Adding persistent subscription support

README.md

@@ -15,7 +15,6 @@ Incomplete/missing features:
 
 - Typed errors: currently most errors are direct instance of Error, which is not practical for error handling
 - Ssl connection: Ssl connetion is not implemented yet
-- Persistent subscription: create/update/delete/connec to a persistent subscription are not implemented yet
 - Set system settings: not implemented yet
 - Performance: there's still some while loop in the code that could be problematic with node.js
 - Tests: tests are only covering happy path scenarios for now

src/client.js

@@ -41,6 +41,8 @@ function eventDataFactory(eventId, type, isJson, data, metadata) {
 module.exports.EventStoreConnection = require('./eventStoreConnection');
 module.exports.UserCredentials = require('./systemData/userCredentials');
 module.exports.EventData = EventData;
+module.exports.PersistentSubscriptionSettings = require('./persistentSubscriptionSettings');
+module.exports.SystemConsumerStrategies = require('./systemConsumerStrategies');
 module.exports.expectedVersion = expectedVersion;
 module.exports.positions = positions;
 

src/clientOperations/connectToPersistentSubscriptionOperation.js

@@ -0,0 +1,122 @@
+var util = require('util');
+var uuid = require('uuid');
+
+var SubscriptionOperation = require('./subscriptionOperation');
+var ClientMessage = require('../messages/clientMessage');
+var TcpCommand = require('../systemData/tcpCommand');
+var TcpFlags = require('../systemData/tcpFlags');
+var TcpPackage = require('../systemData/tcpPackage');
+var createBufferSegment = require('../common/bufferSegment');
+var InspectionResult = require('./../systemData/inspectionResult');
+var InspectionDecision = require('../systemData/inspectionDecision');
+var results = require('../results');
+var SubscriptionDropReason = require('../subscriptionDropReason');
+var PersistentEventStoreSubscription = require('../persistentEventStoreSubscription');
+var ensure = require('../common/utils/ensure');
+
+function ConnectToPersistentSubscriptionOperation(
+    log, cb, groupName, bufferSize, streamId, userCredentials, eventAppeared, subscriptionDropped,
+    verboseLogging, getConnection
+) {
+  SubscriptionOperation.call(this, log, cb, streamId, false, userCredentials, eventAppeared, subscriptionDropped, verboseLogging, getConnection);
+
+  this._groupName = groupName;
+  this._bufferSize = bufferSize;
+  this._subscriptionId = null;
+}
+util.inherits(ConnectToPersistentSubscriptionOperation, SubscriptionOperation);
+
+ConnectToPersistentSubscriptionOperation.prototype._createSubscriptionPackage = function() {
+  var dto = new ClientMessage.ConnectToPersistentSubscription(this._groupName, this._streamId, this._bufferSize);
+  return new TcpPackage(TcpCommand.ConnectToPersistentSubscription,
+      this._userCredentials !== null ? TcpFlags.Authenticated : TcpFlags.None,
+      this._correlationId,
+      this._userCredentials !== null ? this._userCredentials.username : null,
+      this._userCredentials !== null ? this._userCredentials.password : null,
+      createBufferSegment(dto.toBuffer()));
+};
+
+ConnectToPersistentSubscriptionOperation.prototype._inspectPackage = function(pkg) {
+  if (pkg.command == TcpCommand.PersistentSubscriptionConfirmation)
+  {
+    var dto = ClientMessage.PersistentSubscriptionConfirmation.decode(pkg.data.toBuffer());
+    this._confirmSubscription(dto.last_commit_position, dto.last_event_number);
+    this._subscriptionId = dto.subscription_id;
+    return new InspectionResult(InspectionDecision.Subscribed, "SubscriptionConfirmation");
+  }
+  if (pkg.command == TcpCommand.PersistentSubscriptionStreamEventAppeared)
+  {
+    var dto = ClientMessage.PersistentSubscriptionStreamEventAppeared.decode(pkg.data.toBuffer());
