用Rust语言开发微服务

Dubbo Rust 近期发布了首个正式版本，Dubbo Rust 目标是对齐 Dubbo 3 的所有核心功能设计，包括基于 HTTP/2 的高性能通信、用户友好的微服务开发编程模式、通过接入Dubbo Mesh提供丰富的服务治理能力等。相比于其他语言实现，Dubbo Rust 将很好的利用 Rust 语言极致性能、安全和指令级掌控能力的特点。

1►

前置条件

安装 Rust 开发环境

安装 protoc 工具

2►

使用 IDL 定义 Dubbo 服务

Greeter 服务定义如下，包含一个 Unary（Request - Response）模型的 Dubbo 服务。

// ./proto/greeter.proto
syntax = "proto3";


option java_multiple_files = true;


package org.apache.dubbo.sample.tri;


// The request message containing the user's name.
message GreeterRequest{
  string name = 1;
}


// The response message containing the greetings
message GreeterReply {
  string message = 1;
}


service Greeter{
  // unary
  rpc greet(GreeterRequest) returns (GreeterReply);
}

3►

添加 Dubbo-Rust 及相关依赖到项目

# ./Cargo.toml
[package]
name = "example-greeter"
version = "0.1.0"
edition = "2021"


[[bin]]
name = "greeter-server"
path = "src/greeter/server.rs"


[[bin]]
name = "greeter-client"
path = "src/greeter/client.rs"


[dependencies]
http = "0.2"
http-body = "0.4.4"
futures-util = {version = "0.3", default-features = false}
tokio = { version = "1.0", features = [ "rt-multi-thread", "time", "fs", "macros", "net", "signal"] }
prost-derive = {version = "0.10", optional = true}
prost = "0.10.4"
async-trait = "0.1.56"
tokio-stream = "0.1"


dubbo = "0.2.0"
dubbo-config = "0.2.0"


[build-dependencies]
dubbo-build = "0.2.0"

4►

配置 Dubbo - Build 编译 IDL

在项目根目录创建（注意不是 src 目录），创建 build.rs 文件并添加以下内容：

// ./build.rs
fn main() {
    dubbo_build::configure()
        .compile(&["proto/greeter.proto"], &["proto/"])
        .unwrap();
}

这样配置之后，编译项目就可以生成 Dubbo Stub 相关代码。

路径一般在：

./target/debug/build/example-greeter/out/org.apache.dubbo.sample.tri.rs

5►

编写 Dubbo 业务代码

5.1

编写 Dubbo Server

// ./src/greeter/server.rs
use ...


#[tokio::main]
async fn main() {
    register_server(GreeterServerImpl {
        name: "greeter".to_string(),
    });


    // Dubbo::new().start().await;
    Dubbo::new()
        .with_config({
            let r = RootConfig::new();
            match r.load() {
                Ok(config) => config,
                Err(_err) => panic!("err: {:?}", _err), // response was droped
            }
        })
        .start()
        .await;
}


#[allow(dead_code)]
#[derive(Default, Clone)]
struct GreeterServerImpl {
    name: String,
}


// #[async_trait]
#[async_trait]
impl Greeter for GreeterServerImpl {
    async fn greet(
        &self,
        request: Request,
    ) -> Result, dubbo::Status> {
        println!("GreeterServer::greet {:?}", request.metadata);


        Ok(Response::new(GreeterReply {
            message: "hello, dubbo-rust".to_string(),
        }))
    }
}

5.2

配置 dubbo.yaml

dubbo.yaml 指示 Server 端的配置，包括暴露的服务列表、协议配置、监听配置等。

# ./dubbo.yaml
name: dubbo
service:
  org.apache.dubbo.sample.tri.Greeter:
    version: 1.0.0
    group: test
    protocol: triple
    registry: ''
    serializer: json
    protocol_configs:
      triple:
        ip: 0.0.0.0
        port: '8888'
        name: triple
protocols:
  triple:
    ip: 0.0.0.0
    port: '8888'
    name: triple

5.3

编写 Dubbo Client

// ./src/greeter/client.rs
use ...


#[tokio::main]
async fn main() {
    let mut cli = GreeterClient::new().with_uri("http://127.0.0.1:8888".to_string());


    println!("# unary call");
    let resp = cli
        .greet(Request::new(GreeterRequest {
            name: "message from client".to_string(),
        }))
        .await;
    let resp = match resp {
        Ok(resp) => resp,
        Err(err) => return println!("{:?}", err),
    };
    let (_parts, body) = resp.into_parts();
    println!("Response: {:?}", body);
}

6►

运行并总结

6.1

编译

执行 cargo build 来编译 Server 和 Client。

6.2

运行 Server

执行 ./target/debug/greeter-server 来运行 Server，如上文 dubbo.yaml 所配置，Server 会监听 8888 端口，并以 triple 协议提供 RPC 服务。

$ ./target/debug/greeter-server
2022-09-28T2328.104577Z  INFO dubbo: url: Some(Url { uri: "triple://0.0.0.0:8888/org.apache.dubbo.sample.tri.Greeter", protocol: "triple", location: "0.0.0.0:8888", ip: "0.0.0.0", port: "8888", service_key: ["org.apache.dubbo.sample.tri.Greeter"], params: {} })

6.3

运行 Client，验证调用是否成功

执行 ./target/debug/greeter-client 来运行 Client，调用triple://127.0.0.1:8888/org.apache.dubbo.sample.tri.Greeter 下的各种方法。

$ ./target/debug/greeter-client
Response: GreeterReply { message: "hello, dubbo-rust" }

审核编辑：刘清