[exporters/prometheus] Several refactors

exporters/prometheus/include/opentelemetry/exporters/prometheus/collector.h

@@ -12,8 +12,6 @@
 #include "opentelemetry/exporters/prometheus/exporter_utils.h"
 #include "opentelemetry/sdk/metrics/metric_reader.h"
 
-namespace prometheus_client = ::prometheus;
-
 OPENTELEMETRY_BEGIN_NAMESPACE
 namespace exporter
 {
@@ -22,7 +20,7 @@ namespace metrics
 /**
  * The Prometheus Collector maintains the intermediate collection in Prometheus Exporter
  */
-class PrometheusCollector : public prometheus_client::Collectable
+class PrometheusCollector : public ::prometheus::Collectable
 {
 public:
   /**
@@ -38,7 +36,7 @@ class PrometheusCollector : public prometheus_client::Collectable
    *
    * @return all metrics in the metricsToCollect snapshot
    */
-  std::vector<prometheus_client::MetricFamily> Collect() const override;
+  std::vector<::prometheus::MetricFamily> Collect() const override;
 
 private:
   sdk::metrics::MetricReader *reader_;

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

@@ -16,98 +16,13 @@ namespace exporter
 namespace metrics
 {
 /**
- * The Prometheus Utils contains utility functions for Prometheus Exporter
+ * Convert OpenTelemetry metrics data collection to Prometheus metrics data collection
+ *
+ * @param data a collection of metrics in OpenTelemetry
+ * @return a collection of translated metrics that is acceptable by Prometheus
  */
-class PrometheusExporterUtils
-{
-public:
-  /**
-   * Helper function to convert OpenTelemetry metrics data collection
-   * to Prometheus metrics data collection
-   *
-   * @param records a collection of metrics in OpenTelemetry
-   * @return a collection of translated metrics that is acceptable by Prometheus
-   */
-  static std::vector<::prometheus::MetricFamily> TranslateToPrometheus(
-      const sdk::metrics::ResourceMetrics &data);
-
-private:
-  /**
-   * Sanitize the given metric name or label according to Prometheus rule.
-   *
-   * This function is needed because names in OpenTelemetry can contain
-   * alphanumeric characters, '_', '.', and '-', whereas in Prometheus the
-   * name should only contain alphanumeric characters and '_'.
-   */
-  static std::string SanitizeNames(std::string name);
-
-  static opentelemetry::sdk::metrics::AggregationType getAggregationType(
-      const opentelemetry::sdk::metrics::PointType &point_type);
-
-  /**
-   * Translate the OTel metric type to Prometheus metric type
-   */
-  static ::prometheus::MetricType TranslateType(opentelemetry::sdk::metrics::AggregationType kind,
-                                                bool is_monotonic = true);
-
-  /**
-   * Set metric data for:
-   * Counter => Prometheus Counter
-   */
-  template <typename T>
-  static void SetData(std::vector<T> values,
-                      const opentelemetry::sdk::metrics::PointAttributes &labels,
-                      ::prometheus::MetricType type,
-                      ::prometheus::MetricFamily *metric_family);
-
-  /**
-   * Set metric data for:
-   * Histogram => Prometheus Histogram
-   */
-  template <typename T>
-  static void SetData(std::vector<T> values,
-                      const std::vector<double> &boundaries,
-                      const std::vector<uint64_t> &counts,
-                      const opentelemetry::sdk::metrics::PointAttributes &labels,
-                      ::prometheus::MetricFamily *metric_family);
-
-  /**
-   * Set time and labels to metric data
-   */
-  static void SetMetricBasic(::prometheus::ClientMetric &metric,
-                             const opentelemetry::sdk::metrics::PointAttributes &labels);
-
-  /**
-   * Convert attribute value to string
-   */
-  static std::string AttributeValueToString(
-      const opentelemetry::sdk::common::OwnedAttributeValue &value);
-
-  /**
-   * Handle Counter and Gauge.
-   */
-  template <typename T>
-  static void SetValue(std::vector<T> values,
-                       ::prometheus::MetricType type,
-                       ::prometheus::ClientMetric *metric);
-
-  /**
-   * Handle Gauge from MinMaxSumCount
-   */
-  static void SetValue(double value, ::prometheus::ClientMetric *metric);
-
-  /**
-   * Handle Histogram
-   */
-  template <typename T>
-  static void SetValue(std::vector<T> values,
-                       const std::vector<double> &boundaries,
-                       const std::vector<uint64_t> &counts,
-                       ::prometheus::ClientMetric *metric);
-
-  // For testing
-  friend class SanitizeNameTester;
-};
+std::vector<::prometheus::MetricFamily> TranslateToPrometheus(
+    const sdk::metrics::ResourceMetrics &data);
 }  // namespace metrics
 }  // namespace exporter
 OPENTELEMETRY_END_NAMESPACE

exporters/prometheus/src/collector.cc

@@ -4,9 +4,10 @@
 #include "opentelemetry/exporters/prometheus/collector.h"
 #include "opentelemetry/sdk/common/global_log_handler.h"
 
-namespace metric_sdk = opentelemetry::sdk::metrics;
-
 OPENTELEMETRY_BEGIN_NAMESPACE
+
+namespace metric_sdk = sdk::metrics;
+
 namespace exporter
 {
 namespace metrics
@@ -24,7 +25,7 @@ PrometheusCollector::PrometheusCollector(sdk::metrics::MetricReader *reader) : r
  *
  * @return all metrics in the metricsToCollect snapshot
  */
-std::vector<prometheus_client::MetricFamily> PrometheusCollector::Collect() const
+std::vector<::prometheus::MetricFamily> PrometheusCollector::Collect() const
 {
   if (reader_->IsShutdown())
   {
@@ -35,9 +36,9 @@ std::vector<prometheus_client::MetricFamily> PrometheusCollector::Collect() cons
   }
   collection_lock_.lock();
 
-  std::vector<prometheus_client::MetricFamily> result;
+  std::vector<::prometheus::MetricFamily> result;
   reader_->Collect([&result](sdk::metrics::ResourceMetrics &metric_data) {
-    auto prometheus_metric_data = PrometheusExporterUtils::TranslateToPrometheus(metric_data);
+    auto prometheus_metric_data = TranslateToPrometheus(metric_data);
     for (auto &data : prometheus_metric_data)
       result.emplace_back(data);
     return true;