Agency on

arangod/Agency/AgencyCommon.h

@@ -24,12 +24,24 @@
 #ifndef __ARANGODB_CONSENSUS_AGENCY_COMMON__
 #define __ARANGODB_CONSENSUS_AGENCY_COMMON__
 
+#include "Basics/Logger.h"
+
 #include <vector>
 #include <string>
 
 namespace arangodb {
 namespace consensus {
 
+  typedef enum AGENCY_STATUS {
+    OK = 0,
+    RETRACTED_CANDIDACY_FOR_HIGHER_TERM, // Vote for higher term candidate
+                                         // while running. Strange!
+    RESIGNED_LEADERSHIP_FOR_HIGHER_TERM  // Vote for higher term candidate
+                                         // while leading. Very bad!
+  } status_t;
+
+
+    
   /**
    * @brief Agent configuration
    */
@@ -41,8 +53,34 @@ namespace consensus {
     Config () : min_ping(.15), max_ping(.3) {};
     Config (uint32_t i, T min_p, T max_p, std::vector<std::string>& end_p) :
       id(i), min_ping(min_p), max_ping(max_p), end_points(end_p) {}
+    void print (arangodb::LoggerStream& l) const {
+      l << "Config: "
+        << "min_ping(" << min_ping << ")"
+        << "max_ping(" << max_ping << ")"
+        << "size(" << end_points.size() << ")"
+        << end_points;
+    }
   };
 
-}}
+  using config_t = Config<double>;
+  
+  typedef uint64_t term_t;
+  typedef uint32_t id_t;
+  struct  constituent_t {
+    id_t id;
+    std::string endpoint;
+  };
+  typedef std::vector<constituent_t> constituency_t;
+  typedef uint32_t state_t;
+  
+  
+}
+  
+  template<typename T> LoggerStream& operator<< (LoggerStream& l,
+        arangodb::consensus::Config<T> const& c) {
+    
+  }
+
+}
 #endif // __ARANGODB_CONSENSUS_AGENT__
 

arangod/Agency/Agent.cpp

@@ -29,7 +29,7 @@ using namespace arangodb::velocypack;
 Agent::Agent () {
 }
 
-Agent::Agent (Config<double> const& config) : _config(config) {
+Agent::Agent (config_t const& config) : _config(config) {
   _constituent.configure(this);
 
 }
@@ -57,3 +57,12 @@ Log::ret_t Agent::log (std::shared_ptr<Builder> const builder) {
 Config<double> const& Agent::config () const {
   return _config;
 }
+
+void Agent::print (arangodb::LoggerStream& logger) const {
+  logger << _config;
+}
+
+arangodb::LoggerStream& operator<< (arangodb::LoggerStream& l, Agent const& a) {
+  a.print(l);
+  return l;
+}

arangod/Agency/Agent.h

@@ -41,10 +41,9 @@ namespace consensus {
     Agent ();
     
     /**
-     * @brief Construct with program options \n
+     * @brief Construct with program options
-     *        One process starts with options, the \n remaining start with list of peers and gossip.
      */
-    Agent (Config<double> const&);
+    Agent (config_t const&);
 
     /**
      * @brief Clean up
@@ -59,17 +58,38 @@ namespace consensus {
     /**
      * @brief 
      */
-    Log::ret_t
+    Log::ret_t log (std::shared_ptr<arangodb::velocypack::Builder> const);
-      log (std::shared_ptr<arangodb::velocypack::Builder> const);
-
-    Slice const& redirect (Slice const&);
 
+    /**
+     * @brief Vote request
+     */
     bool vote(Constituent::id_t, Constituent::term_t);
 
+    /**
+     * @brief Provide configuration
+     */
     Config<double> const& config () const;
     
+    /**
+     * @brief Start thread
+     */
     void start ();
 
+    /**
+     * @brief Verbose print of myself
+     */ 
+    void print (arangodb::LoggerStream&) const;
+
+    /**
+     * @brief Are we fit to run?
+     */
+    bool fitness () const;
+    
+    /**
+     * @brief 
+     */
+    bool report ( ) const;
+    
   private:
     Constituent _constituent; /**< @brief Leader election delegate */
     Log         _log;         /**< @brief Log replica              */
@@ -77,6 +97,12 @@ namespace consensus {
     
   };
   
-}}
+}
+
+  LoggerStream& operator<< (LoggerStream&, arangodb::consensus::Agent const&);
+  
+}
+
+
 
 #endif

arangod/Agency/ApplicationAgency.cpp

@@ -36,9 +36,7 @@ using namespace arangodb::rest;
 
 ApplicationAgency::ApplicationAgency()
   : ApplicationFeature("agency"), _size(5), _min_election_timeout(.15),
-	  _max_election_timeout(.3) /*, _agent(new consensus::Agent())*/{
+	  _max_election_timeout(.3) {
-	//arangodb::consensus::Config<double> config (5, .15, .9);
-	//_agent = std::uniqe_ptr<agent>(new config);
 
