Fly.io部署Express/Node/Mongoose应用失败求助

问题背景 #

基于Express、Node.js、Mongoose的应用曾成功部署在Fly.io，更换新设备后访问失效。尝试重新部署（含删除原应用、克隆GitHub代码）均失败，应用启动后崩溃。

核心错误日志 #

[1/1] Checking that e28677eb572286 [app] is up and running Smoke checks for e28677eb572286 failed: the app appears to be crashing Check its logs: here's the last lines below, or run 'fly logs -i e28677eb572286': INFO Starting init (commit: 0b28cec)... INFO Preparing to run:docker-entrypoint.sh npm run start` as root
INFO [fly api proxy] listening at /.fly/api
2023/06/23 20:04:23 listening on [fdaa:2:7b4:a7b:21a1:8e24:3a29:2]:22 (DNS: [fdaa::3]:53)

men_oauth@0.2.0 start
node ./bin/www.js
Fri, 23 Jun 2023 20:04:24 GMT express-session deprecated req.secret; provide secret option at file:/app/server.js:46:3
Warning: connect.session() MemoryStore is not
designed for a production environment, as it will leak
memory, and will not scale past a single process.
Listening on port 8080
/app/node_modules/mongoose/lib/connection.js:768
throw new MongooseError('The uri parameter to openUri() must be a ’ +
^
MongooseError: The uri parameter to openUri() must be a string, got “undefined”. Make sure the first parameter to mongoose.connect() or mongoose.createConnection() is a string.
at _createMongoClient (/app/node_modules/mongoose/lib/connection.js:768:11)
at NativeConnection.openUri (/app/node_modules/mongoose/lib/connection.js:705:29)
at Mongoose.connect (/app/node_modules/mongoose/lib/index.js:406:15)
at file:///app/config/database.js:7:10
at ModuleJob.run (node:internal/modules/esm/module_job:194:25)
Node.js v18.15.0
npm notice
npm notice New minor version of npm available! 9.5.0 → 9.7.2
npm notice Changelog: https://github.com/npm/cli/releases/tag/v9.7.2
npm notice Run npm install -g npm@9.7.2 to update!
npm notice
INFO Main child exited normally with code: 1
INFO Starting clean up.
WARN hallpass exited, pid: 232, status: signal: 15 (SIGTERM)
2023/06/23 20:04:25 listening on [fdaa:2:7b4:a7b:21a1:8e24:3a29:2]:22 (DNS: [fdaa::3]:53)
[ 3.130614] reboot: Restarting system
machine did not have a restart policy, defaulting to restart
INFO Starting init (commit: 0b28cec)…
INFO Preparing to run: docker-entrypoint.sh npm run start as root
INFO [fly api proxy] listening at /.fly/api
2023/06/23 20:04:26 listening on [fdaa:2:7b4:a7b:21a1:8e24:3a29:2]:22 (DNS: [fdaa::3]:53)

men_oauth@0.2.0 start
node ./bin/www.js
Fri, 23 Jun 2023 20:04:28 GMT express-session deprecated req.secret; provide secret option at file:/app/server.js:46:3
Warning: connect.session() MemoryStore is not
designed for a production environment, as it will leak
memory, and will not scale past a single process.
Listening on port 8080
/app/node_modules/mongoose/lib/connection.js:768
throw new MongooseError('The uri parameter to openUri() must be a ’ +
^
MongooseError: The uri parameter to openUri() must be a string, got “undefined”. Make sure the first parameter to mongoose.connect() or mongoose.createConnection() is a string.
at _createMongoClient (/app/node_modules/mongoose/lib/connection.js:768:11)
at NativeConnection.openUri (/app/node_modules/mongoose/lib/connection.js:705:29)
at Mongoose.connect (/app/node_modules/mongoose/lib/index.js:406:15)
at file:///app/config/database.js:7:10
at ModuleJob.run (node:internal/modules/esm/module_job:194:25)
Node.js v18.15.0
npm notice
npm notice New minor version of npm available! 9.5.0 → 9.7.2
npm notice Changelog: https://github.com/npm/cli/releases/tag/v9.7.2
npm notice Run npm install -g npm@9.7.2 to update!
npm notice
INFO Main child exited normally with code: 1
INFO Starting clean up.
WARN hallpass exited, pid: 232, status: signal: 15 (SIGTERM)
2023/06/23 20:04:28 listening on [fdaa:2:7b4:a7b:21a1:8e24:3a29:2]:22 (DNS: [fdaa::3]:53)
Error: smoke checks for e28677eb572286 failed: the app appears to be crashing

已尝试操作 #

• 重新安装Fly.io CLI
• 升级Fly.io CLI
• 删除fly.toml文件后重新部署
• 调整实例数量（fly scale count 1/fly scale count 2）
• 重新克隆GitHub代码并部署

排查与解决方案 #

1. 核心问题定位 #

日志中明确显示MongooseError: The uri parameter to openUri() must be a string, got “undefined”，说明应用启动时无法读取MongoDB连接URI，导致Mongoose连接失败。

2. 环境变量配置检查 #

• 本地验证：确认项目根目录的.env文件存在，且包含MONGODB_URI（或代码中使用的变量名），值为有效的MongoDB连接字符串，本地启动应用npm run start验证是否正常连接。
• Fly.io配置：
  • 执行fly secrets list查看已配置的密钥，确认是否有MongoDB连接URI条目。
  • 若缺失，执行fly secrets set MONGODB_URI="你的MongoDB连接字符串"添加密钥（删除应用会连带删除关联secrets，需重新配置）。
  • 确保代码中使用的环境变量名与Fly.io secrets完全一致（大小写敏感）。

3. 代码逻辑检查 #

打开/app/config/database.js，确认URI读取逻辑正确：

• 示例正确代码：

  import mongoose from 'mongoose';
  
  await mongoose.connect(process.env.MONGODB_URI);
  

• 若本地使用dotenv，需确保生产环境不加载本地.env文件，避免与Fly.io secrets冲突。

4. 额外警告处理 #

• express-session秘钥缺失：在express-session配置中添加secret选项，从环境变量读取：

  app.use(session({
    secret: process.env.SESSION_SECRET,
    resave: false,
    saveUninitialized: false
  }))
  

• MemoryStore生产环境警告：生产环境替换为Redis等持久化存储，避免内存泄漏和无法扩展。

内容的提问来源于stack exchange，提问作者CatLover2291