Add support for LowMemory metrics temporality (#2234)

exporters/otlp/BUILD

@@ -20,6 +20,7 @@ cc_library(
         "include/opentelemetry/exporters/otlp/otlp_log_recordable.h",
         "include/opentelemetry/exporters/otlp/otlp_metric_utils.h",
         "include/opentelemetry/exporters/otlp/otlp_populate_attribute_utils.h",
+        "include/opentelemetry/exporters/otlp/otlp_preferred_temporality.h",
         "include/opentelemetry/exporters/otlp/otlp_recordable.h",
         "include/opentelemetry/exporters/otlp/otlp_recordable_utils.h",
         "include/opentelemetry/exporters/otlp/protobuf_include_prefix.h",

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_grpc_metric_exporter_options.h

@@ -4,6 +4,7 @@
 #pragma once
 
 #include "opentelemetry/exporters/otlp/otlp_grpc_exporter_options.h"
+#include "opentelemetry/exporters/otlp/otlp_preferred_temporality.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 
 #include <memory>
@@ -21,8 +22,8 @@ struct OtlpGrpcMetricExporterOptions : public OtlpGrpcExporterOptions
 {
 
   // Preferred Aggregation Temporality
-  sdk::metrics::AggregationTemporality aggregation_temporality =
-      sdk::metrics::AggregationTemporality::kCumulative;
+  PreferredAggregationTemporality aggregation_temporality =
+      PreferredAggregationTemporality::kCumulative;
 };
 
 }  // namespace otlp

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_http_metric_exporter_options.h

@@ -5,7 +5,7 @@
 
 #include "opentelemetry/exporters/otlp/otlp_environment.h"
 #include "opentelemetry/exporters/otlp/otlp_http.h"
-#include "opentelemetry/sdk/metrics/instruments.h"
+#include "opentelemetry/exporters/otlp/otlp_preferred_temporality.h"
 
 #include <chrono>
 #include <cstddef>
@@ -50,8 +50,8 @@ struct OtlpHttpMetricExporterOptions
   OtlpHeaders http_headers = GetOtlpDefaultMetricsHeaders();
 
   // Preferred Aggregation Temporality
-  sdk::metrics::AggregationTemporality aggregation_temporality =
-      sdk::metrics::AggregationTemporality::kCumulative;
+  PreferredAggregationTemporality aggregation_temporality =
+      PreferredAggregationTemporality::kCumulative;
 
 #ifdef ENABLE_ASYNC_EXPORT
   // Concurrent requests

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_metric_utils.h

@@ -9,6 +9,7 @@
 #include "opentelemetry/proto/metrics/v1/metrics.pb.h"
 #include "opentelemetry/proto/resource/v1/resource.pb.h"
 
+#include "opentelemetry/exporters/otlp/otlp_preferred_temporality.h"
 #include "opentelemetry/exporters/otlp/protobuf_include_suffix.h"
 
 #include "opentelemetry/sdk/metrics/export/metric_producer.h"
@@ -52,11 +53,13 @@ class OtlpMetricUtils
       proto::collector::metrics::v1::ExportMetricsServiceRequest *request) noexcept;
 
   static sdk::metrics::AggregationTemporalitySelector ChooseTemporalitySelector(
-      sdk::metrics::AggregationTemporality preferred_aggregation_temporality) noexcept;
+      PreferredAggregationTemporality preferred_aggregation_temporality) noexcept;
   static sdk::metrics::AggregationTemporality DeltaTemporalitySelector(
       sdk::metrics::InstrumentType instrument_type) noexcept;
   static sdk::metrics::AggregationTemporality CumulativeTemporalitySelector(
       sdk::metrics::InstrumentType instrument_type) noexcept;
+  static sdk::metrics::AggregationTemporality LowMemoryTemporalitySelector(
+      sdk::metrics::InstrumentType instrument_type) noexcept;
 };
 
