Allow EC2 Elastic IP association with a network interface

CHANGES.rst

@@ -26,6 +26,12 @@ Common
 Compute
 ~~~~~~~
 
+- [EC2] Allow Elastic IP association with a specific network interface, so
+  instances with multiple interfaces can select the required target. Existing
+  calls continue to associate by instance ID.
+  (GITHUB-1799)
+  [Ishu Patel - @ishu7w]
+
 - [OpenStack] Select service catalog endpoints by service type without filtering
   by the default service name. The service name is only used as a filter when
   explicitly provided via ``ex_force_service_name``.

libcloud/compute/drivers/ec2.py

@@ -3290,7 +3290,7 @@ def ex_describe_all_addresses(self, only_associated=False):
         # shape how the return data is sent back
         return self._to_addresses(response, only_associated)
 
-    def ex_associate_address_with_node(self, node, elastic_ip, domain=None):
+    def ex_associate_address_with_node(self, node, elastic_ip, domain=None, network_interface=None):
         """
         Associate an Elastic IP address with a particular node.
 
@@ -3303,12 +3303,26 @@ def ex_associate_address_with_node(self, node, elastic_ip, domain=None):
         :param      domain: The domain where the IP resides (vpc only)
         :type       domain: ``str``
 
+        :param      network_interface: Optional interface to associate the IP
+                    with instead of the node. Required for nodes with multiple
+                    network interfaces.
+        :type       network_interface: :class:`EC2NetworkInterface`
+
+        For a VPC address on an instance with multiple interfaces, pass
+        ``domain="vpc"`` and the desired interface from
+        :meth:`ex_list_network_interfaces`. The request uses its interface ID
+        instead of the instance ID, as required by EC2.
+
         :return:    A string representation of the association ID which is
                     required for VPC disassociation. EC2/standard
                     addresses return None
         :rtype:     ``None`` or ``str``
         """
-        params = {"Action": "AssociateAddress", "InstanceId": node.id}
+        params = {"Action": "AssociateAddress"}
+        if network_interface is not None:
+            params["NetworkInterfaceId"] = network_interface.id
+        else:
+            params["InstanceId"] = node.id
 
         if domain is not None and domain != "vpc":
             raise AttributeError("Domain can only be set to vpc")
@@ -3322,13 +3336,15 @@ def ex_associate_address_with_node(self, node, elastic_ip, domain=None):
         association_id = findtext(element=response, xpath="associationId", namespace=NAMESPACE)
         return association_id
 
-    def ex_associate_addresses(self, node, elastic_ip, domain=None):
+    def ex_associate_addresses(self, node, elastic_ip, domain=None, network_interface=None):
         """
         Note: This method has been deprecated in favor of
         the ex_associate_address_with_node method.
         """
 
-        return self.ex_associate_address_with_node(node=node, elastic_ip=elastic_ip, domain=domain)
+        return self.ex_associate_address_with_node(
+            node=node, elastic_ip=elastic_ip, domain=domain, network_interface=network_interface
+        )
 
     def ex_disassociate_address(self, elastic_ip, domain=None):
         """

libcloud/test/compute/test_ec2.py

@@ -46,6 +46,7 @@
     EC2NetworkSubnet,
     NimbusNodeDriver,
     EC2PlacementGroup,
+    EC2NetworkInterface,
     IdempotentParamError,
     ExEC2AvailabilityZone,
     OutscaleSASNodeDriver,
@@ -886,6 +887,21 @@ def test_ex_associate_address_with_node(self):
             domain="bogus",
         )
 
+    def test_ex_associate_address_with_network_interface(self):
+        node = Node("i-4382922a", None, None, None, None, self.driver)
+        interface = EC2NetworkInterface("eni-12345678", "secondary", "attached")
+        EC2MockHttp.type = "all_addresses"
+        elastic_ip = self.driver.ex_describe_all_addresses()[3]
+        EC2MockHttp.type = "interface"
+        association_id = self.driver.ex_associate_address_with_node(
+            node, elastic_ip, domain="vpc", network_interface=interface
+        )
+        self.assertEqual("eipassoc-167a8073", association_id)
+        association_id = self.driver.ex_associate_addresses(
+            node, elastic_ip, domain="vpc", network_interface=interface
+        )
+        self.assertEqual("eipassoc-167a8073", association_id)
+
     def test_ex_disassociate_address(self):
         EC2MockHttp.type = "all_addresses"
         elastic_ips = self.driver.ex_describe_all_addresses()
@@ -1681,6 +1697,18 @@ def _AssociateAddress(self, method, url, body, headers):
         return (httplib.OK, body, {}, httplib.responses[httplib.OK])
 
     def _vpc_AssociateAddress(self, method, url, body, headers):
+        params = parse_qs(url.split("?", 1)[1])
+        self.assertEqual(["i-4382922a"], params["InstanceId"])
+        self.assertNotIn("NetworkInterfaceId", params)
+        body = self.fixtures.load("associate_vpc_address.xml")
+        return (httplib.OK, body, {}, httplib.responses[httplib.OK])
+
+    def _interface_AssociateAddress(self, method, url, body, headers):
+        params = parse_qs(url.split("?", 1)[1])
+        self.assertEqual(["eni-12345678"], params["NetworkInterfaceId"])
+        self.assertNotIn("InstanceId", params)
+        self.assertIn("AllocationId", params)
+        self.assertNotIn("PublicIp", params)
         body = self.fixtures.load("associate_vpc_address.xml")
         return (httplib.OK, body, {}, httplib.responses[httplib.OK])