data_sender.h

#ifndef _DATA_SENDER_H
#define _DATA_SENDER_H

#include <north_plugin.h>
#include <reading_set.h>
#include <logger.h>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <perfmonitors.h>

// Send statistics to storage in seconds
#define FLUSH_STATS_INTERVAL 5
// Failure counter before re-recreating statics rows
#define STATS_UPDATE_FAIL_THRESHOLD 3

// BAckoff sending when we see repeated failures
#define FAILURE_BACKOFF_THRESHOLD   10  // Number of consequetive failures to trigger backoff
#define MIN_SEND_BACKOFF        50  // Min backoff in milliseconds
#define MAX_SEND_BACKOFF        500 // Max backoff in milliseconds

class DataLoad;
class NorthService;

class DataSender {
    public:
        DataSender(NorthPlugin *plugin, DataLoad *loader, NorthService *north);
        ~DataSender();
        void            sendThread();
        void            updatePlugin(NorthPlugin *plugin) { m_plugin = plugin; };
        void            pause();
        void            release();
        void            setPerfMonitor(PerformanceMonitor *perfMonitor) { m_perfMonitor = perfMonitor; };
        bool            isRunning() { return !m_shutdown; };
        void            flushStatistics();
        bool            isDryRun();
    private:
        void            updateStatistics(uint32_t increment);
        bool            createStats(const std::string &key, unsigned int value);
        unsigned long       send(ReadingSet *readings);
        void            blockPause();
        void            releasePause();
    private:
        NorthPlugin     *m_plugin;
        DataLoad        *m_loader;
        NorthService        *m_service;
        volatile bool       m_shutdown;
        std::thread     *m_thread;
        Logger          *m_logger;
        bool            m_paused;
        bool            m_sending;
        std::mutex      m_pauseMutex;
        std::condition_variable m_pauseCV;
        PerformanceMonitor  *m_perfMonitor;
        // Statistics send via thread
        std::thread     *m_statsThread;
        std::mutex      m_flushStatsMtx;
        // Statistics save map
        std::condition_variable m_statsCv;
        std::mutex      m_statsMtx;
        std::map<std::string, unsigned int>
                    m_statsPendingEntries;
        int         m_statsUpdateFails;
        // confirmed stats table entries
        std::unordered_set<std::string>
                    m_statsDbEntriesCache;
        unsigned int        m_repeatedFailure;
        unsigned int        m_sendBackoffTime;
};
#endif