Implemented connection to cluster using gossip seeds

src/client.js

@@ -44,6 +44,7 @@ module.exports.UserCredentials = require('./systemData/userCredentials');
 module.exports.EventData = EventData;
 module.exports.PersistentSubscriptionSettings = require('./persistentSubscriptionSettings');
 module.exports.SystemConsumerStrategies = require('./systemConsumerStrategies');
+module.exports.GossipSeed = require('./gossipSeed');
 // Exporting errors
 module.exports.WrongExpectedVersionError = require('./errors/wrongExpectedVersionError');
 module.exports.StreamDeletedError = require('./errors/streamDeletedError');

src/core/clusterDnsEndPointDiscoverer.js

@@ -0,0 +1,240 @@
+var http = require('http');
+var util = require('util');
+var GossipSeed = require('../gossipSeed');
+
+function NodeEndPoints(tcpEndPoint, secureTcpEndPoint) {
+  if (tcpEndPoint === null && secureTcpEndPoint === null) throw new Error('Both endpoints are null.');
+  Object.defineProperties(this, {
+    tcpEndPoint: {
+      enumerable: true,
+      value: tcpEndPoint
+    },
+    secureTcpEndPoint: {
+      enumerable: true,
+      value: secureTcpEndPoint
+    }
+  });
+}
+
+function ClusterDnsEndPointDiscoverer(log, clusterDns, maxDiscoverAttempts, managerExternalHttpPort, gossipSeeds, gossipTimeout) {
+  if (!clusterDns && (!gossipSeeds || gossipSeeds.length === 0)) throw new Error('Both clusterDns and gossipSeeds are null/empty.');
+  this._log = log;
+  this._clusterDns = clusterDns;
+  this._maxDiscoverAttempts = maxDiscoverAttempts;
+  this._managerExternalHttpPort = managerExternalHttpPort;
+  this._gossipSeeds = gossipSeeds;
+  this._gossipTimeout = gossipTimeout;
+  this._oldGossip = null;
+}
+
+ClusterDnsEndPointDiscoverer.prototype.discover = function(failedTcpEndPoint) {
+  var attempt = 1;
+  var self = this;
+  function discover(resolve, reject) {
+    self._discoverEndPoint(failedTcpEndPoint)
+      .then(function (endPoints) {
+        if (!endPoints)
+          self._log.info(util.format("Discovering attempt %d/%d failed: no candidate found.", attempt, self._maxDiscoverAttempts));
+        return endPoints;
+      })
+      .catch(function (exc) {
+        self._log.info(util.format("Discovering attempt %d/%d failed with error: %s.", attempt, self._maxDiscoverAttempts, exc));
+      })
+      .then(function (endPoints) {
+        if (endPoints)
+          return resolve(endPoints);
+        if (attempt++ === self._maxDiscoverAttempts)
+          return reject(new Error('Failed to discover candidate in ' + self._maxDiscoverAttempts + ' attempts.'));
+        setTimeout(discover, 500, resolve, reject);
+      });
+  }
+  return new Promise(function (resolve, reject) {
+    discover(resolve, reject);
+  });
+};
+
+/**
+ * Discover Cluster endpoints
+ * @param {Object} failedTcpEndPoint
+ * @returns {Promise.<NodeEndPoints>}
+ * @private
+ */
+ClusterDnsEndPointDiscoverer.prototype._discoverEndPoint = function (failedTcpEndPoint) {
+  try {
+    var gossipCandidates = this._oldGossip
+      ? this._getGossipCandidatesFromOldGossip(this._oldGossip, failedTcpEndPoint)
+      : this._getGossipCandidatesFromDns();
+    var self = this;
+    var promise = Promise.resolve();
+    var j = 0;
+    for (var i = 0; i < gossipCandidates.length; i++) {
+      promise = promise.then(function (endPoints) {
+        if (endPoints) return endPoints;
+
+        return self._tryGetGossipFrom(gossipCandidates[j++])
+          .then(function (gossip) {
+            if (gossip === null || gossip.members === null || gossip.members.length === 0)
+              return;
+            var bestNode = self._tryDetermineBestNode(gossip.members);
+            if (bestNode !== null) {
+              self._oldGossip = gossip.members;
+              return bestNode;
+            }
+          });
+      });
+    }
+    return promise;
+  } catch (e) {
+    return Promise.reject(e);
+  }
+};
+
+ClusterDnsEndPointDiscoverer.prototype._getGossipCandidatesFromOldGossip = function (oldGossip, failedTcpEndPoint) {
+  if (failedTcpEndPoint === null) return oldGossip;
+  var gossipCandidates = oldGossip.filter(function(x) {
+    //TODO: failedTcpEndpoint.host might not be an ip
+    return (x.externalTcpPort !== failedTcpEndPoint.port && x.externalTcpIp !== failedTcpEndPoint.host);