 }  // namespace otlp

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_preferred_temporality.h

@@ -0,0 +1,23 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace otlp
+{
+
+enum class PreferredAggregationTemporality
+{
+  kUnspecified,
+  kDelta,
+  kCumulative,
+  kLowMemory,
+};
+
+}
+}  // namespace exporter
+OPENTELEMETRY_END_NAMESPACE

exporters/otlp/src/otlp_metric_utils.cc

@@ -247,13 +247,17 @@ void OtlpMetricUtils::PopulateRequest(
 }
 
 sdk::metrics::AggregationTemporalitySelector OtlpMetricUtils::ChooseTemporalitySelector(
-    sdk::metrics::AggregationTemporality preferred_aggregation_temporality) noexcept
+    PreferredAggregationTemporality preferred_aggregation_temporality) noexcept
 {
-  if (preferred_aggregation_temporality == sdk::metrics::AggregationTemporality::kDelta)
+  if (preferred_aggregation_temporality == PreferredAggregationTemporality::kDelta)
   {
     return DeltaTemporalitySelector;
   }
-  return CumulativeTemporalitySelector;
+  else if (preferred_aggregation_temporality == PreferredAggregationTemporality::kCumulative)
+  {
+    return CumulativeTemporalitySelector;
+  }
+  return LowMemoryTemporalitySelector;
 }
 
 sdk::metrics::AggregationTemporality OtlpMetricUtils::DeltaTemporalitySelector(
@@ -279,6 +283,22 @@ sdk::metrics::AggregationTemporality OtlpMetricUtils::CumulativeTemporalitySelec
   return sdk::metrics::AggregationTemporality::kCumulative;
 }
 
+sdk::metrics::AggregationTemporality OtlpMetricUtils::LowMemoryTemporalitySelector(
+    sdk::metrics::InstrumentType instrument_type) noexcept
+{
+  switch (instrument_type)
+  {
+    case sdk::metrics::InstrumentType::kCounter:
+    case sdk::metrics::InstrumentType::kHistogram:
+      return sdk::metrics::AggregationTemporality::kDelta;
+    case sdk::metrics::InstrumentType::kObservableCounter:
+    case sdk::metrics::InstrumentType::kObservableGauge:
+    case sdk::metrics::InstrumentType::kUpDownCounter:
+    case sdk::metrics::InstrumentType::kObservableUpDownCounter:
+      return sdk::metrics::AggregationTemporality::kCumulative;
+  }
+  return sdk::metrics::AggregationTemporality::kUnspecified;
+}
 }  // namespace otlp
 }  // namespace exporter
 OPENTELEMETRY_END_NAMESPACE

exporters/otlp/test/otlp_http_metric_exporter_test.cc

@@ -11,6 +11,7 @@
 
 #include "opentelemetry/proto/collector/metrics/v1/metrics_service.pb.h"
 
+#include "opentelemetry/exporters/otlp/otlp_metric_utils.h"
 #include "opentelemetry/exporters/otlp/protobuf_include_suffix.h"
 
 #include "opentelemetry/common/key_value_iterable_view.h"
@@ -976,6 +977,78 @@ TEST_F(OtlpHttpMetricExporterTestPeer, CheckDefaultTemporality)
 }
 #endif
 
