Distinguish hostnames vs "host:port" strings; minor echo client cleanup (#20)

* Remove explicit host:port parameter from clientRequest

* Save ClientConfig in Client ADT; derive host:port string as needed

* Add Port newtype and endpoint string constructor fn

* Introduce Endpoint newtype for host:port strings; derive them as needed; misc cleanup

* Clean up echo client

examples/echo/echo-client/Main.hs

@@ -1,37 +1,24 @@
+{-# LANGUAGE LambdaCase                      #-}
 {-# LANGUAGE OverloadedStrings               #-}
+{-# OPTIONS_GHC -fno-warn-missing-signatures #-}
+{-# OPTIONS_GHC -fno-warn-unused-binds       #-}
 
-import Control.Concurrent (threadDelay)
-import Control.Monad (forever)
-import Data.ByteString ()
-import qualified Data.Map as M
+import           Control.Monad
 import           Network.GRPC.LowLevel
 
-echoMethod :: MethodName
 echoMethod = MethodName "/echo.Echo/DoEcho"
 
-ntimes :: Int -> IO () -> IO ()
-ntimes 1 f = f
-ntimes n f = f >> (ntimes (n-1) f)
+unregistered c = do
+  clientRequest c echoMethod 1 "hi" mempty
 
-unregClient :: IO ()
-unregClient = do
-  withGRPC $ \grpc ->
-    withClient grpc (ClientConfig "localhost" 50051) $ \client ->
-    ntimes 100000 $ do
-      reqResult <- clientRequest client echoMethod "localhost:50051" 1 "hi" M.empty
-      case reqResult of
-        Left x -> error $ "Got client error: " ++ show x
-        Right resp -> return ()
+registered c = do
+  meth <- clientRegisterMethod c echoMethod Normal
+  clientRegisteredRequest c meth 1 "hi" mempty
 
-regClient :: IO ()
-regClient = do
-  withGRPC $ \grpc ->
-    withClient grpc (ClientConfig "localhost" 50051) $ \client -> ntimes 100000 $ do
-      regMethod <- clientRegisterMethod client echoMethod Normal
-      reqResult <- clientRegisteredRequest client regMethod 1 "hi" M.empty
-      case reqResult of
-        Left x -> error $ "Got client error: " ++ show x
-        Right resp -> return ()
+run f = withGRPC $ \g -> withClient g (ClientConfig "localhost" 50051) $ \c ->
+  f c >>= \case
+    Left e -> error $ "Got client error: " ++ show e
+    _      -> return ()
 
-main :: IO ()
-main = regClient
+main = replicateM_ 100 $ run $
+  registered

grpc-haskell.cabal

@@ -21,7 +21,7 @@ Flag Debug
 flag with-examples
   description: Also build example executables.
   manual:      True
-  default:     False
+  default:     True
 
 library
   build-depends:

src/Network/GRPC/LowLevel/Call.hs

@@ -28,6 +28,16 @@ newtype MethodName = MethodName {unMethodName :: String}
 newtype Host = Host {unHost :: String}
   deriving (Show, Eq, IsString)
 
+newtype Port = Port {unPort :: Int}
+  deriving (Eq, Num, Show)
+
+newtype Endpoint = Endpoint {unEndpoint :: String}
+  deriving (Show, Eq, IsString)
+
+-- | Given a hostname and port, produces a "host:port" string
+endpoint :: Host -> Port -> Endpoint
+endpoint (Host h) (Port p) = Endpoint (h ++ ":" ++ show p)
+
 -- | Represents a registered method. Methods can optionally be registered in
 -- order to make the C-level request/response code simpler.
 -- Before making or awaiting a registered call, the
@@ -36,7 +46,7 @@ newtype Host = Host {unHost :: String}
 -- Contains state for identifying that method in the underlying gRPC library.
 data RegisteredMethod = RegisteredMethod {methodType :: GRPCMethodType,
                                           methodName :: MethodName,
-                                          methodHost :: Host,
+                                          methodEndpoint :: Endpoint,
                                           methodHandle :: C.CallHandle}
 
 -- | Represents one GRPC call (i.e. request) on the client.

