部署在Heroku的Node.js应用出现Redis SETEX方法未定义错误求助

问题现象 #

将Node.js应用部署到Heroku后，触发Redis操作时抛出以下错误，导致系统无法正常运行：

2022-09-14T14:59:46.099027+00:00 app[web.1]: /app/dist/controller/contact/index.js:212
2022-09-14T14:59:46.099044+00:00 app[web.1]:                         return _redisClient.redisClient.SETEX(key, _config.REDIS_DEF_EXP_TIME, JSON.stringify(contacts));
2022-09-14T14:59:46.099045+00:00 app[web.1]:                                                         ^
2022-09-14T14:59:46.099045+00:00 app[web.1]: 
2022-09-14T14:59:46.099046+00:00 app[web.1]: TypeError: Cannot read properties of undefined (reading 'SETEX')
2022-09-14T14:59:46.099046+00:00 app[web.1]:     at _callee5$ (/app/dist/controller/contact/index.js:212:57)
2022-09-14T14:59:46.099046+00:00 app[web.1]:     at tryCatch (/app/node_modules/regenerator-runtime/runtime.js:63:40)
2022-09-14T14:59:46.099047+00:00 app[web.1]:     at Generator.invoke [as _invoke] (/app/node_modules/regenerator-runtime/runtime.js:294:22)
2022-09-14T14:59:46.099047+00:00 app[web.1]:     at Generator.next (/app/node_modules/regenerator-runtime/runtime.js:119:21)
2022-09-14T14:59:46.099048+00:00 app[web.1]:     at asyncGeneratorStep (/app/dist/controller/contact/index.js:22:103)
2022-09-14T14:59:46.099048+00:00 app[web.1]:     at _next (/app/dist/controller/contact/index.js:24:194)
2022-09-14T14:59:46.099048+00:00 app[web.1]:     at /app/dist/controller/contact/index.js:24:364
2022-09-14T14:59:46.099048+00:00 app[web.1]:     at new Promise (<anonymous>)
2022-09-14T14:59:46.099049+00:00 app[web.1]:     at /app/dist/controller/contact/index.js:24:97
2022-09-14T14:59:46.099049+00:00 app[web.1]:     at /app/dist/controller/contact/index.js:226:30
2022-09-14T14:59:46.099049+00:00 app[web.1]:     at /app/node_modules/mongoose/lib/model.js:5074:18
2022-09-14T14:59:46.099050+00:00 app[web.1]:     at processTicksAndRejections (node:internal/process/task_queues:78:11)

环境配置 #

• Node.js Version: 16.x
• Node Redis Version: 4.0.2
• Platform: Heroku Cloud OS

现有Redis配置代码 #

import { createClient } from 'redis';
import { REDIS_URI } from '../config';

export let redisClient;

(async () => {
    try {
        redisClient = createClient({ url: REDIS_URI });
        redisClient.on("error", (err) => console.log("Redis Client Connection Error"));

        console.log("Redis cashe app database connected...");
        await redisClient.connect();
    } catch (error) {
        console.log('Redis app connection Error...', error);
    }
})();

问题原因 #

1. API版本不兼容：Node-Redis v4将v3及更早版本的大写Redis命令（如SETEX）改为驼峰命名方法（setEx），直接调用SETEX会导致方法不存在。
2. 初始化时序问题：当前用异步立即执行函数(IIFE)初始化redisClient，若应用代码在初始化完成前调用，会导致redisClient为undefined。
3. 调用层级错误：从错误日志_redisClient.redisClient.SETEX可见，代码错误地对导入的redisClient再次访问redisClient属性，导致访问到undefined后调用方法失败。

解决方案 #

1. 修正Redis命令调用方式 #

将SETEX改为Node-Redis v4对应的驼峰方法setEx，同时修正调用层级：

// 错误写法
// return _redisClient.redisClient.SETEX(key, _config.REDIS_DEF_EXP_TIME, JSON.stringify(contacts));

// 正确写法（导入的是redisClient变量）
return redisClient.setEx(key, _config.REDIS_DEF_EXP_TIME, JSON.stringify(contacts));

2. 确保客户端初始化完成后再使用 #

将初始化逻辑改为可等待的函数，在应用启动时等待Redis连接完成：

// redis配置文件修改
import { createClient } from 'redis';
import { REDIS_URI } from '../config';

export let redisClient;

export async function initRedis() {
    try {
        redisClient = createClient({ url: REDIS_URI });
        redisClient.on("error", (err) => console.error("Redis Client Connection Error:", err));
        
        await redisClient.connect();
        console.log("Redis cache app database connected...");
    } catch (error) {
        console.error('Redis app connection Error...', error);
        process.exit(1); // 连接失败时退出应用
    }
}

在应用入口文件中调用并等待初始化：

// 入口文件如app.js
import { initRedis } from './path/to/redis-config';

async function startApp() {
    await initRedis();
    // 启动其他服务，如Express/Koa
    app.listen(process.env.PORT || 3000);
}

startApp();

3. 验证Heroku环境变量配置 #

确认Heroku上的REDIS_URI环境变量配置正确，可通过Heroku CLI查看：

heroku config:get REDIS_URI -a your-app-name

确保URI格式为redis://username:password@host:port，避免因地址错误导致客户端初始化失败。

内容的提问来源于stack exchange，提问作者Internazionaleauto