+// Test Preferred aggregtion temporality selection
+TEST_F(OtlpHttpMetricExporterTestPeer, PreferredAggergationTemporality)
+{
+  // Cummulative aggregation selector : use cummulative aggregation for all instruments.
+  std::unique_ptr<OtlpHttpMetricExporter> exporter(new OtlpHttpMetricExporter());
+  EXPECT_EQ(GetOptions(exporter).aggregation_temporality,
+            PreferredAggregationTemporality::kCumulative);
+  auto cumm_selector =
+      OtlpMetricUtils::ChooseTemporalitySelector(GetOptions(exporter).aggregation_temporality);
+  EXPECT_EQ(cumm_selector(opentelemetry::sdk::metrics::InstrumentType::kCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+  EXPECT_EQ(cumm_selector(opentelemetry::sdk::metrics::InstrumentType::kHistogram),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+  EXPECT_EQ(cumm_selector(opentelemetry::sdk::metrics::InstrumentType::kUpDownCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+  EXPECT_EQ(cumm_selector(opentelemetry::sdk::metrics::InstrumentType::kObservableCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+  EXPECT_EQ(cumm_selector(opentelemetry::sdk::metrics::InstrumentType::kObservableGauge),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+  EXPECT_EQ(cumm_selector(opentelemetry::sdk::metrics::InstrumentType::kObservableUpDownCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+
+  // LowMemory aggregation selector use:
+  //   - cummulative aggregtion for Counter and Histogram
+  //   - delta aggregation for up-down counter, observable counter, observable gauge, observable
+  //   up-down counter
+  OtlpHttpMetricExporterOptions opts2;
+  opts2.aggregation_temporality = PreferredAggregationTemporality::kLowMemory;
+  std::unique_ptr<OtlpHttpMetricExporter> exporter2(new OtlpHttpMetricExporter(opts2));
+  EXPECT_EQ(GetOptions(exporter2).aggregation_temporality,
+            PreferredAggregationTemporality::kLowMemory);
+  auto lowmemory_selector =
+      OtlpMetricUtils::ChooseTemporalitySelector(GetOptions(exporter2).aggregation_temporality);
+  EXPECT_EQ(lowmemory_selector(opentelemetry::sdk::metrics::InstrumentType::kCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kDelta);
+  EXPECT_EQ(lowmemory_selector(opentelemetry::sdk::metrics::InstrumentType::kHistogram),
+            opentelemetry::sdk::metrics::AggregationTemporality::kDelta);
+
+  EXPECT_EQ(lowmemory_selector(opentelemetry::sdk::metrics::InstrumentType::kUpDownCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+  EXPECT_EQ(lowmemory_selector(opentelemetry::sdk::metrics::InstrumentType::kObservableCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+  EXPECT_EQ(lowmemory_selector(opentelemetry::sdk::metrics::InstrumentType::kObservableGauge),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+  EXPECT_EQ(
+      lowmemory_selector(opentelemetry::sdk::metrics::InstrumentType::kObservableUpDownCounter),
+      opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+
+  // Delta aggregation selector use:
+  //   - delta aggregtion for Counter, Histogram, Observable Counter, Observable Gauge
+  //   - cummulative aggregation for up-down counter, observable up-down counter
+  OtlpHttpMetricExporterOptions opts3;
+  opts3.aggregation_temporality = PreferredAggregationTemporality::kDelta;
+  std::unique_ptr<OtlpHttpMetricExporter> exporter3(new OtlpHttpMetricExporter(opts3));
+  EXPECT_EQ(GetOptions(exporter3).aggregation_temporality, PreferredAggregationTemporality::kDelta);
+  auto delta_selector =
+      OtlpMetricUtils::ChooseTemporalitySelector(GetOptions(exporter3).aggregation_temporality);
+  EXPECT_EQ(delta_selector(opentelemetry::sdk::metrics::InstrumentType::kCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kDelta);
+  EXPECT_EQ(delta_selector(opentelemetry::sdk::metrics::InstrumentType::kHistogram),
+            opentelemetry::sdk::metrics::AggregationTemporality::kDelta);
+  EXPECT_EQ(delta_selector(opentelemetry::sdk::metrics::InstrumentType::kObservableCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kDelta);
+  EXPECT_EQ(delta_selector(opentelemetry::sdk::metrics::InstrumentType::kObservableGauge),
+            opentelemetry::sdk::metrics::AggregationTemporality::kDelta);
+
+  EXPECT_EQ(delta_selector(opentelemetry::sdk::metrics::InstrumentType::kUpDownCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+  EXPECT_EQ(delta_selector(opentelemetry::sdk::metrics::InstrumentType::kObservableUpDownCounter),
+            opentelemetry::sdk::metrics::AggregationTemporality::kCumulative);
+}
+
 }  // namespace otlp
 }  // namespace exporter
 OPENTELEMETRY_END_NAMESPACE