Http header routing pattern

[gjreasoner]

Proposal

Would like to use a HTTP header in the HTTP request to determine which service to route to using http header based routing pattern.

Use-Case

Imagine hundreds of customers each with 100s of different domains pointed to their own HttpScaledObject.

Rather than maintaining the 100 domains on HTTPScaledObject, you send a custom header X-Customer-Id: customer-id-1 and register the hosts as customer-id-1, customer-id-2.

This means your upstream can add/update/delete host names without needing to update HTTPScaledObjects or extra k8s ingress/services.

Is this a feature you are interested in implementing yourself?

Yes

Anything else?

Can see this being implemented like

• An env variable on the interceptor, KEDA_HTTP_ADDTL_ROUTING_HEADER=X-Customer-Id when blank or missing from the request, it still uses the HTTP Host header

This gives you an easy way to opt into the feature and have fallback/main site domains.

apiVersion: http.keda.sh/v1alpha1
kind: HTTPScaledObject
spec:
  hosts:
  - my-main-site.example.com
  - customer-id-1
  replicas:
    max: 1
    min: 0

While your remaining domains might look like

- custom-domain-1.com
- ...
- custom-domain-99.com
- *.svc.domain.com