+    this._onEventAppeared(new results.ResolvedEvent(dto.event));
+    return new InspectionResult(InspectionDecision.DoNothing, "StreamEventAppeared");
+  }
+  if (pkg.command == TcpCommand.SubscriptionDropped)
+  {
+    var dto = ClientMessage.SubscriptionDropped.decode(pkg.data.toBuffer());
+    if (dto.reason == ClientMessage.SubscriptionDropped.SubscriptionDropReason.AccessDenied)
+    {
+      this.dropSubscription(SubscriptionDropReason.AccessDenied, new Error("You do not have access to the stream."));
+      return new InspectionResult(InspectionDecision.EndOperation, "SubscriptionDropped");
+    }
+    if (dto.reason == ClientMessage.SubscriptionDropped.SubscriptionDropReason.NotFound)
+    {
+      this.dropSubscription(SubscriptionDropReason.NotFound, new Error("Subscription not found"));
+      return new InspectionResult(InspectionDecision.EndOperation, "SubscriptionDropped");
+    }
+    if (dto.reason == ClientMessage.SubscriptionDropped.SubscriptionDropReason.PersistentSubscriptionDeleted)
+    {
+      this.dropSubscription(SubscriptionDropReason.PersistentSubscriptionDeleted, new Error("Persistent subscription deleted."));
+      return new InspectionResult(InspectionDecision.EndOperation, "SubscriptionDropped");
+    }
+    if (dto.reason == ClientMessage.SubscriptionDropped.SubscriptionDropReason.SubscriberMaxCountReached)
+    {
+      this.dropSubscription(SubscriptionDropReason.MaxSubscribersReached, new Error("Maximum subscribers reached."));
+      return new InspectionResult(InspectionDecision.EndOperation, "SubscriptionDropped");
+    }
+    this.dropSubscription(SubscriptionDropReason.UserInitiated, null, this._getConnection());
+    return new InspectionResult(InspectionDecision.EndOperation, "SubscriptionDropped");
+  }
+  return null;
+};
+
+ConnectToPersistentSubscriptionOperation.prototype._createSubscriptionObject = function(lastCommitPosition, lastEventNumber) {
+  return new PersistentEventStoreSubscription(this, this._streamId, lastCommitPosition, lastEventNumber);
+};
+
+ConnectToPersistentSubscriptionOperation.prototype.notifyEventsProcessed = function(processedEvents) {
+  ensure.notNull(processedEvents, "processedEvents");
+  var dto = new ClientMessage.PersistentSubscriptionAckEvents({
+    subscription_id: this._subscriptionId,
+    processed_event_ids: processedEvents.map(function (x) {
+      return new Buffer(uuid.parse(x));
+    })
+  });
+
+  var pkg = new TcpPackage(TcpCommand.PersistentSubscriptionAckEvents,
+      this._userCredentials !== null ? TcpFlags.Authenticated : TcpFlags.None,
+      this._correlationId,
+      this._userCredentials !== null ? this._userCredentials.username : null,
+      this._userCredentials !== null ? this._userCredentials.password : null,
+      createBufferSegment(dto.encode().toBuffer()));
+  this._enqueueSend(pkg);
+};
+
+ConnectToPersistentSubscriptionOperation.prototype.notifyEventsFailed = function(processedEvents, action, reason) {
+  ensure.notNull(processedEvents, "processedEvents");
+  ensure.notNull(reason, "reason");
+  var dto = new ClientMessage.PersistentSubscriptionNakEvents(
+      this._subscriptionId,
+      processedEvents.map(function(x) { return new Buffer(uuid.parse(x)); }),
+      reason,
+      action);
+
+  var pkg = new TcpPackage(TcpCommand.PersistentSubscriptionNakEvents,
+      this._userCredentials != null ? TcpFlags.Authenticated : TcpFlags.None,
+      this._correlationId,
+      this._userCredentials != null ? this._userCredentials.username : null,
+      this._userCredentials != null ? this._userCredentials.password : null,
+      createBufferSegment(dto.toBuffer()));
+  this._enqueueSend(pkg);
+};
+
+module.exports = ConnectToPersistentSubscriptionOperation;

