Int -> Hooks -> IO Connection
+connectWithHooks hostName portId timeoutOpt hooks = do
     connCtx <- CC.connect hostName portId timeoutOpt
     connReplies <- newIORef []
     connPending <- newIORef []
@@ -74,7 +79,7 @@ disconnect Conn{..} = CC.disconnect connCtx
 --  The 'Handle' is 'hFlush'ed when reading replies from the 'connCtx'.
 send :: Connection -> S.ByteString -> IO ()
 send Conn{..} s = do
-  CC.send connCtx s
+  sendHook hooks (CC.send connCtx) s
 
   -- Signal that we expect one more reply from Redis.
   n <- atomicModifyIORef' connPendingCnt $ \n -> let n' = n+1 in (n', n')
@@ -88,10 +93,11 @@ send Conn{..} s = do
 
 -- |Take a reply-thunk from the list of future replies.
 recv :: Connection -> IO Reply
-recv Conn{..} = do
-  (r:rs) <- readIORef connReplies
-  writeIORef connReplies rs
-  return r
+recv Conn{..} =
+  receiveHook hooks $ do
+    (r:rs) <- readIORef connReplies
+    writeIORef connReplies rs
+    return r
 
 -- | Flush the socket.  Normally, the socket is flushed in 'recv' (actually 'conGetReplies'), but
 -- for the multithreaded pub/sub code, the sending thread needs to explicitly flush the subscription