README.md

hello-world-client

hello-world-client is a project as an example of use gRPC protocol over Spring boot application. This project contains an API controller HelloWorldClientController.java , definition service HelloWorldService.proto and gRPC client implementation HelloWorldClientServiceImpl.

hello-world-client expose port 8080 to be call by http request(GET). When controller is invoked, the client service gRPC sent request to HelloWorldServerService.java

Configuration

Application properties

There are different application properties depending on environment. For select application properties is necessary send an environment variable (JAVA_OPTS=-Dspring.profiles.active=local). An example this is:

server.port=8080
spring.application.name=hello-world-client
grpc.client.hello-world-server.address=static://localhost:9898/
grpc.client.hello-world-server.enable-keep-alive=true
grpc.client.hello-world-server.keep-alive-without-calls=true
grpc.client.hello-world-server.negotiation-type=plaintext

gRPC Java converter

To translate a proto file to a java class, use maven plugin

<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:3.12.0:exe:${os.detected.classifier}</protocArtifact>
                <pluginId>grpc-java</pluginId>
                <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.34.0:exe:${os.detected.classifier}</pluginArtifact>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                        <goal>compile-custom</goal>
                        <goal>test-compile</goal>
                        <goal>test-compile-custom</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

after, it is necessary compile the project for executing proto translate

mvn protobuf:compile

Usage

mvn spring-boot:run

Docker

Build docker image from Dockerfile

docker build -t hello-world-client .

Run docker container

docker run -dit --rm --name hello-world-client -p8080:8080 --env JAVA_OPTS=-Dspring.profiles.active=standalone hello-world-client