+  });
+  return this._arrangeGossipCandidates(gossipCandidates);
+};
+
+ClusterDnsEndPointDiscoverer.prototype._arrangeGossipCandidates = function (members) {
+  var result = new Array(members.length);
+  var i = -1;
+  var j = members.length;
+  for (var k = 0; k < members.length; ++k)
+  {
+    if (members[k].state === 'Manager')
+      result[--j] = new GossipSeed({host: members[k].externalHttpIp, port: members[k].externalHttpPort});
+    else
+      result[++i] = new GossipSeed({host: members[k].externalHttpIp, port: members[k].externalHttpPort});
+  }
+  this._randomShuffle(result, 0, i); // shuffle nodes
+  this._randomShuffle(result, j, members.length - 1); // shuffle managers
+  return result;
+};
+
+ClusterDnsEndPointDiscoverer.prototype._getGossipCandidatesFromDns = function () {
+  var endpoints = [];
+  if(this._gossipSeeds !== null && this._gossipSeeds.length > 0)
+  {
+    endpoints = this._gossipSeeds;
+  }
+  else
+  {
+    //TODO: dns resolve
+    throw new Error('Not implemented.');
+    //endpoints = ResolveDns(_clusterDns).Select(x => new GossipSeed(new IPEndPoint(x, _managerExternalHttpPort))).ToArray();
+  }
+
+  this._randomShuffle(endpoints, 0, endpoints.length-1);
+  return endpoints;
+};
+
+ClusterDnsEndPointDiscoverer.prototype._tryGetGossipFrom = function (endPoint) {
+  var options = {
+    hostname: endPoint.endPoint.hostname,
+    port: endPoint.endPoint.port,
+    path: '/gossip?format=json'
+  };
+  if (endPoint.hostHeader) {
+    options.headers = {'Host': endPoint.hostHeader};
+  }
+  var self = this;
+  return new Promise(function (resolve, reject) {
+    try {
+      http
+        .request(options, function (res) {
+          var result = '';
+          if (res.statusCode !== 200) {
+            self._log.info('Trying to get gossip from', endPoint, 'failed with status code:', res.statusCode);
+            resolve();
+            return;
+          }
+          res.on('data', function (chunk) {
+            result += chunk.toString();
+          });
+          res.on('end', function () {
+            try {
+              result = JSON.parse(result);
+            } catch (e) {
+              return resolve();
+            }
+            resolve(result);
+          });
+        })
+        .setTimeout(self._gossipTimeout, function () {
+          self._log.info('Trying to get gossip from', endPoint, 'timed out.');
+          resolve();
+        })
+        .on('error', function (e) {
+          self._log.info('Trying to get gossip from', endPoint, 'failed with error:', e);
+          resolve();
+        })
+        .end();
+    } catch(e) {
+      reject(e);
+    }
+  });
+};
+
+const VNodeStates = {
+  'Initializing': 0,
+  'Unknown': 1,
+  'PreReplica': 2,
+  'CatchingUp': 3,
+  'Clone': 4,
+  'Slave': 5,
+  'PreMaster': 6,
+  'Master': 7,
+  'Manager': 8,
+  'ShuttingDown': 9,
+  'Shutdown': 10
+};
+
+ClusterDnsEndPointDiscoverer.prototype._tryDetermineBestNode = function (members) {
+  var notAllowedStates = [
+    'Manager',
+    'ShuttingDown',
+    'Shutdown'
+  ];
+  var node = members
+    .filter(function (x) {
+      return (x.isAlive && notAllowedStates.indexOf(x.state) === -1);
+    })
+    .sort(function (a, b) {
+      return VNodeStates[b.state] - VNodeStates[a.state];
+    })[0];
+  if (!node)
+  {
+    //_log.Info("Unable to locate suitable node. Gossip info:\n{0}.", string.Join("\n", members.Select(x => x.ToString())));
+    return null;
+  }
+
+  var normTcp = {host: node.externalTcpIp, port: node.externalTcpPort};
+  var secTcp = node.externalSecureTcpPort > 0
+    ? {host: externalTcpIp, port: node.externalSecureTcpPort}
+    : null;
+  this._log.info(util.format("Discovering: found best choice [%j,%j] (%s).", normTcp, secTcp == null ? "n/a" : secTcp, node.state));
+  return new NodeEndPoints(normTcp, secTcp);
+};
+
+function rndNext(min, max) {
+  min = Math.ceil(min);
+  max = Math.floor(max);
+  return Math.floor(Math.random() * (max - min)) + min;
+}
+
+ClusterDnsEndPointDiscoverer.prototype._randomShuffle = function (arr, i, j) {
+  if (i >= j)
+    return;
+  for (var k = i; k <= j; ++k)
+  {
+    var index = rndNext(k, j + 1);
+    var tmp = arr[index];
+    arr[index] = arr[k];
+    arr[k] = tmp;
+  }
+};
+
+module.exports = ClusterDnsEndPointDiscoverer;

