call-ec-function.yml

apiVersion: kubeless.io/v1beta1
kind: Function
metadata:
  finalizers:
  - kubeless.io/function
  labels:
    created-by: kubeless
    function: calculate-promotion
    example: call-ec
  name: calculate-promotion
spec:
  deployment:
    spec:
      template:
        spec:
          containers:
          - env:
            - name: EC_SVC_URL
              value: target_url
  deps: |
    {
      "name": "calculate-promotion",
      "version": "0.0.1",
      "dependencies": {
        "request": "^2.85.0"
      }
    }
  function: |-
    const request = require('request');

    const USER_ID_PARAM = "user-id";
    const ORDER_THRESHOLD_PARAM = "threshold";
    const ACCESS_TOKEN_HEADER = "access-token";

    module.exports = {
    	'calculate-promotion': (event, context) => {
    		return new Promise((resolve, reject) => {
    			console.log("Starting calculate-promotion lambda function")

    			const request = event.extensions.request;
    			const threshold = request.query[ORDER_THRESHOLD_PARAM];

    			if (validateRequest(request)) {
    				const accessToken = request.headers[ACCESS_TOKEN_HEADER];
    				const userId = request.query[USER_ID_PARAM];
    				const url = `${process.env.EC_SVC_URL}/rest/v2/electronics/users/${userId}/orders`;
    				const options = {
    					url: url,
    					headers: {
    						[ACCESS_TOKEN_HEADER]: `Bearer ${accessToken}`
    					},
    					json: true
    				};

    				calculatePromotion(options, threshold, resolve, reject);
    			} else {
    				reject({
    					stack: "user-id and threshold params need to be specified"
    				})
    			}
    		})
    	}
    };

    function validateRequest(request) {
    	return request.query[USER_ID_PARAM] != undefined && request.query[ORDER_THRESHOLD_PARAM] != undefined;
    }

    function calculatePromotion(options, threshold, resolve, reject) {
    	request.get(options, (error, response, body) => {
    		if (!error) {
    			if (response.statusCode == 200) {
    				console.log('Getting orders from EC succeeded.');
    				const s = calculateTotalPrice(body.orders);

    				resolve({promotion: s > threshold});
    			}
    			else {
    				reject({
    					stack: `Getting orders returned unexpected status: ${response.statusCode}.`
    				})
    			}
    		} else {
    			reject({
    				stack: "Failed to get orders."
    			})
    		}
    	})
    }

    function calculateTotalPrice(orders) {
    	return orders.reduce((sum, order) => sum + order.total.value, 0)
    }

  function-content-type: text
  handler: call-ec.calculate-promotion
  horizontalPodAutoscaler:
    spec:
      maxReplicas: 0
  runtime: nodejs8
  service:
    ports:
    - name: http-function-port
      port: 8080
      protocol: TCP
      targetPort: 8080
    selector:
      created-by: kubeless
      function: calculate-promotion
    type: ClusterIP
  timeout: "180"