[EXPORTERS] Remove prometheus timestamps

CHANGELOG.md

@@ -15,6 +15,9 @@ Increment the:
 
 ## [Unreleased]
 
+* [EXPORTER] Remove explicit timestamps from metric points exported by Prometheus
+  [#3895](https://github.com/open-telemetry/opentelemetry-cpp/pull/3895)
+
 * [BUILD] Fix benchmark genrule capturing stderr into JSON output
   [#3925](https://github.com/open-telemetry/opentelemetry-cpp/pull/3925)
 

exporters/prometheus/include/opentelemetry/exporters/prometheus/exporter_utils.h

@@ -153,7 +153,6 @@ class PrometheusExporterUtils
    * Add a target_info metric to collect resource attributes
    */
   static void SetTarget(const sdk::metrics::ResourceMetrics &data,
-                        std::chrono::nanoseconds time,
                         const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope,
                         std::vector<::prometheus::MetricFamily> *output);
 
@@ -166,7 +165,6 @@ class PrometheusExporterUtils
                       const opentelemetry::sdk::metrics::PointAttributes &labels,
                       const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope,
                       ::prometheus::MetricType type,
-                      std::chrono::nanoseconds time,
                       ::prometheus::MetricFamily *metric_family,
                       const opentelemetry::sdk::resource::Resource *resource);
 
@@ -180,7 +178,6 @@ class PrometheusExporterUtils
                       const std::vector<uint64_t> &counts,
                       const opentelemetry::sdk::metrics::PointAttributes &labels,
                       const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope,
-                      std::chrono::nanoseconds time,
                       ::prometheus::MetricFamily *metric_family,
                       const opentelemetry::sdk::resource::Resource *resource);
 
@@ -190,7 +187,6 @@ class PrometheusExporterUtils
   static void SetMetricBasic(
       ::prometheus::ClientMetric &metric,
       const opentelemetry::sdk::metrics::PointAttributes &labels,
-      std::chrono::nanoseconds time,
       const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope,
       const opentelemetry::sdk::resource::Resource *resource);
 

exporters/prometheus/src/exporter_utils.cc

@@ -5,7 +5,6 @@
 #include <prometheus/metric_family.h>
 #include <prometheus/metric_type.h>
 #include <algorithm>
-#include <chrono>
 #include <cstddef>
 #include <cstdint>
 #include <functional>
@@ -19,7 +18,6 @@
 #include <utility>
 #include <vector>
 
-#include "opentelemetry/common/timestamp.h"
 #include "opentelemetry/exporters/prometheus/exporter_utils.h"
 #include "opentelemetry/nostd/variant.h"
 #include "opentelemetry/sdk/common/attribute_utils.h"
@@ -138,9 +136,8 @@ std::vector<prometheus_client::MetricFamily> PrometheusExporterUtils::TranslateT
   // Append target_info as the first metric
   if (populate_target_info && !data.scope_metric_data_.empty())
   {
-    SetTarget(data,
-              data.scope_metric_data_.begin()->metric_data_.begin()->end_ts.time_since_epoch(),
-              without_otel_scope ? nullptr : (*data.scope_metric_data_.begin()).scope_, &output);
+    SetTarget(data, without_otel_scope ? nullptr : (*data.scope_metric_data_.begin()).scope_,
+              &output);
   }
 
