Data Warehouse Services Client

This Node.js package registers the SAP default task types at the Data Warehouse Scheduler that need access to the local HDI and DWF containers of the consuming project. In addition it runs an HTTP server to provide task type related endpoints for value helps and task execution.

Usage

Add this package as dependency in a standard Node.js module in your XSA application.

In your development descriptor mta.yaml ensure that HDI (type com.sap.xs.hdi-container and DWF (type com.sap.xs.dwf-edw-client) services are bound in the resources section. For example:

resources:
- name: myapp-dws
  type: com.sap.xs.dwf-edw-client
  properties:
      dwf-edw-client-name: ${service-name}
- name: myapp-hdi
  type: com.sap.xs.hdi-container
  properties:
      hdi-container-name: ${service-name}

The service instances have to be required by the module consuming this package

modules:
- name: myapp-Backend
  type: nodejs
  path: Backend
  requires:
    - name: myapp-hdi
    - name: myapp-dws

In the start script of your Node.js module load this package and instantiate the client for the Task Orchestration Engine of the Data Warehouse Scheduler (TOE):

const xsenv = require('@sap/xsenv');
const dwsClient = require('@sap/dwf-dws-client');

const loopBackUrl = JSON.parse(process.env.VCAP_APPLICATION).full_application_uris[0];
const rejectUnauth = true;
const TaskChain = dwsClient.taskChain.createTaskChainClient(
  xsenv.getServices({
    dwf: {
      tag: 'dwf'
    }
  }).dwf,
  loopBackUrl,
  rejectUnauth
);

To allow the scheduler to call the registered endpoints, start an HTTP server and expose the routes. Below, you see an example using express.js. Be aware that this example omits proper authentication and authorization checks which must be implemented for productive use.

const PORT = process.env.PORT || 3000;
const express = require('express');
const app = express();

TaskChain.addRouter(app, '/backend');
app.listen(PORT, err => {
  if (err) {
    console.error(err);
    process.exit(2);
  }

  TaskChain.registerTaskGroups(err1 => {
    if (err1) {
      console.error(err1);
      process.exit(1);
    }
    console.log('Backend module listening on: ' + PORT);
  });
});