Network.GRPC.Client.Helpers

Set of helpers helping with writing gRPC clients with not much exposure of the http2-client complexity.

The GrpcClient handles automatic background connection-level window updates to prevent the connection from starving and pings to force a connection alive.

There is no automatic reconnection, retry, or healthchecking. These features are not planned in this library and should be added at higher-levels.

Documentation

data GrpcClient

A simplified gRPC Client connected via an HTTP2Client to a given server. Each call from one client will share similar headers, timeout, compression.

Constructors

GrpcClient

Fields

• _grpcClientHttp2Client :: Http2Client

  Underlying HTTP2 client.

• _grpcClientAuthority :: Authority

  Authority header of the server the client is connected to.

• _grpcClientHeaders :: [(ByteString, ByteString)]

  Extra HTTP2 headers to pass to every call (e.g., authentication tokens).

• _grpcClientTimeout :: Timeout

  Timeout for RPCs.

• _grpcClientCompression :: Compression

  Compression shared for every call and expected for every answer.

• _grpcClientBackground :: BackgroundTasks

  Running background tasks.

data BackgroundTasks

Constructors

BackgroundTasks

Fields

• backgroundWindowUpdate :: Async ()

  Periodically give the server credit to use the connection.

• backgroundPing :: Async ()

  Periodically ping the server.

data GrpcClientConfig

Configuration to setup a GrpcClient.

Constructors

GrpcClientConfig

Fields

• _grpcClientConfigHost :: !HostName

  Hostname of the server.

• _grpcClientConfigPort :: !PortNumber

  Port of the server.

• _grpcClientConfigHeaders :: ![(ByteString, ByteString)]

  Extra HTTP2 headers to pass to every call (e.g., authentication tokens).

• _grpcClientConfigTimeout :: !Timeout

  Timeout for RPCs.

• _grpcClientConfigCompression :: !Compression

  Compression shared for every call and expected for every answer.

• _grpcClientConfigTLS :: !(Maybe ClientParams)

  TLS parameters for the session.

• _grpcClientConfigGoAwayHandler :: GoAwayHandler

  HTTP2 handler for GoAways.

• _grpcClientConfigFallbackHandler :: FallBackFrameHandler

  HTTP2 handler for unhandled frames.

• _grpcClientConfigWindowUpdateDelay :: Int

  Delay in microsecond between to window updates.

• _grpcClientConfigPingDelay :: Int

  Delay in microsecond between to pings.

grpcClientConfigSimple :: HostName -> PortNumber -> UseTlsOrNot -> GrpcClientConfig

type UseTlsOrNot = Bool

tlsSettings :: UseTlsOrNot -> HostName -> PortNumber -> Maybe ClientParams

setupGrpcClient :: GrpcClientConfig -> IO GrpcClient

rawUnary :: (Service s, HasMethod s m) => RPC s m -> GrpcClient -> MethodInput s m -> IO (Either TooMuchConcurrency (RawReply (MethodOutput s m)))

rawStreamServer :: (Service s, HasMethod s m, MethodStreamingType s m ~ ServerStreaming) => RPC s m -> GrpcClient -> a -> MethodInput s m -> (a -> HeaderList -> MethodOutput s m -> IO a) -> IO (Either TooMuchConcurrency (a, HeaderList, HeaderList))

rawStreamClient :: (Service s, HasMethod s m, MethodStreamingType s m ~ ClientStreaming) => RPC s m -> GrpcClient -> a -> (a -> IO (a, Either StreamDone (CompressMode, MethodInput s m))) -> IO (Either TooMuchConcurrency (a, RawReply (MethodOutput s m)))