src/logger.hpp

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2022, Arizona Board of Regents.
 *
 * 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.
 *
 * 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/>.
 *
 * Author: Jerald Paul Abraham <jeraldabraham@email.arizona.edu>
 */

#ifndef NDNTG_LOGGER_HPP
#define NDNTG_LOGGER_HPP

#include <cstdlib>
#include <fstream>
#include <string>

#include <boost/filesystem.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>

namespace ndntg {

class Logger
{
public:
  explicit
  Logger(const std::string& module)
    : m_module(module)
  {
  }

  void
  log(const std::string& logLine, bool printTime, bool printToConsole)
  {
    if (m_logLocation.length() > 0) {
      if (printTime)
        m_logFile << getTimestamp() << " - ";
      m_logFile << logLine << std::endl;
      m_logFile.flush();
      if (printToConsole) {
        if (printTime)
          std::cout << getTimestamp() << " - ";
        std::cout << logLine << std::endl;
      }
    }
    else {
      if (printTime)
        std::cout << getTimestamp() << " - ";
      std::cout << logLine << std::endl;
    }
  }

  void
  initializeLog(const std::string& instanceId)
  {
    m_logLocation = "";
    const char* envVar = std::getenv("NDN_TRAFFIC_LOGFOLDER");
    if (envVar != nullptr)
      m_logLocation = envVar;

    if (m_logLocation.empty()) {
      std::cout << "Environment variable NDN_TRAFFIC_LOGFOLDER not set.\n"
                << "Using default output for logging." << std::endl;
      return;
    }

    boost::filesystem::path logdir(m_logLocation);
    if (boost::filesystem::exists(logdir)) {
      if (boost::filesystem::is_directory(logdir)) {
        auto logfile = logdir / (m_module + '_' + instanceId + ".log");
        m_logFile.open(logfile.string(), std::ofstream::out | std::ofstream::trunc);
        if (m_logFile.is_open()) {
          std::cout << "Log file initialized: " << logfile << std::endl;
        }
        else {
          std::cout << "ERROR: Unable to initialize a log file at: " << m_logLocation << std::endl
                    << "Using default output for logging." << std::endl;
          m_logLocation = "";
        }
      }
      else {
        std::cout << "NDN_TRAFFIC_LOGFOLDER should be a directory.\n"
                  << "Using default output for logging." << std::endl;
        m_logLocation = "";
      }
    }
    else {
      std::cout << "NDN_TRAFFIC_LOGFOLDER does not exist.\n"
                << "Using default output for logging." << std::endl;
      m_logLocation = "";
    }
  }

private:
  static std::string
  getTimestamp()
  {
    auto now = boost::posix_time::second_clock::local_time();
    return to_simple_string(now);
  }

private:
  std::string m_module;
  std::string m_logLocation;
  std::ofstream m_logFile;
};

} // namespace ndntg

#endif // NDNTG_LOGGER_HPP