grpc-java/compiler/README.md

gRPC Java Codegen Plugin for Protobuf Compiler

This generates the Java interfaces out of the service definition from a .proto file. It works with the Protobuf Compiler (protoc).

Normally you don't need to compile the codegen by yourself, since pre-compiled binaries for common platforms are available on Maven Central:

1. Navigate to https://mvnrepository.com/artifact/io.grpc/protoc-gen-grpc-java
2. Click into a version
3. Click "Files"

However, if the pre-compiled binaries are not compatible with your system, you may want to build your own codegen.

System requirement

• Linux, Mac OS X with Clang, or Windows with MSYS2
• Java 7 or up
• Protobuf 3.12.0 or up

Compiling and testing the codegen

Change to the compiler directory:

$ cd $GRPC_JAVA_ROOT/compiler

To compile the plugin:

$ ../gradlew java_pluginExecutable

To test the plugin with the compiler:

$ ../gradlew test

You will see a PASS if the test succeeds.

To compile a proto file and generate Java interfaces out of the service definitions:

$ protoc --plugin=protoc-gen-grpc-java=build/exe/java_plugin/protoc-gen-grpc-java \
  --grpc-java_out="$OUTPUT_FILE" --proto_path="$DIR_OF_PROTO_FILE" "$PROTO_FILE"

To generate Java interfaces with protobuf lite:

$ protoc --plugin=protoc-gen-grpc-java=build/exe/java_plugin/protoc-gen-grpc-java \
  --grpc-java_out=lite:"$OUTPUT_FILE" --proto_path="$DIR_OF_PROTO_FILE" "$PROTO_FILE"

Installing the codegen to Maven local repository

This will compile a codegen and put it under your ~/.m2/repository. This will make it available to any build tool that pulls codegens from Maven repositories.

$ ../gradlew publishToMavenLocal

Creating a release of gRPC Java

Please follow the instructions in RELEASING.md under the root directory for details on how to create a new release.