ttrpc 0.2.0

# ttrpc-rust

`ttrpc-rust` is a Rust version of [ttrpc](https://github.com/containerd/ttrpc). [ttrpc](https://github.com/containerd/ttrpc) is GRPC for low-memory environments.

The ttrpc compiler of `ttrpc-rust` `ttrpc_rust_plugin` is modified from gRPC compiler of [gRPC-rs](https://github.com/pingcap/grpc-rs) [grpcio-compiler](https://github.com/pingcap/grpc-rs/tree/master/compiler).

# Usage

To generate the sources from proto files:

1. Install protoc from github.com/protocolbuffers/protobuf

2. Install protobuf-codegen from github.com/pingcap/grpc-rs
```
cd grpc-rs
cargo install --force protobuf-codegen
```

3. Install ttrpc_rust_plugin from ttrpc-rust/compiler
```
cd ttrpc-rust/compiler
cargo install --force --path .
```

4. Generate the sources:

```
$ protoc --rust_out=. --ttrpc_out=. --plugin=protoc-gen-ttrpc=`which ttrpc_rust_plugin` example.proto
```

# Run Examples
1. Go to the directory

    `$ cd ttrpc-rust/example`

2. Start the server

    `$ cargo run --example server unix:///tmp/1`

3. Start a client

    `$ cargo run --example client /tmp/1`

# Notes: the version of protobuf
protobuf-codegen, ttrpc_rust_plugin and your code should use the same version protobuf.
You will get following fail if use the different version protobuf.
```
27 | const _PROTOBUF_VERSION_CHECK: () = ::protobuf::VERSION_2_8_0;
   |                                                 ^^^^^^^^^^^^^ help: a constant with a similar name exists: `VERSION_2_10_1`
```
The reason is that [files generated by protobuf-codegen are compatible only with the same version of runtime](https://github.com/stepancheg/rust-protobuf/commit/2ab4d50c27c4dd7803b64ce1a43e2c134532c7a6)

To fix this issue:
1. Rebuild protobuf-codegen with new protobuf:
```
cd grpc-rs
cargo clean
cargo update
cargo install --force protobuf-codegen
```
2. Rebuild ttrpc_rust_plugin with new protobuf:
```
cd ttrpc-rust/compiler
cargo clean
cargo update
cargo install --force --path .
```
3. Build your project.