Add host-id to AddressTranslator

Author: sylwiaszunejko

cassandra/connection.py

@@ -244,11 +244,19 @@ def create(self, row):
         if port is None:
             port = self.port if self.port else 9042
 
+        # Extract host metadata for V2 address translation
+        host_id = row.get("host_id")
+
+        # Use V2 API if available, fall back to V1
+        translator = self.cluster.address_translator
+        if hasattr(translator, 'translate_with_host_id'):
+            translated_addr = translator.translate_with_host_id(addr, host_id)
+        else:
+            translated_addr = translator.translate(addr)
+
         # create the endpoint with the translated address
         # TODO next major, create a TranslatedEndPoint type
-        return DefaultEndPoint(
-            self.cluster.address_translator.translate(addr),
-            port)
+        return DefaultEndPoint(translated_addr, port)
 
 
 @total_ordering

cassandra/policies.py

@@ -1210,9 +1210,27 @@ class AddressTranslator(object):
     def translate(self, addr):
         """
         Accepts the node ip address, and returns a translated address to be used connecting to this node.
+
+        Legacy V1 API for backward compatibility. New implementations should override translate_with_host.
         """
         raise NotImplementedError()
 
+    def translate_with_host_id(self, addr, host_id):
+        """
+        V2 API: Accepts the node ip address and optional Host ID, returns translated address.
+
+        :param addr: The node IP address to translate
+        :param host_id: Host ID
+        :return: Translated address to be used for connecting
+
+        This method provides access to Host metadata (especially host_id) which is required
+        for PrivateLink and similar scenarios where translation is keyed by Host ID rather
+        than IP address.
+
+        Default implementation delegates to translate() for backward compatibility.
+        """
+        return self.translate(addr)
+
 
 class IdentityTranslator(AddressTranslator):
     """
@@ -1221,6 +1239,9 @@ class IdentityTranslator(AddressTranslator):
     def translate(self, addr):
         return addr
 
+    def translate_with_host_id(self, addr, host_id):
+        return addr
+
 
 class EC2MultiRegionTranslator(AddressTranslator):
     """

tests/unit/test_policies.py

@@ -1442,7 +1442,7 @@ def test_identity_translator(self):
     def test_ec2_multi_region_translator(self, *_):
         ec2t = EC2MultiRegionTranslator()
         addr = '127.0.0.1'
-        translated = ec2t.translate(addr)
+        translated = ec2t.translate_with_host_id(addr, "")
         assert translated is not addr  # verifies that the resolver path is followed
         assert translated == addr  # and that it resolves to the same address