gin-tonic

gin-tonic offers:

• a protobuf de-/serialization (like prost)
• a replacement for prost-build)
• a tonic codec implementation
• a wrapper for tonic-build adding some extra extra features

While all this can be achieved using the mentioned crates; gin-tonic also offers traits for converting any Rust type into a protobuf wire type. You are asking why?

If you want to pass a UUID via protobuf you likely end up doing:

message Foo {
  string my_uuid = 1;
}

Using prost-build and tonic-build this will generate the following Rust struct:

struct Foo {
    my_uuid: String,
}

As you notice the Rust type here is String, but in your actual code you want to use an actual uuid::Uuid. Now you have to do a fallible conversion into your code.

gin-tonic solves this by adding options to the protobuf file:

import "gin/proto/gin.proto";

message Foo {
  string my_uuid = 1 [(gin_tonic.v1.rust_type) = "uuid::Uuid"];
}

Using the gin-tonic code generator this generates the following Rust code:

struct Foo {
    my_uuid: uuid::Uuid,
}

For the UUID case gin-tonic offers two features:

• uuid_string => proto transport is string, parsing error is handled within wire type conversion
• uuid_bytes => proto transport is bytes, this does not require additional error handling

You can add you own types by implementing the FromWire and IntoWire traits for your type.

Benchmarks

Currently the decoding performance is slightly better than prost, while encoding requires some work.

gin tonic:

decode                  time:   [699.72 ns 700.71 ns 701.81 ns]
encode                  time:   [846.49 ns 848.09 ns 849.86 ns]

prost:

decode                  time:   [778.30 ns 782.24 ns 788.19 ns]
encode                  time:   [622.77 ns 623.87 ns 625.02 ns]