buffa-protos

Third-party protos compiled for the buffa Rust protobuf runtime.

buffa-types carries the protobuf well-known types — the ones that ship with protoc. This carries the other ones a service ends up needing. Today that is google.rpc.

What is here

Package	Holds
google.rpc	Status, the Code enum, and the error_details.proto payloads that go in Status.details — BadRequest, RetryInfo, ErrorInfo, QuotaFailure, PreconditionFailure, ResourceInfo, RequestInfo, Help, LocalizedMessage, DebugInfo

Vendored from googleapis, generated with the pinned plugin in buf.gen.yaml, and committed — so a consumer needs neither buf nor protoc to build.

Why not generate it per service

Because google.rpc.Status is a shared type, and generating it into each service makes it a different Rust type in each one. A Status built by a library cannot then be assigned to a Status field on a message generated somewhere else, and the compiler is right to refuse — they are unrelated types that happen to share a name.

That is the same reason google.protobuf lives in buffa-types rather than being emitted into every crate that mentions a Timestamp.

It is also 8,000-odd lines a service does not have to carry or regenerate.

Using it

Point the buffa codegen at this crate instead of generating the package again:

- remote: buf.build/anthropics/buffa:v0.9.1
  out: src/proto
  include_imports: true
  opt:
    - file_per_package=true
    # Do not generate the package...
    - exclude_package=.google.rpc
    # ...name it here instead.
    - extern_path=.google.rpc=::buffa_protos::google::rpc

buffa-protos = { git = "https://github.com/protoc-contrib/buffa-protos", rev = "..." }

Pin a rev. This is a git dependency with no published releases, so a branch would mean the crate can change under a build that did not ask it to.

The module path mirrors the proto package — google.rpc.Status is buffa_protos::google::rpc::Status — which is what lets the extern_path be a single package-prefix mapping rather than one entry per type.

Adding a package

1. Vendor the .proto under proto/.
2. Run buf generate --clean.
3. Mount the emitted <package>.rs in src/lib.rs, and add it to the ignore list in rustfmt.toml.

Anything the new package imports from google.protobuf resolves to buffa-types with no further configuration — that is the extern_path already in buf.gen.yaml, and it is what stops this crate shipping a second Any. Anything it imports from a package this crate does not carry has to be vendored alongside it.

--clean matters: the output is committed, so a package renamed or removed upstream would otherwise leave a stale file behind that still compiles. CI regenerates and fails on any diff, which catches both that and a moved pin.

Development

nix develop        # cargo, rustc, clippy, rustfmt, buf
cargo test
buf generate --clean && git diff --exit-code -- src/generated

buf is for regenerating only. The generated code is committed, so building this crate — or anything depending on it — needs neither buf nor protoc.

License

The vendored protos are Google's, Apache-2.0. This repository is Apache-2.0; see LICENSE.