[WIP] Implement Aggregation Storage

sdk/include/opentelemetry/sdk/_metrics/aggregator/histogram_aggregator.h

@@ -10,6 +10,7 @@
 #  include <vector>
 #  include "opentelemetry/_metrics/instrument.h"
 #  include "opentelemetry/sdk/_metrics/aggregator/aggregator.h"
+#  include "opentelemetry/sdk/metrics/"
 #  include "opentelemetry/version.h"
 
 OPENTELEMETRY_BEGIN_NAMESPACE

sdk/include/opentelemetry/sdk/metrics/aggregation/aggregation.h

@@ -24,9 +24,9 @@ class InstrumentMonotonicityAwareAggregation
 class Aggregation
 {
 public:
-  virtual void Aggregate(long value, const PointAttributes &attributes = {}) noexcept = 0;
+  virtual void Aggregate(long value) noexcept = 0;
 
-  virtual void Aggregate(double value, const PointAttributes &attributes = {}) noexcept = 0;
+  virtual void Aggregate(double value) noexcept = 0;
 
   virtual PointType Collect() noexcept = 0;
 };

sdk/include/opentelemetry/sdk/metrics/aggregation/drop_aggregation.h

@@ -19,9 +19,9 @@ class DropAggregation : public Aggregation
 public:
   DropAggregation() = default;
 
-  void Aggregate(long value, const PointAttributes &attributes = {}) noexcept override {}
+  void Aggregate(long value) noexcept override {}
 
-  void Aggregate(double value, const PointAttributes &attributes = {}) noexcept override {}
+  void Aggregate(double value) noexcept override {}
 
   PointType Collect() noexcept override { return DropPointData(); }
 };

sdk/include/opentelemetry/sdk/metrics/aggregation/histogram_aggregation.h

@@ -33,9 +33,9 @@ class LongHistogramAggregation : public Aggregation
 public:
   LongHistogramAggregation();
 
-  void Aggregate(long value, const PointAttributes &attributes = {}) noexcept override;
+  void Aggregate(long value) noexcept override;
 
-  void Aggregate(double value, const PointAttributes &attributes = {}) noexcept override {}
+  void Aggregate(double value) noexcept override {}
 
   PointType Collect() noexcept override;
 
@@ -52,9 +52,9 @@ class DoubleHistogramAggregation : public Aggregation
 public:
   DoubleHistogramAggregation();
 
-  void Aggregate(long value, const PointAttributes &attributes = {}) noexcept override {}
+  void Aggregate(long value) noexcept override {}
 
-  void Aggregate(double value, const PointAttributes &attributes = {}) noexcept override;
+  void Aggregate(double value) noexcept override;
 
   PointType Collect() noexcept override;
 

sdk/include/opentelemetry/sdk/metrics/aggregation/lastvalue_aggregation.h

@@ -18,9 +18,9 @@ class LongLastValueAggregation : public Aggregation
 public:
   LongLastValueAggregation();
 
-  void Aggregate(long value, const PointAttributes &attributes = {}) noexcept override;
+  void Aggregate(long value) noexcept override;
 
-  void Aggregate(double value, const PointAttributes &attributes = {}) noexcept override {}
+  void Aggregate(double value) noexcept override {}
 
   PointType Collect() noexcept override;
 
@@ -35,9 +35,9 @@ class DoubleLastValueAggregation : public Aggregation
 public:
   DoubleLastValueAggregation();
 
-  void Aggregate(long value, const PointAttributes &attributes = {}) noexcept override {}
+  void Aggregate(long value) noexcept override {}
 
-  void Aggregate(double value, const PointAttributes &attributes = {}) noexcept override;
+  void Aggregate(double value) noexcept override;
 
   PointType Collect() noexcept override;
 

sdk/include/opentelemetry/sdk/metrics/aggregation/sum_aggregation.h

@@ -33,9 +33,9 @@ class LongSumAggregation : public Aggregation, InstrumentMonotonicityAwareAggreg
 public:
   LongSumAggregation(bool is_monotonic);
 
-  void Aggregate(long value, const PointAttributes &attributes = {}) noexcept override;
+  void Aggregate(long value) noexcept override;
 
-  void Aggregate(double value, const PointAttributes &attributes = {}) noexcept override {}
+  void Aggregate(double value) noexcept override {}
 
   PointType Collect() noexcept override;
 
@@ -50,9 +50,9 @@ class DoubleSumAggregation : public Aggregation, InstrumentMonotonicityAwareAggr
 public:
   DoubleSumAggregation(bool is_monotonic);
 
-  void Aggregate(long value, const PointAttributes &attributes = {}) noexcept override {}
+  void Aggregate(long value) noexcept override {}
 
