Allow args for .bucket

fixes #161

elasticsearch_dsl/aggs.py

@@ -58,8 +58,8 @@ def __getitem__(self, agg_name):
     def __setitem__(self, agg_name, agg):
         self.aggs[agg_name] = A(agg)
 
-    def _agg(self, bucket, name, agg_type, **params):
-        agg = self[name] = A(agg_type, **params)
+    def _agg(self, bucket, name, agg_type, *args,**params):
+        agg = self[name] = A(agg_type, *args, **params)
 
         # For chaining - when creating new buckets return them...
         if bucket:
@@ -68,11 +68,11 @@ def _agg(self, bucket, name, agg_type, **params):
         else:
             return self._base
 
-    def metric(self, name, agg_type, **params):
-        return self._agg(False, name, agg_type, **params)
+    def metric(self, name, agg_type, *args, **params):
+        return self._agg(False, name, agg_type, *args, **params)
 
-    def bucket(self, name, agg_type, **params):
-        return self._agg(True, name, agg_type, **params)
+    def bucket(self, name, agg_type, *args, **params):
+        return self._agg(True, name, agg_type, *args, **params)
 
 
 class Bucket(AggBase, Agg):

test_elasticsearch_dsl/test_aggs.py

@@ -126,6 +126,21 @@ def test_filter_can_be_instantiated_using_positional_args():
 
     assert a == aggs.A('filter', filter.F('term', f=42))
 
+def test_filter_aggregation_as_nested_agg():
+    a = aggs.Terms(field='tags')
+    a.bucket('filtered', 'filter', filter.F('term', f=42))
+
+    assert {
+        'terms': {'field': 'tags'},
+        'aggs': {
+            'filtered': {
+                'filter': {
+                    'term': {'f': 42}
+                },
+            }
+        }
+    } == a.to_dict()
+
 def test_filter_aggregation_with_nested_aggs():
     a = aggs.Filter(filter.F('term', f=42))
     a.bucket('testing', 'terms', field='tags')