src/clientOperations/createPersistentSubscriptionOperation.js

@@ -0,0 +1,74 @@
+var util = require('util');
+var uuid = require('uuid');
+
+var ensure = require('../common/utils/ensure');
+var OperationBase = require('../clientOperations/operationBase');
+var TcpCommand = require('../systemData/tcpCommand');
+var ClientMessage = require('../messages/clientMessage');
+var SystemConsumerStrategies = require('../systemConsumerStrategies');
+var InspectionDecision = require('../systemData/inspectionDecision');
+var InspectionResult = require('./../systemData/inspectionResult');
+var results = require('../results');
+
+
+function CreatePersistentSubscriptionOperation(log, cb, stream, groupName, settings, userCredentials) {
+  OperationBase.call(this, log, cb, TcpCommand.CreatePersistentSubscription, TcpCommand.CreatePersistentSubscriptionCompleted, userCredentials);
+
+  ensure.notNull(settings, "settings");
+  this._resolveLinkTos = settings.resolveLinkTos;
+  this._stream = stream;
+  this._groupName = groupName;
+  this._startFromBeginning = settings.startFrom;
+  this._maxRetryCount = settings.maxRetryCount;
+  this._liveBufferSize = settings.liveBufferSize;
+  this._readBatchSize = settings.readBatchSize;
+  this._bufferSize = settings.historyBufferSize;
+  this._recordStatistics = settings.extraStatistics;
+  this._messageTimeoutMilliseconds = settings.messageTimeout;
+  this._checkPointAfter = settings.checkPointAfter;
+  this._minCheckPointCount = settings.minCheckPointCount;
+  this._maxCheckPointCount = settings.maxCheckPointCount;
+  this._maxSubscriberCount = settings.maxSubscriberCount;
+  this._namedConsumerStrategy = settings.namedConsumerStrategy;
+
+  this._responseType = ClientMessage.CreatePersistentSubscriptionCompleted;
+}
+util.inherits(CreatePersistentSubscriptionOperation, OperationBase);
+
+CreatePersistentSubscriptionOperation.prototype._createRequestDto = function() {
+  return new ClientMessage.CreatePersistentSubscription(this._groupName, this._stream, this._resolveLinkTos,
+      this._startFromBeginning, this._messageTimeoutMilliseconds, this._recordStatistics, this._liveBufferSize,
+      this._readBatchSize, this._bufferSize, this._maxRetryCount,
+      this._namedConsumerStrategy == SystemConsumerStrategies.RoundRobin, this._checkPointAfter,
+      this._maxCheckPointCount, this._minCheckPointCount, this._maxSubscriberCount, this._namedConsumerStrategy);
+};
+
+CreatePersistentSubscriptionOperation.prototype._inspectResponse = function(response) {
+  switch (response.result)
+  {
+    case ClientMessage.CreatePersistentSubscriptionCompleted.CreatePersistentSubscriptionResult.Success:
+      this._succeed();
+      return new InspectionResult(InspectionDecision.EndOperation, "Success");
+    case ClientMessage.CreatePersistentSubscriptionCompleted.CreatePersistentSubscriptionResult.Fail:
+      this.fail(new Error(util.format("Subscription group %s on stream %s failed '%s'", this._groupName, this._stream, response.reason)));
+      return new InspectionResult(InspectionDecision.EndOperation, "Fail");
+    case ClientMessage.CreatePersistentSubscriptionCompleted.CreatePersistentSubscriptionResult.AccessDenied:
+      this.fail(new Error(util.format("Write access denied for stream '%s'.", this._stream)));
+      return new InspectionResult(InspectionDecision.EndOperation, "AccessDenied");
+    case ClientMessage.CreatePersistentSubscriptionCompleted.CreatePersistentSubscriptionResult.AlreadyExists:
+      this.fail(new Error(util.format("Subscription group %s on stream %s already exists", this._groupName, this._stream)));
+      return new InspectionResult(InspectionDecision.EndOperation, "AlreadyExists");
+    default:
+      throw new Error(util.format("Unexpected OperationResult: %s.", response.result));
+  }
+};
+
+CreatePersistentSubscriptionOperation.prototype._transformResponse = function(response) {
+  return new results.PersistentSubscriptionCreateResult(results.PersistentSubscriptionCreateStatus.Success);
+};
+
+CreatePersistentSubscriptionOperation.prototype.toString = function() {
+  return util.format("Stream: %s, Group Name: %s", this._stream, this._groupName);
+};
+
+module.exports = CreatePersistentSubscriptionOperation;

src/clientOperations/deletePersistentSubscriptionOperation.js

@@ -0,0 +1,55 @@
+var util = require('util');
+var uuid = require('uuid');
+
+var ensure = require('../common/utils/ensure');
+var OperationBase = require('../clientOperations/operationBase');
+var TcpCommand = require('../systemData/tcpCommand');
+var ClientMessage = require('../messages/clientMessage');
+var InspectionDecision = require('../systemData/inspectionDecision');
+var InspectionResult = require('./../systemData/inspectionResult');
+var results = require('../results');
+
+
+function DeletePersistentSubscriptionOperation(log, cb, stream, groupName, userCredentials) {
+  OperationBase.call(this, log, cb, TcpCommand.DeletePersistentSubscription, TcpCommand.DeletePersistentSubscriptionCompleted, userCredentials);
+
+  this._stream = stream;
+  this._groupName = groupName;
+
+  this._responseType = ClientMessage.DeletePersistentSubscriptionCompleted;
+}
+util.inherits(DeletePersistentSubscriptionOperation, OperationBase);
+
+DeletePersistentSubscriptionOperation.prototype._createRequestDto = function() {
+  return new ClientMessage.DeletePersistentSubscription(this._groupName, this._stream);
+};
+
+DeletePersistentSubscriptionOperation.prototype._inspectResponse = function(response) {
+  switch (response.result)
+  {
+    case ClientMessage.DeletePersistentSubscriptionCompleted.DeletePersistentSubscriptionResult.Success:
+      this._succeed();
+      return new InspectionResult(InspectionDecision.EndOperation, "Success");
+    case ClientMessage.DeletePersistentSubscriptionCompleted.DeletePersistentSubscriptionResult.Fail:
+      this.fail(new Error(util.format("Subscription group %s on stream %s failed '%s'", this._groupName, this._stream, response.reason)));
+      return new InspectionResult(InspectionDecision.EndOperation, "Fail");
+    case ClientMessage.DeletePersistentSubscriptionCompleted.DeletePersistentSubscriptionResult.AccessDenied:
+      this.fail(new Error(util.format("Write access denied for stream '%s'.", this._stream)));
+      return new InspectionResult(InspectionDecision.EndOperation, "AccessDenied");
+    case ClientMessage.DeletePersistentSubscriptionCompleted.DeletePersistentSubscriptionResult.DoesNotExist:
+      this.fail(new Error(util.format("Subscription group %s on stream %s does not exist", this._groupName, this._stream)));
+      return new InspectionResult(InspectionDecision.EndOperation, "DoesNotExist");
+    default:
+      throw new Error(util.format("Unexpected OperationResult: %s.", response.result));
+  }
+};
+
+DeletePersistentSubscriptionOperation.prototype._transformResponse = function(response) {
+  return new results.PersistentSubscriptionDeleteResult(results.PersistentSubscriptionDeleteStatus.Success);
+};
+
+DeletePersistentSubscriptionOperation.prototype.toString = function() {
+  return util.format("Stream: %s, Group Name: %s", this._stream, this._groupName);
+};
+
+module.exports = DeletePersistentSubscriptionOperation;

