Fix attachment issue ( thanks @gunzy83 )

cloud/amazon/ec2_eni.py

@@ -241,7 +241,6 @@ try:
 except ImportError:
     HAS_BOTO = False
 
-
 def get_eni_info(interface):
 
     # Private addresses
@@ -390,7 +389,10 @@ def modify_eni(connection, vpc_id, module, eni):
                 secondary_addresses_to_remove_count = current_secondary_address_count - secondary_private_ip_address_count
                 connection.unassign_private_ip_addresses(network_interface_id=eni.id, private_ip_addresses=current_secondary_addresses[:secondary_addresses_to_remove_count], dry_run=False)
 
-        if attached == True and instance_id is not None:
+        if attached == True:
+            if eni.attachment and eni.attachment.instance_id != instance_id:
+                detach_eni(eni, module)
+            if eni.attachment is None:
                 eni.attach(instance_id, device_index)
                 wait_for_eni(eni, "attached")
                 changed = True
@@ -451,13 +453,20 @@ def find_eni(connection, module):
     eni_id = module.params.get("eni_id")
     subnet_id = module.params.get('subnet_id')
     private_ip_address = module.params.get('private_ip_address')
+    instance_id = module.params.get('instance_id')
+    device_index = module.params.get('device_index')
 
     try:
         filters = {}
-        if private_ip_address:
-            filters['private-ip-address'] = private_ip_address
         if subnet_id:
             filters['subnet-id'] = subnet_id
+        if private_ip_address:
+            filters['private-ip-address'] = private_ip_address
+        else:
+            if instance_id:
+                filters['attachment.instance-id'] = instance_id
+            if device_index:
+                filters['attachment.device-index'] = device_index
 
         eni_result = connection.get_all_network_interfaces(eni_id, filters=filters)
         if len(eni_result) > 0: