protoc compiler not working with grpc plugin

Question

So I'm trying to follow the tutorial at https://grpc.io/docs/tutorials/basic/java.html#generating-client-and-server-code, but I'm having trouble compiling using the grpc plugin with the protoc compiler. I've setup my pom.xml properly with the plugin(I think), but the compiler doesn't generate the files that the guide needs(namely, RouteGuideGrpc.java).

I'm currently compiling the .proto using "mvn protobuf:compile"

pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>maven</artifactId>
<version>0.0.1-SNAPSHOT</version>

<dependencies>
    <!-- https://mvnrepository.com/artifact/com.google.protobuf/protobuf-java -->
    <dependency>
        <groupId>com.google.protobuf</groupId>
        <artifactId>protobuf-java</artifactId>
        <version>3.6.1</version>
    </dependency>
    <dependency>
        <groupId>io.grpc</groupId>
        <artifactId>grpc-netty-shaded</artifactId>
        <version>1.14.0</version>
    </dependency>
    <dependency>
        <groupId>io.grpc</groupId>
        <artifactId>grpc-protobuf</artifactId>
        <version>1.14.0</version>
    </dependency>
    <dependency>
        <groupId>io.grpc</groupId>
        <artifactId>grpc-stub</artifactId>
        <version>1.14.0</version>
    </dependency>
</dependencies>
<build>
    <extensions>
        <extension>
            <groupId>kr.motd.maven</groupId>
            <artifactId>os-maven-plugin</artifactId>
            <version>1.5.0.Final</version>
        </extension>
    </extensions>
    <plugins>
        <plugin>
            <groupId>org.xolstice.maven.plugins</groupId>
            <artifactId>protobuf-maven-plugin</artifactId>
            <version>0.5.1</version>
            <configuration>
                <protocArtifact>com.google.protobuf:protoc:3.5.1-1:exe:${os.detected.classifier}</protocArtifact>
                <pluginId>grpc-java</pluginId>
                <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.14.0:exe:${os.detected.classifier}</pluginArtifact>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                        <goal>compile-custom</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

Does anyone know why this happens or how to add the grpc plugin to the protobuf compiler? Did I not install the plugin properly?

btw: I'm a giant noob at using maven.

Eric Anderson Eric Anderson · Accepted Answer · 2018-08-18T00:39:41

You're configuration appears correct. However, protobuf:compile does not run any protoc plugins (which includes the gRPC plugin); that's what protobuf:compile-custom does.

So you simply need to run:

mvn protobuf:compile-custom

The output will be placed in the target/generated-sources/protobuf/grpc-java/ folder.

protoc compiler not working with grpc plugin

2 Answers