src/clientOperations/operationBase.js

@@ -51,7 +51,7 @@ OperationBase.prototype._succeed = function() {
 
 OperationBase.prototype.createNetworkPackage = function(correlationId) {
   var dto = this._createRequestDto();
-  var buf = dto.encode().toBuffer();
+  var buf = dto.toBuffer();
   return new TcpPackage(
       this._requestCommand,
       this.userCredentials ? TcpFlags.Authenticated : TcpFlags.None,

src/clientOperations/subscriptionOperation.js

@@ -39,6 +39,10 @@ function SubscriptionOperation(
   this._actionQueue = [];
 }
 
+SubscriptionOperation.prototype._enqueueSend = function(pkg) {
+  this._getConnection().enqueueSend(pkg);
+};
+
 SubscriptionOperation.prototype.subscribe = function(correlationId, connection) {
   if (connection === null) throw new TypeError("connection is null.");
 
@@ -60,7 +64,7 @@ SubscriptionOperation.prototype.unsubscribe = function() {
 
 SubscriptionOperation.prototype._createUnsubscriptionPackage = function() {
   var msg = new ClientMessage.UnsubscribeFromStream();
-  var data = new BufferSegment(msg.encode().toBuffer());
+  var data = new BufferSegment(msg.toBuffer());
   return new TcpPackage(TcpCommand.UnsubscribeFromStream, TcpFlags.None, this._correlationId, null, null, data);
 };
 
@@ -182,11 +186,12 @@ SubscriptionOperation.prototype.dropSubscription = function(reason, err, connect
       this._log.debug("Subscription %s to %s: closing subscription, reason: %s, exception: %s...",
           this._correlationId, this._streamId || "<all>", reason, err);
 
-    if (reason !== SubscriptionDropReason.UserInitiated)
+    if (reason !== SubscriptionDropReason.UserInitiated && this._subscription === null)
     {
       if (err === null) throw new Error(util.format("No exception provided for subscription drop reason '%s", reason));
       //TODO: this should be last thing to execute
       this._cb(err);
+      return;
     }
 
     if (reason === SubscriptionDropReason.UserInitiated && this._subscription !== null && connection !== null)
@@ -223,7 +228,7 @@ SubscriptionOperation.prototype._onEventAppeared = function(e) {
   if (this._subscription === null) throw new Error("Subscription not confirmed, but event appeared!");
 
   if (this._verboseLogging)
-    this._log.debug("Subscription %s to %s: event appeared (%s, %d, %s @ %j).",
+    this._log.debug("Subscription %s to %s: event appeared (%s, %d, %s @ %s).",
         this._correlationId, this._streamId || "<all>",
         e.originalStreamId, e.originalEventNumber, e.originalEvent.eventType, e.originalPosition);
 
@@ -250,7 +255,7 @@ SubscriptionOperation.prototype._executeActions = function() {
     }
     catch (err)
     {
-      this._log.error(err, "Exception during executing user callback: %s.", err.Message);
+      this._log.error(err, "Exception during executing user callback: %s.", err.message);
     }
     action = this._actionQueue.shift();
   }

