如何获得回溯3条件‘数据源’和‘模型-配置’：以下说明，但不工作

Question

编辑:如果我假设“本地”变体只能覆盖已经定义的结构，我就能够让它在半路上工作。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，我们不想让MongoDB以任何方式参与进来。任何帮助都非常感谢！

我们需要根据节点env变量配置回退数据源和模型配置。具体来说，我们需要在MongoDB作为本地开发的DB和部署时的DynamoDB之间切换。我遵循了这里的指令，上面写着

​

显然，根据这个职位的说法，我认为一个文件必须具有“常规”的datasources.json和model-config.json，而其他文件只能添加其中定义的内容。

在任何情况下，我都添加了datasources.local.js和model-config.local.js，但是仍然会出现错误。环境变量LOOPBACK_ENV在.env文件中被正确设置(在本例中为“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。这里是回收站3号，节点12.13。任何帮助都非常感谢！

// 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
                }
            }
        ]
    }
}

  //  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
    }
  };
}

//  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
  }

}

// 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

嗯，我不确定我会对你的问题做出正确的回答--但以下是我在我的项目中通常做的事情：

根据配置的不同，我在server文件夹中有许多文件，根据加载的配置，这些文件具有不同的用途。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

..。对每个环境和文件都是如此。

然后，根据环境的不同，我使用一个特定的命令启动应用程序：

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。如果不提供任何文件，则将读取第一个文件(在我的示例/server/middleware.json和/server/datasources.json中)

希望这能有所帮助！