src/Network/GRPC/LowLevel/Client.hs

@@ -19,20 +19,22 @@ import           Network.GRPC.LowLevel.Op
 -- | Represents the context needed to perform client-side gRPC operations.
 data Client = Client {clientChannel :: C.Channel,
                       clientCQ :: CompletionQueue,
-                      clientHostPort :: String}
+                      clientConfig :: ClientConfig
+                     }
 
 -- | Configuration necessary to set up a client.
-data ClientConfig = ClientConfig {clientServerHost :: Host,
-                                  clientServerPort :: Int}
+data ClientConfig = ClientConfig {serverHost :: Host,
+                                  serverPort :: Port}
+
+clientEndpoint :: ClientConfig -> Endpoint
+clientEndpoint ClientConfig{..} = endpoint serverHost serverPort
 
 createClient :: GRPC -> ClientConfig -> IO Client
-createClient grpc conf@ClientConfig{..} = do
-  let clientHostPort = (unHost clientServerHost)
-                       ++ ":"
-                       ++ (show clientServerPort)
-  clientChannel <- C.grpcInsecureChannelCreate clientHostPort nullPtr C.reserved
+createClient grpc clientConfig = do
+  let Endpoint e = clientEndpoint clientConfig
+  clientChannel <- C.grpcInsecureChannelCreate e nullPtr C.reserved
   clientCQ <- createCompletionQueue grpc
-  return $ Client{..}
+  return Client{..}
 
 destroyClient :: Client -> IO ()
 destroyClient Client{..} = do
@@ -59,12 +61,11 @@ clientRegisterMethod :: Client
                         -- ^ method name, e.g. "/foo"
                         -> GRPCMethodType
                         -> IO RegisteredMethod
-clientRegisterMethod Client{..} name Normal = do
+clientRegisterMethod Client{..} meth Normal = do
+  let e = clientEndpoint clientConfig
   handle <- C.grpcChannelRegisterCall clientChannel
-                                      (unMethodName name)
-                                      clientHostPort
-                                      C.reserved
-  return $ RegisteredMethod Normal name (Host clientHostPort) handle
+              (unMethodName meth) (unEndpoint e) C.reserved
+  return $ RegisteredMethod Normal meth e handle
 clientRegisterMethod _ _ _ = error "Streaming methods not yet implemented."
 
 -- | Create a new call on the client for a registered method.
@@ -98,22 +99,21 @@ withClientRegisteredCall client regmethod timeout f = do
 -- registered method version, but we include this for completeness and testing.
 clientCreateCall :: Client
                  -> MethodName
-                    -- ^ The method name
-                    -> Host
-                    -- ^ The host.
                  -> TimeoutSeconds
                  -> IO (Either GRPCIOError ClientCall)
-clientCreateCall Client{..} method host timeout = do
+clientCreateCall Client{..} meth timeout = do
   let parentCall = C.Call nullPtr
   C.withDeadlineSeconds timeout $ \deadline -> do
     channelCreateCall clientChannel parentCall C.propagateDefaults
-                      clientCQ method host deadline
+                      clientCQ meth (clientEndpoint clientConfig) deadline
 
-withClientCall :: Client -> MethodName -> Host -> TimeoutSeconds
+withClientCall :: Client
+               -> MethodName
+               -> TimeoutSeconds
                -> (ClientCall -> IO (Either GRPCIOError a))
                -> IO (Either GRPCIOError a)
-withClientCall client method host timeout f = do
-  createResult <- clientCreateCall client method host timeout
+withClientCall client method timeout f = do
+  createResult <- clientCreateCall client method timeout
   case createResult of
     Left x -> return $ Left x
     Right call -> f call `finally` logDestroy call
@@ -201,18 +201,16 @@ clientRegisteredRequest client@(Client{..}) rm@(RegisteredMethod{..})
 clientRequest :: Client
                  -> MethodName
                  -- ^ Method name, e.g. "/foo"
-                 -> Host
-                 -- ^ Host. Not sure if used.
                  -> TimeoutSeconds
+                 -- ^ "Number of seconds until request times out"
                  -> ByteString
                  -- ^ Request body.
                  -> MetadataMap
                  -- ^ Request metadata.
                  -> IO (Either GRPCIOError NormalRequestResult)
-clientRequest client@(Client{..}) (MethodName method) (Host host)
-              timeLimit body meta =
-  fmap join $
-  withClientCall client (MethodName method) (Host host) timeLimit $ \call -> do
+clientRequest client@Client{..} meth timeLimit body meta =
+  fmap join $ do
+  withClientCall client meth timeLimit $ \call -> do
     let ops = clientNormalRequestOps body meta
     results <- runClientOps call clientCQ ops timeLimit
     grpcDebug "clientRequest: ops ran."