 }
 
@@ -63,15 +61,33 @@ void ApplicationAgency::setupOptions(
 
 
 
-
 bool ApplicationAgency::prepare() {
+  
   if (_disabled) {
     return true;
   }
+
+  if (_min_election_timeout <= 0.) {
+    LOG(FATAL) << "agency.election-timeout-min must not be negative!";
+  } else if (_min_election_timeout < .15) {
+    LOG(WARN)  << "very short agency.election-timeout-min!";
+  }
+  
+  if (_max_election_timeout <= _min_election_timeout) {
+    LOG(FATAL) << "agency.election-timeout-max must not be shorter than or"
+               << "equal to agency.election-timeout-min.";
+  }
+  
+  if (_max_election_timeout <= 2*_min_election_timeout) {
+    LOG(WARN)  << "agency.election-timeout-max should probably be chosen longer!";
+  }
+    
   _agent = std::unique_ptr<consensus::Agent>(new consensus::Agent(
      consensus::Config<double>(_agent_id, _min_election_timeout,
        _max_election_timeout, _agency_endpoints)));
+  
   return true;
+  
 }
 
 

arangod/Agency/Constituent.cpp

@@ -36,10 +36,12 @@ using namespace arangodb::rest;
 void Constituent::configure(Agent* agent) {
   _agent = agent;
   _votes.resize(_agent->config().end_points.size());
+  if (_agent->config().id == (_votes.size()-1)) // Last will notify eveyone
+    notifyAll();
 }
 
 Constituent::Constituent() : Thread("Constituent"), _term(0), _id(0),
-  _gen(std::random_device()()), _mode(CANDIDATE), _run(true), _agent(0) {}
+  _gen(std::random_device()()), _mode(APPRENTICE), _run(true), _agent(0) {}
 
 Constituent::~Constituent() {}
 
@@ -63,17 +65,20 @@ Constituent::mode_t Constituent::mode () const {
   return _mode;
 }
 
-void Constituent::becomeFollower() {
+void Constituent::follow() {
   _votes.assign(_votes.size(),false); // void all votes
   _mode = FOLLOWER;
 }
 
-void Constituent::becomeLeader() {
+void Constituent::lead() {
-
+  _mode = LEADER;
 }
 
-void Constituent::becomeCadidate() {
+void Constituent::candidate() {
+  _mode = CANDIDATE;
+}
 
+size_t Constituent::notifyAll () {
 }
 
 // Vote for the requester if and only if I am follower
@@ -81,12 +86,14 @@ bool Constituent::vote(id_t id, term_t term) {
 	if (id == _id) {       // Won't vote for myself
 		return false;
 	} else {
-	  if (term > _term) {  // Candidate with higher term: ALWAYS turn
+	  if (term > _term) {  // Candidate with higher term: ALWAYS turn follower
-      if (_mode > FOLLOWER)
+      if (_mode > FOLLOWER) {
         LOG(WARN) << "Cadidate with higher term. Becoming follower";
-	    becomeFollower ();
+      }
+	    follow ();
+      _term = term;      // Raise term
 			return true;
-		} else {
+		} else {             // Myself running or leading
 			return false;
 		}
 	}
@@ -146,14 +153,13 @@ void Constituent::callElection() {
             _votes[i] = false;
             continue;
           } else {
-            LOG(WARN) << body->slice().get("vote");
+            _votes[i] = (body->slice().get("vote").isEqualString("TRUE")); // Record vote
           }
         }
-        //LOG(WARN) << body->toString();
+        LOG(WARN) << body->toString();
       } else { // Request failed
         _votes[i] = false;
       }
-
     }
   }
 }
@@ -161,7 +167,7 @@ void Constituent::callElection() {
 void Constituent::run() {
   while (true) {
     LOG(WARN) << _mode;
-    if (_mode == FOLLOWER) {
+    if (_mode == FOLLOWER || _mode == APPRENTICE) {
       LOG(WARN) << "sleeping ... ";
       std::this_thread::sleep_for(sleepFor());
     } else {

arangod/Agency/Constituent.h

@@ -49,17 +49,9 @@ class Constituent : public arangodb::basics::Thread {
 public:
 
   enum mode_t {
-    FOLLOWER, CANDIDATE, LEADER
+    APPRENTICE = -1, FOLLOWER, CANDIDATE, LEADER
   };
   typedef std::chrono::duration<double> duration_t;
-  typedef uint64_t term_t;
-  typedef uint32_t id_t;
-  struct  constituent_t {
-    id_t id;
-    std::string endpoint;
-  };
-  typedef std::vector<constituent_t> constituency_t;
-  typedef uint32_t state_t;
   typedef std::uniform_real_distribution<double> dist_t; 
   
   Constituent ();
@@ -113,6 +105,13 @@ private:
    */
   void countVotes();
 
+  /**
+   * @brief Notify everyone, that we are good to go.
+   *        This is the task of the last process starting up.
+   *        Will be taken care of by gossip
+   */
+  size_t notifyAll ();
+  
   /**
    * @brief Sleep for how long
    */