Zig-Protobuf

About

Zig-Protobuf is an implementation of Google's Protocal Buffers (Protobuf). The project is currently in development and incomplete. It has two parts, protoc-zig, a protoc plugin that parses .proto files and generates zig code, and a Protobuf interface that is currently focused on serializing the protobuf wire format.

The goal is to take .proto files and produce readable zig code with an easy to use encoding and decoding API that can be used in zig programs. Here is an example of the output of parsing a .proto message (imports are not shown, using proto3 syntax)

message SearchRequest {
    string query = 1;
    int32 page_number = 2;
    int32 result_per_page = 3;
}

pub const SearchRequest = struct{
    query: []const u8 = "",
    page_number: i32 = 0,
    result_per_page: i32 = 0,

    pub const descriptor_pool = enum(u32){page_number = 2,query = 1,result_per_page = 3};
    pub fn ParseFromString(string: []const u8, allocator: Allocator) DecodeError!SearchRequest{
        return ProtobufMessage(SearchRequest).ParseFromString(string, allocator);
    }
    pub fn SerializeToString(message: SearchRequest, allocator: Allocator) []const u8 {
        return ProtobufMessage(SearchRequest).SerializeToString(message, allocator);
    }
};

Usage

You will need protoc installed, see the installation on the protobuf GitHub Repo.

protoc --plugin=protoc-gen-zigpb=<path to zigpb> --zigpb_out=../generated --proto_path=<path to your proto files> <proto files to compile>

You can also place the zigpb under /usr/bin to avoid passing a path to the plugin each time

Development

You will need the full libprotobuf installed, see here Note: Make sure you use the same compiler you plan on using to build the protoc-zig code, for example, if you plan on using zig as your c++ compiler for protoc-zig you must also build libprotobuf with zig's c++ toolchain. Once built, see tools/prepare_env.py, this will copy over the protobuf implementation into a header file for the plugin to generate when parsing .proto files. Once done you can either use cmake or zig build to build the plugin.

Zig Build

zig build

Cmake

cd protoc-zig
mkdir build
cd build
CC="zig cc" CXX="zig c++" cmake ..
make

Testing

The script generate_zig_protobuf.py will take the files in test-protos and generate the zig structs from them in generated The script generate_encoded.py will generate some binary data to test decoding with, it takes an optional parameter to the path of zigpb, by default it assumes you built with cmake

Once set up you can then run zig test src/main.zig or zig test src/main.zig --test-filter <test-name>

Notes

• So far the zig file generation works only with the proto3 syntax currently and is probably incomplete and will most likely change
• Haven't done too much on encoding yet
• In the future would like to support additional features like converting to JSON, gRPC, and proto2 syntax
• Built with zig version 0.12.0-dev.146+020105d0d