   for (const auto &instrumentation_info : data.scope_metric_data_)
@@ -151,7 +148,6 @@ std::vector<prometheus_client::MetricFamily> PrometheusExporterUtils::TranslateT
       auto unit        = metric_data.instrument_descriptor.unit_;
       prometheus_client::MetricFamily metric_family;
       metric_family.help = metric_data.instrument_descriptor.description_;
-      auto time          = metric_data.end_ts.time_since_epoch();
       auto front         = metric_data.point_data_attr_.front();
       auto kind          = getAggregationType(front.point_data);
       bool is_monotonic  = true;
@@ -185,7 +181,7 @@ std::vector<prometheus_client::MetricFamily> PrometheusExporterUtils::TranslateT
             sum = static_cast<double>(nostd::get<int64_t>(histogram_point_data.sum_));
           }
           SetData(std::vector<double>{sum, static_cast<double>(histogram_point_data.count_)},
-                  boundaries, counts, point_data_attr.attributes, scope, time, &metric_family,
+                  boundaries, counts, point_data_attr.attributes, scope, &metric_family,
                   data.resource_);
         }
         else if (type == prometheus_client::MetricType::Gauge)
@@ -196,15 +192,15 @@ std::vector<prometheus_client::MetricFamily> PrometheusExporterUtils::TranslateT
             auto last_value_point_data =
                 nostd::get<sdk::metrics::LastValuePointData>(point_data_attr.point_data);
             std::vector<metric_sdk::ValueType> values{last_value_point_data.value_};
-            SetData(values, point_data_attr.attributes, scope, type, time, &metric_family,
+            SetData(values, point_data_attr.attributes, scope, type, &metric_family,
                     data.resource_);
           }
           else if (nostd::holds_alternative<sdk::metrics::SumPointData>(point_data_attr.point_data))
           {
             auto sum_point_data =
                 nostd::get<sdk::metrics::SumPointData>(point_data_attr.point_data);
             std::vector<metric_sdk::ValueType> values{sum_point_data.value_};
-            SetData(values, point_data_attr.attributes, scope, type, time, &metric_family,
+            SetData(values, point_data_attr.attributes, scope, type, &metric_family,
                     data.resource_);
           }
           else
@@ -221,7 +217,7 @@ std::vector<prometheus_client::MetricFamily> PrometheusExporterUtils::TranslateT
             auto sum_point_data =
                 nostd::get<sdk::metrics::SumPointData>(point_data_attr.point_data);
             std::vector<metric_sdk::ValueType> values{sum_point_data.value_};
-            SetData(values, point_data_attr.attributes, scope, type, time, &metric_family,
+            SetData(values, point_data_attr.attributes, scope, type, &metric_family,
                     data.resource_);
           }
           else
@@ -605,7 +601,6 @@ prometheus_client::MetricType PrometheusExporterUtils::TranslateType(
 
 void PrometheusExporterUtils::SetTarget(
     const sdk::metrics::ResourceMetrics &data,
-    std::chrono::nanoseconds time,
     const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope,
     std::vector<::prometheus::MetricFamily> *output)
 {
@@ -624,7 +619,7 @@ void PrometheusExporterUtils::SetTarget(
   metric.info.value                       = 1.0;
 
   metric_sdk::PointAttributes empty_attributes;
-  SetMetricBasic(metric, empty_attributes, time, scope, data.resource_);
+  SetMetricBasic(metric, empty_attributes, scope, data.resource_);
 
   for (auto &label : data.resource_->GetAttributes())
   {
@@ -645,13 +640,12 @@ void PrometheusExporterUtils::SetData(
     const metric_sdk::PointAttributes &labels,
     const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope,
     prometheus_client::MetricType type,
-    std::chrono::nanoseconds time,
     prometheus_client::MetricFamily *metric_family,
     const opentelemetry::sdk::resource::Resource *resource)
 {
   metric_family->metric.emplace_back();
   prometheus_client::ClientMetric &metric = metric_family->metric.back();
-  SetMetricBasic(metric, labels, time, scope, resource);
+  SetMetricBasic(metric, labels, scope, resource);
   SetValue(values, type, &metric);
 }
 
@@ -666,13 +660,12 @@ void PrometheusExporterUtils::SetData(
     const std::vector<uint64_t> &counts,
     const metric_sdk::PointAttributes &labels,
     const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope,
-    std::chrono::nanoseconds time,
     prometheus_client::MetricFamily *metric_family,
     const opentelemetry::sdk::resource::Resource *resource)
 {
   metric_family->metric.emplace_back();
   prometheus_client::ClientMetric &metric = metric_family->metric.back();
-  SetMetricBasic(metric, labels, time, scope, resource);
+  SetMetricBasic(metric, labels, scope, resource);
   SetValue(values, boundaries, counts, &metric);
 }
 
