grpc-rest-go

This repository shows an example gRPC service contains set of methods to demonstrate basic RPC as well as server, client and bidirection streaming RPC's.

The server exposes a gRPC API as well as a compatible REStful API using the grpc-gateway. Note, the RESTful API is not compatible with streaming RPC's and will only work on basic RPC calls.

A sample command line client is also provided to enable the sending of gRPC requests to the server.

Pre Requisites

• go 1.12+
• protoc 3.0.0+

Install

To build the executables pingserver and pingclient run the following commands

go build ./cmd/...

Try it out

Running the below command will start a gRPC server listening on localhost:8080 and a HTTP server listening on http://localhost:8081.

pingserver

With the above running, you can then connect to the server using the pingclient cli tool. The below commands invoke their corresponding methods on the server and log the responses.

Invoke the Ping RPC

pingclient ping

> 2019/09/15 14:56:46 Sending Ping Request:
> 2019/09/15 14:56:46 Received Ping Response: Pong

Invoke the PingStream RPC

pingclient pingstream 3

> 2019/09/15 14:58:15 Sending PingStream Request: Ping ... 1
> 2019/09/15 14:58:15 Sending PingStream Request: Ping ... 2
> 2019/09/15 14:58:15 Sending PingStream Request: Ping ... 3
> 2019/09/15 14:58:15 Received PingStream Response: 3

Invoke the PongStream RPC

pingclient pongstream 3

> 2019/09/15 14:59:11 Sending PongStream Request: 3
> 2019/09/15 14:59:11 Received PongStream Response: Pong ... 1
> 2019/09/15 14:59:11 Received PongStream Response: Pong ... 2
> 2019/09/15 14:59:11 Received PongStream Response: Pong ... 3

Invoke the PingPongStream RPC

pingclient pingpongstream 3

> 2019/09/15 14:59:54 Sending PingPongStream Request: Ping ... 1
> 2019/09/15 14:59:54 Sending PingPongStream Request: Ping ... 2
> 2019/09/15 14:59:54 Sending PingPongStream Request: Ping ... 3
> 2019/09/15 14:59:54 Received PingPongStream Response: Pong ... 1
> 2019/09/15 14:59:54 Received PingPongStream Response: Pong ... 2
> 2019/09/15 14:59:54 Received PingPongStream Response: Pong ... 3

Sending a HTTP Request through the Reverse Proxy gRPC Gateway

curl http://localhost:8081/v1/ping

Generating Protobuf Definitions

To generate the golang protobuf definitions contained in pkg/pingv1/ping_api.pb.go

protoc -I $PATH_TO_GOOGLEAPIS -I api/proto/ api/proto/ping_api.proto --go_out=plugins=grpc:pkg/pingv1

To generate reverse proxy allowing translation from gRPC to REST contained in pkg/pingv1/ping_api.pb.gw.go

protoc -I $PATH_TO_GOOGLEAPIS -I api/proto/ api/proto/ping_api.proto --grpc-gateway_out=logtostderr=true:pkg/pingv1

To generate swagger definitions matching the RESTful API contained in api/rest/ping_api.swagger.json

protoc -I $PATH_TO_GOOGLEAPIS -I api/proto/ api/proto/ping_api.proto --swagger_out=logtostderr=true:api/rest