如何修复npm ERR！将MEAN应用程序部署到Heroku时，代码为ELIFECYCLE

Question

我在将后端部署到Heroku时遇到问题。我使用的是带有Mongo Atlas数据库的MEAN堆栈。该应用程序在本地运行良好。但一旦我部署了它，它就会以npm ERR! code ELIFECYCLE崩溃。显然，Mongo Atlas要求您将IP地址列入白名单。我读过的一篇文章说，如果我把连接字符串添加到Heroku环境变量中，它会很好地工作。所以我已经这样做了，并用名称connectionString保存了它。然而，这并没有奏效。连接字符串是否需要特定的名称？我已经在下面发布了我的Heroku日志。注意，我已经尝试删除我的node_modules和package.json并重新安装它们，同时将我的节点版本更改为10.x。

2021-03-17T07:22:23.865572+00:00 app[api]: Deploy 2cbf3bbb by user [e-mail]
2021-03-17T07:22:23.865572+00:00 app[api]: Release v9 created by user [e-mail]
2021-03-17T07:22:24.515688+00:00 heroku[web.1]: State changed from crashed to starting
2021-03-17T07:22:25.000000+00:00 app[api]: Build succeeded
2021-03-17T07:22:27.638401+00:00 heroku[web.1]: Starting process with command `npm start`
2021-03-17T07:22:30.298270+00:00 app[web.1]:
2021-03-17T07:22:30.298283+00:00 app[web.1]: > backend@1.1.1 start /app
2021-03-17T07:22:30.298284+00:00 app[web.1]: > node index.js
2021-03-17T07:22:30.298284+00:00 app[web.1]:
2021-03-17T07:22:31.387500+00:00 app[web.1]: WARNING: NODE_ENV value of 'production' did not match any deployment config file names.
2021-03-17T07:22:31.387844+00:00 app[web.1]: WARNING: See https://github.com/lorenwest/node-config/wiki/Strict-Mode
2021-03-17T07:22:31.931808+00:00 heroku[web.1]: State changed from starting to up
2021-03-17T07:23:01.761238+00:00 app[web.1]: npm ERR! code ELIFECYCLE
2021-03-17T07:23:01.761850+00:00 app[web.1]: npm ERR! errno 1
2021-03-17T07:23:01.770367+00:00 app[web.1]: npm ERR! backend@1.1.1 start: `node index.js`
2021-03-17T07:23:01.770621+00:00 app[web.1]: npm ERR! Exit status 1
2021-03-17T07:23:01.770728+00:00 app[web.1]: npm ERR!
2021-03-17T07:23:01.772482+00:00 app[web.1]: npm ERR! Failed at the backend@1.1.1 start script.
2021-03-17T07:23:01.772597+00:00 app[web.1]: npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
2021-03-17T07:23:01.781656+00:00 app[web.1]:
2021-03-17T07:23:01.781807+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2021-03-17T07:23:01.781869+00:00 app[web.1]: npm ERR!     /app/.npm/_logs/2021-03-17T07_23_01_773Z-debug.log
2021-03-17T07:23:01.841833+00:00 heroku[web.1]: Process exited with status 1
2021-03-17T07:23:01.965241+00:00 heroku[web.1]: State changed from up to crashed
2021-03-17T07:23:01.973670+00:00 heroku[web.1]: State changed from crashed to starting
2021-03-17T07:23:06.945061+00:00 heroku[web.1]: Starting process with command `npm start`
2021-03-17T07:23:11.079200+00:00 app[web.1]:
2021-03-17T07:23:11.079239+00:00 app[web.1]: > backend@1.1.1 start /app
2021-03-17T07:23:11.079239+00:00 app[web.1]: > node index.js
2021-03-17T07:23:11.079239+00:00 app[web.1]:
2021-03-17T07:23:12.636407+00:00 app[web.1]: WARNING: NODE_ENV value of 'production' did not match any deployment config file names.
2021-03-17T07:23:12.639137+00:00 app[web.1]: WARNING: See https://github.com/lorenwest/node-config/wiki/Strict-Mode
2021-03-17T07:23:13.442612+00:00 heroku[web.1]: State changed from starting to up
2021-03-17T07:23:43.404828+00:00 app[web.1]: npm ERR! code ELIFECYCLE
2021-03-17T07:23:43.405294+00:00 app[web.1]: npm ERR! errno 1
2021-03-17T07:23:43.419129+00:00 app[web.1]: npm ERR! backend@1.1.1 start: `node index.js`
2021-03-17T07:23:43.419414+00:00 app[web.1]: npm ERR! Exit status 1
2021-03-17T07:23:43.419741+00:00 app[web.1]: npm ERR!
2021-03-17T07:23:43.420082+00:00 app[web.1]: npm ERR! Failed at the backend@1.1.1 start script.
2021-03-17T07:23:43.420380+00:00 app[web.1]: npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
2021-03-17T07:23:43.437105+00:00 app[web.1]:
2021-03-17T07:23:43.439175+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2021-03-17T07:23:43.439472+00:00 app[web.1]: npm ERR!     /app/.npm/_logs/2021-03-17T07_23_43_421Z-debug.log
2021-03-17T07:23:43.562438+00:00 heroku[web.1]: Process exited with status 1
2021-03-17T07:23:43.638872+00:00 heroku[web.1]: State changed from up to crashed```

Answer 1

所以我解决了这个问题。连接到数据库时，我使用配置模块加载Mongodb Atlas连接字符串。mongoose.connect(config.get('configurationString'), {useNewUrlParser: true, useUnifiedTopology: true, useFindAndModify: false, useCreateIndex: true}).then(() => winston.info("Connected to MongoDB..."))

我将config.get('connectionString')更改为process.env.MONGODB_URL，然后使用heroku config:set MONGODB_URL="<YOUR MONGODB ATLAS CONNECTION STRING>"将MONGODB_URL env变量添加到heroku。还要确保您有一个Procfile并添加行web:node index.js