Problem Sub Path Ingress Controller for Backend Service - kubernetes

Question

I have problem setting path ingress controller for backend service. For example i want setup :
frontend app with angular (Path :/)
backend service with NodeJs (Path :/webservice).
NodeJS : Index.js
const express = require('express')
const app = express()
const port = 4000
app.get('/', (req, res) => res.send('Welcome to myApp!'))
app.use('/data/office', require('./roffice'));
app.listen(port, () => console.log(`Example app listening on port ${port}!`))
Another Route:roffice.js
var express = require('express')
var router = express.Router()
router.get('/getOffice', async function (req, res) {
res.send('Get Data Office')
});
module.exports = router
Deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: ws-stack
spec:
selector:
matchLabels:
run: ws-stack
replicas: 2
template:
metadata:
labels:
run: ws-stack
spec:
containers:
- name: ws-stack
image: wsstack/node/img
imagePullPolicy: IfNotPresent
ports:
- containerPort: 4000
Service.yaml
apiVersion: v1
kind: Service
metadata:
name: service-wsstack
labels:
run: service-wsstack
spec:
type: NodePort
ports:
- port: 80
protocol: TCP
nodePort: 30009
targetPort: 4000
selector:
run: ws-stack
ingress.yaml
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
name: stack-ingress
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /
nginx.ingress.kubernetes.io/use-regex: "true"
spec:
rules:
- host: hello-world.info
- http:
paths:
- path: /
backend:
serviceName: service-ngstack --> frondend
servicePort: 80
- path: /webservice
backend:
serviceName: service-wsstack --> backend
servicePort: 80
i setup deployment, service and ingress successfully. but when i called with curl
curl http://<minikubeip>/webservice --> Welcome to myApp! => Correct
curl http://<minikubeip>/webservice/data/office/getOffice --> Welcome to myApp! => Not correct
if i called another route, the result is the same 'Welcome to myApp'. But if i used Nodeport
curl http://<minikubeip>:30009/data/office/getOffice => 'Get Data Office', working properly.
What is the problem? any solution? Thank you

Answer 1

TL;DR
nginx.ingress.kubernetes.io/rewrite-target: /$2
path: /webservice($|/)(.*)
Explanation
The problem is from that line in your ingress:
nginx.ingress.kubernetes.io/rewrite-target: /
You're telling nginx to rewrite your url to / whatever it matched.
/webservice => /
/webservice/data/office/getOffice => /
To do what you're trying to do use regex, here is a simple example:
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
name: stack-ingress
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
nginx.ingress.kubernetes.io/use-regex: "true"
spec:
rules:
- host: hello-world.info
- http:
paths:
- path: /
backend:
serviceName: service-ngstack --> frondend
servicePort: 80
- path: /webservice($|/)(.*)
backend:
serviceName: service-wsstack --> backend
servicePort: 80
This way you're asking nginx to rewrite your url with the second matching group.
Finally it gives you:
/webservice => /
/webservice/data/office/getOffice => /data/office/getOffice