prometheus-exporter: fix labels out of place for data points with different attribute sets

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- prometheus-exporter: fix labels out of place for data points with different
+  attribute sets
+  ([#4413](https://github.com/open-telemetry/opentelemetry-python/pull/4413))
 - Tolerates exceptions when loading resource detectors via `OTEL_EXPERIMENTAL_RESOURCE_DETECTORS`
   ([#4373](https://github.com/open-telemetry/opentelemetry-python/pull/4373))
 

exporter/opentelemetry-exporter-prometheus/src/opentelemetry/exporter/prometheus/__init__.py

@@ -224,15 +224,14 @@ def _translate_to_prometheus(
                     metrics.append(metric)
 
         for metric in metrics:
-            label_valuess = []
+            label_values_data_points = []
+            label_keys_data_points = []
             values = []
 
-            pre_metric_family_ids = []
+            per_metric_family_ids = []
 
             metric_name = sanitize_full_name(metric.name)
-
             metric_description = metric.description or ""
-
             metric_unit = map_unit(metric.unit)
 
             for number_data_point in metric.data.data_points:
@@ -243,7 +242,7 @@ def _translate_to_prometheus(
                     label_keys.append(sanitize_attribute(key))
                     label_values.append(self._check_value(value))
 
-                pre_metric_family_ids.append(
+                per_metric_family_ids.append(
                     "|".join(
                         [
                             metric_name,
@@ -254,7 +253,8 @@ def _translate_to_prometheus(
                     )
                 )
 
-                label_valuess.append(label_values)
+                label_values_data_points.append(label_values)
+                label_keys_data_points.append(label_keys)
                 if isinstance(number_data_point, HistogramDataPoint):
                     values.append(
                         {
@@ -268,8 +268,11 @@ def _translate_to_prometheus(
                 else:
                     values.append(number_data_point.value)
 
-            for pre_metric_family_id, label_values, value in zip(
-                pre_metric_family_ids, label_valuess, values
+            for per_metric_family_id, label_keys, label_values, value in zip(
+                per_metric_family_ids,
+                label_keys_data_points,
+                label_values_data_points,
+                values,
             ):
                 is_non_monotonic_sum = (
                     isinstance(metric.data, Sum)
@@ -291,7 +294,7 @@ def _translate_to_prometheus(
                     and not should_convert_sum_to_gauge
                 ):
                     metric_family_id = "|".join(
-                        [pre_metric_family_id, CounterMetricFamily.__name__]
+                        [per_metric_family_id, CounterMetricFamily.__name__]
                     )
 
                     if metric_family_id not in metric_family_id_metric_family:
@@ -311,7 +314,7 @@ def _translate_to_prometheus(
                     or should_convert_sum_to_gauge
                 ):
                     metric_family_id = "|".join(
-                        [pre_metric_family_id, GaugeMetricFamily.__name__]
+                        [per_metric_family_id, GaugeMetricFamily.__name__]
                     )
 
                     if (
@@ -331,7 +334,7 @@ def _translate_to_prometheus(
                     ].add_metric(labels=label_values, value=value)
                 elif isinstance(metric.data, Histogram):
                     metric_family_id = "|".join(
-                        [pre_metric_family_id, HistogramMetricFamily.__name__]
+                        [per_metric_family_id, HistogramMetricFamily.__name__]
                     )
 
                     if (

exporter/opentelemetry-exporter-prometheus/tests/test_prometheus_exporter.py

@@ -638,3 +638,59 @@ def test_semconv(self):
                 """
             ),
         )
+
+    def test_multiple_data_points_with_different_label_sets(self):
+        hist_point_1 = HistogramDataPoint(
+            attributes={"http_target": "/foobar", "net_host_port": 8080},
+            start_time_unix_nano=1641946016139533244,
+            time_unix_nano=1641946016139533244,
+            count=6,
+            sum=579.0,
+            bucket_counts=[1, 3, 2],
+            explicit_bounds=[123.0, 456.0],
+            min=1,
+            max=457,
+        )
+        hist_point_2 = HistogramDataPoint(
+            attributes={"net_host_port": 8080},
+            start_time_unix_nano=1641946016139533245,
+            time_unix_nano=1641946016139533245,
+            count=7,
+            sum=579.0,
+            bucket_counts=[1, 3, 3],
+            explicit_bounds=[123.0, 456.0],
+            min=1,
+            max=457,
+        )
+
+        metric = Metric(
+            name="http.server.request.duration",
+            description="test multiple label sets",
+            unit="s",
+            data=Histogram(
+                data_points=[hist_point_1, hist_point_2],
+                aggregation_temporality=AggregationTemporality.CUMULATIVE,
+            ),
+        )
+
+        self.verify_text_format(
+            metric,
+            dedent(
+                """\
+                # HELP http_server_request_duration_seconds test multiple label sets
+                # TYPE http_server_request_duration_seconds histogram
+                http_server_request_duration_seconds_bucket{http_target="/foobar",le="123.0",net_host_port="8080"} 1.0
+                http_server_request_duration_seconds_bucket{http_target="/foobar",le="456.0",net_host_port="8080"} 4.0
+                http_server_request_duration_seconds_bucket{http_target="/foobar",le="+Inf",net_host_port="8080"} 6.0
+                http_server_request_duration_seconds_count{http_target="/foobar",net_host_port="8080"} 6.0
+                http_server_request_duration_seconds_sum{http_target="/foobar",net_host_port="8080"} 579.0
+                # HELP http_server_request_duration_seconds test multiple label sets
+                # TYPE http_server_request_duration_seconds histogram
+                http_server_request_duration_seconds_bucket{le="123.0",net_host_port="8080"} 1.0
+                http_server_request_duration_seconds_bucket{le="456.0",net_host_port="8080"} 4.0
+                http_server_request_duration_seconds_bucket{le="+Inf",net_host_port="8080"} 7.0
+                http_server_request_duration_seconds_count{net_host_port="8080"} 7.0
+                http_server_request_duration_seconds_sum{net_host_port="8080"} 579.0
+                """
+            ),
+        )