Check exemplars are only where they're meant to be.

brian-brazil · brian-brazil · commit 95c7285415ed · 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
@@ -250,7 +250,6 @@ def build_metric(name, documentation, typ, unit, samples):
             raise ValueError("Units not allowed for this metric type: " + name)
         metric = core.Metric(name, documentation, typ, unit)
         # TODO: check labelvalues are valid utf8
-        # TODO: check only histogram buckets have exemplars.
         # TODO: check samples are appropriately grouped and ordered
         # TODO: check info/stateset values are 1/0
         # TODO: check for metadata in middle of samples
@@ -320,18 +319,22 @@ def build_metric(name, documentation, typ, unit, samples):
                 raise ValueError("Invalid line: " + line)
         else:
             sample = _parse_sample(line)
-            if sample[0] not in allowed_names:
+            if sample.name not in allowed_names:
                 if name != '':
                     yield build_metric(name, documentation, typ, unit, samples)
                 # Start an untyped metric.
-                name = sample[0]
+                name = sample.name
                 documentation = ''
                 unit = ''
                 typ = 'untyped'
                 samples = [sample]
-                allowed_names = [sample[0]]
+                allowed_names = [sample.name]
             else:
                 samples.append(sample)
+            if sample.exemplar and not (
+                    typ in ['histogram', 'gaugehistogram']
+                    and sample.name.endswith('_bucket')):
+                raise ValueError("Invalid line only histogram/gaugehistogram buckets can have exemplars: " + line)
 
     if name != '':
         yield build_metric(name, documentation, typ, unit, samples)
diff --git a/tests/openmetrics/test_parser.py b/tests/openmetrics/test_parser.py
@@ -134,7 +134,7 @@ def test_simple_gaugehistogram(self):
 """)
         self.assertEqual([GaugeHistogramMetricFamily("a", "help", gsum_value=2, buckets=[("1", 0.0), ("+Inf", 3.0)])], list(families))
 
-    def test_histogram_exemplars(self):
+    def test_gaugehistogram_exemplars(self):
         families = text_string_to_metric_families("""# TYPE a gaugehistogram
 # HELP a help
 a_bucket{le="1"} 0 # {a="b"} 0.5
@@ -451,6 +451,10 @@ 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'),
+                # 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'),
+                ('# TYPE a_bucket gauge\na_bucket 1 # {a="b"} 0.5\n# EOF\n'),
                 ]:
             with self.assertRaises(ValueError):
                 list(text_string_to_metric_families(case))
