从零搭建 Node.js 企业级 Web 服务器(十二):远程调用

关于远程调用

远程调用(简称 RPC)主要是指服务器或集群之间对处理过程的调用。通过远程调用可以打通不同系统之间的数据与功能,或是抽离与建立公共的逻辑统一提供服务。远程调用的两端也称为远程调用的客户端与服务端,一般是多对多的关系,需要引入注册与发现机制进行治理,下图为最常见实践:

ec9167646e5c4e2f700e5d997ecc4aaf5095b4bf.jpg

治理机制通常是因地制宜的,可以基于 ZooKeeper 建设,本章不再展开。

gRPC

gPRC 是谷歌开源的一款跨语言高性能的 RPC 框架,底层使用 protobuf 进行数据交换,已在谷歌、奈非、思科等企业大规模应用。以下为 gRPC 的调用过程,客户端先进行 DNS 解析,再根据解析结果直连服务端或向负载均衡/治理服务获取服务端信息再连接:

32bf1586530cb8b2d97177936492028a84f443b1.jpg

本章将基于上一章已完成的工程 host1-tech/nodejs-server-examples - 11-schedule 加入远程调用功能实现一个简单消息的输入与输出,现在到工程根目录安装 grpc 相关模块:

$ yarn add @grpc/grpc-js @grpc/proto-loader # 本地安装 @grpc/grpc-js、@grpc/proto-loader
# ...
info Direct dependencies
├─ @grpc/grpc-js@1.1.3
└─ @grpc/proto-loader@0.5.5
# ...

加上远程调用

通过 .proto 文件定义远程接口并写入基于该定义的 gRPC 客户端与服务端:

$ mkdir src/rpc       # 新建 src/rpc 存放远程调用逻辑

$ mkdir src/rpc/echo  # 新建 src/rpc/echo

$ tree src -L 1       # 展示 src 目录内容结构
src
├── config
├── controllers
├── middlewares
├── models
├── moulds
├── rpc
├── schedules
├── server.js
├── services
└── utils
// src/rpc/echo/def.proto
syntax = "proto3";

service Echo {
  rpc Get(EchoRequest) returns (EchoResponse) {}
}

message EchoRequest { string message = 1; }

message EchoResponse { string message = 1; }
// src/rpc/echo/client.js
const { resolve } = require('path');
const { promisify } = require('util');
const protoLoader = require('@grpc/proto-loader');
const grpc = require('@grpc/grpc-js');
const { rpc } = require('../../config');

class EchoClient {
  grpcClient;

  async init() {
    const grpcObject = grpc.loadPackageDefinition(
      await protoLoader.load(resolve(__dirname, 'def.proto'))
    );

    this.grpcClient = new grpcObject.Echo(
      `${rpc.domain}:${rpc.port}`,
      grpc.credentials.createInsecure()
    );
  }

  get = async ({ s, logger }) => {
    const { grpcClient } = this;

    const { message } = await promisify(
      grpcClient.get.bind(grpcClient, { message: s })
    )();

    logger.info('Echo/Get Invoked');

    return { message };
  };
}

let client;
module.exports = async () => {
  if (!client) {
    client = new EchoClient();
    await client.init();
  }
  return client;
};
// src/rpc/echo/server.js
const { resolve } = require('path');
const { callbackify } = require('util');
const protoLoader = require('@grpc/proto-loader');
const grpc = require('@grpc/grpc-js');

class EchoServer {
  grpcServer;

  async init() {
    const grpcObject = grpc.loadPackageDefinition(
      await protoLoader.load(resolve(__dirname, 'def.proto'))
    );

    this.grpcServer.addService(grpcObject.Echo.service, this);
  }

  get = callbackify(async (call) => {
    const { message } = call.request;
    return { message };
  });
}

let server;
module.exports = async (grpcServer) => {
  if (!server) {
    server = new EchoServer();
    Object.assign(server, { grpcServer });
    await server.init();
  }
  return server;
};
// src/config/index.js
// ...
const config = {
  // 默认配置
  default: {
    // ...
+    
+    rpc: {
+      domain: 'localhost',
+      port: process.env.PORT_RPC || 9001,
+    },
  },
  // ...
};
// ...

开启 gRPC 日志输出并初始化:

# .env
LOG_LEVEL='debug'
+
+GRPC_TRACE='all'
+GRPC_VERBOSITY='DEBUG'
// src/utils/logger.js
// ...
+const GRPC_LOGGER_REGEXP = /^.+Z\s+\|\s+/;
+
+function grpcLogger(logger, level = 'debug') {
+  const verbosities = ['debug', 'info', 'error'];
+
+  return {
+    error(severity, message) {
+      if (typeof severity != 'number') {
+        message = severity;
+        severity = 0;
+      }
+
+      if (typeof message != 'string') {
+        message = String(message || '');
+      }
+
+      logger[verbosities[severity] || level](
+        message.replace(GRPC_LOGGER_REGEXP, '')
+      );
+    },
+  };
+}
+
module.exports = logger;

-Object.assign(module.exports, { logging });
+Object.assign(module.exports, { logging, grpcLogger });
// src/rpc/index.js
const { promisify } = require('util');
const grpc = require('@grpc/grpc-js');
const { rpc } = require('../config');
const logger = require('../utils/logger');
const echoClient = require('./echo/client');
const echoServer = require('./echo/server');
const { grpcLogger } = logger;

module.exports = async function initRpc() {
  grpc.setLogger(grpcLogger(logger.child({ type: 'rpc' }), 'debug'));

