Building Rust Protos

The process of building a Rust library for a Protobuf definition is similar to other programming languages:

1. Use the language-agnostic proto_library rule:

   proto_library(
       name = "person_proto",
       srcs = ["person.proto"],
   )
   

2. Create a Rust library:

   load("//third_party/protobuf/rust:defs.bzl", "rust_proto_library")
   
   proto_library(
       name = "person_proto",
       srcs = ["person.proto"],
   )
   
   rust_proto_library(
       name = "person_rust_proto",
       deps = [":person_proto"],
   )
   

3. Use the library by including it in a Rust binary:

   load("//third_party/bazel_rules/rules_rust/rust:defs.bzl", "rust_binary")
   load("//third_party/protobuf/rust:defs.bzl", "rust_proto_library")
   
   proto_library(
       name = "person_proto",
       srcs = ["person.proto"],
   )
   
   rust_proto_library(
       name = "person_rust_proto",
       deps = [":person_proto"],
   )
   
   rust_binary(
       name = "greet",
       srcs = ["greet.rs"],
       deps = [
           ":person_rust_proto",
       ],
   )
   

Note: Don’t use rust_upb_proto_library or rust_cc_proto_library directly. rust_proto_library checks the global build flag to choose the appropriate backend for you.