--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancFramework/Sources/MetricsRegistry.h	Wed Jun 10 20:30:34 2020 +0200
@@ -0,0 +1,191 @@
+/**
+ * Orthanc - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2020 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * In addition, as a special exception, the copyright holders of this
+ * program give permission to link the code of its release with the
+ * OpenSSL project's "OpenSSL" library (or with modified versions of it
+ * that use the same license as the "OpenSSL" library), and distribute
+ * the linked executables. You must obey the GNU General Public License
+ * in all respects for all of the code used other than "OpenSSL". If you
+ * modify file(s) with this exception, you may extend this exception to
+ * your version of the file(s), but you are not obligated to do so. If
+ * you do not wish to do so, delete this exception statement from your
+ * version. If you delete this exception statement from all source files
+ * in the program, then also delete it here.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#pragma once
+
+#include "OrthancFramework.h"
+
+#if !defined(ORTHANC_SANDBOXED)
+#  error The macro ORTHANC_SANDBOXED must be defined
+#endif
+
+#if ORTHANC_SANDBOXED == 1
+#  error The class MetricsRegistry cannot be used in sandboxed environments
+#endif
+
+#include <boost/thread/mutex.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
+
+namespace Orthanc
+{
+  enum MetricsType
+  {
+    MetricsType_Default,
+    MetricsType_MaxOver10Seconds,
+    MetricsType_MaxOver1Minute,
+    MetricsType_MinOver10Seconds,
+    MetricsType_MinOver1Minute
+  };
+  
+  class ORTHANC_PUBLIC MetricsRegistry : public boost::noncopyable
+  {
+  private:
+    class Item;
+
+    typedef std::map<std::string, Item*>   Content;
+
+    bool          enabled_;
+    boost::mutex  mutex_;
+    Content       content_;
+
+    void SetValueInternal(const std::string& name,
+                          float value,
+                          MetricsType type);
+
+  public:
+    MetricsRegistry() :
+      enabled_(true)
+    {
+    }
+
+    ~MetricsRegistry();
+
+    bool IsEnabled() const
+    {
+      return enabled_;
+    }
+
+    void SetEnabled(bool enabled);
+
+    void Register(const std::string& name,
+                  MetricsType type);
+
+    void SetValue(const std::string& name,
+                  float value,
+                  MetricsType type)
+    {
+      // Inlining to avoid loosing time if metrics are disabled
+      if (enabled_)
+      {
+        SetValueInternal(name, value, type);
+      }
+    }
+    
+    void SetValue(const std::string& name,
+                  float value)
+    {
+      SetValue(name, value, MetricsType_Default);
+    }
+
+    MetricsType GetMetricsType(const std::string& name);
+
+    // https://prometheus.io/docs/instrumenting/exposition_formats/#text-based-format
+    void ExportPrometheusText(std::string& s);
+
+
+    class ORTHANC_PUBLIC SharedMetrics : public boost::noncopyable
+    {
+    private:
+      boost::mutex      mutex_;
+      MetricsRegistry&  registry_;
+      std::string       name_;
+      float             value_;
+
+    public:
+      SharedMetrics(MetricsRegistry& registry,
+                    const std::string& name,
+                    MetricsType type) :
+        registry_(registry),
+        name_(name),
+        value_(0)
+      {
+      }
+
+      void Add(float delta);
+    };
+
+
+    class ORTHANC_PUBLIC ActiveCounter : public boost::noncopyable
+    {
+    private:
+      SharedMetrics&   metrics_;
+
+    public:
+      ActiveCounter(SharedMetrics& metrics) :
+        metrics_(metrics)
+      {
+        metrics_.Add(1);
+      }
+
+      ~ActiveCounter()
+      {
+        metrics_.Add(-1);
+      }
+    };
+
+
+    class ORTHANC_PUBLIC Timer : public boost::noncopyable
+    {
+    private:
+      MetricsRegistry&          registry_;
+      std::string               name_;
+      MetricsType               type_;
+      bool                      active_;
+      boost::posix_time::ptime  start_;
+
+      void Start();
+
+    public:
+      Timer(MetricsRegistry& registry,
+            const std::string& name) :
+        registry_(registry),
+        name_(name),
+        type_(MetricsType_MaxOver10Seconds)
+      {
+        Start();
+      }
+
+      Timer(MetricsRegistry& registry,
+            const std::string& name,
+            MetricsType type) :
+        registry_(registry),
+        name_(name),
+        type_(type)
+      {
+        Start();
+      }
+
+      ~Timer();
+    };
+  };
+}