Crate prost_protovalidate_build 

Compile-time code generator for Protocol Buffer validation.

Generates impl prost_protovalidate::Validate for messages that have only standard buf.validate rules (no CEL expressions). Validators run through monomorphized direct field access at runtime — no prost-reflect transcoding, no CEL interpreter on the hot path. Messages with any CEL rules are excluded and must use the runtime prost_protovalidate::Validator instead.

Usage

In your build.rs:

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // First, compile protos with prost-build (writes descriptor set)
    let descriptor_path = std::path::PathBuf::from(std::env::var("OUT_DIR")?)
        .join("file_descriptor_set.bin");
    prost_build::Config::new()
        .file_descriptor_set_path(&descriptor_path)
        .compile_protos(&["proto/service.proto"], &["proto/"])?;

    // Then generate validation impls
    prost_protovalidate_build::Builder::new()
        .file_descriptor_set_path(&descriptor_path)?
        .compile()?;
    Ok(())
}

Then include the generated code alongside the prost-generated code:

include!(concat!(env!("OUT_DIR"), "/validate_impl.rs"));

Structs

Builder

Builder for configuring and running the validation code generator.

Enums

Error

Errors that can occur during code generation.