I am running a FastAPI backend service on GKE. There's a legacy endpoint that uses a GET request with body attached to it. I know that GET requests are not supposed to have a body, but this is a legacy endpoint used by a library therefore I have no choice but to support it.

Currently when a GET request with body is send to GKE, I get the following response:

I have tested the endpoint locally and it works without issues. I don't know exactly what the issue is but GCP is definitely intercepting the request at some point and rejecting it due to it having a body.

The only workaround I can think of currently is using a some sort of proxy and converting the request before it reaches GKE. Unfortunately, I'm not a GCP expert.

Has anyone had any experience tackling an issue like this? What would be an optimal solution here, granted that the endpoint has to be supported currently?

EDIT: Added ingress config:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: XXX
  namespace: XXX
  annotations:
    ingress.kubernetes.io/ssl-redirect: "false"
    kubernetes.io/ingress.global-static-ip-name: XXX
    #ingress.kubernetes.io/enable-cors: "true"
    
spec:
  tls:
  - hosts:
    - 'XXX'
    secretName: tls-secret
  rules:
  - host: XXX
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: XXX
            port:
              number: 80
      - path: /api
        pathType: Prefix
        backend:
          service:
            name: XXX
            port:
              number: 80