ceph/src/jaegertracing/opentelemetry-cpp/exporters/prometheus/include/opentelemetry/exporters/prometheus/exporter.h

   1 // Copyright The OpenTelemetry Authors
   2 // SPDX-License-Identifier: Apache-2.0
   3
   4 #pragma once
   5 #ifndef ENABLE_METRICS_PREVIEW
   6 #  include <memory>
   7 #  include <string>
   8 #  include <vector>
   9
  10 #  include <prometheus/exposer.h>
  11 #  include "opentelemetry/common/spin_lock_mutex.h"
  12 #  include "opentelemetry/exporters/prometheus/collector.h"
  13 #  include "opentelemetry/nostd/span.h"
  14 #  include "opentelemetry/sdk/common/env_variables.h"
  15 #  include "opentelemetry/sdk/metrics/metric_exporter.h"
  16 #  include "opentelemetry/version.h"
  17
  18 /**
  19  * This class is an implementation of the MetricsExporter interface and
  20  * exports Prometheus metrics data. Functions in this class should be
  21  * called by the Controller in our data pipeline.
  22  */
  23
  24 OPENTELEMETRY_BEGIN_NAMESPACE
  25
  26 namespace exporter
  27 {
  28 namespace metrics
  29 {
  30
  31 inline const std::string GetPrometheusDefaultHttpEndpoint()
  32 {
  33   constexpr char kPrometheusEndpointEnv[]     = "PROMETHEUS_EXPORTER_ENDPOINT";
  34   constexpr char kPrometheusEndpointDefault[] = "localhost:9464";
  35
  36   auto endpoint = opentelemetry::sdk::common::GetEnvironmentVariable(kPrometheusEndpointEnv);
  37   return endpoint.size() ? endpoint : kPrometheusEndpointDefault;
  38 }
  39
  40 /**
  41  * Struct to hold Prometheus exporter options.
  42  */
  43 struct PrometheusExporterOptions
  44 {
  45   // The endpoint the Prometheus backend can collect metrics from
  46   std::string url = GetPrometheusDefaultHttpEndpoint();
  47 };
  48
  49 class PrometheusExporter : public sdk::metrics::MetricExporter
  50 {
  51 public:
  52   /**
  53    * Constructor - binds an exposer and collector to the exporter
  54    * @param options: options for an exposer that exposes
  55    *  an HTTP endpoint for the exporter to connect to
  56    */
  57   PrometheusExporter(const PrometheusExporterOptions &options);
  58
  59   /**
  60    * Exports a batch of Metric Records.
  61    * @param records: a collection of records to export
  62    * @return: returns a ReturnCode detailing a success, or type of failure
  63    */
  64   sdk::common::ExportResult Export(const sdk::metrics::ResourceMetrics &data) noexcept override;
  65
  66   /**
  67    * Force flush the exporter.
  68    */
  69   bool ForceFlush(
  70       std::chrono::microseconds timeout = (std::chrono::microseconds::max)()) noexcept override;
  71
  72   /**
  73    * Shuts down the exporter and does cleanup.
  74    * Since Prometheus is a pull based interface,
  75    * we cannot serve data remaining in the intermediate
  76    * collection to to client an HTTP request being sent,
  77    * so we flush the data.
  78    */
  79   bool Shutdown(std::chrono::microseconds timeout = std::chrono::microseconds(0)) noexcept override;
  80
  81   /**
  82    * @return: returns a shared_ptr to
  83    * the PrometheusCollector instance
  84    */
  85   std::shared_ptr<PrometheusCollector> &GetCollector();
  86
  87   /**
  88    * @return: Gets the shutdown status of the exporter
  89    */
  90   bool IsShutdown() const;
  91
  92 private:
  93   // The configuration options associated with this exporter.
  94   const PrometheusExporterOptions options_;
  95   /**
  96    * exporter shutdown status
  97    */
  98   bool is_shutdown_;
  99
 100   /**
 101    * Pointer to a
 102    * PrometheusCollector instance
 103    */
 104   std::shared_ptr<PrometheusCollector> collector_;
 105
 106   /**
 107    * Pointer to an
 108    * Exposer instance
 109    */
 110   std::unique_ptr<::prometheus::Exposer> exposer_;
 111
 112   /**
 113    * friend class for testing
 114    */
 115   friend class PrometheusExporterTest;
 116
 117   /**
 118    * PrometheusExporter constructor with no parameters
 119    * Used for testing only
 120    */
 121   PrometheusExporter();
 122 };
 123 }  // namespace metrics
 124 }  // namespace exporter
 125 OPENTELEMETRY_END_NAMESPACE
 126 #endif  // ENABLE_METRICS_PREVIEW