src/core/eventStoreConnectionLogicHandler.js

@@ -624,7 +624,7 @@ EventStoreConnectionLogicHandler.prototype._timerTick = function() {
 };
 
 EventStoreConnectionLogicHandler.prototype._manageHeartbeats = function() {
-  if (this._connection == null) throw new Error();
+  if (this._connection == null) return;
 
   var timeout = this._heartbeatInfo.isIntervalStage ? this._settings.heartbeatInterval : this._settings.heartbeatTimeout;
   if (Date.now() - this._heartbeatInfo.timeStamp < timeout)

src/eventStoreConnection.js

@@ -1,6 +1,8 @@
 var EventStoreNodeConnection = require('./eventStoreNodeConnection');
 var StaticEndpointDiscoverer = require('./core/staticEndpointDiscoverer');
+var ClusterDnsEndPointDiscoverer = require('./core/clusterDnsEndPointDiscoverer');
 var NoopLogger = require('./common/log/noopLogger');
+var ensure = require('./common/utils/ensure');
 
 var defaultConnectionSettings = {
   log: new NoopLogger(),
@@ -25,7 +27,13 @@ var defaultConnectionSettings = {
   failOnNoServerResponse: false,
   heartbeatInterval: 750,
   heartbeatTimeout: 1500,
-  clientConnectionTimeout: 1000
+  clientConnectionTimeout: 1000,
+
+  // Cluster Settings
+  clusterDns: '',
+  maxDiscoverAttemps: 10,
+  externalGossipPort: 0,
+  gossipTimeout: 1000
 };
 
