Working on legislator interfaces

Makefile.am

@@ -74,7 +74,8 @@ EVENTS = \
 
 LEGISLATOR = \
            src/legislator/legislator.cc \
-           src/legislator/legislator-factory.cc
+           src/legislator/legislator-factory.cc \
+           src/legislator/ledger.cc
 
 SOCKET = \
          src/socket/default-socket.cc \

config-files/one-legislator.json

@@ -3,7 +3,7 @@
         {
             "ip" : "127.0.0.1",
             "port" : 8000,
-            "name" : "test",
+            "name" : "legislator1",
             "self" : true
         }
     ]

src/law/ballot.hh

@@ -0,0 +1,15 @@
+#pragma once
+#include <unordered_set>
+
+#include "decree.hh"
+
+namespace paxos
+{
+    struct Ballot
+    {
+        int id;
+        Decree decree;
+        std::unordered_set<std::string> quorum;
+        std::unordered_set<std::string> voters;
+    }
+}

src/law/decree.hh

@@ -0,0 +1,9 @@
+#pragma once
+
+namespace paxos
+{
+    struct Decree
+    {
+        int decree;
+    };
+}

src/legislator/ledger.cc

@@ -0,0 +1,65 @@
+#include "ledger.hh"
+#include <fstream>
+#include <filesystem>
+
+namespace paxos
+{
+    Ledger::Ledger(std::string path)
+        : base_path_(path)
+    {
+        std::filesystem::create_directory(path);
+        base_path_ += "/";
+    }
+
+    std::vector<Decree> Ledger::get_decrees()
+    {
+        return std::vector<Decree>();
+    }
+
+    int Ledger::last_tried()
+    {
+        return read_file(base_path_ + "last-tried.txt");
+    }
+
+    void Ledger::set_last_tried(int b)
+    {
+        write_file(base_path_ + "last-tried.txt", b);
+    }
+
+
+    int Ledger::prev_vote()
+    {
+        return read_file(base_path_ + "prev-vote.txt");
+    }
+
+    void Ledger::set_prev_vote(int v)
+    {
+        write_file(base_path_ + "prev-vote.txt", v);
+    }
+
+    int Ledger::next_bal()
+    {
+        return read_file(base_path_ + "next-bal.txt");
+    }
+
+    void Ledger::set_next_bal(int b)
+    {
+        write_file(base_path_ + "next-bal.txt", b);
+    }
+
+    int Ledger::read_file(std::string path)
+    {
+        std::ifstream stream(path);
+        if (!stream.good())
+            return -1;
+        int res;
+        stream >> res;
+        return res;
+    }
+
+    void Ledger::write_file(std::string path, int n)
+    {
+        std::ofstream stream(path);
+        stream << n;
+    }
+}

src/legislator/ledger.hh

@@ -0,0 +1,31 @@
+#pragma once
+#include <string>
+#include <vector>
+
+#include "law/decree.hh"
+
+namespace paxos
+{
+    class Ledger
+    {
+    public:
+        Ledger(std::string path);
+
+        std::vector<Decree> get_decrees();
+
+        int last_tried();
+        void set_last_tried(int b);
+
+        int prev_vote();
+        void set_prev_vote(int v);
+
+        int next_bal();
+        void set_next_bal(int b);
+
+    private:
+        std::string base_path_;
+
+        int read_file(std::string path);
+        void write_file(std::string path, int n);
+    };
+}

src/legislator/legislator.cc

@@ -1,9 +1,63 @@
 #include "legislator.hh"
+#include "misc/logger.hh"
+#include <string>
 
