node.js - 如何获取 Loopback 3 条件 'datasources' 和 'model-config' : following instructions and doesn't work

Question

编辑:如果我假设“本地”变体只能覆盖已经定义的结构，我就能让它部分工作。也就是说，我需要在 datasources.json 中定义数据源“DynamoDB”和“mongo”，并在 datasources.local.js 中覆盖它们。然而，这不是我们想要做的——当我们部署到 AWS 时，我们不希望 MongoDB 以任何方式参与其中。非常感谢任何帮助!

<小时/>

我们需要根据 Node env 变量配置 Loopback 数据源和模型配置。具体来说，我们需要在本地开发时使用 MongoDB 作为数据库，在部署时使用 DynamoDB。我按照说明here进行操作，其中说

显然，根据this post ，我认为必须拥有“常规”datasources.json 和 model-config.json，其他文件只能添加到那里定义的内容。

无论如何，我添加了 datasources.local.js 和 model-config.local.js 但仍然收到错误。 .env 文件中的环境变量 LOOPBACK_ENV 已正确设置(在本例中设置为“mongo”)

AssertionError [ERR_ASSERTION]: Event is referencing a dataSource that does not exist: "mongo"
    at configureModel (/Users/abc/Documents/projects/abc-adj-new/node_modules/loopback/lib/application.js:584:5)
    at Function.app.model (/Users/abc/Documents/projects/abc-adj-new/node_modules/loopback/lib/application.js:126:5)
    at /Users/abc/Documents/projects/abc-adj-new/node_modules/loopback-boot/lib/executor.js:203:9
    at Array.forEach (<anonymous>)
    at setupModels (/Users/abc/Documents/projects/chatbot-adj-new/node_modules/loopback-boot/lib/executor.js:199:23)
    at execute (/Users/abc/Documents/projects/abc-adj-new/node_modules/loopback-boot/lib/executor.js:40:3)
    at bootLoopBackApp (/Users/abc/Documents/projects/abc-adj-new/node_modules/loopback-boot/index.js:154:3)
    at Object.<anonymous> (/Users/abc/Documents/projects/abc-adj-new/server/server.js:79:1)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Function.Module.runMain (internal/modules/cjs/loader.js:1025:10)
    at internal/main/run_main_module.js:17:11 {
  generatedMessage: false,
  code: 'ERR_ASSERTION',
  actual: false,
  expected: true,
  operator: '=='
}

我将添加以下文件。这是环回 3， Node 12.13。非常感谢任何帮助!

// server/datasources.json
{
    "db": {
        "name": "db",
        "connector": "memory"
    },


    "emailDataSource": {
        "name": "emailDataSource",
        "connector": "mail",
        "transports": [
            {
                "type": "smtp",
                "host": "smtp-service",
                "secure": false,
                "port": 25,
                "tls": {
                    "rejectUnauthorized": false
                }
            }
        ]
    }
}

<小时/>

  //  server/datasources.local.js
   if (process.env.LOOPBACK_ENV === "mongo") {
  module.exports = {

    "dynamodb": {
      "name": "dynamodb",
      "connector": "dynamodb",
      "region": "ap-northeast-1",
      "credentials": "shared",
      "profile": "iamrole"
    }

  };
} else {
  module.exports = {

    "mongo": {
      "url": "${MONGO_URL}",
      "name": "mongo",
      "connector": "mongodb",
      "allowExtendedOperators": true,
      "useNewUrlParser": true
    }
  };
}

<小时/>

//  server/model-config.json
{
  "_meta": {
    "sources": [
      "loopback/common/models",
      "loopback/server/models",
      "../common/models",
      "./models",
      "../node_modules/bot-analytics/models"
    ],
    "mixins": [
      "loopback/common/mixins",
      "loopback/server/mixins",
      "../common/mixins",
      "./mixins",
      "../node_modules/amf-lb-expose-remote-methods-mixin/lib"
    ]
  },
  "Variable": {
    "dataSource": "db",
    "public": true
  }

}

<小时/>

// server/model-config.js
if (process.env.LOOPBACK_ENV === "mongo") {
  module.exports ={

    "Event": {
      "dataSource": "mongo",
      "public": true
    },
    "History": {
      "dataSource": "mongo",
      "public": true
    },
    "Email": {
      "dataSource": "mongo"
    },
    "FileUpload": {
      "dataSource": "mongo",
      "public": true
    } ,
    "ADJUser" : {
      "dataSource": "mongo"
    }
  }

} else {
  module.exports = {

    "Event": {
      "dataSource": "dynamodb",
      "public": true
    },
    "History": {
      "dataSource": "dynamodb",
      "public": true
    },
    "Email": {
      "dataSource": "dynamodb"
    },
    "FileUpload": {
      "dataSource": "dynamodb",
      "public": true
    } ,
    "ADJUser" : {
      "dataSource": "dynamodb"
    }
  }

}

Answer 1

好吧，我不确定我能否正确回答您的问题 - 但这是我在项目中通常做的事情:

我在 server 文件夹中有许多文件，具体取决于配置，这些文件根据加载的配置服务于不同的目的。通常喜欢:

/server/middleware.json (for localhost)
/server/middleware.staging.json
/server/middleware.production.json

/server/datasources.json (for localhost)
/server/datasources.staging.json
/server/datasources.production.json

...每个环境和文件依此类推。

然后，根据环境，我使用特定命令启动应用程序:

NODE_ENV=production npm start server/server.js

NODE_ENV 属性将告诉应用程序要读取哪个配置文件。如果您不提供任何内容，则将读取第一个文件(在我的示例中为 /server/middleware.json 和 /server/datasources.json)

希望这有帮助!