add more tests, and cardinality limit configurable at Sync storage

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

@@ -40,9 +40,10 @@ class SyncMetricStorage : public MetricStorage, public SyncWritableMetricStorage
                     const AttributesProcessor *attributes_processor,
                     nostd::shared_ptr<ExemplarReservoir> &&exemplar_reservoir
                         OPENTELEMETRY_MAYBE_UNUSED,
-                    const AggregationConfig *aggregation_config)
+                    const AggregationConfig *aggregation_config,
+                    size_t attributes_limit = kAggregationCardinalityLimit)
       : instrument_descriptor_(instrument_descriptor),
-        attributes_hashmap_(new AttributesHashMap()),
+        attributes_hashmap_(new AttributesHashMap(attributes_limit)),
         attributes_processor_(attributes_processor),
 #ifdef ENABLE_METRICS_EXEMPLAR_PREVIEW
         exemplar_reservoir_(exemplar_reservoir),

sdk/test/metrics/cardinality_limit_test.cc

@@ -1,10 +1,12 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
+#include "common.h"
 #include "opentelemetry/common/key_value_iterable_view.h"
 #include "opentelemetry/sdk/metrics/aggregation/sum_aggregation.h"
 #include "opentelemetry/sdk/metrics/instruments.h"
 #include "opentelemetry/sdk/metrics/state/attributes_hashmap.h"
+#include "opentelemetry/sdk/metrics/state/sync_metric_storage.h"
 
 #include <gtest/gtest.h>
 #include <functional>
@@ -26,23 +28,82 @@ TEST(CardinalityLimit, AttributesHashMapBasicTests)
   {
     OrderedAttributeMap attributes = {{"key", std::to_string(i)}};
     auto hash                      = opentelemetry::sdk::common::GetHashForAttributeMap(attributes);
-    hash_map.GetOrSetDefault(attributes, aggregation_callback, hash)->Aggregate(record_value);
+    static_cast<LongSumAggregation *>(
+        hash_map.GetOrSetDefault(attributes, aggregation_callback, hash))
+        ->Aggregate(record_value);
   }
   EXPECT_EQ(hash_map.Size(), 10);
-  // add 5 unique metric points above limit
+  // add 5 unique metric points above limit, they should get consolidated as single metric point.
   for (auto i = 10; i < 15; i++)
   {
     OrderedAttributeMap attributes = {{"key", std::to_string(i)}};
     auto hash                      = opentelemetry::sdk::common::GetHashForAttributeMap(attributes);
-    hash_map.GetOrSetDefault(attributes, aggregation_callback, hash)->Aggregate(record_value);
+    static_cast<LongSumAggregation *>(
+        hash_map.GetOrSetDefault(attributes, aggregation_callback, hash))
+        ->Aggregate(record_value);
   }
   EXPECT_EQ(hash_map.Size(), 11);  // only one more metric point should be added as overflow.
   // get the overflow metric point
   auto agg = hash_map.GetOrSetDefault(
       OrderedAttributeMap({{kAttributesLimitOverflowKey, kAttributesLimitOverflowValue}}),
       aggregation_callback, kOverflowAttributesHash);
   EXPECT_NE(agg, nullptr);
-  auto sum_agg = reinterpret_cast<LongSumAggregation *>(agg);
-  EXPECT_EQ(nostd::get<long>(nostd::get<SumPointData>(sum_agg->ToPoint()).value_),
+  auto sum_agg = static_cast<LongSumAggregation *>(agg);
+  EXPECT_EQ(nostd::get<int64_t>(nostd::get<SumPointData>(sum_agg->ToPoint()).value_),
             record_value * 5);
-}
+}
+
+class WritableMetricStorageCardinalityLimitTestFixture
+    : public ::testing::TestWithParam<AggregationTemporality>
+{};
+
+TEST_P(WritableMetricStorageCardinalityLimitTestFixture, LongCounterSumAggregation)
+{
+  auto sdk_start_ts               = std::chrono::system_clock::now();
+  const size_t attributes_limit   = 10;
+  InstrumentDescriptor instr_desc = {"name", "desc", "1unit", InstrumentType::kCounter,
+                                     InstrumentValueType::kLong};
+  std::unique_ptr<DefaultAttributesProcessor> default_attributes_processor{
+      new DefaultAttributesProcessor{}};
+  SyncMetricStorage storage(instr_desc, AggregationType::kSum, default_attributes_processor.get(),
+                            ExemplarReservoir::GetNoExemplarReservoir(), nullptr, attributes_limit);
+
+  long record_value = 100;
+  // add 10 unique metric points, and 5 more above limit.
+  for (auto i = 0; i < 15; i++)
+  {
+    std::map<std::string, std::string> attributes = {{"key", std::to_string(i)}};
+    storage.RecordLong(record_value,
+                       KeyValueIterableView<std::map<std::string, std::string>>(attributes),
+                       opentelemetry::context::Context{});
+  }
+  AggregationTemporality temporality = GetParam();
+  std::shared_ptr<CollectorHandle> collector(new MockCollectorHandle(temporality));
+  std::vector<std::shared_ptr<CollectorHandle>> collectors;
+  collectors.push_back(collector);
+  //... Some computation here
+  auto collection_ts      = std::chrono::system_clock::now();
+  size_t count_attributes = 0;
+  bool overflow_present   = false;
+  storage.Collect(
+      collector.get(), collectors, sdk_start_ts, collection_ts, [&](const MetricData &metric_data) {
+        for (const auto &data_attr : metric_data.point_data_attr_)
+        {
+          const auto &data = opentelemetry::nostd::get<SumPointData>(data_attr.point_data);
+          count_attributes++;
+          if (opentelemetry::nostd::get<std::string>(data_attr.attributes.begin()->second) ==
+              kAttributesLimitOverflowValue)
+          {
+            EXPECT_EQ(nostd::get<int64_t>(data.value_), record_value * 5);
+            overflow_present = true;
+          }
+        }
+        return true;
+      });
+  EXPECT_EQ(count_attributes, attributes_limit + 1);  // +1 for overflow metric point.
+  EXPECT_EQ(overflow_present, true);
+}
+INSTANTIATE_TEST_SUITE_P(All,
+                         WritableMetricStorageCardinalityLimitTestFixture,
+                         ::testing::Values(AggregationTemporality::kCumulative,
+                                           AggregationTemporality::kDelta));