add tagged series decode method

webapp/graphite/tags/utils.py

@@ -100,6 +100,17 @@ def encode(metric, sep='.'):
     # metric isn't tagged, just replace dots with the separator and trim any leading separator
     return metric.replace('.', sep).lstrip(sep)
 
+  @staticmethod
+  def decode(path, sep='.'):
+    """
+    Helper function to decode tagged series from storage in whisper etc
+    """
+    if path.startswith('_tagged'):
+      return path.split(sep, 3)[-1].replace('_DOT_', '.')
+
+    # metric isn't tagged, just replace the separator with dots
+    return path.replace(sep, '.')
+
   def __init__(self, metric, tags, series_id=None):
     self.metric = metric
     self.tags = tags

webapp/tests/test_tags.py

@@ -30,6 +30,9 @@ def test_taggedseries(self):
     # test encoding
     self.assertEqual(TaggedSeries.encode(parsed.path), '_tagged.2b0.2af.test_DOT_a;blah=blah;hello=tiger')
 
+    # test decoding
+    self.assertEqual(TaggedSeries.decode('_tagged.2b0.2af.test_DOT_a;blah=blah;hello=tiger'), parsed.path)
+
     # test path without tags
     parsed = TaggedSeries.parse('test.a')
     self.assertIsInstance(parsed, TaggedSeries)
@@ -40,7 +43,10 @@ def test_taggedseries(self):
     self.assertEqual(parsed.path, 'test.a')
 
     # test encoding
-    self.assertEqual(TaggedSeries.encode(parsed.path), 'test.a')
+    self.assertEqual(TaggedSeries.encode('test.a', sep='/'), 'test/a')
+
+    # test encoding
+    self.assertEqual(TaggedSeries.decode('test/a', sep='/'), 'test.a')
 
     # test parsing openmetrics
     parsed = TaggedSeries.parse(r'test.a{hello="tiger",blah="bla\"h"}')