Metrics SDK: View API (#1110)

sdk/include/opentelemetry/sdk/metrics/view.h → sdk/include/opentelemetry/sdk/metrics/aggregator/aggregator.h

@@ -4,24 +4,23 @@
 #pragma once
 #ifndef ENABLE_METRICS_PREVIEW
 #  include "opentelemetry/version.h"
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace metrics
 {
-/**
- * View defines the interface to allow SDK user to
- * customize the metrics before exported.
- */
 
-class View
+class Aggregator
+{
+  // TBD
+};
+
+class NoOpAggregator : public Aggregator
 {
-public:
-  virtual ~View() = default;
   // TBD
 };
+
 }  // namespace metrics
 }  // namespace sdk
 OPENTELEMETRY_END_NAMESPACE
-#endif
+#endif

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

@@ -0,0 +1,52 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifndef ENABLE_METRICS_PREVIEW
+#  include "opentelemetry/nostd/string_view.h"
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace metrics
+{
+enum class InstrumentType
+{
+  kCounter,
+  kHistogram,
+  kUpDownCounter,
+  kObservableCounter,
+  kObservableGauge,
+  kObservableUpDownCounter
+};
+
+enum class InstrumentValueType
+{
+  kInt,
+  kLong,
+  kFloat,
+  kDouble
+};
+
+struct InstrumentDescriptor
+{
+  std::string name_;
+  std::string description_;
+  std::string unit_;
+  InstrumentType type_;
+  InstrumentValueType valueType_;
+};
+
+/*class InstrumentSelector {
+public:
+InstrumentSelector(opentelemetry::nostd::string_view name,
+opentelemetry::sdk::metrics::InstrumentType type): name_(name.data()), type_(type) {} InstrumentType
+GetType(){return type_;} std::string GetNameFilter() { return name_;}
+
+private:
+std::string name_;
+InstrumentType type_;
+};*/
+}  // namespace metrics
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE
+#endif

sdk/include/opentelemetry/sdk/metrics/meter_context.h

@@ -8,7 +8,9 @@
 #  include <vector>
 #  include "opentelemetry/sdk/metrics/metric_exporter.h"
 #  include "opentelemetry/sdk/metrics/metric_reader.h"
-#  include "opentelemetry/sdk/metrics/view.h"
+#  include "opentelemetry/sdk/metrics/view/instrument_selector.h"
+#  include "opentelemetry/sdk/metrics/view/meter_selector.h"
+#  include "opentelemetry/sdk/metrics/view/view_registry.h"
 #  include "opentelemetry/sdk/resource/resource.h"
 #  include "opentelemetry/version.h"
 
@@ -31,11 +33,12 @@ class MeterContext
    * @param views The views to be configured with meter context.
    * @param resource  The resource for this meter context.
    */
-  MeterContext(std::vector<std::unique_ptr<sdk::metrics::MetricExporter>> &&exporters,
-               std::vector<std::unique_ptr<MetricReader>> &&readers,
-               std::vector<std::unique_ptr<View>> &&views,
-               opentelemetry::sdk::resource::Resource resource =
-                   opentelemetry::sdk::resource::Resource::Create({})) noexcept;
+  MeterContext(
+      std::vector<std::unique_ptr<sdk::metrics::MetricExporter>> &&exporters,
+      std::vector<std::unique_ptr<MetricReader>> &&readers,
+      std::unique_ptr<ViewRegistry> views = std::unique_ptr<ViewRegistry>(new ViewRegistry()),
+      opentelemetry::sdk::resource::Resource resource =
+          opentelemetry::sdk::resource::Resource::Create({})) noexcept;
 
   /**
    * Obtain the resource associated with this meter context.
@@ -71,7 +74,9 @@ class MeterContext
    * Note: This view may not receive any in-flight meter data, but will get newly created meter
    * data. Note: This method is not thread safe, and should ideally be called from main thread.
    */
-  void AddView(std::unique_ptr<View> view) noexcept;
+  void AddView(std::unique_ptr<InstrumentSelector> instrument_selector,
+               std::unique_ptr<MeterSelector> meter_selector,
+               std::unique_ptr<View> view) noexcept;
 
