protoc-gen-rust-grpc

A protoc plugin that generates Rust gRPC service code for use with the grpc crate. This crate is generally not needed directly; instead most users will use grpc-protobuf-build, which depends on this crate.

NOTE: This version is a preview and not recommended for any production use. All APIs are unstable. Proceed at your own risk.

Note: as part of compiling, the source files for protoc are downloaded from the protobuf github repository. The archive's checksum is verified before compiling.

Using from Rust

A build.rs script will ensure the protoc and protoc-gen-rust-grpc binaries are compiled, and the functions protoc and protoc_gen_rust_grpc can be used to find their locations.

Skipping C++ Compilation

If you want to bypass the C++ compilation step in your application, set the following environment variable:

export PROTOC_GEN_RUST_GRPC_NO_BUILD=1

When set, the C++ build is skipped, and no binaries will be present in the output directory. This will cause grpc-protobuf-build to fall back to the GRPC_RUST_PROTOC_DIR environment variable, and then your PATH to find the protoc plugin.

Building binaries manually

Requirements:

• CMake 3.14 or higher
• C++17 compatible compiler

From the src/cpp_source directory:

# Create build directory
mkdir build && cd build

# Configure (downloads protobuf and dependencies automatically)
cmake .. -DCMAKE_BUILD_TYPE=Release

# Build
cmake --build . --parallel

# Optional: specify a different protobuf version
cmake .. -DCMAKE_BUILD_TYPE=Release -DPROTOBUF_VERSION=28.3

The binaries will be in build/bin/:

• protoc - The protobuf compiler
• protoc-gen-rust-grpc - The Rust gRPC code generator plugin

Usage

Note: It's generally recommended to use grpc_protobuf_build::CodeGen and/or protobuf_codegen::CodeGen instead of invoking protoc directly.

# Add the plugin to PATH
export PATH="$PWD/build/bin:$PATH"

# Generate Rust gRPC code
protoc \
  --rust_opt="experimental-codegen=enabled,kernel=upb" \
  --rust_out=./generated \
  --rust-grpc_out=./generated \
  your_service.proto

Available Options

• message_module_path=PATH (optional): Specifies the Rust path to the module where Protobuf messages are defined.

  • Default: self
  • Example: message_module_path=crate::pb::messages

• crate_mapping=PATH (optional): Specifies the path to a crate mapping file for multi-crate projects.