ApMonBackend.h

// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.

///
/// \file ApMonBackend.h
/// \author Adam Wegrzynek <adam.wegrzynek@cern.ch>
///

#ifndef ALICEO2_MONITORING_BACKENDS_APMONBACKEND_H
#define ALICEO2_MONITORING_BACKENDS_APMONBACKEND_H

#include "Monitoring/Backend.h"
#include <ApMon.h>
#include <string>
#include <chrono>
#include <memory>
#include <functional>

namespace o2
{
/// ALICE O2 Monitoring system
namespace monitoring
{
/// Monitoring backends
namespace backends
{

/// \brief Backend that uses AppMon (MonALISA)
///
/// Uses ApMonBackend library to push metric to MonALISA Service.
/// ApMonBackend accepts timestamps as integers, therefore a cast is needed.
///
/// \author Adam Wegrzynek <adam.wegrzynek@cern.ch>
class ApMonBackend final : public Backend
{
 public:
  /// Constructs AppMon backend
  /// \param path 	filepath to ApMonBackend configuration file
  ApMonBackend(const std::string& path);

  /// Default destructor
  ~ApMonBackend() = default;

  /// Sends multiple metrics not related to each other
  /// \@param metrics  vector of metrics
  void send(std::vector<Metric>&& metrics) override;

  /// Sends metric via MonALISA
  /// ApMonBackend's intances is type-aware therefore cast of metric value is needed
  /// \param metric           reference to metric object:
  void send(const Metric& metric) override;

  /// Extends entity value
  /// \param name             tag name (unused)
  /// \param value            tag value that is concatenated to entity string
  void addGlobalTag(std::string_view name, std::string_view value) override;

 private:
  /// Sends batch of metrics
  /// \param metrics  vector of metrics
  void sendBatch(const std::vector<std::reference_wrapper<const Metric>>& metrics);

  /// Converts timestamp to format supported by ApMonBackend
  /// \param timestamp 	timestamp in std::chrono::time_point format
  /// \return 		timestamp as integer (milliseconds from epoch)
  int convertTimestamp(const std::chrono::time_point<std::chrono::system_clock>& timestamp);

  /// Gets node name
  /// It looks for environment variable ALIEN_PROC_ID and if it is not set, it uses hostname as node name
  /// \return node name as string
  std::string getNodeName();

  std::unique_ptr<ApMon> mApMon; ///< ApMon object
  std::string mEntity;            ///< MonALISA entity, created out of global tags
  inline static constexpr std::string_view mClusterName = "O2Monitoring_Nodes"; ///< MonALISA cluster name
};

} // namespace backends
} // namespace monitoring
} // namespace o2

#endif // ALICEO2_MONITORING_BACKENDS_APMONBACKEND_H