Added the ability to filter by tag-key.

moto/ec2/models.py

@@ -1,9 +1,9 @@
 from __future__ import unicode_literals
-import six
 import copy
 import itertools
 from collections import defaultdict
 
+import six
 import boto
 from boto.ec2.instance import Instance as BotoInstance, Reservation
 from boto.ec2.blockdevicemapping import BlockDeviceMapping, BlockDeviceType
@@ -70,7 +70,7 @@ from .utils import (
     random_volume_id,
     random_vpc_id,
     random_vpc_peering_connection_id,
-)
+    is_filter_matching)
 
 
 class InstanceState(object):
@@ -93,6 +93,9 @@ class TaggedEC2Instance(object):
                 if tag['key'] == tagname:
                     return tag['value']
 
+        if filter_name == 'tag-key':
+            return [tag['key'] for tag in tags]
+
 
 class NetworkInterface(object):
     def __init__(self, subnet, private_ip_address, device_index=0, public_ip_auto_assign=True, group_ids=None):
@@ -1194,7 +1197,7 @@ class VPCBackend(object):
 
         if filters:
             for (_filter, _filter_value) in filters.items():
-                vpcs = [ vpc for vpc in vpcs if vpc.get_filter_value(_filter) in _filter_value ]
+                vpcs = [ vpc for vpc in vpcs if is_filter_matching(vpc, _filter, _filter_value) ]
 
         return vpcs
 

moto/ec2/utils.py

@@ -278,6 +278,19 @@ def filter_reservations(reservations, filter_dict):
     return result
 
 
+def is_filter_matching(obj, filter, filter_value):
+    value = obj.get_filter_value(filter)
+
+    if isinstance(value, six.string_types):
+        return value in filter_value
+
+    try:
+        value = set(value)
+        return value.issubset(filter_value) or value.issuperset(filter_value)
+    except TypeError:
+        return value in filter_value
+
+
 # not really random ( http://xkcd.com/221/ )
 def random_key_pair():
     return {