protojure.grpc.client.api — io.github.protojure/grpc-client 2.3.0

Provider independent client API for invoking GRPC requests

Provider clj protocol

disconnect clj

(disconnect this)

Disconnects from the GRPC endpoint and releases all resources held by the underlying provider

invoke clj

(invoke this params)

Invokes a GRPC-based remote-procedure against the provider

Parameters

A map with the following entries:

Value	Type	Description
service	String	The GRPC service-name of the endpoint
method	String	The GRPC method-name of the endpoint
metadata	map	Optional [string string] tuples that will be submitted as attributes to the request, such as via HTTP headers for GRPC-HTTP2
input	map	See Input section below
output	map	See Output section below

Unary vs Streaming Input

Any GRPC Service endpoint can define methods that take either unary or streaming inputs or outputs. This API assumes core.async channels in either case as a 'streaming first' design. For unary input, simply produce one message before closing the stream. Closing the stream indicates that the input is complete.

Input

The input parameter is a map with the following fields:

Value	Type	Description
f	(fn [map])	A protobuf new-XX function, such as produced by the protoc-gen-clojure compiler, to be applied to any outbound request messages
ch	core.async/chan	A core.async channel used to send input parameters. Close to complete.

Output

The output parameter is a map with the following fields:

Value	Type	Description
f	(fn [is])	A protobuf pb->msg function, such as produced by the protoc-gen-clojure compiler, to be applied to any incoming response messages
ch	core.async/chan	A core.async channel that will be populated with any GRPC return messages. Unary responses arrive as a single message on the channel. Will close when the response is complete.

Return value

A promise that, on success, evaluates to a map with the following entries:

Value	Type	Description
status	Int	The GRPC status code returned from the remote procedure
message	String	The GRPC message (if any) returned from the remote procedure

Example

(let [{:keys [status message]} @(invoke client {:service "my.service"
                                                :method "MyMethod"
                                                :input {:f myservice/new-MyRequest :ch input}
                                                :output {:f myservice/pb->MyResponse :ch output}})]
     (println "status:" status))