Grpc 實戰Java 調用python

背景

主要是爲了解決在java代碼中調用python服務的問題，考慮到性能的要求，還是決定採用RPC協議調用

服務端

1. 接口定義文件，注意java和python定義文件相同

syntax = "proto3";

option java_multiple_files = true;
option java_package = "com.xx";
option java_outer_classname = "HelloWorldProto";
option objc_class_prefix = "HLW";

package grpc_demo;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

2. 生成python文件

入代碼片

python3 -m grpc_tools.protoc --python_out=../ --grpc_python_out=../ -I. helloworld.proto

3.python服務端

from concurrent import futures

import grpc

import demo.helloworld_pb2 as helloworld_pb2
import demo.helloworld_pb2_grpc as helloworld_pb2_grpc


class Greeter(helloworld_pb2_grpc.GreeterServicer):

    def SayHello(self, request, context):
        print("收到請求")
        return helloworld_pb2.HelloReply(message='Hello, %s!' % request.name)


def serve():
    server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
    helloworld_pb2_grpc.add_GreeterServicer_to_server(Greeter(), server)
    server.add_insecure_port('[::]:50051')
    server.start()
    server.wait_for_termination()


if __name__ == '__main__':
    #logging.basicConfig()
    serve()

客戶端

1. 用配置文件 ，生成java文件，在target裏面出現，注意配置文件要相同

    <dependencies>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-netty-shaded</artifactId>
            <version>1.26.0</version>
        </dependency>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-protobuf</artifactId>
            <version>1.26.0</version>
        </dependency>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-stub</artifactId>
            <version>1.26.0</version>
        </dependency>
    </dependencies>


    <build>
        <extensions>
            <extension>
                <groupId>kr.motd.maven</groupId>
                <artifactId>os-maven-plugin</artifactId>
                <version>1.6.2</version>
            </extension>
        </extensions>
        <plugins>
            <plugin>
                <groupId>org.xolstice.maven.plugins</groupId>
                <artifactId>protobuf-maven-plugin</artifactId>
                <version>0.6.1</version>
                <configuration>
                    <protocArtifact>com.google.protobuf:protoc:3.11.0:exe:${os.detected.classifier}</protocArtifact>
                    <pluginId>grpc-java</pluginId>
                    <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.26.0:exe:${os.detected.classifier}</pluginArtifact>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>compile-custom</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

2. 客戶端編寫

public class HelloWorldClient {
    private static final Logger logger = Logger.getLogger(HelloWorldClient.class.getName());

    private final ManagedChannel channel;
    private final GreeterGrpc.GreeterBlockingStub blockingStub;

    /**
     * Construct client connecting to HelloWorld server at {@code host:port}.
     */
    public HelloWorldClient(String host, int port) {
        this(ManagedChannelBuilder.forAddress(host, port)
                // Channels are secure by default (via SSL/TLS). For the example we disable TLS to avoid
                // needing certificates.
                .usePlaintext()
                .build());
    }

    /**
     * Construct client for accessing HelloWorld server using the existing channel.
     */
    HelloWorldClient(ManagedChannel channel) {
        this.channel = channel;
        blockingStub = GreeterGrpc.newBlockingStub(channel);
    }

    public void shutdown() throws InterruptedException {
        channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
    }

    /**
     * Say hello to server.
     */
    public void greet(String name) {
        logger.info("Will try to greet " + name + " ...");
        HelloRequest request = HelloRequest.newBuilder().setName(name).build();
        HelloReply response;
        try {
            response = blockingStub.sayHello(request);
        } catch (StatusRuntimeException e) {
            logger.log(Level.WARNING, "RPC failed: {0}", e.getStatus());
            return;
        }
        logger.info("Greeting: " + response.getMessage());
    }

    /**
     * Greet server. If provided, the first element of {@code args} is the name to use in the
     * greeting.
     */
    public static void main(String[] args) throws Exception {
        // Access a service running on the local machine on port 50051
        HelloWorldClient client = new HelloWorldClient("localhost", 50051);
        try {
            String user = "world";
            // Use the arg as the name to greet if provided
            if (args.length > 0) {
                user = args[0];
            }
            client.greet(user);
        } finally {
            client.shutdown();
        }
    }
}

測試

1. 啓動服務端
2. 啓動客戶端
3. 結果 Greeting: Hello, world!