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kubernetestraefiktraefik-ingress

Can we set priority for the middlewares in traefik v2?

Using the v1.7.9 in kubernetes I'm facing this issue:

if I set a rate limit (traefik.ingress.kubernetes.io/rate-limit) and custom response headers (traefik.ingress.kubernetes.io/custom-response-headers) then when a request gets rate limited, the custom headers won't be set. I guess it's because of some ordering/priority among these plugins. And I totally agree that reaching the rate-limit should return the response as soon as is possible, but it would be nice, if we could modify the priorities if we need.

The question therefore is: will we be able to set priorities for the middlewares?

I couldn't find any clue of it in the docs nor among the github issues.

Concrete use-case:

I want CORS-policy headers to always be set, even if the rate-limiting kicked in. I want this because my SPA won't get the response object otherwise, because the browser won't allow it:

Access to XMLHttpRequest at 'https://api.example.com/api/v1/resource' from origin 'https://cors.exmaple.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

In this case it would be a fine solution if i could just set the priority of the headers middleware higher than the rate limit middleware.

Solution

  • For future reference, a working example that demonstrates such an ordering is here:

    apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: ratelimit
spec:
  rateLimit:
      average: 100
      burst: 50
---
apiVersion: traefik.containo.us/v1alpha1
kind: Middleware
metadata:
  name: response-header
spec:
  headers:
    customResponseHeaders:
      X-Custom-Response-Header: "value"
---
apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
  name: ingressroute
spec:
# more fields...
  routes:
    # more fields...
    middlewares: # the middlewares will be called in this order
    - name: response-header
    - name: ratelimit

    I asked the same question on the Containous' community forum: https://community.containo.us/t/can-we-set-priority-for-the-middlewares-in-v2/1326