   /**
    * Force all active Exporters and Readers to flush any buffered meter data
@@ -89,7 +94,7 @@ class MeterContext
   opentelemetry::sdk::resource::Resource resource_;
   std::vector<std::unique_ptr<MetricExporter>> exporters_;
   std::vector<std::unique_ptr<MetricReader>> readers_;
-  std::vector<std::unique_ptr<View>> views_;
+  std::unique_ptr<ViewRegistry> views_;
 };
 
 }  // namespace metrics

sdk/include/opentelemetry/sdk/metrics/meter_provider.h

@@ -28,10 +28,11 @@ class MeterProvider final : public opentelemetry::metrics::MeterProvider
    * @param views The views for this meter provider
    * @param resource  The resources for this meter provider.
    */
-  MeterProvider(std::vector<std::unique_ptr<MetricExporter>> &&exporters,
-                std::vector<std::unique_ptr<MetricReader>> &&readers,
-                std::vector<std::unique_ptr<View>> &&views,
-                sdk::resource::Resource resource = sdk::resource::Resource::Create({})) noexcept;
+  MeterProvider(
+      std::vector<std::unique_ptr<MetricExporter>> &&exporters,
+      std::vector<std::unique_ptr<MetricReader>> &&readers,
+      std::unique_ptr<ViewRegistry> views = std::unique_ptr<ViewRegistry>(new ViewRegistry()),
+      sdk::resource::Resource resource    = sdk::resource::Resource::Create({})) noexcept;
 
   /**
    * Initialize a new meter provider with a specified context
@@ -78,7 +79,9 @@ class MeterProvider final : public opentelemetry::metrics::MeterProvider
    * Note: This view may not receive any in-flight meter data, but will get newly created meter
    * data. Note: This method is not thread safe, and should ideally be called from main thread.
    */
-  void AddView(std::unique_ptr<View> view) noexcept;
+  void AddView(std::unique_ptr<InstrumentSelector> instrument_selector,
+               std::unique_ptr<MeterSelector> meter_selector,
+               std::unique_ptr<View> view) noexcept;
 
   /**
    * Shutdown the meter provider.

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

@@ -0,0 +1,49 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifndef ENABLE_METRICS_PREVIEW
+
+#  include <memory>
+#  include "opentelemetry/sdk/metrics/aggregator/aggregator.h"
+#  include "opentelemetry/sdk/metrics/instruments.h"
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace metrics
+{
+class Aggregation
+{
+public:
+  virtual ~Aggregation() = default;
+  virtual opentelemetry::sdk::metrics::Aggregator &CreateAggregator(
+      opentelemetry::sdk::metrics::InstrumentDescriptor instrument_descriptor) noexcept = 0;
+};
+
+class NoOpAggregation : public Aggregation
+{
+
+  opentelemetry::sdk::metrics::Aggregator &CreateAggregator(
+      opentelemetry::sdk::metrics::InstrumentDescriptor instrument_descriptor) noexcept override
+  {
+    static opentelemetry::sdk::metrics::NoOpAggregator noop_aggregator;
+    return noop_aggregator;
+  }
+};
+
+class DefaultAggregation : public Aggregation
+{
+
+  opentelemetry::sdk::metrics::Aggregator &CreateAggregator(
+      opentelemetry::sdk::metrics::InstrumentDescriptor instrument_descriptor) noexcept override
+  {
+    // TBD - This shouldn't return noop_aggregator
+    static opentelemetry::sdk::metrics::NoOpAggregator noop_aggregator;
+    return noop_aggregator;
+  }
+};
+
+}  // namespace metrics
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE
+#endif