src/clientOperations/updatePersistentSubscriptionOperation.js

@@ -0,0 +1,74 @@
+var util = require('util');
+var uuid = require('uuid');
+
+var ensure = require('../common/utils/ensure');
+var OperationBase = require('../clientOperations/operationBase');
+var TcpCommand = require('../systemData/tcpCommand');
+var ClientMessage = require('../messages/clientMessage');
+var SystemConsumerStrategies = require('../systemConsumerStrategies');
+var InspectionDecision = require('../systemData/inspectionDecision');
+var InspectionResult = require('./../systemData/inspectionResult');
+var results = require('../results');
+
+
+function UpdatePersistentSubscriptionOperation(log, cb, stream, groupName, settings, userCredentials) {
+  OperationBase.call(this, log, cb, TcpCommand.UpdatePersistentSubscription, TcpCommand.UpdatePersistentSubscriptionCompleted, userCredentials);
+
+  ensure.notNull(settings, "settings");
+  this._resolveLinkTos = settings.resolveLinkTos;
+  this._stream = stream;
+  this._groupName = groupName;
+  this._startFromBeginning = settings.startFrom;
+  this._maxRetryCount = settings.maxRetryCount;
+  this._liveBufferSize = settings.liveBufferSize;
+  this._readBatchSize = settings.readBatchSize;
+  this._bufferSize = settings.historyBufferSize;
+  this._recordStatistics = settings.extraStatistics;
+  this._messageTimeoutMilliseconds = settings.messageTimeout;
+  this._checkPointAfter = settings.checkPointAfter;
+  this._minCheckPointCount = settings.minCheckPointCount;
+  this._maxCheckPointCount = settings.maxCheckPointCount;
+  this._maxSubscriberCount = settings.maxSubscriberCount;
+  this._namedConsumerStrategy = settings.namedConsumerStrategy;
+
+  this._responseType = ClientMessage.UpdatePersistentSubscriptionCompleted;
+}
+util.inherits(UpdatePersistentSubscriptionOperation, OperationBase);
+
+UpdatePersistentSubscriptionOperation.prototype._createRequestDto = function() {
+  return new ClientMessage.UpdatePersistentSubscription(this._groupName, this._stream, this._resolveLinkTos,
+      this._startFromBeginning, this._messageTimeoutMilliseconds, this._recordStatistics, this._liveBufferSize,
+      this._readBatchSize, this._bufferSize, this._maxRetryCount,
+      this._namedConsumerStrategy == SystemConsumerStrategies.RoundRobin, this._checkPointAfter,
+      this._maxCheckPointCount, this._minCheckPointCount, this._maxSubscriberCount, this._namedConsumerStrategy);
+};
+
+UpdatePersistentSubscriptionOperation.prototype._inspectResponse = function(response) {
+  switch (response.result)
+  {
+    case ClientMessage.UpdatePersistentSubscriptionCompleted.UpdatePersistentSubscriptionResult.Success:
+      this._succeed();
+      return new InspectionResult(InspectionDecision.EndOperation, "Success");
+    case ClientMessage.UpdatePersistentSubscriptionCompleted.UpdatePersistentSubscriptionResult.Fail:
+      this.fail(new Error(util.format("Subscription group %s on stream %s failed '%s'", this._groupName, this._stream, response.reason)));
+      return new InspectionResult(InspectionDecision.EndOperation, "Fail");
+    case ClientMessage.UpdatePersistentSubscriptionCompleted.UpdatePersistentSubscriptionResult.AccessDenied:
+      this.fail(new Error(util.format("Write access denied for stream '%s'.", this._stream)));
+      return new InspectionResult(InspectionDecision.EndOperation, "AccessDenied");
+    case ClientMessage.UpdatePersistentSubscriptionCompleted.UpdatePersistentSubscriptionResult.DoesNotExist:
+      this.fail(new Error(util.format("Subscription group %s on stream %s does not exist", this._groupName, this._stream)));
+      return new InspectionResult(InspectionDecision.EndOperation, "DoesNotExist");
+    default:
+      throw new Error(util.format("Unexpected OperationResult: %s.", response.result));
+  }
+};
+
+UpdatePersistentSubscriptionOperation.prototype._transformResponse = function(response) {
+  return new results.PersistentSubscriptionUpdateResult(results.PersistentSubscriptionUpdateStatus.Success);
+};
+
+UpdatePersistentSubscriptionOperation.prototype.toString = function() {
+  return util.format("Stream: %s, Group Name: %s", this._stream, this._groupName);
+};
+
+module.exports = UpdatePersistentSubscriptionOperation;

src/clientOperations/volatileSubscriptionOperation.js

@@ -26,7 +26,7 @@ VolatileSubscriptionOperation.prototype._createSubscriptionPackage = function()
       this._correlationId,
       this._userCredentials != null ? this._userCredentials.username : null,
       this._userCredentials != null ? this._userCredentials.password : null,
-      new BufferSegment(dto.encode().toBuffer()));
+      new BufferSegment(dto.toBuffer()));
 };
 
 VolatileSubscriptionOperation.prototype._inspectPackage = function(pkg) {

src/common/utils/ensure.js

@@ -4,3 +4,8 @@ module.exports.notNullOrEmpty = function(value, name) {
   if (value === '')
     throw new Error(name + " is empty.");
 };
+
+module.exports.notNull = function(value, name) {
+  if (value === null)
+    throw new Error(name + " is null.");
+};

src/core/eventStoreConnectionLogicHandler.js

@@ -7,6 +7,7 @@ var TcpPackageConnection = require('../transport/tcp/tcpPackageConnection');
 var OperationsManager = require('./operationsManager');
 var SubscriptionsManager = require('./subscriptionsManager');
 var VolatileSubscriptionOperation = require('../clientOperations/volatileSubscriptionOperation');
+var ConnectToPersistentSubscriptionOperation = require('../clientOperations/connectToPersistentSubscriptionOperation');
 var messages = require('./messages');
 
 var TcpPackage = require('../systemData/tcpPackage');
@@ -70,6 +71,9 @@ function EventStoreConnectionLogicHandler(esConnection, settings) {
   this._queue.registerHandler(messages.StartSubscriptionMessage, function(msg) {
     self._startSubscription(msg);
   });
+  this._queue.registerHandler(messages.StartPersistentSubscriptionMessage, function(msg) {
+    self._startPersistentSubscription(msg);
+  });
 
