Tag: code-generation

Protocol Buffers, which are protobuf for short, is much compact than XML and JSON and hence a great choice for designing efficient inter-service communication. In this post we will see how to generate Python code from protobuf code.

An example protobuf for product recommendation

syntax = "proto3";

enum ProductCategory {
    DAIRY = 0;
    VEGETABLES = 1;
    PROCESSED_FOOD = 2;
}

message ProductRecommendationRequest {
    int32 user_id = 1;
    ProductCategory category = 2;
    int32 max_results = 3;
}

message ProductRecommendation {
    int32 id = 1;
    string name = 2;
}

message ProductRecommendationResponse {
    repeated ProductRecommendation recommendations = 1;
}

service Recommendations {
    rpc Recommend (ProductRecommendationRequest) returns (ProductRecommendationResponse);
}

Getting grpcio-tools library

pip install grpcio-tools

Generating Python code from protobuf

python -m grpc_tools.protoc -I . --python_out=. --grpc_python_out=. products.proto

Output

This generates several Python files from the .proto file. Here’s a breakdown:

• python -m grpc_tools.protoc invokes the protobuf compiler, which will generate Python code from the protobuf code.
• -I . tells the compiler to look into current directory to find imported protobuf files. We are not importing any files but this option is needed still.
• --python_out=. --grpc_python_out=. this options tells the compiler where to output the Python files. It will generate two files, and you could put each in a separate directory with these options if you wanted to.
• products.proto is the path to the protobuf file

Please let us know your questions in the comments below.