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egg-grpc

NPM version build status Test coverage David deps Known Vulnerabilities npm download

grpc 的 eggjs 插件

安装

$ npm i egg-grpc --save
// {app_root}/config/plugin.js
exports.grpc = {
  enable: true,
  package: 'egg-grpc',
};

配置

// {app_root}/config/config.default.js
exports.grpc = {
  endpoint: 'localhost:50051',
  // dir: 'app/proto', // proto 文件目录，相对路径
  // property: 'grpc', // 默认挂载到 `ctx.grpc.**`
  // loadOpts: { convertFieldsToCamelCase: true, }, // message field case: `string user_name` -> `userName`
};

更多参数配置见 config/config.default.js。

使用说明

示例代码：

app/proto
├── egg
│   └── test
│       ├── game.proto
│       └── message.proto
├── uc
│   └── test.proto
└── share.proto
// app/proto/share.proto
syntax = "proto3";

package egg.share;

message Status {
  string code = 1;
  string err_msg = 2;
}

service ShowCase {
  rpc Echo(Status) returns (Status) {}
}

快速开始:

// 仅跟 `package` 定义有关，跟 proto 文件路径无关。
const client = ctx.grpc.egg.share.showCase;
const result = yield client.echo({ code: 200 });
console.log(result);

文件目录

  • 默认从 app/proto 目录加载 proto 文件。
  • 目录仅用于文件管理，不影响到挂载到 ctx 和 app 上的访问路径，后者仅跟 package 定义有关。
  • 譬如上述的 app/proto/share.proto 文件，定义为 package egg;，所以对应的访问方式：
    • yield ctx.grpc.egg.share.showCase.echo(data, meta, options)
    • new app.grpcProto.egg.share.Status({ code: 200 })
    • new app.grpcProto.egg.share.ShowCase(address)
    • new ctx.grpcProto.egg.share.ShowCase(address)

命名转换规则

术语 命名规范(proto 定义) 加载后
package 小写，用 . 分隔 若存在 _，则驼峰
service 类名风格，首字母大写 初始化到 ctx 后为驼峰格式
rpc 类名风格，首字母大写 驼峰格式
message 类名风格，首字母大写 按原格式挂载在 app.grpcProto 上
field 下划线风格，全小写 驼峰格式
enums 下划线风格，全大写 不变

API

自定义选项

  • {Number} timeout - 语法糖，等价于 { deadline: Date.now() + timeout }

Service && Message

你可以通过 ctx.mypackage.myService.myRpc({ id: 1 }) 获取到 grpc service 的实例并执行 rpc 方法。

一般来说，message 是无需实例化的，只需传递普通的 object，grpc 会自动校验。当然你也可以使用 new app.grpcProto.mypackage.SomeMessage({ id: 1 })。

Unary RPC

/**
 * Unary RPC, such as `rpc Echo(Request) returns (Response) {}`
 * @param {Object} data - data sent to sever
 * @param {Object|grpc.Metadata} [metadata] - metadata, support plain object
 * @param {Object} [options] - { timeout }
 * @return {Promise} response promise chain
 * @see http://www.grpc.io/docs/guides/concepts.html#unary-rpc
 */
// const client = ctx.grpc.<package>.<service>;
yield client.echo(data, metadata, options);
yield client.echo(data, options);

Client Streaming RPC

/**
 * Client Streaming RPC, such as `rpc EchoClientStream(stream Request) returns (Response) {}`
 * @param {Object|grpc.Metadata} [metadata] - metadata, support plain object
 * @param {Object} [options] - { timeout }
 * @param {Function} [callback] - callback for response, `(err, response) => {}`
 * @return {Stream} write stream
 * @see http://www.grpc.io/docs/guides/concepts.html#client-streaming-rpc
 */
const stream = client.echoClientStream(meta, options, callback);
// const stream = client.echoClientStream(callback);
// const stream = client.echoClientStream(meta, callback);
// trigger order: metadata -> callback -> status
stream.once('metadata', meta => {});
stream.once('status', status => {});
stream.on('error', status => {});
// send data to server or end
stream.write(data1);
stream.write(data2);
stream.end(data4);

Server Streaming RPC

/**
 * Server Streaming RPC, such as `rpc EchoServerStream(Request) returns (stream Response) {}`
 * @param {Object} data - data sent to sever
 * @param {Object|grpc.Metadata} [metadata] - metadata, support plain object
 * @param {Object} [options] - { timeout }
 * @return {Stream} read stream
 * @see http://www.grpc.io/docs/guides/concepts.html#server-streaming-rpc
 */
const stream = client.echoServerStream(data, meta, options);
// trigger order: metadata -> data -> status -> end
stream.on('data', response => {});
stream.on('end', response => {});
stream.once('metadata', meta => {});
stream.once('status', status => {});
stream.on('error', status => {});

Bidirectional Streaming RPC

/**
 * Bidirectional Streaming RPC, such as `rpc echoStreamStream(stream Request) returns (stream Response) {}`
 * @param {Object|grpc.Metadata} [metadata] - metadata, support plain object
 * @param {Object} [options] - { timeout }
 * @return {Stream} duplex stream
 * @see http://www.grpc.io/docs/guides/concepts.html#bidirectional-streaming-rpc
 */
const stream = client.echoStreamStream(meta, options);
// trigger order: metadata -> data -> status -> end
stream.on('data', response => {});
stream.on('end', () => {});
stream.once('metadata', meta => {});
stream.once('status', status => {});
stream.on('error', status => {});
// send data to server or end
stream.write(data1);
stream.write(data2);
stream.end(data3);

示例

参见 grpc.tests.js.

问题反馈

访问并发起 issue.

License

MIT