ingress rewrite domain www to non-www url - kubernetes

Question

I am trying to redirect my domain 'www.test.example.com' to test.example.com
in ingress i have added annotation
nginx.ingress.kubernetes.io/configuration-snippet: |
if ($host = 'www.test.wotnot.io' ) {
rewrite ^/(.*)$ https://app.test.wotnot.io/$1 permanent;
}
it's not working as expected.
For testing i have try this
nginx.ingress.kubernetes.io/configuration-snippet: |
if ($host = 'test.example.com' ) {
rewrite ^/(.*)$ https://google.com/$1 permanent;
}
which is working fine.
My site is working on test.example.com and ssl certificate.
Whole ingress
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
certmanager.k8s.io/cluster-issuer: wordpress-staging
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/from-to-www-redirect: "true"
#nginx.ingress.kubernetes.io/configuration-snippet: |
#if ($host = 'www.test.wotnot.io' ) {
# rewrite ^/(.*)$ https://test.example.io/$1 permanent;
#}
name: wordpress-staging-ingress
spec:
rules:
- host: test.example.io
http:
paths:
- backend:
serviceName: wordpress-site
servicePort: 80
path: /
tls:
- hosts:
- test.example.io
secretName: wordpress-staging

Answer 1

Ingress has an annotation nginx.ingress.kubernetes.io/from-to-www-redirect: "true" which already handle this:
In some scenarios is required to redirect from www.domain.com to
domain.com or vice versa. To enable this feature use the annotation
nginx.ingress.kubernetes.io/from-to-www-redirect: "true"
Attention: For HTTPS to HTTPS redirects is mandatory the SSL Certificate defined in the Secret, located in the TLS section of Ingress, contains both FQDN in the common name of the certificate.
It's better that you use it instead of fighting/tweaking the configuration-snippet annotation.