-  void Aggregate(double value, const PointAttributes &attributes = {}) noexcept override;
+  void Aggregate(double value) noexcept override;
 
   PointType Collect() noexcept override;
 

sdk/include/opentelemetry/sdk/metrics/data/metric_data.h

@@ -17,16 +17,15 @@ namespace sdk
 namespace metrics
 {
 
-using PointAttributes = opentelemetry::sdk::common::AttributeMap;
-using PointType       = opentelemetry::nostd::
+using PointType = opentelemetry::nostd::
     variant<SumPointData, HistogramPointData, LastValuePointData, DropPointData>;
 
 class MetricData
 {
 public:
   opentelemetry::sdk::resource::Resource *resource_;
   opentelemetry::sdk::instrumentationlibrary::InstrumentationLibrary *instrumentation_library_;
-  PointAttributes attributes_;
+  MetricAttributes attributes_;
   InstrumentDescriptor instrument_descriptor;
   PointType point_data_;
 };

sdk/include/opentelemetry/sdk/metrics/data/point_data.h

@@ -5,6 +5,7 @@
 #ifndef ENABLE_METRICS_PREVIEW
 #  include "opentelemetry/common/timestamp.h"
 #  include "opentelemetry/nostd/variant.h"
+#  include "opentelemetry/sdk/metrics/instruments.h"
 #  include "opentelemetry/version.h"
 
 #  include <vector>
@@ -18,13 +19,6 @@ namespace metrics
 using ValueType = nostd::variant<long, double>;
 using ListType  = nostd::variant<std::vector<long>, std::vector<double>>;
 
-enum class AggregationTemporarily
-{
-  kUnspecified,
-  kDelta,
-  kCummulative
-};
-
 class SumPointData
 {
 public:

sdk/include/opentelemetry/sdk/metrics/instruments.h

@@ -4,11 +4,16 @@
 #pragma once
 #ifndef ENABLE_METRICS_PREVIEW
 #  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/sdk/common/attribute_utils.h"
+
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace metrics
 {
+
+typedef opentelemetry::sdk::common::OrderedAttributeMap MetricAttributes;
+
 enum class InstrumentType
 {
   kCounter,
@@ -27,6 +32,22 @@ enum class InstrumentValueType
   kDouble
 };
 
+enum class AggregationType
+{
+  kDefault,
+  kDrop,
+  kLastValue,
+  kSum,
+  kHistogram
+};
+
+enum class AggregationTemporarily
+{
+  kUnspecified,
+  kDelta,
+  kCummulative
+};
+
 struct InstrumentDescriptor
 {
   std::string name_;

sdk/include/opentelemetry/sdk/metrics/state/metric_storage.h

@@ -0,0 +1,73 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifndef ENABLE_METRICS_PREVIEW
+#  include "opentelemetry/common/key_value_iterable_view.h"
+#  include "opentelemetry/sdk/metrics/data/metric_data.h"
+#  include "opentelemetry/sdk/metrics/instruments.h"
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace metrics
+{
+
+/* Represent the storage from which to collect the metrics */
+
+class MetricStorage
+{
+public:
+  /* collect the metrics from this storage */
+  virtual bool Collect(AggregationTemporarily aggregation_temporarily,
+                       nostd::function_ref<bool(MetricData)> callback) noexcept = 0;
+};
+
+class WritableMetricStorage
+{
+public:
+  virtual void RecordLong(long value) noexcept = 0;
+
+  virtual void RecordLong(long value,
+                          const opentelemetry::common::KeyValueIterable &attributes) noexcept = 0;
+
+  virtual void RecordDouble(double value) noexcept = 0;
+
+  virtual void RecordDouble(double value,
+                            const opentelemetry::common::KeyValueIterable &attributes) noexcept = 0;
+};
+
+class NoopMetricStorage : public MetricStorage
+{
+public:
+  bool Collect(AggregationTemporarily aggregation_temporarily,
+               nostd::function_ref<bool(MetricData)> callback) noexcept override
+  {
+    MetricData metric_data;
+    if (callback(metric_data))
+    {
+      return true;
+    }
+    return false;
+  }
+};
+
+class NoopWritableMetricStorage : public WritableMetricStorage
+{
+public:
+  void RecordLong(long value) noexcept = 0;
+
+  void RecordLong(long value,
+                  const opentelemetry::common::KeyValueIterable &attributes) noexcept override
+  {}
+
+  void RecordDouble(double value) noexcept override {}
+
+  void RecordDouble(double value,
+                    const opentelemetry::common::KeyValueIterable &attributes) noexcept override
+  {}
+};
+
+}  // namespace metrics
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE
+#endif