move static functions outside main class

src/charm.py

@@ -102,7 +102,7 @@
 # - Example invalid: "value@", "value#", "value space"
 ANNOTATION_VALUE_PATTERN = re.compile(r"^[\w.\-_]+$")
 
-
+# Based on https://github.com/kubernetes/apimachinery/blob/master/pkg/util/validation/validation.go#L206
 # Regex for DNS1123 subdomains:
 # - Starts with a lowercase letter or number ([a-z0-9])
 # - May contain dashes (-), but not consecutively, and must not start or end with them
@@ -113,6 +113,7 @@
     r"^[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$"
 )
 
+# Based on https://github.com/kubernetes/apimachinery/blob/master/pkg/util/validation/validation.go#L32
 # Regex for Kubernetes qualified names:
 # - Starts with an alphanumeric character ([A-Za-z0-9])
 # - Can include dashes (-), underscores (_), dots (.), or alphanumeric characters in the middle
@@ -388,66 +389,6 @@ def _basic_auth_user(self) -> Optional[str]:
         """
         return cast(Optional[str], self.config.get("basic_auth_user", None))
 
-    def _validate_annotation_key(self, key: str) -> bool:
-        """Validate the annotation key."""
-        if len(key) > 253:
-            logger.error(f"Invalid annotation key: '{key}'. Key length exceeds 253 characters.")
-            return False
-
-        if not is_qualified_name(key.lower()):
-            logger.error(
-                f"Invalid annotation key: '{key}'. Must follow Kubernetes annotation syntax."
-            )
-            return False
-
-        if key.startswith(("kubernetes.io/", "k8s.io/")):
-            logger.error(f"Invalid annotation: Key '{key}' uses a reserved prefix.")
-            return False
-
-        return True
-
-    def _validate_annotation_value(self, value: str) -> bool:
-        """Validate the annotation value."""
-        if not ANNOTATION_VALUE_PATTERN.match(value):
-            logger.error(
-                f"Invalid annotation value: '{value}'. Must follow Kubernetes annotation syntax."
-            )
-            return False
-
-        return True
-
-    def _parse_annotations(self, annotations: Optional[str]) -> Optional[Dict[str, str]]:
-        """Parse and validate annotations from a string.
-
-        logic is based on Kubernetes annotation validation as described here:
-        https://github.com/kubernetes/apimachinery/blob/v0.31.3/pkg/api/validation/objectmeta.go#L44
-        """
-        if not annotations:
-            return {}
-
-        annotations = annotations.strip().rstrip(",")  # Trim spaces and trailing commas
-
-        try:
-            parsed_annotations = {
-                key.strip(): value.strip()
-                for key, value in (pair.split("=", 1) for pair in annotations.split(",") if pair)
-            }
-        except ValueError:
-            logger.error(
-                "Invalid format for 'loadbalancer_annotations'. "
-                "Expected format: key1=value1,key2=value2."
-            )
-            return None
-
-        # Validate each key-value pair
-        for key, value in parsed_annotations.items():
-            if not self._validate_annotation_key(key) or not self._validate_annotation_value(
-                value
-            ):
-                return None
-
-        return parsed_annotations
-
     @property
     def _loadbalancer_annotations(self) -> Optional[dict]:
         """Parse the loadbalancer annotations from the config.
@@ -459,7 +400,7 @@ def _loadbalancer_annotations(self) -> Optional[dict]:
             A dictionary of valid annotations if the config is valid, otherwise None.
         """
         annotations = cast(Optional[str], self.config.get("loadbalancer_annotations", None))
-        return self._parse_annotations(annotations)
+        return parse_annotations(annotations)
 
     def _on_forward_auth_config_changed(self, event: AuthConfigChangedEvent):
         if self._is_forward_auth_enabled:
@@ -1318,6 +1259,65 @@ def _validate_config(self):
                 logger.warning(invalid_hostname_and_routing_mode_message)
 
 
+def validate_annotation_key(key: str) -> bool:
+    """Validate the annotation key."""
+    if len(key) > 253:
+        logger.error(f"Invalid annotation key: '{key}'. Key length exceeds 253 characters.")
+        return False
+
+    if not is_qualified_name(key.lower()):
+        logger.error(f"Invalid annotation key: '{key}'. Must follow Kubernetes annotation syntax.")
+        return False
+
+    if key.startswith(("kubernetes.io/", "k8s.io/")):
+        logger.error(f"Invalid annotation: Key '{key}' uses a reserved prefix.")
+        return False
+
+    return True
+
+
+def validate_annotation_value(value: str) -> bool:
+    """Validate the annotation value."""
+    if not ANNOTATION_VALUE_PATTERN.match(value):
+        logger.error(
+            f"Invalid annotation value: '{value}'. Must follow Kubernetes annotation syntax."
+        )
+        return False
+
+    return True
+
+
+def parse_annotations(annotations: Optional[str]) -> Optional[Dict[str, str]]:
+    """Parse and validate annotations from a string.
+
+    logic is based on Kubernetes annotation validation as described here:
+    https://github.com/kubernetes/apimachinery/blob/v0.31.3/pkg/api/validation/objectmeta.go#L44
+    """
+    if not annotations:
+        return {}
+
+    annotations = annotations.strip().rstrip(",")  # Trim spaces and trailing commas
+
+    try:
+        parsed_annotations = {
+            key.strip(): value.strip()
+            for key, value in (pair.split("=", 1) for pair in annotations.split(",") if pair)
+        }
+    except ValueError:
+        logger.error(
+            "Invalid format for 'loadbalancer_annotations'. "
+            "Expected format: key1=value1,key2=value2."
+        )
+        return None
+
+    # Validate each key-value pair
+    for key, value in parsed_annotations.items():
+        if not validate_annotation_key(key) or not validate_annotation_value(value):
+            return None
+
+    return parsed_annotations
+
+
 def is_qualified_name(value: str) -> bool:
     """Check if a value is a valid Kubernetes qualified name."""
     parts = value.split("/")