ceph/src/jaegertracing/opentelemetry-cpp/third_party/prometheus-cpp/core/include/prometheus/registry.h

   1 #pragma once
   2
   3 #include <memory>
   4 #include <mutex>
   5 #include <string>
   6 #include <vector>
   7
   8 #include "prometheus/collectable.h"
   9 #include "prometheus/detail/core_export.h"
  10 #include "prometheus/family.h"
  11 #include "prometheus/labels.h"
  12 #include "prometheus/metric_family.h"
  13
  14 namespace prometheus {
  15
  16 class Counter;
  17 class Gauge;
  18 class Histogram;
  19 class Summary;
  20
  21 namespace detail {
  22
  23 template <typename T>
  24 class Builder;  // IWYU pragma: keep
  25
  26 }
  27 /// \brief Manages the collection of a number of metrics.
  28 ///
  29 /// The Registry is responsible to expose data to a class/method/function
  30 /// "bridge", which returns the metrics in a format Prometheus supports.
  31 ///
  32 /// The key class is the Collectable. This has a method - called Collect() -
  33 /// that returns zero or more metrics and their samples. The metrics are
  34 /// represented by the class Family<>, which implements the Collectable
  35 /// interface. A new metric is registered with BuildCounter(), BuildGauge(),
  36 /// BuildHistogram() or BuildSummary().
  37 ///
  38 /// The class is thread-safe. No concurrent call to any API of this type causes
  39 /// a data race.
  40 class PROMETHEUS_CPP_CORE_EXPORT Registry : public Collectable {
  41  public:
  42   /// \brief How to deal with repeatedly added family names for a type.
  43   ///
  44   /// Adding a family with the same name but different types is always an error
  45   /// and will lead to an exception.
  46   enum class InsertBehavior {
  47     /// \brief If a family with the same name and labels already exists return
  48     /// the existing one. If no family with that name exists create it.
  49     /// Otherwise throw.
  50     Merge,
  51     /// \brief Throws if a family with the same name already exists.
  52     Throw,
  53   };
  54
  55   /// \brief name Create a new registry.
  56   ///
  57   /// \param insert_behavior How to handle families with the same name.
  58   explicit Registry(InsertBehavior insert_behavior = InsertBehavior::Merge);
  59
  60   /// \brief Deleted copy constructor.
  61   Registry(const Registry&) = delete;
  62
  63   /// \brief Deleted copy assignment.
  64   Registry& operator=(const Registry&) = delete;
  65
  66   /// \brief Deleted move constructor.
  67   Registry(Registry&&) = delete;
  68
  69   /// \brief Deleted move assignment.
  70   Registry& operator=(Registry&&) = delete;
  71
  72   /// \brief name Destroys a registry.
  73   ~Registry() override;
  74
  75   /// \brief Returns a list of metrics and their samples.
  76   ///
  77   /// Every time the Registry is scraped it calls each of the metrics Collect
  78   /// function.
  79   ///
  80   /// \return Zero or more metrics and their samples.
  81   std::vector<MetricFamily> Collect() const override;
  82
  83   /// \brief Removes a metrics family from the registry.
  84   ///
  85   /// Please note that this operation invalidates the previously
  86   /// returned reference to the Family and all of their added
  87   /// metric objects.
  88   ///
  89   /// \tparam T One of the metric types Counter, Gauge, Histogram or Summary.
  90   /// \param family The family to remove
  91   ///
  92   /// \return True if the family was found and removed.
  93   template <typename T>
  94   bool Remove(const Family<T>& family);
  95
  96  private:
  97   template <typename T>
  98   friend class detail::Builder;
  99
 100   template <typename T>
 101   std::vector<std::unique_ptr<Family<T>>>& GetFamilies();
 102
 103   template <typename T>
 104   bool NameExistsInOtherType(const std::string& name) const;
 105
 106   template <typename T>
 107   Family<T>& Add(const std::string& name, const std::string& help,
 108                  const Labels& labels);
 109
 110   const InsertBehavior insert_behavior_;
 111   std::vector<std::unique_ptr<Family<Counter>>> counters_;
 112   std::vector<std::unique_ptr<Family<Gauge>>> gauges_;
 113   std::vector<std::unique_ptr<Family<Histogram>>> histograms_;
 114   std::vector<std::unique_ptr<Family<Summary>>> summaries_;
 115   mutable std::mutex mutex_;
 116 };
 117
 118 }  // namespace prometheus