rust-protobuf

Protobuf implementation in Rust.

• Written in pure rust
• Generate rust code
• Has runtime library for generated code (Coded{Input|Output}Stream impl)
• Supports both Protobuf versions 2 and 3

About versions and branches

• 2.*.* is the latest stable version. 2.*.* versions follow semver conventions.
• 1.7.* is previous stable version
• 1.6.* was republished as 2.0.* and no longer maintained. Should be compatible with 2.0.*. If you are using 1.6.* please update to 2.0.*.
• 1.5.* was republished as 1.7.* and no longer maintained. Should be compatible with 1.7.*. If you are using 1.5.* please update to 1.7.*.

1.7+ 2.* versions should follow semver conventions. However, if you are developing critical library it's probably better to specify version as ~2.0 (>= 2.0 and <= 2.1), but not as 2.0 (>= 2.0 and <= 3.0).

Version 3.* will not follow semver conventions, releases from master will be published as 3.*. 3.* branch can be considered experimental.

Eventually some 3.* version will be stable enough and will be re-released as 4.0.

See CHANGELOG.md for a list of changes and compatility issues between versions.

How to generate rust code

There are several ways to generate rust code from .proto files

Invoke protoc programmatically with protoc-rust crate (recommended)

Have a look at readme in protoc-rust crate.

Use pure rust protobuf parser and code generator (alpha)

Readme should be in protobuf-codegen-pure crate.

Use protoc-gen-rust plugin

Readme is here.

Generated code

Have a look at generated files, used internally in rust-protobuf:

• descriptor.rs for descriptor.proto (that is part of Google protobuf)

Rustdoc

docs.rs hosts rustdoc for protobuf.

Getting help

Feel free to open an issue if you need help with rust-protobuf.

Copy-on-write

Rust-protobuf can be used with bytes crate.

To enable Bytes you need to:

1. Enable with-bytes feature in rust-protobuf:

[dependencies]
protobuf = { version = "~2.0", features = ["with-bytes"] }

2. Enable bytes option

with Customize when codegen is invoked programmatically:

protoc_rust::run(protoc_rust::Args {
    ...
    customize: Customize {
        carllerche_bytes_for_bytes: Some(true),
        carllerche_bytes_for_string: Some(true),
        ..Default::default()
    },
 });

or in .proto file:

import "rustproto.proto";

option (rustproto.carllerche_bytes_for_bytes_all) = true;
option (rustproto.carllerche_bytes_for_string_all) = true;

With these options enabled, fields of type bytes or string are generated as Bytes or Chars respectively. When CodedInputStream is constructed from Bytes object, fields of these types get subslices of original Bytes object, instead of being allocated on heap.

serde_derive support

(Only in master, not released yet)

Rust-protobuf can be used with serde.

To enable serde you need to:

1. Enable serde option

with Customize when codegen is invoked programmatically:

protoc_rust::run(protoc_rust::Args {
    ...
    customize: Customize {
        serde_derive: Some(true),
        ..Default::default()
    },
 });

or in .proto file:

import "rustproto.proto";

option (rustproto.serde_derive_all) = true;

You may now Serialize and Deserialize messages:

let my_message = MyMessage::new();
serde_json::to_string(&my_message).unwrap();

Related projects

• quick-protobuf — alternative protobuf implementation in Rust
• prost — another protobuf implementation in Rust
• serde-protobuf
• grpc-rust — implementation of gRPC based on this library
• grpc-rs — another gRPC implementation for Rust