Traefik middleware is a component, that allows to modify http requests before passing it to the service. There are different usecases for the middleware:

• redirect
• rewrite
• security, like basic auth
• rate limiting

Let me show how to implement basic traefik middleware.

redirect

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: redirect
  namespace: home
spec:
  redirectRegex:
    regex: "^https://piasecki\\.it/$"
    replacement: "https://piasecki.it/?effect=mirror&camera=true"
    permanent: false

This resource will redirect from https://piasecki.it/ to https://piasecki.it/?effect=mirror&camera=true . To use it, you need to modify ingress, by adding home-redirect@kubernetescrd to traefik.ingress.kubernetes.io/router.middlewares annotation.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    cert-manager.io/cluster-issuer: letsencrypt-prod
    spec.ingressClassName: traefik
    traefik.ingress.kubernetes.io/router.middlewares: cert-manager-redirect-https@kubernetescrd,home-redirect@kubernetescrd

In the effect, ?effect=mirror&camera=true will be added to user request, whenever he will visit https://piasecki.it/ . It is possible to do the same thing, but transparently for the user by using rewrite.

Rewrite

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: rewrite
  namespace: home
spec:
  replacePathRegex:
    regex: "^/$"
    replacement: "/?effect=mirror&camera=true"

It should work. But it did not. What the backend received was

10.42.0.36 - - [16/Nov/2024 12:30:03] "GET /%3Feffect=mirror&camera=true HTTP/1.1" 404 -

? was encoded to %3F and it resulted with 404 error.

There are a few solutions, but they require working with backend.

• correct path parsing
• parsing custom headers

I guess I will stick with the redirect then.