Spring Boot 2.0 starter for Reactive gRPC (https://github.com/salesforce/reactive-grpc) to bring reactive style for grpc-java.
- Please clone the repository and install reactive-grpc-spring-boot-starter artifact to your local Maven repository.
$ git clone [email protected]:linux-china/reactive-grpc-spring-boot-starter.git
$ cd reactive-grpc-spring-boot-starter
$ mvn -P release -DskipTests clean install
- Add dependency and repository in your pom.xml. Now reactive-grpc-spring-boot-starter hosted by jitpack
<project>
...
<dependencies>
<dependency>
<groupId>com.github.linux-china</groupId>
<artifactId>reactive-grpc-spring-boot-starter</artifactId>
<version>1.0.0-SNAPSHOT</version>
</dependency>
</dependencies>
</project>- Add protobuf-maven-plugin with Reactor-gRPC protocPlugin included. Attention: proto files should be in "src/main/proto" directory
<build>
<extensions>
<extension>
<groupId>kr.motd.maven</groupId>
<artifactId>os-maven-plugin</artifactId>
<version>1.6.1</version>
</extension>
</extensions>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<parameters>true</parameters>
</configuration>
</plugin>
<plugin>
<groupId>org.xolstice.maven.plugins</groupId>
<artifactId>protobuf-maven-plugin</artifactId>
<version>0.6.1</version>
<configuration>
<protocArtifact>com.google.protobuf:protoc:${protobuf-java.version}:exe:${os.detected.classifier}
</protocArtifact>
<pluginId>grpc-java</pluginId>
<pluginArtifact>io.grpc:protoc-gen-grpc-java:${grpc.version}:exe:${os.detected.classifier}
</pluginArtifact>
<protocPlugins>
<protocPlugin>
<id>reactor-grpc</id>
<groupId>com.salesforce.servicelibs</groupId>
<artifactId>reactor-grpc</artifactId>
<version>${reactive-grpc.version}</version>
<mainClass>com.salesforce.reactorgrpc.ReactorGrpcGenerator</mainClass>
</protocPlugin>
</protocPlugins>
</configuration>
<executions>
<execution>
<goals>
<goal>compile</goal>
<goal>compile-custom</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>- Implement Reactive Service with @ReactiveGrpcService annotation.
@Service
@ReactiveGrpcService
public class ReactiveGreeterImpl extends ReactorGreeterGrpc.GreeterImplBase {
@Override
public Mono<HelloReply> sayHello(Mono<HelloRequest> request) {
return request.map(helloRequest -> HelloReply.newBuilder().setMessage("Hello " + helloRequest.getName()).build());
}
@Override
public Mono<HelloReply> sayHelloAgain(Mono<HelloRequest> request) {
return request.map(helloRequest -> HelloReply.newBuilder().setMessage("Hello Again " + helloRequest.getName()).build());
}
}- Start you Spring application and you will get following output on your console.
09:40:17.366 [INFO ] o.m.s.b.r.g.ReactiveGrpcAutoConfiguration - gRPC server started on: 50051
09:40:17.379 [INFO ] o.m.s.b.r.g.ReactiveGrpcAutoConfiguration - Reactive gRPC service exposed: org.mvnsearch.spring.boot.reactive.grpc.demo.ReactiveGreeterImpl
- Use Evans to test gRPC service
$ evans src/main/proto/greeter.proto
You don't need to setup anything for Reactive gRPC service. If you want to change listen port(default is 50051), please change as following in application.properties:
grpc.reactive.port=50051gRPC has different starters to integration with Spring Boot, for example:
- https://github.com/yidongnan/grpc-spring-boot-starter
- https://github.com/LogNet/grpc-spring-boot-starter
The main difference is code style in these starters. If you like Reactive style, please choose Reactive gRPC. If you think native style fine, please use starters above.
- gRPC native style:
//server side
public void sayHello(HelloRequest req, StreamObserver<HelloReply> responseObserver) {
HelloReply reply = HelloReply.newBuilder().setMessage("Hello ==> " + req.getName()).build();
responseObserver.onNext(reply);
responseObserver.onCompleted();
}
//client side
asyncStub.sayHello(HelloRequest.newBuilder().setName(name).build(), new StreamObserver<HelloReply>() {
@Override
public void onNext(HelloReply reply) {
}
@Override
public void onError(Throwable throwable) {
}
@Override
public void onCompleted() {
}
});
- gRPC reactive style:
//server side
public Mono<HelloReply> sayHello(Mono<HelloRequest> request) {
return request.map(helloRequest -> HelloReply.newBuilder().setMessage("Hello " + helloRequest.getName()).build());
}
//client side
Mono<HelloRequest> request = Mono.just(HelloRequest.newBuilder().setName("Jack").build());
request.as(greeter::sayHello)
.map(HelloReply::getMessage)
.subscribe(System.out::println);
Please refer MapStruct to map DDD model and Protobuf message, and MapStruct 1.3 with Protobuf builder support.
Please execute "mvn -DskipTests clean package" and run ReactiveGrpcDemoApplication
- Publish artifact to Maven repository
- Actuator endpoint to output proto sources
- SSL for gRPC by using certificate in Spring Boot https://github.com/grpc/grpc-java/blob/master/SECURITY.md
server.ssl.enabled=true
server.ssl.key-store=${user.home}/domain_certs/localhost.com/localhost.com.p12
server.ssl.key-store-type=PKCS12
server.ssl.key-store-password=changeit
- Reactive gRPC: https://github.com/salesforce/reactive-grpc
- Project Reactor: https://projectreactor.io/
- Evans: expressive universal gRPC client https://github.com/ktr0731/evans
- MapStruct: http://mapstruct.org/
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