sdk/include/opentelemetry/sdk/metrics/view/attributes_processor.h

@@ -0,0 +1,34 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifndef ENABLE_METRICS_PREVIEW
+#  include "opentelemetry/sdk/common/attribute_utils.h"
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace metrics
+{
+using MetricAttributes = opentelemetry::sdk::common::AttributeMap;
+
+class AttributesProcessor
+{
+public:
+  virtual MetricAttributes process(
+      const opentelemetry::common::KeyValueIterable &attributes) noexcept = 0;
+};
+
+class DefaultAttributesProcessor : public AttributesProcessor
+{
+  MetricAttributes process(
+      const opentelemetry::common::KeyValueIterable &attributes) noexcept override
+  {
+    MetricAttributes result(attributes);
+    return result;
+  }
+};
+
+}  // namespace metrics
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE
+#endif

sdk/include/opentelemetry/sdk/metrics/view/instrument_selector.h

@@ -0,0 +1,36 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#ifndef ENABLE_METRICS_PREVIEW
+#  include "opentelemetry/nostd/string_view.h"
+#  include "opentelemetry/sdk/metrics/instruments.h"
+#  include "opentelemetry/sdk/metrics/view/predicate_factory.h"
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace metrics
+{
+class InstrumentSelector
+{
+public:
+  InstrumentSelector(opentelemetry::sdk::metrics::InstrumentType instrument_type,
+                     opentelemetry::nostd::string_view name)
+      : name_filter_{std::move(PredicateFactory::GetPredicate(name, PredicateType::kPattern))},
+        instrument_type_{instrument_type}
+  {}
+
+  // Returns name filter predicate. This shouldn't be deleted
+  const opentelemetry::sdk::metrics::Predicate *const GetNameFilter() { return name_filter_.get(); }
+
+  // Returns instrument filter.
+  InstrumentType GetInstrumentType() { return instrument_type_; }
+
+private:
+  opentelemetry::sdk::metrics::InstrumentType instrument_type_;
+  std::unique_ptr<opentelemetry::sdk::metrics::Predicate> name_filter_;
+};
+}  // namespace metrics
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE
+#endif

sdk/include/opentelemetry/sdk/metrics/view/meter_selector.h

@@ -0,0 +1,47 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+#include "opentelemetry/nostd/string_view.h"
+#include "opentelemetry/sdk/metrics/view/predicate_factory.h"
+#ifndef ENABLE_METRICS_PREVIEW
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace metrics
+{
+class MeterSelector
+{
+public:
+  MeterSelector(opentelemetry::nostd::string_view name,
+                opentelemetry::nostd::string_view version,
+                opentelemetry::nostd::string_view schema)
+      : name_filter_{std::move(PredicateFactory::GetPredicate(name, PredicateType::kExact))},
+        version_filter_{std::move(PredicateFactory::GetPredicate(version, PredicateType::kExact))},
+        schema_filter_{std::move(PredicateFactory::GetPredicate(schema, PredicateType::kExact))}
+  {}
+
+  // Returns name filter predicate. This shouldn't be deleted
+  const opentelemetry::sdk::metrics::Predicate *const GetNameFilter() { return name_filter_.get(); }
+
+  // Returns version filter predicate. This shouldn't be deleted
+  const opentelemetry::sdk::metrics::Predicate *const GetVersionFilter()
+  {
+    return version_filter_.get();
+  }
+
+  // Returns schema filter predicate. This shouldn't be deleted
+  const opentelemetry::sdk::metrics::Predicate *const GetSchemaFilter()
+  {
+    return schema_filter_.get();
+  }
+
+private:
+  std::unique_ptr<opentelemetry::sdk::metrics::Predicate> name_filter_;
+  std::unique_ptr<opentelemetry::sdk::metrics::Predicate> version_filter_;
+  std::unique_ptr<opentelemetry::sdk::metrics::Predicate> schema_filter_;
+};
+}  // namespace metrics
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE
+#endif