Fix OTLPMetricExporter ignores preferred_aggregation property (#3603)

* fix #3522 OTLPMetricExporter ignores preferred_aggregation

* make OTLPMetricExporter pass the preferred_aggregation argument to the _common_configuration function

* Remove unnecessary import from metrics encoder

* docs: added changelog entry for pr #3603

* Added unit test to make sure preferred_aggregation override works

* chore: break aggregation and temporality config in two functions

* chore: removed instrument_class_aggregation variable external declaration, to avoid possible problems with linters

* chore: removed unnecessary variable declaration

* docs: moved changelog entry to unreleased

* chore: added preferred_aggregation argument to _common_configuration call

* chore: added unit test for grpc otlp metric exporter

* test: moved preferred_aggregation test to class

* chore: fix linter findings on metrics_encoder/__init__.py

* chore: fix linter findings on grpc/metrics_exporter/__init__.py

* chore: fix linter findings on http/metrics_exporter/__init__.py

* fix: removed code duplicate

* chore: fixed linter errors

* Ignoring pylint for protected access

* Fix Aggregation import

* Rename getter methods to private

---------

Co-authored-by: Diego Hurtado <ocelotl@users.noreply.github.com>

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Fix `OTLPMetricExporter` ignores `preferred_aggregation` property
+  ([#3603](https://github.com/open-telemetry/opentelemetry-python/pull/3603))
 - Logs: set `observed_timestamp` field
   ([#3565](https://github.com/open-telemetry/opentelemetry-python/pull/3565))
 - Add missing Resource SchemaURL in OTLP exporters

exporter/opentelemetry-exporter-otlp-proto-common/src/opentelemetry/exporter/otlp/proto/common/_internal/metrics_encoder/__init__.py

@@ -16,6 +16,7 @@
 from opentelemetry.sdk.metrics.export import (
     MetricExporter,
 )
+from opentelemetry.sdk.metrics.view import Aggregation
 from os import environ
 from opentelemetry.sdk.metrics import (
     Counter,
@@ -65,9 +66,18 @@ class OTLPMetricExporterMixin:
     def _common_configuration(
         self,
         preferred_temporality: Dict[type, AggregationTemporality] = None,
+        preferred_aggregation: Dict[type, Aggregation] = None,
     ) -> None:
 
-        instrument_class_temporality = {}
+        MetricExporter.__init__(
+            self,
+            preferred_temporality=self._get_temporality(preferred_temporality),
+            preferred_aggregation=self._get_aggregation(preferred_aggregation),
+        )
+
+    def _get_temporality(
+        self, preferred_temporality: Dict[type, AggregationTemporality]
+    ) -> Dict[type, AggregationTemporality]:
 
         otel_exporter_otlp_metrics_temporality_preference = (
             environ.get(
@@ -119,6 +129,13 @@ def _common_configuration(
 
         instrument_class_temporality.update(preferred_temporality or {})
 
+        return instrument_class_temporality
+
+    def _get_aggregation(
+        self,
+        preferred_aggregation: Dict[type, Aggregation],
+    ) -> Dict[type, Aggregation]:
+
         otel_exporter_otlp_metrics_default_histogram_aggregation = environ.get(
             OTEL_EXPORTER_OTLP_METRICS_DEFAULT_HISTOGRAM_AGGREGATION,
             "explicit_bucket_histogram",
@@ -128,7 +145,9 @@ def _common_configuration(
             "base2_exponential_bucket_histogram"
         ):
 
-            histogram_aggregation_type = ExponentialBucketHistogramAggregation
+            instrument_class_aggregation = {
+                Histogram: ExponentialBucketHistogramAggregation(),
+            }
 
         else:
 
@@ -145,13 +164,13 @@ def _common_configuration(
                     otel_exporter_otlp_metrics_default_histogram_aggregation,
                 )
 
-            histogram_aggregation_type = ExplicitBucketHistogramAggregation
+            instrument_class_aggregation = {
+                Histogram: ExplicitBucketHistogramAggregation(),
+            }
 
-        MetricExporter.__init__(
-            self,
-            preferred_temporality=instrument_class_temporality,
-            preferred_aggregation={Histogram: histogram_aggregation_type()},
-        )
+        instrument_class_aggregation.update(preferred_aggregation or {})
+
+        return instrument_class_aggregation
 
 
 def encode_metrics(data: MetricsData) -> ExportMetricsServiceRequest:

exporter/opentelemetry-exporter-otlp-proto-grpc/src/opentelemetry/exporter/otlp/proto/grpc/metric_exporter/__init__.py

@@ -127,7 +127,9 @@ def __init__(
             else compression
         )
 
-        self._common_configuration(preferred_temporality)
+        self._common_configuration(
+            preferred_temporality, preferred_aggregation
+        )
 
         OTLPExporterMixin.__init__(
             self,

exporter/opentelemetry-exporter-otlp-proto-grpc/tests/test_otlp_metrics_exporter.py

@@ -968,6 +968,24 @@ def test_exponential_explicit_bucket_histogram(self):
                 ExplicitBucketHistogramAggregation,
             )
 
+    def test_preferred_aggregation_override(self):
+
+        histogram_aggregation = ExplicitBucketHistogramAggregation(
+            boundaries=[0.05, 0.1, 0.5, 1, 5, 10],
+        )
+
+        exporter = OTLPMetricExporter(
+            preferred_aggregation={
+                Histogram: histogram_aggregation,
+            },
+        )
+
+        self.assertEqual(
+            # pylint: disable=protected-access
+            exporter._preferred_aggregation[Histogram],
+            histogram_aggregation,
+        )
+
 
 def _resource_metrics(
     index: int, scope_metrics: List[ScopeMetrics]

exporter/opentelemetry-exporter-otlp-proto-http/src/opentelemetry/exporter/otlp/proto/http/metric_exporter/__init__.py

@@ -135,7 +135,9 @@ def __init__(
                 {"Content-Encoding": self._compression.value}
             )
 
-        self._common_configuration(preferred_temporality)
+        self._common_configuration(
+            preferred_temporality, preferred_aggregation
+        )
 
     def _export(self, serialized_data: str):
         data = serialized_data

exporter/opentelemetry-exporter-otlp-proto-http/tests/metrics/test_otlp_metrics_exporter.py

@@ -479,3 +479,19 @@ def test_2xx_status_code(self, mock_otlp_metric_exporter):
             OTLPMetricExporter().export(MagicMock()),
             MetricExportResult.SUCCESS,
         )
+
+    def test_preferred_aggregation_override(self):
+
+        histogram_aggregation = ExplicitBucketHistogramAggregation(
+            boundaries=[0.05, 0.1, 0.5, 1, 5, 10],
+        )
+
+        exporter = OTLPMetricExporter(
+            preferred_aggregation={
+                Histogram: histogram_aggregation,
+            },
+        )
+
+        self.assertEqual(
+            exporter._preferred_aggregation[Histogram], histogram_aggregation
+        )