src/Network/GRPC/LowLevel/CompletionQueue.hs

@@ -237,15 +237,18 @@ channelCreateRegisteredCall
                                               handle deadline C.reserved
     return $ Right $ ClientCall call
 
-channelCreateCall :: C.Channel -> C.Call -> C.PropagationMask -> CompletionQueue
-                     -> MethodName -> Host -> C.CTimeSpecPtr
+channelCreateCall :: C.Channel
+                  -> C.Call
+                  -> C.PropagationMask
+                  -> CompletionQueue
+                  -> MethodName
+                  -> Endpoint
+                  -> C.CTimeSpecPtr
                   -> IO (Either GRPCIOError ClientCall)
-channelCreateCall
-  chan parent mask cq@CompletionQueue{..} (MethodName methodName) (Host host)
-  deadline =
+channelCreateCall chan parent mask cq@CompletionQueue{..} meth endpt deadline =
   withPermission Push cq $ do
-    call <- C.grpcChannelCreateCall chan parent mask unsafeCQ methodName host
-                                    deadline C.reserved
+    call <- C.grpcChannelCreateCall chan parent mask unsafeCQ
+              (unMethodName meth) (unEndpoint endpt) deadline C.reserved
     return $ Right $ ClientCall call
 
 -- | Create the call object to handle a registered call.

src/Network/GRPC/LowLevel/Server.hs

@@ -24,41 +24,47 @@ import           Network.GRPC.LowLevel.GRPC
 import           Network.GRPC.LowLevel.Op
 
 -- | Wraps various gRPC state needed to run a server.
-data Server = Server {internalServer :: C.Server, serverCQ :: CompletionQueue,
-                      registeredMethods :: [RegisteredMethod]}
+data Server = Server
+  { internalServer :: C.Server
+  , serverCQ :: CompletionQueue
+  , registeredMethods :: [RegisteredMethod]
+  , serverConfig :: ServerConfig
+  }
 
--- | Configuration needed to start a server. There might be more fields that
--- need to be added to this in the future.
-data ServerConfig =
-  ServerConfig {hostName          :: Host,
-                -- ^ Name of the host the server is running on. Not sure
-                -- how this is used. Setting to "localhost" works fine in tests.
-                port              :: Int,
-                -- ^ Port to listen for requests on.
-                methodsToRegister :: [(MethodName, GRPCMethodType)]
-                -- ^ List of (method name, method host, method type) tuples
-                -- specifying all methods to register. You can also handle
-                -- other unregistered methods with `serverHandleNormalCall`.
+-- | Configuration needed to start a server.
+data ServerConfig = ServerConfig
+  { host :: Host
+    -- ^ Name of the host the server is running on. Not sure how this is
+    -- used. Setting to "localhost" works fine in tests.
+  , port :: Port
+    -- ^ Port on which to listen for requests.
+  , methodsToRegister :: [(MethodName, GRPCMethodType)]
+    -- ^ List of (method name, method type) tuples specifying all methods to
+    -- register. You can also handle other unregistered methods with
+    -- `serverHandleNormalCall`.
   }
   deriving (Show, Eq)
 