  // init rpc servers
  const grpcServer = new grpc.Server();
  await echoServer(grpcServer);

  await promisify(grpcServer.bindAsync.bind(grpcServer))(
    `0.0.0.0:${rpc.port}`,
    grpc.ServerCredentials.createInsecure()
  );
  grpcServer.start();

  // init rpc clients
  await echoClient();
};
// src/server.js
const express = require('express');
const { resolve } = require('path');
const { promisify } = require('util');
const initMiddlewares = require('./middlewares');
const initControllers = require('./controllers');
const initSchedules = require('./schedules');
+const initRpc = require('./rpc');
const logger = require('./utils/logger');

const server = express();
const port = parseInt(process.env.PORT || '9000');
const publicDir = resolve('public');
const mouldsDir = resolve('src/moulds');

async function bootstrap() {
+  await initRpc();
  server.use(await initMiddlewares());
  server.use(express.static(publicDir));
  server.use('/moulds', express.static(mouldsDir));
  server.use(await initControllers());
  server.use(errorHandler);
  await initSchedules();
  await promisify(server.listen.bind(server, port))();
  logger.info(`> Started on port ${port}`);
}
// ...

添加 gRPC 客户端 logger 与控制层入口:

// src/middlewares/trace.js
const { v4: uuid } = require('uuid');
const morgan = require('morgan');
const onFinished = require('on-finished');
const logger = require('../utils/logger');
const { logging } = logger;

module.exports = function traceMiddleware() {
  return [
    morgan('common', { skip: () => true }),
    (req, res, next) => {
      req.uuid = uuid();
      req.logger = logger.child({ uuid: req.uuid });
      req.loggerSql = req.logger.child({ type: 'sql' });
      req.logging = logging(req.loggerSql, 'info');
+      req.loggerRpc = req.logger.child({ type: 'rpc' });

      onFinished(res, () => {
        // ...
      });

      next();
    },
  ];
};
// src/controllers/echo.js
const { Router } = require('express');
const cc = require('../utils/cc');
const rpcEchoClient = require('../rpc/echo/client');

class EchoController {
  rpcEchoClient;

  async init() {
    this.rpcEchoClient = await rpcEchoClient();

    const router = Router();
    router.get('/', this.get);
    return router;
  }

  get = cc(async (req, res) => {
    const { s = '' } = req.query;
    const message = await this.rpcEchoClient.get({ s, logger: req.loggerRpc });
    res.send({ success: true, message });
  });
}

module.exports = async () => {
  const c = new EchoController();
  return await c.init();
};
// src/controllers/index.js
const { Router } = require('express');
const shopController = require('./shop');
const chaosController = require('./chaos');
const healthController = require('./health');
const loginController = require('./login');
const csrfController = require('./csrf');
+const echoController = require('./echo');

module.exports = async function initControllers() {
  const router = Router();
  router.use('/api/shop', await shopController());
  router.use('/api/chaos', await chaosController());
  router.use('/api/health', await healthController());
  router.use('/api/login', await loginController());
  router.use('/api/csrf', await csrfController());
+  router.use('/api/echo', await echoController());
  return router;
};

访问 http://localhost:9000/api/echo?s=Hello%20RPC 即可看到效果:

055f756e61f91f40c4f6f737041ef91d2ccd73f6.jpg

同时在命令行能够看到充分的 gRPC 日志:

# ...
08:20:52.320Z DEBUG 12-rpc: dns_resolver | Resolver constructed for target dns:0.0.0.0:9001 (type=rpc)
08:20:52.321Z DEBUG 12-rpc: dns_resolver | Resolution update requested for target dns:0.0.0.0:9001 (type=rpc)
08:20:52.321Z DEBUG 12-rpc: dns_resolver | Returning IP address for target dns:0.0.0.0:9001 (type=rpc)
08:20:52.322Z DEBUG 12-rpc: server | Attempting to bind 0.0.0.0:9001 (type=rpc)
08:20:52.324Z DEBUG 12-rpc: server | Successfully bound 0.0.0.0:9001 (type=rpc)
08:20:52.327Z DEBUG 12-rpc: resolving_load_balancer | dns:localhost:9001 IDLE -> IDLE (type=rpc)
08:20:52.327Z DEBUG 12-rpc: connectivity_state | dns:localhost:9001 IDLE -> IDLE (type=rpc)
08:20:52.327Z DEBUG 12-rpc: dns_resolver | Resolver constructed for target dns:localhost:9001 (type=rpc)
# ...

本章源码

host1-tech/nodejs-server-examples - 12-rpc

更多阅读

从零搭建 Node.js 企业级 Web 服务器(零):静态服务
从零搭建 Node.js 企业级 Web 服务器(一):接口与分层
从零搭建 Node.js 企业级 Web 服务器(二):校验
从零搭建 Node.js 企业级 Web 服务器(三):中间件
从零搭建 Node.js 企业级 Web 服务器(四):异常处理
从零搭建 Node.js 企业级 Web 服务器(五):数据库访问
从零搭建 Node.js 企业级 Web 服务器(六):会话
从零搭建 Node.js 企业级 Web 服务器(七):认证登录
从零搭建 Node.js 企业级 Web 服务器(八):网络安全
从零搭建 Node.js 企业级 Web 服务器(九):配置项
从零搭建 Node.js 企业级 Web 服务器(十):日志
从零搭建 Node.js 企业级 Web 服务器(十一):定时任务
从零搭建 Node.js 企业级 Web 服务器(十二):远程调用
从零搭建 Node.js 企业级 Web 服务器(十三):断点调试与性能分析
从零搭建 Node.js 企业级 Web 服务器(十四):自动化测试
从零搭建 Node.js 企业级 Web 服务器(十五):总结与展望

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