proto_ros

This project provides utilities for the translation between Protocol Buffers message definitions (proto files) and ROS message definitions (msg files).

proto2msg

The proto2msg script translates Protobuf (proto) files into equivalent ROS Message (msg) files.

Usage:

proto2msg <proto_dir> <msg_dir> (--recursive)

For each proto file in proto_dir equivalent msg files are created in msg_dir.

To translate a single protofile use the following command:

Usage: protoc --proto_path=<proto_dir> --msg_out=<msg_dir> <file.proto>

Limitations

• proto3 syntax
• enums are translated to constants
• No support for 'oneof' and 'any' types
• No support for extensions
• No support for options
• No support for service

The Protobuf Compiler (protoc) parses the proto file and provides it packed in a CodeGeneratorRequest to the protoc_gen_msg plugin (via stdin). This plugin generates a set of ROS message definition (msg) files from the parsed proto file. It returns the generated msg files packed in a CodeGeneratorResponse (via stdout) to the compiler.

msg2proto

The msg2proto script translates ROS message (msg) files into Protobuf (proto) files.

Usage:

msg2proto <msg_dir> <proto_dir> (--package <packagename>)

For each msg file in msg_dir an equivalent proto file is created in proto_dir.

Limitations:

• proto3 syntax
• no support for default values (defaults are skipped)
• constants are translated to comments
• no support for string and array bounds (both treated as unbounded)

We defined a Parsing Expression Grammar for ROS messages and use Parsimonious for the actual parsing.

Installation

Install protoc, the Protobuf compiler:

sudo apt install protobuf-compiler

Install our proto_ros package from PyPi:

pip install proto_ros

Or install it from GitHub:

pip install "git+https://github.com/dortmans/proto_ros.git"