   this._queue.registerHandler(messages.EstablishTcpConnectionMessage, function(msg) {
     self._establishTcpConnection(msg.endPoints);
@@ -249,7 +253,7 @@ function createSubscriptionItem(operation, maxRetries, timeout) {
     isSubscribed: false
   };
   subscriptionItem.toString = (function(){
-    return util.format("Subscription %s (%s): %s, is subscribed: %s, retry count: %d, created: %d, last updated: %d",
+    return util.format("Subscription %s (%s): %s, is subscribed: %s, retry count: %d, created: %s, last updated: %s",
         this.operation.constructor.name, this.correlationId, this.operation, this.isSubscribed, this.retryCount,
         new Date(this.createdTime).toISOString().substr(11,12),
         new Date(this.lastUpdated).toISOString().substr(11,12));
@@ -269,7 +273,9 @@ EventStoreConnectionLogicHandler.prototype._startSubscription = function(msg) {
       var operation = new VolatileSubscriptionOperation(this._settings.log, msg.cb, msg.streamId, msg.resolveLinkTos,
               msg.userCredentials, msg.eventAppeared, msg.subscriptionDropped,
               this._settings.verboseLogging, function() { return self._connection });
-      this._logDebug("StartSubscription %s %s, %s, %d, %d.", operation.constructor.name, operation, msg.maxRetries, msg.timeout, this._state === ConnectionState.Connected ? "fire" : "enqueue");
+      this._logDebug("StartSubscription %s %s, %s, %d, %d.",
+          this._state === ConnectionState.Connected ? "fire" : "enqueue",
+          operation.constructor.name, operation, msg.maxRetries, msg.timeout);
       var subscription = createSubscriptionItem(operation, msg.maxRetries, msg.timeout);
       if (this._state === ConnectionState.Connecting)
         this._subscriptions.enqueueSubscription(subscription);
@@ -284,6 +290,34 @@ EventStoreConnectionLogicHandler.prototype._startSubscription = function(msg) {
   }
 };
 
+EventStoreConnectionLogicHandler.prototype._startPersistentSubscription = function(msg) {
+  var self = this;
+  switch (this._state)
+  {
+    case ConnectionState.Init:
+      msg.cb(new Error(util.format("EventStoreConnection '%s' is not active.", this._esConnection.connectionName)));
+      break;
+    case ConnectionState.Connecting:
+    case ConnectionState.Connected:
+      var operation = new ConnectToPersistentSubscriptionOperation(this._settings.log, msg.cb, msg.subscriptionId,
+              msg.bufferSize, msg.streamId, msg.userCredentials, msg.eventAppeared, msg.subscriptionDropped,
+              this._settings.verboseLogging, function() { return self._connection });
+      this._logDebug("StartSubscription %s %s, %s, %d, %d.",
+          this._state === ConnectionState.Connected ? "fire" : "enqueue",
+          operation.constructor.name, operation, msg.maxRetries, msg.timeout);
+      var subscription = createSubscriptionItem(operation, msg.maxRetries, msg.timeout);
+      if (this._state === ConnectionState.Connecting)
+        this._subscriptions.enqueueSubscription(subscription);
+      else
+        this._subscriptions.startSubscription(subscription, this._connection);
+      break;
+    case ConnectionState.Closed:
+      msg.cb(new Error("Connection closed. " + this._esConnection.connectionName));
+      break;
+    default: throw new Error(util.format("Unknown state: %s.", this._state));
+  }
+};
+
 EventStoreConnectionLogicHandler.prototype._establishTcpConnection = function(endPoints) {
   var endPoint = this._settings.useSslConnection ? endPoints.secureTcpEndPoint : endPoints.tcpEndPoint;
   if (endPoint == null)
@@ -397,7 +431,7 @@ EventStoreConnectionLogicHandler.prototype._tcpConnectionClosed = function(conne
   this._state = ConnectionState.Connecting;
   this._connectingPhase = ConnectingPhase.Reconnecting;
 
-  this._logDebug("TCP connection to [%j, L%j, %s] closed.", connection.remoteEndPoint, connection.localEndPoint, connection.connectionId);
+  this._logDebug("TCP connection to [%j, L%j, %s] closed. %s", connection.remoteEndPoint, connection.localEndPoint, connection.connectionId, error);
 
   this._subscriptions.purgeSubscribedAndDroppedSubscriptions(this._connection.connectionId);
   this._reconnInfo = {

src/core/messages.js

@@ -1,4 +1,5 @@
 var util = require('util');
+var ensure = require('../common/utils/ensure');
 
 function Message() {
 }
@@ -76,6 +77,22 @@ util.inherits(TcpConnectionClosedMessage, Message);
 function TimerTickMessage() {}
 util.inherits(TimerTickMessage, Message);
 
