strip_path and preserve_host attributes in KongIngress object. What do they do?

Question

I have a KongIngress object configuration attributes regarding to Ingress resource which call to kong as an Ingress controller. I actually have this configuration:

apiVersion: configuration.konghq.com/v1
kind: KongIngress
metadata:
  name: echo-site-ingress
  namespace: hello-world
  annotations:
    kubernetes.io/ingress.class: "kong"
proxy:
  protocols:
    - http
    - https
#  path: /
route:
  methods:
    - POST
    - GET
  strip_path: true
  preserve_host: true
---
#My Ingress resource
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
    cert-manager.io/cluster-issuer: letsencrypt-prod
    kubernetes.io/ingress.class: kong
    plugins.konghq.com: helloworld-customer-acceptance-basic-auth, hello-world-customer-acceptance-acl
  name: echo-site-ingress
  namespace: hello-world
spec:
  rules:
  - host: hello-world.bgarcial.me
    http:
      paths:
      - backend:
          serviceName: echo
          servicePort: 80
        path: /
  tls: 
  - hosts:
    - hello-world.bgarcial.me
    secretName: letsencrypt-prod

The questions are:

What are doing in my kind:KongIngress object resource the strip_path and preserve_host attributes?

I read the documentation here, but it is not clear for me:

Regarding to strip_path I see this one:

When matching a Route via one of the paths, strip the matching prefix from the upstream request URL. Defaults to true. but as we can see, I am not using the path attribute inside my KongIngress object (I commented for illustration purposes about my question)

So, how strip_path attribute value is applied here?

It is because I am using in my Ingress resource the path: / attribute and my Ingress and my KongIngress resources are working together?

I really don't have a clue about it, but I would like to know how is this about behind scenes.

score 9 · Accepted Answer · answered Apr 21 '20 at 14:19

When preserv_host annotation is enabled the host header of the request will be sent as is to the Service in Kubernetes. Well explained in the documentation.

strip_path can be configured to strip the matching part of your path from the HTTP request before it is proxied.

If it is set to "true", the part of the path specified in the Ingress rule will be stripped out before the request is sent to the service. For example, when it is set to "true", the Ingress rule has a path of /foo and the HTTP request that matches the Ingress rule has the path /foo/bar/something, then the request sent to the Kubernetes service will have the path /bar/something. So when you use curl $YOUR_HOST/foo/bar/something, under real path value in the output you will see /bar/something

And if set to false no path manipulation is performed and in your case can be changed to such as there is no manipulation to be done.

For kubernetes ingress controller you need to add `konghq.com/strip-path: true` to `annotations` — Persi, Sep 03 '20 at 10:23

strip_path and preserve_host attributes in KongIngress object. What do they do?

1 Answers1