cube.js 动态schema 编译处理

cube.js 支持动态schema 的编译生成（只执行一次）

一些约定

基于asyncModule() 函数，自定义的schema 需要放schema 目录下（当然可以自己扩展resopitryFactory）
sql 以及drillMembers 需要是函数，函数的签名为()=>string

参考使用

• schema 帮助函数
  sql 函数以及drillMembers 的处理，按照上边的约定
  schema/utils.js

 

export const convertStringPropToFunction = (propNames, dimensionDefinition) => {

  const newResult = { ...dimensionDefinition }

    propNames.forEach((propName) => {

    const propValue = newResult[propName]

 

      if (!propValue) {

      return

      }

    newResult[propName] = () => propValue

    })

    return newResult

  };

 

 

export const transformDimensions = (dimensions) => {

  return Object.keys(dimensions).reduce((result, dimensionName) => {

    const dimensionDefinition = dimensions[dimensionName]

      return {

      ...result,

      [dimensionName]: convertStringPropToFunction(

        ['sql'],

        dimensionDefinition

      )

    }

    }, {})

  };

 

 

export const transformMeasures = (measures) => {

  return Object.keys(measures).reduce((result, dimensionName) => {

    const dimensionDefinition = measures[dimensionName]

      return {

      ...result,

      [dimensionName]: convertStringPropToFunction(

        ['sql', 'drillMembers'],

        dimensionDefinition

      )

    }

    }, {})

  };

• schema 动态生成
  基于node-fetch 通过api 获取定义 asyncModule 是比较重要的

 

const fetch = require('node-fetch');

import {

  transformDimensions,

  transformMeasures,

} from './utils';

asyncModule(async () => {

  const dynamicCubes = await (

    await fetch('http://localhost:8080/app.json')

  ).json();

 

 

  console.log(dynamicCubes);

  dynamicCubes.forEach((dynamicCube) => {

    const dimensions = transformDimensions(dynamicCube.dimensions);

    const measures = transformMeasures(dynamicCube.measures);

 

 

    cube(dynamicCube.title, {

      sql: dynamicCube.sql,

      dimensions,

      measures,

      preAggregations: {

        main: {

          type: `originalSql`,

        },

      },

    });

  });

});

app.json

[

  {

    "preAggregations": {

      "mydemo": {

        "type": "autoRollup",

        "measureReferences": [

          "DynamicCubeSchema.price"

        ],

        "dimensionReferences": [

          "name"

        ],

        "external": true

      }

    },

    "dimensions": {

      "name": {

        "sql": "name",

        "type": "string"

      }

    },

    "measures": {

      "price": {

        "drillMembers": [

          "name",

          "id"

        ],

        "type": "count"

      }

    },

    "title": "DynamicCubeSchema",

    "sql": "SELECT * FROM demoapp"

  }

]

运行&&效果

• 入口
  index.js 基于throng 提升多线程能力

 

const CubejsServer = require('@cubejs-backend/server');

const cubejs = require("./cube")

const throng = require('throng')

const WORKERS = process.env.WEB_CONCURRENCY || 2

const server = new CubejsServer(cubejs);

throng(WORKERS, start)

function start(){

    server

    .listen()

    .then(({ version, port }) => {

      console.log(`🚀 Cube.js server (${version}) is listening on ${port}`);

    })

    .catch((e) => {

      console.error('Fatal error during server start: ');

      console.error(e.stack || e);

    });

}

• 启动
  需要先启动提供动态schema 的api 然后提供cube.js 效果
  

   

   

说明

完整代码可以参考GitHub https://github.com/rongfengliang/cubejs-pre-age/tree/v2 包含了cubestore的使用，但是一些不太好的地方是es6 string 模版的
支持，因为api 的特性，但是我们可以通过扩展function 支持，参考

 

 String.prototype.interpolate = function(params) {

      const names = Object.keys(params);

      const vals = Object.values(params);

      return new Function(...names, `return \`${this}\`;`)(...vals);

    }

参考资料

https://cube.dev/docs/schema-execution-environment#cube-js-globals-cube-and-others
https://cube.dev/docs/schema/dynamic-schema-creation
https://github.com/rongfengliang/cubejs-pre-age/tree/v2