build.rs

use std::io::Result;

fn main() -> Result<()> {
    prost_build::compile_protos(&["src/tutorial.proto"], &["src/"])?;
    Ok(())
}

Cargo.toml

[package]
name = "prostdemo"
version = "0.1.0"
authors = ["Marko Mikulicic <[email protected]>"]
edition = "2018"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
prost = "0.7"
bytes = "1.0"

[build-dependencies]
prost-build = { version = "0.7" }

main.rs

pub mod tut {
    include!(concat!(env!("OUT_DIR"), "/tutorial.rs"));
}

fn main() {
    let x = tut::Person {
        phone_type: tut::person::PhoneType::Home.into(),
        ..Default::default()
    };
    println!("the fields itself is an i32: {:?}", x.phone_type);

    let e = tut::person::PhoneType::from_i32(x.phone_type).unwrap();
    println!("You can turn it into an enum with from_i32: {:?}", e);
}

tutorial.rs

pub mod tut {
    include!(concat!(env!("OUT_DIR"), "/tutorial.rs"));
}

fn main() {
    let x = tut::Person {
        phone_type: tut::person::PhoneType::Home.into(),
        ..Default::default()
    };
    println!("the fields itself is an i32: {:?}", x.phone_type);

    let e = tut::person::PhoneType::from_i32(x.phone_type).unwrap();
    println!("You can turn it into an enum with from_i32: {:?}", e);
}