+function StartPersistentSubscriptionMessage(
+    cb, subscriptionId, streamId, bufferSize, userCredentials, eventAppeared, subscriptionDropped,
+    maxRetries, operationTimeout
+) {
+  this.cb = cb;
+  this.subscriptionId = subscriptionId;
+  this.streamId = streamId;
+  this.bufferSize = bufferSize;
+  this.userCredentials = userCredentials;
+  this.eventAppeared = eventAppeared;
+  this.subscriptionDropped = subscriptionDropped;
+  this.maxRetries = maxRetries;
+  this.timeout = operationTimeout;
+}
+util.inherits(StartPersistentSubscriptionMessage, Message);
+
 module.exports = {
   StartConnectionMessage: StartConnectionMessage,
   CloseConnectionMessage: CloseConnectionMessage,
@@ -86,5 +103,6 @@ module.exports = {
   TcpConnectionErrorMessage: TcpConnectionErrorMessage,
   TcpConnectionEstablishedMessage: TcpConnectionEstablishedMessage,
   TcpConnectionClosedMessage: TcpConnectionClosedMessage,
-  TimerTickMessage: TimerTickMessage
+  TimerTickMessage: TimerTickMessage,
+  StartPersistentSubscriptionMessage: StartPersistentSubscriptionMessage
 };

src/eventStoreNodeConnection.js

@@ -16,10 +16,14 @@ var ReadStreamEventsForwardOperation = require('./clientOperations/readStreamEve
 var ReadStreamEventsBackwardOperation = require('./clientOperations/readStreamEventsBackwardOperation');
 var ReadAllEventsForwardOperation = require('./clientOperations/readAllEventsForwardOperation');
 var ReadAllEventsBackwardOperation = require('./clientOperations/readAllEventsBackwardOperation');
+var CreatePersistentSubscriptionOperation = require('./clientOperations/createPersistentSubscriptionOperation');
+var UpdatePersistentSubscriptionOperation = require('./clientOperations/updatePersistentSubscriptionOperation');
+var DeletePersistentSubscriptionOperation = require('./clientOperations/deletePersistentSubscriptionOperation');
 
 var EventStoreTransaction = require('./eventStoreTransaction');
 var EventStoreStreamCatchUpSubscription = require('./eventStoreStreamCatchUpSubscription');
 var EventStoreAllCatchUpSubscription = require('./eventStoreAllCatchUpSubscription');
+var EventStorePersistentSubscription = require('./eventStorePersistentSubscription');
 
 var results = require('./results');
 var systemStreams = require('./common/systemStreams');
@@ -83,7 +87,6 @@ EventStoreNodeConnection.prototype.close = function() {
   this._handler.enqueueMessage(new messages.CloseConnectionMessage("Connection close requested by client.", null));
 };
 
-// --- Writing ---
 /**
  * Delete a stream (async)
  * @param {string} stream
@@ -193,7 +196,6 @@ EventStoreNodeConnection.prototype.commitTransaction = function(transaction, use
   });
 };
 
-// --- Reading ---
 /**
  * Read a single event (async)
  * @param {string} stream
@@ -328,7 +330,6 @@ EventStoreNodeConnection.prototype.readAllEventsBackward = function(
   });
 };
 
-// --- Subscriptions ---
 /**
  * Subscribe to a stream (async)
  * @param {!string} stream
@@ -435,24 +436,99 @@ EventStoreNodeConnection.prototype.subscribeToAllFrom = function(
   return catchUpSubscription;
 };
 
-EventStoreNodeConnection.prototype.connectToPersistentSubscription = function() {
+/**
-  //TODO: connect to persistent subscription
+ * Subscribe to a persistent subscription
-  throw new Error("Not implemented.");
+ * @param {string} stream
+ * @param {string} groupName
+ * @param {function} eventAppeared
+ * @param {function} [subscriptionDropped]
+ * @param {UserCredentials} [userCredentials]
+ * @param {number} [bufferSize]
+ * @param {boolean} [autoAck]
+ */
+EventStoreNodeConnection.prototype.connectToPersistentSubscription = function(
+    stream, groupName, eventAppeared, subscriptionDropped, userCredentials, bufferSize, autoAck
+) {
+  ensure.notNullOrEmpty(groupName, "groupName");
+  ensure.notNullOrEmpty(stream, "stream");
+  ensure.notNull(eventAppeared, "eventAppeared");
+
+  subscriptionDropped = subscriptionDropped || null;
+  userCredentials = userCredentials || null;
+  bufferSize = bufferSize === undefined ? 10 : bufferSize;
+  autoAck = autoAck === undefined ? true : !!autoAck;
+
+  var subscription = new EventStorePersistentSubscription(
+      groupName, stream, eventAppeared, subscriptionDropped, userCredentials, this._settings.log,
+      this._settings.verboseLogging, this._settings, this._handler, bufferSize, autoAck);
+  subscription.start();
+
+  return subscription;
 };
 
