src/util/metricsbackend.h

   1 /*
   2 Minetest
   3 Copyright (C) 2013-2020 Minetest core developers team
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #pragma once
  21 #include <memory>
  22 #include "config.h"
  23 #include "util/thread.h"
  24
  25 class MetricCounter
  26 {
  27 public:
  28         MetricCounter() = default;
  29
  30         virtual ~MetricCounter() {}
  31
  32         virtual void increment(double number = 1.0) = 0;
  33         virtual double get() const = 0;
  34 };
  35
  36 typedef std::shared_ptr<MetricCounter> MetricCounterPtr;
  37
  38 class SimpleMetricCounter : public MetricCounter
  39 {
  40 public:
  41         SimpleMetricCounter() = delete;
  42
  43         virtual ~SimpleMetricCounter() {}
  44
  45         SimpleMetricCounter(const std::string &name, const std::string &help_str) :
  46                         MetricCounter(), m_name(name), m_help_str(help_str),
  47                         m_counter(0.0)
  48         {
  49         }
  50
  51         virtual void increment(double number)
  52         {
  53                 MutexAutoLock lock(m_mutex);
  54                 m_counter += number;
  55         }
  56         virtual double get() const
  57         {
  58                 MutexAutoLock lock(m_mutex);
  59                 return m_counter;
  60         }
  61
  62 private:
  63         std::string m_name;
  64         std::string m_help_str;
  65
  66         mutable std::mutex m_mutex;
  67         double m_counter;
  68 };
  69
  70 class MetricGauge
  71 {
  72 public:
  73         MetricGauge() = default;
  74         virtual ~MetricGauge() {}
  75
  76         virtual void increment(double number = 1.0) = 0;
  77         virtual void decrement(double number = 1.0) = 0;
  78         virtual void set(double number) = 0;
  79         virtual double get() const = 0;
  80 };
  81
  82 typedef std::shared_ptr<MetricGauge> MetricGaugePtr;
  83
  84 class SimpleMetricGauge : public MetricGauge
  85 {
  86 public:
  87         SimpleMetricGauge() = delete;
  88
  89         SimpleMetricGauge(const std::string &name, const std::string &help_str) :
  90                         MetricGauge(), m_name(name), m_help_str(help_str), m_gauge(0.0)
  91         {
  92         }
  93
  94         virtual ~SimpleMetricGauge() {}
  95
  96         virtual void increment(double number)
  97         {
  98                 MutexAutoLock lock(m_mutex);
  99                 m_gauge += number;
 100         }
 101         virtual void decrement(double number)
 102         {
 103                 MutexAutoLock lock(m_mutex);
 104                 m_gauge -= number;
 105         }
 106         virtual void set(double number)
 107         {
 108                 MutexAutoLock lock(m_mutex);
 109                 m_gauge = number;
 110         }
 111         virtual double get() const
 112         {
 113                 MutexAutoLock lock(m_mutex);
 114                 return m_gauge;
 115         }
 116
 117 private:
 118         std::string m_name;
 119         std::string m_help_str;
 120
 121         mutable std::mutex m_mutex;
 122         double m_gauge;
 123 };
 124
 125 class MetricsBackend
 126 {
 127 public:
 128         MetricsBackend() = default;
 129
 130         virtual ~MetricsBackend() {}
 131
 132         virtual MetricCounterPtr addCounter(
 133                         const std::string &name, const std::string &help_str);
 134         virtual MetricGaugePtr addGauge(
 135                         const std::string &name, const std::string &help_str);
 136 };
 137
 138 #if USE_PROMETHEUS
 139 MetricsBackend *createPrometheusMetricsBackend();
 140 #endif