refactor to process dns overrides func

Author: juanbe

src/aks-preview/azext_aks_preview/agentpool_decorator.py

@@ -1448,6 +1448,13 @@ def set_up_managed_system_mode(self, agentpool: AgentPool) -> AgentPool:
 
         return agentpool
 
+    def _process_dns_overrides(self, overrides_dict, target_dict, build_override_func):
+        """Helper method to safely process DNS overrides with null checks."""
+        if overrides_dict is not None:
+            for key, value in overrides_dict.items():
+                if value is not None:
+                    target_dict[key] = build_override_func(value)
+
     def set_up_localdns_profile(self, agentpool: AgentPool) -> AgentPool:
         """Set up local DNS profile for the AgentPool object if provided via --localdns-config."""
         self._ensure_agentpool(agentpool)
@@ -1477,17 +1484,16 @@ def build_override(override_dict):
                 return self.models.LocalDNSOverride(**filtered)
 
             # Build kubeDNSOverrides and vnetDNSOverrides from the localdns_profile
-            kube_overrides = localdns_profile.get("kubeDNSOverrides")
-            if kube_overrides is not None:
-                for key, value in kube_overrides.items():
-                    if value is not None:
-                        kube_dns_overrides[key] = build_override(value)
-
-            vnet_overrides = localdns_profile.get("vnetDNSOverrides")
-            if vnet_overrides is not None:
-                for key, value in vnet_overrides.items():
-                    if value is not None:
-                        vnet_dns_overrides[key] = build_override(value)
+            self._process_dns_overrides(
+                localdns_profile.get("kubeDNSOverrides"),
+                kube_dns_overrides,
+                build_override
+            )
+            self._process_dns_overrides(
+                localdns_profile.get("vnetDNSOverrides"),
+                vnet_dns_overrides,
+                build_override
+            )
 
             agentpool.local_dns_profile = self.models.LocalDNSProfile(
                 mode=localdns_profile.get("mode"),
@@ -1820,17 +1826,16 @@ def build_override(override_dict):
                 return self.models.LocalDNSOverride(**filtered)
 
             # Build kubeDNSOverrides and vnetDNSOverrides from the localdns_profile
-            kube_overrides = localdns_profile.get("kubeDNSOverrides")
-            if kube_overrides is not None:
-                for key, value in kube_overrides.items():
-                    if value is not None:
-                        kube_dns_overrides[key] = build_override(value)
-
-            vnet_overrides = localdns_profile.get("vnetDNSOverrides")
-            if vnet_overrides is not None:
-                for key, value in vnet_overrides.items():
-                    if value is not None:
-                        vnet_dns_overrides[key] = build_override(value)
+            self._process_dns_overrides(
+                localdns_profile.get("kubeDNSOverrides"),
+                kube_dns_overrides,
+                build_override
+            )
+            self._process_dns_overrides(
+                localdns_profile.get("vnetDNSOverrides"),
+                vnet_dns_overrides,
+                build_override
+            )
 
             agentpool.local_dns_profile = self.models.LocalDNSProfile(
                 mode=localdns_profile.get("mode"),