Regex paths in kubernetes Ingress not getting created as regex location in Nginx Ingress Controller - kubernetes-ingress

Question

I am using Nginx Ingress Controller helm chart 0.6.0 and nginx ingress controller tag 1.8.0, kubernetes 1.15.
When I define a path in my Ingress which uses a regex, it does not work since it does not get specified as a regex in the Nginx controller's configuration file location section.
I need to use a version of nginx ingress controller which additionally supports VirtualServer and VirtualServerRoutes.
kind: Ingress
metadata:
name: test-ingress
namespace: ingress-test
annotations:
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/use-regex: "true"
spec:
rules:
- host: test.any-xyz.com
http:
paths:
- path: /quack5/(.*)
backend:
serviceName: test
servicePort: 80
When I apply this, the nginx ingress controller has set up the location as a non-regex expression
$ kubectl -n nginx-ingress-controller exec nginx-ingress-controller-nginx-ingress-79984b9747-8pl4w -- grep -R quack /etc/nginx/conf.d
$ /etc/nginx/conf.d/ingress-test-test-ingress.conf: location /quack5/(.*) {
I expect to see location ~* /quack5/(.*) {

Answer 1

Try to add nginx.ingress.kubernetes.io/rewrite-target annotation to your Nginx Ingress Controller definition file.
Delete nginx.ingress.kubernetes.io/use-regex: "true" annotation.
EDIT:
I think the problem might be in the buildLocation function (&& location.Rewrite.Target != path). If the path and the nginx.ingress.kubernetes.io/rewrite-target are equal the nginx Location is not prefixed with ~* and handled as regex.
if len(location.Rewrite.Target) > 0 && location.Rewrite.Target != path {
if path == slash {
return fmt.Sprintf("~* %s", path)
}
// baseuri regex will parse basename from the given location
baseuri := `(?<baseuri>.*)`
if !strings.HasSuffix(path, slash) {
// Not treat the slash after "location path" as a part of baseuri
baseuri = fmt.Sprintf(`\/?%s`, baseuri)
}
return fmt.Sprintf(`~* ^%s%s`, path, baseuri)
}
return path
I would suggest a directive to specify that the spec.rules.http.paths.path should end up as a regex Location, regardless of what nginx.ingress.kubernetes.io/rewrite-target might be (even if it not specified). currently the only way to get the Location to be threatened as regex (added ~*) is to define a nginx.ingress.kubernetes.io/rewrite-target that is different from spec.rules.http.paths.path.
Please take a look: ingress-regex, ingress-path-matching, path-not-threated-as-regex.