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:

``yaml
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

`yaml
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):

`js
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.

`js
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);
});
});
``