config.hpp

/*
 *    Copyright (C) 2019-2021 Joshua Boudreau <jboudreau@45drives.com>
 *
 *    This file is part of autotier.
 *
 *    autotier 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.
 *
 *    autotier 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 autotier.  If not, see <https://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "alert.hpp"
 
#include <45d/config/ConfigParser.hpp>
#include <boost/filesystem.hpp>
#include <chrono>
namespace fs = boost::filesystem;
 
#define DEFAULT_CONFIG_PATH "/etc/autotier.conf"
#define TIER_PERIOD_DISBLED -1
#define LOG_LEVEL_NOT_SET   -1
 
template<class T>
/* ConfigOverride is used with command line flags
 * to allow for easy overridding of configuration values.
 */
class ConfigOverride {
private:
    T value_;
    /* The value to override with.
     */
    bool overridden_;
    /* Whether or not the field is overridden.
     * Since ConfigOverride objects are constructed in main()
     * without a valuem, overridden_ will be set to false. If
     * the value is updated through copying a newly constructed
     * ConfigOverride object with a value, this will be true.
     */
public:
    ConfigOverride(void) : value_() {
        overridden_ = false;
    }
    ConfigOverride(const T &value_passed) : value_(value_passed) {
        overridden_ = true;
    }
    ~ConfigOverride(void) = default;
    const T &value(void) const {
        return value_;
    }
    const bool &overridden(void) const {
        return overridden_;
    }
};
 
struct ConfigOverrides {
    ConfigOverride<Logger::log_level_t> log_level_override;
};
 
class Tier;
 
class Config : public ffd::ConfigParser {
public:
    enum LogLevel { NONE, NORMAL, DEBUG }; 
    Config(const fs::path &config_path,
           std::list<Tier> &tiers,
           const ConfigOverrides &config_overrides);
    /* open config file at config_path, parse global and tier options,
     * populate list of tiers
     */
    Config(const fs::path &config_path, const ConfigOverrides &config_overrides);
    /* Only read global.
     */
    ~Config() = default;
    /* Default destructor.
     */
    size_t copy_buff_sz(void) const;
    /* Get copy_buff_sz_.
     */
    std::chrono::seconds tier_period_s(void) const;
    /* Get tier_period_s_.
     */
    bool strict_period(void) const;
    /* Return true if strict_period_ == 1, else 0.
     */
    fs::path run_path(void) const;
    /* Get run_path_.
     */
    void dump(const std::list<Tier> &tiers, std::stringstream &ss) const;
    /* print out loaded options from config file for the global section
     * and for each tier
     */
private:
    Logger::log_level_t log_level_;
    size_t copy_buff_sz_;
    std::chrono::seconds tier_period_s_;
    bool strict_period_;
    fs::path run_path_;
    void load_config(const fs::path &config_path,
                     std::list<Tier> &tiers,
                     const ConfigOverrides &config_overrides);
};
 
void init_config_file(const fs::path &config_path);