+serverEndpoint :: ServerConfig -> Endpoint
+serverEndpoint ServerConfig{..} = endpoint host port
+
 startServer :: GRPC -> ServerConfig -> IO Server
-startServer grpc ServerConfig{..} = do
+startServer grpc conf@ServerConfig{..} = do
+  let e = serverEndpoint conf
   server <- C.grpcServerCreate nullPtr C.reserved
-  let hostPort = (unHost hostName) ++ ":" ++ (show port)
-  actualPort <- C.grpcServerAddInsecureHttp2Port server hostPort
-  when (actualPort /= port) (error $ "Unable to bind port: " ++ (show port))
+  actualPort <- C.grpcServerAddInsecureHttp2Port server (unEndpoint e)
+  when (actualPort /= unPort port) $
+    error $ "Unable to bind port: " ++ show port
   cq <- createCompletionQueue grpc
   serverRegisterCompletionQueue server cq
-  methods <- forM methodsToRegister $
-               \(name, mtype) ->
-                 serverRegisterMethod server name (Host hostPort) mtype
+  methods <- forM methodsToRegister $ \(name, mtype) ->
+               serverRegisterMethod server name e mtype
   C.grpcServerStart server
-  return $ Server server cq methods
+  return $ Server server cq methods conf
 
 stopServer :: Server -> IO ()
 -- TODO: Do method handles need to be freed?
-stopServer (Server server cq _) = do
+stopServer (Server server cq _ _) = do
   grpcDebug "stopServer: calling shutdownNotify."
   shutdownNotify
   grpcDebug "stopServer: cancelling all calls."
@@ -96,23 +102,22 @@ withServer grpc cfg f = bracket (startServer grpc cfg) stopServer f
 serverRegisterMethod :: C.Server
                      -> MethodName
                      -- ^ method name, e.g. "/foo"
-                        -> Host
-                        -- ^ host name, e.g. "localhost". I have no idea
-                        -- why this is needed since we have to supply a host
-                        -- name to start a server in the first place. It doesn't
-                        -- seem to have any effect, even if it's filled with
-                        -- nonsense.
+                     -> Endpoint
+                     -- ^ Endpoint name name, e.g. "localhost:9999". I have no
+                     -- idea why this is needed since we have to provide these
+                     -- parameters to start a server in the first place. It
+                     -- doesn't seem to have any effect, even if it's filled
+                     -- with nonsense.
                      -> GRPCMethodType
-                        -- ^ Type of method this will be. In the future, this
-                        -- will be used to switch to the correct handling logic.
+                     -- ^ Type of method this will be. In the future, this will
+                     -- be used to switch to the correct handling logic.
                      -- Currently, the only valid choice is 'Normal'.
                      -> IO RegisteredMethod
-serverRegisterMethod internalServer name host Normal = do
+serverRegisterMethod internalServer meth e Normal = do
   handle <- C.grpcServerRegisterMethod internalServer
-                                       (unMethodName name)
-                                       (unHost host)
+              (unMethodName meth) (unEndpoint e)
   grpcDebug $ "registered method to handle " ++ show handle
-  return $ RegisteredMethod Normal name host handle
+  return $ RegisteredMethod Normal meth e handle
 serverRegisterMethod _ _ _ _ = error "Streaming methods not implemented yet."
 
 -- | Create a 'Call' with which to wait for the invocation of a registered

tests/LowLevelTests.hs

@@ -78,7 +78,7 @@ payloadLowLevelClient = TestClient $ \grpc ->
 payloadLowLevelClientUnregistered :: TestClient
 payloadLowLevelClientUnregistered = TestClient $ \grpc -> do
   withClient grpc (ClientConfig "localhost" 50051) $ \client -> do
-    reqResult <- clientRequest client "/foo" "localhost" 10 "Hello!" M.empty
+    reqResult <- clientRequest client "/foo" 10 "Hello!" M.empty
     case reqResult of
       Left x -> error $ "Client got error: " ++ show x
       Right (NormalRequestResult
@@ -166,7 +166,7 @@ testWithClientCall =
   grpcTest "Client - Create/destroy call" $ \grpc -> do
   let conf = ClientConfig "localhost" 50051
   withClient grpc conf $ \client -> do
-    result <- withClientCall client "foo" "localhost" 10 $
+    result <- withClientCall client "foo" 10 $
                 const $ return $ Right ()
     case result of
       Left err -> error $ show err