Support _total suffix for counter sample names, according to the spec

alopezz · alopezz · commit fa7412071cc0 · 2023-03-24T18:13:58.000+01:00
Signed-off-by: Alex López &lt;alex.lopez.zorzano@gmail.com&gt;
diff --git a/prometheus_client/parser.py b/prometheus_client/parser.py
@@ -158,7 +158,8 @@ def build_metric(name: str, documentation: str, typ: str, samples: List[Sample])
             else:
                 new_samples = []
                 for s in samples:
-                    new_samples.append(Sample(s[0] + '_total', *s[1:]))
+                    sample_name = s.name if s.name.endswith('_total') else s.name + '_total'
+                    new_samples.append(Sample(sample_name, *s[1:]))
                     samples = new_samples
         metric = Metric(name, documentation, typ)
         metric.samples = samples
@@ -194,7 +195,7 @@ def build_metric(name: str, documentation: str, typ: str, samples: List[Sample])
                     samples = []
                 typ = parts[3]
                 allowed_names = {
-                    'counter': [''],
+                    'counter': ['_total', ''],
                     'gauge': [''],
                     'summary': ['_count', '_sum', ''],
                     'histogram': ['_count', '_sum', '_bucket'],
diff --git a/tests/test_parser.py b/tests/test_parser.py
@@ -22,6 +22,13 @@ def test_simple_counter(self):
         families = text_string_to_metric_families("""# TYPE a counter
 # HELP a help
 a 1
+""")
+        self.assertEqualMetrics([CounterMetricFamily("a", "help", value=1)], list(families))
+
+    def test_counter_with_suffix(self):
+        families = text_string_to_metric_families("""# TYPE a counter
+# HELP a help
+a_total 1
 """)
         self.assertEqualMetrics([CounterMetricFamily("a", "help", value=1)], list(families))
 
