Traslate nginx ingress rule with snippet to Istio - istio

Question

I have a nginx ingress controller and expose services with him, we planned change to istio to ingress traffic.
I have a ingress rule that contains snippet:
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$1
nginx.ingress.kubernetes.io/server-snippet: |
location ~* "^/" {
proxy_pass "https://127.0.0.1";
proxy_set_header Host $http_x_forwarded_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_connect_timeout 10s;
proxy_send_timeout 120s;
proxy_read_timeout 120s;
client_max_body_size 300m;
}
name: foo
spec:
ingressClassName: bar
rules:
- host: foo.bar
tls:
- hosts:
- foo.bar
This ingress copy http_x_forwarded_host to Host and send to nginx ingress.
There are any idea to convert this rule to istio?
Thanks.
Marco

Answer 1

Welcome to SO!,
It should be doable theoretically with below Istio building components:
Use regex based rewrites
nginx.ingress.kubernetes.io/rewrite-target => EnvoyFilter to HTTP_ROUTE object
(example to be found on github here)
Forward 'X-Forwarded-For/X-Real-IP' headers to upstream host
If your application needs to know the real client IP address use the Gateway Network Topology (Alpha) feature.
Remark:
Attached by you the source manifest file seems to be suffering from a known issue of latest nginx ingress controller, which reveals in following error on my env:
Error from server (BadRequest): error when creating "STDIN": admission webhook "validate.nginx.ingress.kubernetes.io" denied the request:
-------------------------------------------------------------------------------
Error: exit status 1
2021/06/21 11:05:45 [emerg] 851#851: invalid number of arguments in "proxy_set_header" directive in /tmp/nginx-cfg063051389:453
nginx: [emerg] invalid number of arguments in "proxy_set_header" directive in /tmp/nginx-cfg063051389:453
nginx: configuration file /tmp/nginx-cfg063051389 test failed