 namespace paxos
 {
     Legislator::Legislator(const LegislatorConfig& config)
-        : config_(config)
+        : config_(config), ledger(config.name)
     {
+        log("created legislator " + config.name, blue);
+    }
+
+    void Legislator::initiate_ballot()
+    {
+        int new_ballot_number = ledger.last_tried() + 1;
+        ledger.set_last_tried(new_ballot_number);
+        log(config_.name + " is initiating ballot " + std::to_string(new_ballot_number), cyan);
+        send_next_ballot(new_ballot_number);
+    }
+
+    void Legislator::send_next_ballot(int ballot)
+    {
+        ballot = ballot;
+        return;
+    }
+
+    void Legislator::receive_next_ballot(int ballot, std::string sender)
+    {
+        log(config_.name + " has received a NextBallot("
+                + std::to_string(ballot)
+                + ") from " + sender, cyan);
+        int next_ballot = ledger.next_bal();
+        if (ballot <= next_ballot)
+        {
+            log("but it was discarded because ballot " + std::to_string(ballot)
+                    + " is inferior or equal to nextBallot "
+                    + std::to_string(next_ballot), red);
+            return;
+        }
+        ledger.set_next_bal(ballot);
+        int previous_vote = ledger.prev_vote();
+        previous_vote = previous_vote;
+        //XXX send a LastVote to sender
+    }
+
+    void Legislator::receive_enough_last_vote
+        (std::unordered_map<std::string, int> quorum_last_votes)
+    {
+        quorum_last_votes = quorum_last_votes;
+        //find d to satisfy B3
+        //send BeginBallot to the quorum
+    }
+
+    void Legislator::receive_begin_ballot(int ballot, int decree)
+    {
+        if (ballot != ledger.next_bal())
+            return;
+        ledger.set_prev_vote(ballot);
+
+        decree = decree;
+        //XXX send Voted
     }
 }

src/legislator/legislator.hh

@@ -1,5 +1,7 @@
 #pragma once
 #include "config/config.hh"
+#include "ledger.hh"
+#include <unordered_map>
 
 namespace paxos
 {
@@ -9,6 +11,21 @@ namespace paxos
         Legislator(const LegislatorConfig& config);
         LegislatorConfig config_;
 
+        void initiate_ballot();
+
+        void send_next_ballot(int ballot);
+
+        void receive_next_ballot(int ballot, std::string sender);
+
+        void receive_enough_last_vote
+            (std::unordered_map<std::string, int> quorum_last_votes);
+
+        void receive_begin_ballot(int ballot, int decree);
+
+        Ledger ledger;
     };
     using shared_legislator = std::shared_ptr<Legislator>;
+
+    extern shared_legislator self;
+    extern std::vector<shared_legislator> legislators;
 }

src/legislator/vote.hh

@@ -0,0 +1,13 @@
+#pragma once
+#include "legislator.hh"
+#include "law/decree.hh"
+
+namespace paxos
+{
+    struct Vote
+    {
+        Legislator legislator;
+        int ballot_id;
+        Decree decree;
+    };
+}

src/main.cc

@@ -1,10 +1,14 @@
 #include <iostream>
+#include <vector>
 
 #include "config/config.hh"
 #include "legislator/legislator-factory.hh"
 #include "events/register.hh"
+#include "misc/logger.hh"
 
 paxos::EventWatcherRegistry paxos::event_register;
+std::vector<paxos::shared_legislator> paxos::legislators;
+paxos::shared_legislator paxos::self;
 
 ev_signal sigint_watcher;
 static void sigint_cb(struct ev_loop* loop, ev_signal*, int)
@@ -12,6 +16,13 @@ static void sigint_cb(struct ev_loop* loop, ev_signal*, int)
     ev_break(loop, EVBREAK_ALL);
 }
 
+ev_signal sigstop_watcher;
+static void sigstop_cb(struct ev_loop*, ev_signal*, int)
+{
+    log("SIGSTOP detected trying to initiate ballot", paxos::red);
+    paxos::self->initiate_ballot();
+}
+
 
 int main(int, char **argv)
 {
@@ -20,11 +31,14 @@ int main(int, char **argv)
     ev_signal_init(&sigint_watcher, sigint_cb, SIGINT);
     paxos::event_register.get_event_loop().register_sigint_watcher(&sigint_watcher);
 
-    paxos::LegislatorFactory::Create(server_config.self_);
+    ev_signal_init(&sigstop_watcher, sigstop_cb, SIGTSTP);
+    paxos::event_register.get_event_loop().register_sigint_watcher(&sigstop_watcher);
+
+    paxos::self = paxos::LegislatorFactory::Create(server_config.self_);
 
     for (auto config : server_config.legislators_)
     {
-        paxos::LegislatorFactory::Create(config);
+        paxos::legislators.push_back(paxos::LegislatorFactory::Create(config));
     }
     
     paxos::event_register.get_event_loop()();

src/misc/logger.cc

@@ -2,7 +2,7 @@
 
 #include <iostream>
 
-namespace http
+namespace paxos
 {
     void log(std::string str, Color color)
     {

src/misc/logger.hh

@@ -2,7 +2,7 @@
 
 #include <string>
 
-namespace http
+namespace paxos
 {
     enum Color
     {