Merge pull request #2322 from TimWhalen/master

convert prefetched values generator to reusable iterator

webapp/graphite/render/datalib.py

@@ -16,6 +16,7 @@
 import collections
 import re
 import time
+import types
 from six import text_type
 
 from django.conf import settings
@@ -271,6 +272,13 @@ def prefetchData(requestContext, pathExpressions):
       ),
     ))
 
+  # Several third-party readers including rrdtool and biggraphite return values in a
+  # generator which can only be iterated on once. These must be converted to a list.
+  for pathExpression, items in prefetched.items():
+    for i, (name, (time_info, values)) in enumerate(items):
+      if isinstance(values, types.GeneratorType):
+        prefetched[pathExpression][i] = (name, (time_info, list(values)))
+
   if not requestContext.get('prefetched'):
     requestContext['prefetched'] = {}