From a36cee15e24fad4b518ea6fb60cf2e293e32c0e6 Mon Sep 17 00:00:00 2001
From: David Ashpole <dashpole@google.com>
Date: Thu, 21 Sep 2023 15:54:01 +0000
Subject: [PATCH] address comments

---
 exporters/prometheus/src/exporter_utils.cc    | 32 ++++++++++++-------
 .../sdk/metrics/export/metric_producer.h      | 15 ++++++++-
 2 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/exporters/prometheus/src/exporter_utils.cc b/exporters/prometheus/src/exporter_utils.cc
index f20ba5ef9e..a033b17254 100644
--- a/exporters/prometheus/src/exporter_utils.cc
+++ b/exporters/prometheus/src/exporter_utils.cc
@@ -20,6 +20,10 @@ namespace exporter
 {
 namespace metrics
 {
+
+static constexpr const char *kScopeNameKey = "otel_scope_name";
+static constexpr const char *kScopeVersionKey = "otel_scope_version";
+
 /**
  * Helper function to convert OpenTelemetry metrics data collection
  * to Prometheus metrics data collection
@@ -273,30 +277,36 @@ void PrometheusExporterUtils::SetMetricBasic(
 {
   metric.timestamp_ms = time.count() / 1000000;
 
-  size_t i = 0;
   if (!labels.empty())
   {
-    metric.label.resize(labels.size());
+    metric.label.reserve(labels.size() + 2);
     for (auto const &label : labels)
     {
-      auto sanitized          = SanitizeNames(label.first);
-      metric.label[i].name    = sanitized;
-      metric.label[i++].value = AttributeValueToString(label.second);
+      prometheus_client::ClientMetric::Label sanitizedLabel;
+      sanitizedLabel.name  = SanitizeNames(label.first);
+      sanitizedLabel.value = AttributeValueToString(label.second);
+      metric.label.push_back(std::move(sanitizedLabel));
     }
   }
+  if (!scope)
+  {
+    return;
+  }
   auto scope_name = scope->GetName();
   if (!scope_name.empty())
   {
-    metric.label.resize(i + 1);
-    metric.label[i].name    = "otel_scope_name";
-    metric.label[i++].value = scope_name;
+    prometheus_client::ClientMetric::Label label;
+    label.name  = std::move(kScopeNameKey);
+    label.value = std::move(scope_name);
+    metric.label.push_back(std::move(label));
   }
   auto scope_version = scope->GetVersion();
   if (!scope_version.empty())
   {
-    metric.label.resize(i + 1);
-    metric.label[i].name    = "otel_scope_version";
-    metric.label[i++].value = scope_version;
+    prometheus_client::ClientMetric::Label label;
+    label.name  = std::move(kScopeNameKey);
+    label.value = std::move(scope_version);
+    metric.label.push_back(std::move(label));
   }
 }
 
diff --git a/sdk/include/opentelemetry/sdk/metrics/export/metric_producer.h b/sdk/include/opentelemetry/sdk/metrics/export/metric_producer.h
index 2a0c87fcaa..b05298de34 100644
--- a/sdk/include/opentelemetry/sdk/metrics/export/metric_producer.h
+++ b/sdk/include/opentelemetry/sdk/metrics/export/metric_producer.h
@@ -31,8 +31,21 @@ namespace metrics
  */
 struct ScopeMetrics
 {
-  const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope_;
+  const opentelemetry::sdk::instrumentationscope::InstrumentationScope *scope_ = nullptr;
   std::vector<MetricData> metric_data_;
+
+  template <class ScopePtr, class MetricDataType>
+  inline ScopeMetrics(ScopePtr &&scope, MetricDataType &&metric)
+      : scope_{std::move(scope)}, metric_data_{std::move(metric)}
+  {}
+
+  inline ScopeMetrics() {}
+  inline ScopeMetrics(const ScopeMetrics &) = default;
+  inline ScopeMetrics(ScopeMetrics &&)      = default;
+
+  inline ScopeMetrics &operator=(const ScopeMetrics &) = default;
+
+  inline ScopeMetrics &operator=(ScopeMetrics &&) = default;
 };
 
 struct ResourceMetrics