http2-client-grpc-0.5.0.3: Implement gRPC-over-HTTP2 clients.

Safe HaskellNone
LanguageHaskell2010

Network.GRPC.Client.Helpers

Description

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.

Synopsis

Documentation

data GrpcClient Source #

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

data BackgroundTasks Source #

Constructors

BackgroundTasks 

Fields

data GrpcClientConfig Source #

Configuration to setup a GrpcClient.

Constructors

GrpcClientConfig 

Fields

close :: GrpcClient -> IO () Source #

Cancels background tasks and closes the underlying HTTP2 client.

rawUnary Source #

Arguments

:: (Service s, HasMethod s m) 
=> RPC s m

The RPC to call.

-> GrpcClient

An initialized client.

-> MethodInput s m

The input.

-> IO (Either TooMuchConcurrency (RawReply (MethodOutput s m))) 

Run an unary query.

unaryOutput :: (Applicative f, Field3 a1 b1 (Either c1 a2) (Either c1 b2)) => (a2 -> f b2) -> Either c2 (Either c3 a1) -> f (Either c2 (Either c3 b1)) Source #

Prism helper to unpack an unary gRPC call output.

 out <- rawUnary rpc grpc method
   print $ out ^? unaryOutput . somefield

rawStreamServer Source #

Arguments

:: (Service s, HasMethod s m, MethodStreamingType s m ~ ServerStreaming) 
=> RPC s m

The RPC to call.

-> GrpcClient

An initialized client.

-> a

An initial state.

-> MethodInput s m

The input of the stream request.

-> (a -> HeaderList -> MethodOutput s m -> IO a)

A state-passing handler called for each server-sent output. Headers are repeated for convenience but are the same for every iteration.

-> IO (Either TooMuchConcurrency (a, HeaderList, HeaderList)) 

Calls for a server stream of requests.

rawStreamClient Source #

Arguments

:: (Service s, HasMethod s m, MethodStreamingType s m ~ ClientStreaming) 
=> RPC s m

The RPC to call.

-> GrpcClient

An initialized client.

-> a

An initial state.

-> (a -> IO (a, Either StreamDone (CompressMode, MethodInput s m)))

A state-passing step function to decide the next message.

-> IO (Either TooMuchConcurrency (a, RawReply (MethodOutput s m))) 

Sends a streams of requests to the server.

Messages are submitted to the HTTP2 underlying client and hence this function can block until the HTTP2 client has some network credit.

rawSteppedBidirectional Source #

Arguments

:: (Service s, HasMethod s m, MethodStreamingType s m ~ BiDiStreaming) 
=> RPC s m

The RPC to call.

-> GrpcClient

An initialized client.

-> a

An initial state.

-> RunBiDiStep s m a

The sequential program to iterate between sending and receiving messages.

-> IO (Either TooMuchConcurrency a) 

Starts a bidirectional ping-pong like stream with the server.

This handler is well-suited when the gRPC application has a deterministic protocols, that is, when after sending a message a client can know how many messages to wait for before sending the next message.

rawGeneralStream Source #

Arguments

:: (Service s, HasMethod s m) 
=> RPC s m

The RPC to call.

-> GrpcClient

An initialized client.

-> a

An initial state for the incoming loop.

-> (a -> IncomingEvent s m a -> IO a)

A state-passing function for the incoming loop.

-> b

An initial state for the outgoing loop.

-> (b -> IO (b, OutgoingEvent s m b))

A state-passing function for the ougoing loop.

-> IO (Either TooMuchConcurrency (a, b)) 

Starts a stream with the server.

This handler allows to concurrently write messages and wait for incoming messages.