fix(ext/prometheus): support minmaxsumcount aggregator (#945)

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

@@ -67,22 +67,22 @@ API
 import collections
 import logging
 import re
-from typing import Sequence
+from typing import Iterable, Optional, Sequence, Union
 
-from prometheus_client import start_http_server
 from prometheus_client.core import (
     REGISTRY,
-    CollectorRegistry,
     CounterMetricFamily,
+    SummaryMetricFamily,
     UnknownMetricFamily,
 )
 
-from opentelemetry.metrics import Counter, Metric, ValueRecorder
+from opentelemetry.metrics import Counter, ValueRecorder
 from opentelemetry.sdk.metrics.export import (
     MetricRecord,
     MetricsExporter,
     MetricsExportResult,
 )
+from opentelemetry.sdk.metrics.export.aggregate import MinMaxSumCountAggregator
 
 logger = logging.getLogger(__name__)
 
@@ -110,7 +110,7 @@ class PrometheusMetricsExporter(MetricsExporter):
 
 
 class CustomCollector:
-    """ CustomCollector represents the Prometheus Collector object
+    """CustomCollector represents the Prometheus Collector object
     https://github.com/prometheus/client_python#custom-collectors
     """
 
@@ -121,7 +121,7 @@ class CustomCollector:
             r"[^\w]", re.UNICODE | re.IGNORECASE
         )
 
-    def add_metrics_data(self, metric_records: Sequence[MetricRecord]):
+    def add_metrics_data(self, metric_records: Sequence[MetricRecord]) -> None:
         self._metrics_to_export.append(metric_records)
 
     def collect(self):
@@ -152,25 +152,35 @@ class CustomCollector:
             metric_name = self._prefix + "_"
         metric_name += self._sanitize(metric_record.instrument.name)
 
+        description = getattr(metric_record.instrument, "description", "")
         if isinstance(metric_record.instrument, Counter):
             prometheus_metric = CounterMetricFamily(
-                name=metric_name,
+                name=metric_name, documentation=description, labels=label_keys
-                documentation=metric_record.instrument.description,
-                labels=label_keys,
             )
             prometheus_metric.add_metric(
                 labels=label_values, value=metric_record.aggregator.checkpoint
             )
         # TODO: Add support for histograms when supported in OT
         elif isinstance(metric_record.instrument, ValueRecorder):
-            prometheus_metric = UnknownMetricFamily(
+            value = metric_record.aggregator.checkpoint
+            if isinstance(metric_record.aggregator, MinMaxSumCountAggregator):
+                prometheus_metric = SummaryMetricFamily(
                     name=metric_name,
-                documentation=metric_record.instrument.description,
+                    documentation=description,
                     labels=label_keys,
                 )
                 prometheus_metric.add_metric(
-                labels=label_values, value=metric_record.aggregator.checkpoint
+                    labels=label_values,
+                    count_value=value.count,
+                    sum_value=value.sum,
                 )
+            else:
+                prometheus_metric = UnknownMetricFamily(
+                    name=metric_name,
+                    documentation=description,
+                    labels=label_keys,
+                )
+                prometheus_metric.add_metric(labels=label_values, value=value)
 
         else:
             logger.warning(
@@ -178,8 +188,8 @@ class CustomCollector:
             )
         return prometheus_metric
 
-    def _sanitize(self, key):
+    def _sanitize(self, key: str) -> str:
-        """ sanitize the given metric name or label according to Prometheus rule.
+        """sanitize the given metric name or label according to Prometheus rule.
         Replace all characters other than [A-Za-z0-9_] with '_'.
         """
         return self._non_letters_nor_digits_re.sub("_", key)

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

@@ -15,6 +15,7 @@
 import unittest
 from unittest import mock
 
+from prometheus_client import generate_latest
 from prometheus_client.core import CounterMetricFamily
 
 from opentelemetry.exporter.prometheus import (
@@ -24,7 +25,11 @@ from opentelemetry.exporter.prometheus import (
 from opentelemetry.metrics import get_meter_provider, set_meter_provider
 from opentelemetry.sdk import metrics
 from opentelemetry.sdk.metrics.export import MetricRecord, MetricsExportResult
-from opentelemetry.sdk.metrics.export.aggregate import SumAggregator
+from opentelemetry.sdk.metrics.export.aggregate import (
+    MinMaxSumCountAggregator,
+    SumAggregator,
+)
+from opentelemetry.sdk.util import get_dict_as_key
 
 
 class TestPrometheusMetricExporter(unittest.TestCase):
@@ -35,7 +40,7 @@ class TestPrometheusMetricExporter(unittest.TestCase):
             "testname", "testdesc", "unit", int, metrics.Counter,
         )
         labels = {"environment": "staging"}
-        self._labels_key = metrics.get_dict_as_key(labels)
+        self._labels_key = get_dict_as_key(labels)
 
         self._mock_registry_register = mock.Mock()
         self._registry_register_patch = mock.patch(
@@ -70,13 +75,32 @@ class TestPrometheusMetricExporter(unittest.TestCase):
             self.assertEqual(len(exporter._collector._metrics_to_export), 1)
             self.assertIs(result, MetricsExportResult.SUCCESS)
 
+    def test_min_max_sum_aggregator_to_prometheus(self):
+        meter = get_meter_provider().get_meter(__name__)
+        metric = meter.create_metric(
+            "test@name", "testdesc", "unit", int, metrics.ValueRecorder, []
+        )
+        labels = {}
+        key_labels = get_dict_as_key(labels)
+        aggregator = MinMaxSumCountAggregator()
+        aggregator.update(123)
+        aggregator.update(456)
+        aggregator.take_checkpoint()
+        record = MetricRecord(metric, key_labels, aggregator)
+        collector = CustomCollector("testprefix")
+        collector.add_metrics_data([record])
+        result_bytes = generate_latest(collector)
+        result = result_bytes.decode("utf-8")
+        self.assertIn("testprefix_test_name_count 2.0", result)
+        self.assertIn("testprefix_test_name_sum 579.0", result)
+
     def test_counter_to_prometheus(self):
         meter = get_meter_provider().get_meter(__name__)
         metric = meter.create_metric(
             "test@name", "testdesc", "unit", int, metrics.Counter,
         )
         labels = {"environment@": "staging", "os": "Windows"}
-        key_labels = metrics.get_dict_as_key(labels)
+        key_labels = get_dict_as_key(labels)
         aggregator = SumAggregator()
         aggregator.update(123)
         aggregator.take_checkpoint()
@@ -107,7 +131,7 @@ class TestPrometheusMetricExporter(unittest.TestCase):
             "tesname", "testdesc", "unit", int, StubMetric
         )
         labels = {"environment": "staging"}
-        key_labels = metrics.get_dict_as_key(labels)
+        key_labels = get_dict_as_key(labels)
         record = MetricRecord(metric, key_labels, None)
         collector = CustomCollector("testprefix")
         collector.add_metrics_data([record])