Support internalTrafficPolicy in synapse.ingress.service configuration

[watermelon0339]

Is your feature request related to a problem? Please describe.
Currently, the synapse.ingress.service configuration only exposes the synapse.ingress.service.type option. It would be very helpful to also support internalTrafficPolicy as part of this configuration, for example: synapse.ingress.service.internalTrafficPolicy.

Adding this option would provide more flexibility in controlling service traffic routing, especially for clusters where internal traffic handling policies are important for performance and reliability.

Describe the solution you'd like

https://github.com/element-hq/ess-helm/blob/main/charts/matrix-stack/templates/synapse/synapse_http_service.yaml

{{- with $.Values.synapse -}}
{{- if .enabled -}}
apiVersion: v1
kind: Service
metadata:
  labels:
    {{- include "element-io.synapse-ingress.labels" (dict "root" $ "context" $.Values.haproxy) | nindent 4 }}
  name: {{ $.Release.Name }}-synapse
  namespace: {{ $.Release.Namespace }}
spec:
  type: {{ .ingress.service.type | default $.Values.ingress.service.type }}
  internalTrafficPolicy: {{ .ingress.service.internalTrafficPolicy | default "Cluster" }} # 👈👈 Here
  ipFamilyPolicy: PreferDualStack
  ports:
  - name: haproxy-synapse
    port: 8008
    targetPort: haproxy-synapse
  - name: haproxy-403
    port: 8009
    targetPort: haproxy-403
  selector:
    app.kubernetes.io/instance: "{{ $.Release.Name }}-haproxy"
{{- end -}}
{{- end -}}

Describe alternatives you've considered

helm upgrade --install  xxxx
kubectl patch service ess-synapse -n ess -p '{"spec":{"internalTrafficPolicy":"Local"}}'

[benbz]

Thanks for the request. We're not opposed to this but it isn't a high priority for us to implement ourselves unless there's requests from paying customers.

We'd happily accept a community PR along the lines of

• Per-Ingress service.internalTrafficPolicy
• Defaults to global-/common-Ingress service.internalTrafficPolicy if omitted
• Per-Ingress setting is omitted by default
• Global-/Common-Ingress setting is `Cluster by default
• Appropriate manifest tests around this

Basically exactly the same as how the per-Ingress vs global-/common-Ingress service.type is done