 
@@ -40,24 +48,63 @@ function merge(a,b) {
   return c;
 }
 
+function createFromTcpEndpoint(settings, tcpEndpoint, connectionName) {
+  if (!tcpEndpoint.port || !tcpEndpoint.hostname) throw new TypeError('endPoint object must have hostname and port properties.');
+  var mergedSettings = merge(defaultConnectionSettings, settings || {});
+  var endpointDiscoverer = new StaticEndpointDiscoverer(tcpEndpoint, settings.useSslConnection);
+  return new EventStoreNodeConnection(mergedSettings, null, endpointDiscoverer, connectionName || null);
+}
+
+function createFromStringEndpoint(settings, endPoint, connectionName) {
+  var m = endPoint.match(/^(tcp|discover):\/\/([^:]):?(\d+)?$/);
+  if (!m) throw new Error('endPoint string must be tcp://hostname[:port] or discover://dns[:port]');
+  var scheme = m[1];
+  var hostname = m[2];
+  var port = m[3] ? parseInt(m[3]) : 1113;
+  if (scheme === 'tcp') {
+    var tcpEndpoint = {
+      hostname: hostname,
+      port: port
+    };
+    return createFromTcpEndpoint(settings, tcpEndpoint, connectionName);
+  }
+  if (scheme === 'discover') {
+    throw new Error('Not implemented.');
+  }
+  throw new Error('Invalid scheme for endPoint: ' + scheme);
+}
+
+function createFromGossipSeeds(connectionSettings, gossipSeeds, connectionName) {
+  ensure.notNull(connectionSettings, "connectionSettings");
+  ensure.notNull(gossipSeeds, "gossipSeeds");
+  var mergedSettings = merge(defaultConnectionSettings, connectionSettings || {});
+  var clusterSettings = {
+    clusterDns: '',
+    gossipSeeds: gossipSeeds,
+    externalGossipPort: 0,
+    maxDiscoverAttempts: mergedSettings.maxDiscoverAttempts,
+    gossipTimeout: mergedSettings.gossipTimeout
+  };
+  var endPointDiscoverer = new ClusterDnsEndPointDiscoverer(connectionSettings.log,
+    clusterSettings.clusterDns,
+    clusterSettings.maxDiscoverAttempts,
+    clusterSettings.externalGossipPort,
+    clusterSettings.gossipSeeds,
+    clusterSettings.gossipTimeout
+  );
+  return new EventStoreNodeConnection(mergedSettings, clusterSettings, endPointDiscoverer, connectionName);
+}
+
 /**
  * Create an EventStore connection
  * @param {object} settings
- * @param {string|object} endPoint
+ * @param {string|object|array} endPointOrGossipSeeds
  * @param {string} [connectionName]
  * @returns {EventStoreNodeConnection}
  */
-module.exports.create = function(settings, endPoint, connectionName) {
-  if (typeof endPoint === 'object') {
-    var mergedSettings = merge(defaultConnectionSettings, settings || {});
-    var endpointDiscoverer = new StaticEndpointDiscoverer(endPoint, settings.useSslConnection);
-    return new EventStoreNodeConnection(mergedSettings, endpointDiscoverer, connectionName || null);
-  }
-  if (typeof endPoint === 'string') {
-    //TODO: tcpEndpoint represented as tcp://hostname:port
-    //TODO: cluster discovery via dns represented as discover://dns:?port
-    throw new Error('Not implemented.');
-  }
-  //TODO: cluster discovery via gossip seeds in settings
-  throw new Error('Not implemented.');
+module.exports.create = function(settings, endPointOrGossipSeeds, connectionName) {
+  if (Array.isArray(endPointOrGossipSeeds)) return createFromGossipSeeds(settings, endPointOrGossipSeeds, connectionName);
+  if (typeof endPointOrGossipSeeds === 'object') return createFromTcpEndpoint(settings, endPointOrGossipSeeds, connectionName);
+  if (typeof endPointOrGossipSeeds === 'string') return createFromStringEndpoint(settings, endPointOrGossipSeeds, connectionName);
+  throw new TypeError('endPointOrGossipSeeds must be an object, a string or an array.');
 };

src/eventStoreNodeConnection.js

@@ -34,14 +34,16 @@ const MaxReadSize = 4096;
 
 /**
  * @param settings
+ * @param clusterSettings
  * @param endpointDiscoverer
  * @param connectionName
  * @constructor
  * @property {string} connectionName
  */
-function EventStoreNodeConnection(settings, endpointDiscoverer, connectionName) {
+function EventStoreNodeConnection(settings, clusterSettings, endpointDiscoverer, connectionName) {
   this._connectionName = connectionName || ['ES-', uuid.v4()].join('');
   this._settings = settings;
+  this._clusterSettings = clusterSettings;
   this._endpointDiscoverer = endpointDiscoverer;
   this._handler = new EventStoreConnectionLogicHandler(this, settings);
 

src/gossipSeed.js

@@ -0,0 +1,13 @@
+module.exports = function GossipSeed(endPoint, hostName) {
+  if (typeof endPoint !== 'object' || !endPoint.hostname || !endPoint.port) throw new TypeError('endPoint must be have hostname and port properties.');
+  Object.defineProperties(this, {
+    endPoint: {
+      enumerable: true,
+      value: endPoint
+    },
+    hostName: {
+      enumerable: true,
+      value: hostName
+    }
+  });
+};