@@ -682,11 +675,9 @@ void PrometheusExporterUtils::SetData(
 void PrometheusExporterUtils::SetMetricBasic(
     prometheus_client::ClientMetric &metric,
     const metric_sdk::PointAttributes &labels,
-    std::chrono::nanoseconds time,
     const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope,
     const opentelemetry::sdk::resource::Resource *resource)
 {
-  metric.timestamp_ms = time.count() / 1000000;
   if (labels.empty() && nullptr == resource)
   {
     return;

exporters/prometheus/test/prometheus_test_helper.h

@@ -23,6 +23,10 @@ struct TestDataPoints
   Resource resource = Resource::Create(ResourceAttributes{});
   nostd::unique_ptr<InstrumentationScope> instrumentation_scope =
       InstrumentationScope::Create("library_name", "1.2.0");
+  opentelemetry::common::SystemTimestamp start_ts =
+      opentelemetry::common::SystemTimestamp{std::chrono::microseconds{1766662500000}};
+  opentelemetry::common::SystemTimestamp end_ts =
+      opentelemetry::common::SystemTimestamp{std::chrono::microseconds{1766662560000}};
 
   /**
    * Helper function to create ResourceMetrics
@@ -39,8 +43,7 @@ struct TestDataPoints
         metric_sdk::InstrumentDescriptor{"library_name", "description", "unit",
                                          metric_sdk::InstrumentType::kCounter,
                                          metric_sdk::InstrumentValueType::kDouble},
-        metric_sdk::AggregationTemporality::kDelta, opentelemetry::common::SystemTimestamp{},
-        opentelemetry::common::SystemTimestamp{},
+        metric_sdk::AggregationTemporality::kDelta, start_ts, end_ts,
         std::vector<metric_sdk::PointDataAttributes>{
             {metric_sdk::PointAttributes{{"a1", "b1"}}, sum_point_data},
             {metric_sdk::PointAttributes{{"a2", "b2"}}, sum_point_data2}}};
@@ -67,13 +70,13 @@ struct TestDataPoints
         metric_sdk::InstrumentDescriptor{"library_name", "description", "unit",
                                          metric_sdk::InstrumentType::kHistogram,
                                          metric_sdk::InstrumentValueType::kDouble},
-        metric_sdk::AggregationTemporality::kDelta, opentelemetry::common::SystemTimestamp{},
-        opentelemetry::common::SystemTimestamp{},
+        metric_sdk::AggregationTemporality::kDelta, start_ts, end_ts,
         std::vector<metric_sdk::PointDataAttributes>{
             {metric_sdk::PointAttributes{{"a1", "b1"}}, histogram_point_data},
             {metric_sdk::PointAttributes{{"a2", "b2"}}, histogram_point_data2}}};
     data.scope_metric_data_ = std::vector<metric_sdk::ScopeMetrics>{
         {instrumentation_scope.get(), std::vector<metric_sdk::MetricData>{metric_data}}};
+
     return data;
   }
 
@@ -93,8 +96,7 @@ struct TestDataPoints
         metric_sdk::InstrumentDescriptor{"library_name", "description", "unit",
                                          metric_sdk::InstrumentType::kCounter,
                                          metric_sdk::InstrumentValueType::kDouble},
-        metric_sdk::AggregationTemporality::kDelta, opentelemetry::common::SystemTimestamp{},
-        opentelemetry::common::SystemTimestamp{},
+        metric_sdk::AggregationTemporality::kDelta, start_ts, end_ts,
         std::vector<metric_sdk::PointDataAttributes>{
             {metric_sdk::PointAttributes{{"a1", "b1"}}, last_value_point_data},
             {metric_sdk::PointAttributes{{"a2", "b2"}}, last_value_point_data2}}};
@@ -113,8 +115,7 @@ struct TestDataPoints
         metric_sdk::InstrumentDescriptor{"library_name", "description", "unit",
                                          metric_sdk::InstrumentType::kCounter,
                                          metric_sdk::InstrumentValueType::kDouble},
-        metric_sdk::AggregationTemporality::kDelta, opentelemetry::common::SystemTimestamp{},
-        opentelemetry::common::SystemTimestamp{},
+        metric_sdk::AggregationTemporality::kDelta, start_ts, end_ts,
         std::vector<metric_sdk::PointDataAttributes>{
             {metric_sdk::PointAttributes{{"a1", "b1"}}, drop_point_data},
             {metric_sdk::PointAttributes{{"a2", "b2"}}, drop_point_data2}}};