A custom Python protoc plugin
A basic skeleton for a custom Python plugin for protoc, Google’s official compiler for protobuf.
A plugin is just a program which reads a
CodeGeneratorRequestprotocol buffer from standard input and then writes aCodeGeneratorResponseprotocol buffer to standard output. These message types are defined in plugin.proto. We recommend that all third-party code generators be written as plugins, as this allows all generators to provide a consistent interface and share a single parser implementation.
I’ve also written two small blog posts about this example, see here and here.
These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.
I ran and tested the code with Python 3.9 on macOS 10.15.7.
Clone the repo to your local machine.
Create a virtual environment for Python 3 with:
python3 -m pip install virtualenvpython3 -m virtualenv env
Activate the virtual environment with:
source env/bin/activate
Install the required Python packages with:
pip3 install -r requirements.txt
To install protoc (on Mac):
brew install protobuf
Validate your installation with:
protoc --version
The output should be libprotoc 3.14.0 or similar.
On Linux you can use:
apt install -y protobuf-compiler
Make sure the virtual environment is activated.
Simply run make, or the below to start the code generation:
protoc example.proto --plugin=protoc-gen-custom-plugin=./plugin.py --custom-plugin_out=.
Note that custom-plugin is both the last portion of the plugin name and the first part of the out argument.
