Can we set priority for the middlewares in v2?

Traefik Traefik v2
1

Hi, I've asked the same question on stackoverflow some time ago, but I got no relevant answers: https://stackoverflow.com/questions/56644462/can-we-set-priority-for-the-middlewares-in-traefik-v2

The question is the following:

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.

2

Hello,

In the v2, the middlewares can ordered in the order you want, you can put the same type of middleware several times with different configurations on the same route.

https://docs.traefik.io/v2.0/middlewares/overview/

3

Hi, thanks for your reply.

I've read that doc earlier, but didn't give v2 a try yet.
I didn't find any example for ordering middlewares, that's why I asked.

So I'm just guessing that something like this will work?

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

So the ordering can be defined in the IngressRoute resource, right?

# ...
    middlewares: # the middlewares will be called in this order
    - name: response-header
    - name: ratelimit
4

Yes the definition order is the calling order.

1 Like
5

awesome, thank you! :slight_smile:

6

Does this apply to definition order in a labels-only v2 setup?

7

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