Check for exemplars being too long.

brian-brazil · brian-brazil · commit 61480b20bb1a · 2018-10-03T14:14:13.000+01:00
Signed-off-by: Brian Brazil &lt;brian.brazil@robustperception.io&gt;
diff --git a/prometheus_client/openmetrics/parser.py b/prometheus_client/openmetrics/parser.py
@@ -217,6 +217,9 @@ def _parse_sample(text):
     ts = _parse_timestamp(timestamp)
     exemplar = None
     if exemplar_labels is not None:
+        exemplar_length = sum([len(k) + len(v) + 3 for k, v in exemplar_labels.items()]) + 2
+        if exemplar_length > 64:
+            raise ValueError("Exmplar labels are too long: " + text)
         exemplar = core.Exemplar(exemplar_labels,
                 _parse_value(exemplar_value),
                 _parse_timestamp(exemplar_timestamp))
diff --git a/tests/openmetrics/test_parser.py b/tests/openmetrics/test_parser.py
@@ -122,13 +122,13 @@ def test_histogram_exemplars(self):
 # HELP a help
 a_bucket{le="1"} 0 # {a="b"} 0.5
 a_bucket{le="2"} 2 123 # {a="c"} 0.5
-a_bucket{le="+Inf"} 3 # {a="d"} 4 123
+a_bucket{le="+Inf"} 3 # {a="1234567890123456789012345678901234567890123456789012345678"} 4 123
 # EOF
 """)
         hfm = HistogramMetricFamily("a", "help")
         hfm.add_sample("a_bucket", {"le": "1"}, 0.0, None, Exemplar({"a": "b"}, 0.5))
         hfm.add_sample("a_bucket", {"le": "2"}, 2.0, Timestamp(123, 0), Exemplar({"a": "c"}, 0.5)), 
-        hfm.add_sample("a_bucket", {"le": "+Inf"}, 3.0, None, Exemplar({"a": "d"}, 4, Timestamp(123, 0)))
+        hfm.add_sample("a_bucket", {"le": "+Inf"}, 3.0, None, Exemplar({"a": "1234567890123456789012345678901234567890123456789012345678"}, 4, Timestamp(123, 0)))
         self.assertEqual([hfm], list(families))
 
     def test_simple_gaugehistogram(self):
@@ -484,6 +484,7 @@ def test_invalid_input(self):
                 ('# TYPE a histogram\na_bucket{le="+Inf"} 1 # {}1\n# EOF\n'),
                 ('# TYPE a histogram\na_bucket{le="+Inf"} 1 # {} 1 \n# EOF\n'),
                 ('# TYPE a histogram\na_bucket{le="+Inf"} 1 # {} 1 1 \n# EOF\n'),
+                ('# TYPE a histogram\na_bucket{le="+Inf"} 1 # {a="12345678901234567890123456789012345678901234567890123456789"} 1 1\n# EOF\n'),
                 # Exemplars on unallowed samples.
                 ('# TYPE a histogram\na_sum 1 # {a="b"} 0.5\n# EOF\n'),
                 ('# TYPE a gaugehistogram\na_sum 1 # {a="b"} 0.5\n# EOF\n'),
