pluppens/grpc-spring-boot-starter

Spring Boot starter module for gRPC framework.

Spring boot starter for gRPC framework.

Features

Auto-configures and runs the embedded gRPC server with @GRpcService-enabled beans as part of spring-boot application.

Setup

repositories {
   jcenter()
   // maven { url "http://oss.jfrog.org/oss-snapshot-local" } //for snashot builds

}
dependencies {
    compile('org.lognet:grpc-spring-boot-starter:0.0.6')
}

Note	If you are using protobuf version lower than 3.0.0, please use org.lognet:grpc-spring-boot-starter:0.0.3

Usage

• Start by generating stub and server interface(s) from your .proto file(s).

• Annotate your server interface implementation(s) with @org.lognet.springboot.grpc.GRpcService

• Optionally configure the server port in your application.yml/properties. Default port is 6565

 grpc:
    port : 6565

Show case

In the 'grpc-spring-boot-starter-demo' project you can find fully functional example with integration test.

Service implementation

The service definition from .proto file looks like this :

service Greeter {
    rpc SayHello ( HelloRequest) returns (  HelloReply) {}
}

Note the generated io.grpc.examples.GreeterGrpc.GreeterImplBase class that extends io.grpc.BindableService.(The generated classes were intentionally committed for demo purposes).

All you need to do is to annotate your service implementation with @org.lognet.springboot.grpc.GRpcService

    @GRpcService
    public static class GreeterService extends  GreeterGrpc.GreeterImplBase{
        @Override
        public void sayHello(GreeterOuterClass.HelloRequest request, StreamObserver<GreeterOuterClass.HelloReply> responseObserver) {
            final GreeterOuterClass.HelloReply.Builder replyBuilder = GreeterOuterClass.HelloReply.newBuilder().setMessage("Hello " + request.getName());
            responseObserver.onNext(replyBuilder.build());
            responseObserver.onCompleted();
        }
    }

Interceptors support

The starter supports the registration of two kinds of interceptors: Global and Per Service.
In both cases the interceptor has to implement io.grpc.ServerInterceptor interface.

• Per service

@GRpcService(interceptors = { LogInterceptor.class })
public  class GreeterService extends  GreeterGrpc.GreeterImplBase{
    // ommited
}

LogInterceptor will be instantiated via spring factory if there is bean of type LogInterceptor, or via no-args constructor otherwise.

• Global

@GRpcGlobalInterceptor
public  class MyInterceptor implements ServerInterceptor{
    // ommited
}

The annotation on java config factory method is also supported :

 @Configuration
 public class MyConfig{
     @Bean
     @GRpcGlobalInterceptor
     public  ServerInterceptor globalInterceptor(){
         return new ServerInterceptor(){
             @Override
             public <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall(ServerCall<ReqT, RespT> call, Metadata headers, ServerCallHandler<ReqT, RespT> next) {
                // your logic here
                 return next.startCall(call, headers);
             }
         };
     }
 }

The particular service also has the opportunity to disable the global interceptors :

@GRpcService(applyGlobalInterceptors = false)
public  class GreeterService extends  GreeterGrpc.GreeterImplBase{
    // ommited
}

On the roadmap

• Customized gRPC server builder with compression/decompression registry .

• Custom Executor service.

• Transport security.

License

Apache 2.0