RAFTConsensus.h

/*
This program has been developed by students from the bachelor Computer Science at
Utrecht University within the Software Project course.
© Copyright Utrecht University (Department of Information and Computing Sciences)
*/
 
#pragma once
#include "Networking.h"
#include "Statistics.h"
 
#include <vector>
#include <boost/shared_ptr.hpp>
#include <mutex>
#include <prometheus/counter.h>
 
#define RESPONSE_OK "ok"
#define HEARTBEAT_TIME 1000000
#define LEADER_DROPOUT_WAIT_TIME 1000000
 
 
class TcpConnection;
class RequestHandler;
 
struct Connection
{
  public:
    boost::shared_ptr<TcpConnection> connection;
    std::string ip;
    std::string port;
 
    Connection(boost::shared_ptr<TcpConnection> conn, std::string ip, std::string port)
        : connection(conn), ip(ip), port(port)
    {
    }
};
 
class RAFTConsensus
{
public:
    ~RAFTConsensus();
 
    RAFTConsensus(Statistics *stats) : stats(stats)
    {
    }
 
    void start(RequestHandler* requestHandler, 
        std::vector<std::pair<std::string, std::string>> ips, 
        bool assumeLeader = false);
 
    virtual bool isLeader() { return leader; };
 
    virtual std::string passRequestToLeader(std::string requestType, std::string client, std::string request);
 
    virtual std::string connectNewNode(boost::shared_ptr<TcpConnection> connection, std::string request);
 
    virtual std::vector<std::pair<std::string, std::string>> getIps(std::string file = ".env");
 
    virtual std::vector<std::string> getCurrentIPs();
 
    virtual std::string getMyIP()
    {
        return myIp;
    }
 
private:
    void connectToLeader(std::vector<std::pair<std::string, std::string>> ips);
 
 
    void listenForHeartbeat();
 
    void handleHeartbeat(std::string heartbeat);
 
    void handleInitialData(std::vector<std::string> initialData);
 
    void tryConnectingWithIp(std::string &ip, std::string &port, std::string &response);
 
 
    void heartbeatSender();
 
    std::string getHeartbeat();
 
    void listenForRequests(boost::shared_ptr<TcpConnection> connection);
 
    void dropConnection(int i);
 
    std::string connectionToString(Connection connection);
 
    bool leader;
    bool stop = false;
    bool started = false;
    std::mutex mtx;
    Statistics *stats;
 
    // Non-leader variables.
    NetworkHandler* networkhandler;
    std::string leaderIp, leaderPort, myIp, myPort;
    std::vector<std::pair<std::string, std::string>> nonLeaderNodes;
 
    // Leader variables.
    std::vector<Connection>* others;
    RequestHandler* requestHandler;
    std::string nodeConnectionChange = "";
};