-EventStoreNodeConnection.prototype.createPersistentSubscription = function() {
+/**
-  //TODO: create persistent subscription
+ * @param {string} stream
-  throw new Error("Not implemented.");
+ * @param {string} groupName
+ * @param {PersistentSubscriptionSettings} settings
+ * @param {UserCredentials} [userCredentials]
+ * @returns {Promise.<PersistentSubscriptionCreateResult>}
+ */
+EventStoreNodeConnection.prototype.createPersistentSubscription = function(stream, groupName, settings, userCredentials) {
+  ensure.notNullOrEmpty(stream, "stream");
+  ensure.notNullOrEmpty(groupName, "groupName");
+  ensure.notNull(settings, "settings");
+
+  var self = this;
+  return new Promise(function(resolve, reject){
+    function cb(err, result) {
+      if (err) return reject(err);
+      resolve(result);
+    }
+    self._enqueueOperation(
+        new CreatePersistentSubscriptionOperation(self._settings.log, cb, stream, groupName, settings, userCredentials || null));
+  });
 };
 
-EventStoreNodeConnection.prototype.updatePersistentSubscription = function() {
+/**
-  //TODO: update persistent subscription
+ * @param {string} stream
-  throw new Error("Not implemented.");
+ * @param {string} groupName
+ * @param {string} settings
+ * @param {UserCredentials} [userCredentials]
+ * @returns {Promise.<PersistentSubscriptionUpdateResult>}
+ */
+EventStoreNodeConnection.prototype.updatePersistentSubscription = function(stream, groupName, settings, userCredentials) {
+  ensure.notNullOrEmpty(stream, "stream");
+  ensure.notNullOrEmpty(groupName, "groupName");
+  ensure.notNull(settings, "settings");
+  var self = this;
+  return new Promise(function(resolve, reject) {
+    function cb(err, result) {
+      if (err) return reject(err);
+      resolve(result);
+    }
+    self._enqueueOperation(
+        new UpdatePersistentSubscriptionOperation(self._settings.log, cb, stream, groupName, settings, userCredentials || null));
+  });
 };
 
-EventStoreNodeConnection.prototype.deletePersistentSubscription = function() {
+/**
-  //TODO: delete persistent subscription
+ * @param {string} stream
-  throw new Error("Not implemented.");
+ * @param {string} groupName
+ * @param {UserCredentials} [userCredentials]
+ * @returns {Promise.<PersistentSubscriptionDeleteResult>}
+ */
+EventStoreNodeConnection.prototype.deletePersistentSubscription = function(stream, groupName, userCredentials) {
+  ensure.notNullOrEmpty(stream, "stream");
+  ensure.notNullOrEmpty(groupName, "groupName");
+  var self = this;
+  return new Promise(function(resolve, reject) {
+    function cb(err, result) {
+      if (err) return reject(err);
+      resolve(result);
+    }
+    self._enqueueOperation(
+        new DeletePersistentSubscriptionOperation(self._settings.log, cb, stream, groupName, userCredentials || null));
+  });
 };
 
 EventStoreNodeConnection.prototype.setStreamMetadata = function() {

src/eventStorePersistentSubscription.js

@@ -0,0 +1,35 @@
+var util = require('util');
+
+var EventStorePersistentSubscriptionBase = require('./eventStorePersistentSubscriptionBase');
+var messages = require('./core/messages');
+
+function EventStorePersistentSubscription(
+    subscriptionId, streamId, eventAppeared, subscriptionDropped, userCredentials, log, verboseLogging, settings,
+    handler, bufferSize, autoAck
+) {
+  bufferSize = bufferSize === undefined ? 10 : bufferSize;
+  autoAck = autoAck === undefined ? true : !!autoAck;
+
+  EventStorePersistentSubscriptionBase.call(this, subscriptionId, streamId, eventAppeared, subscriptionDropped,
+                                            userCredentials, log, verboseLogging, settings, bufferSize, autoAck);
+
+  this._handler = handler;
+}
+util.inherits(EventStorePersistentSubscription, EventStorePersistentSubscriptionBase);
+
+EventStorePersistentSubscription.prototype._startSubscription = function(
+    subscriptionId, streamId, bufferSize, userCredentials, onEventAppeared, onSubscriptionDropped, settings
+) {
+  var self = this;
+  return new Promise(function(resolve, reject){
+    function cb(err, result) {
+      if (err) return reject(err);
+      resolve(result);
+    }
+    self._handler.enqueueMessage(new messages.StartPersistentSubscriptionMessage(cb, subscriptionId, streamId,
+        bufferSize, userCredentials, onEventAppeared, onSubscriptionDropped, settings.maxRetries,
+        settings.operationTimeout));
+  });
+};
+
+module.exports = EventStorePersistentSubscription;

src/eventStorePersistentSubscriptionBase.js

@@ -0,0 +1,167 @@
+var util = require('util');
+var ensure = require('./common/utils/ensure');
+var PersistentSubscriptionNakEventAction = require('./persistentSubscriptionNakEventAction');
+var SubscriptionDropReason = require('./subscriptionDropReason');
+
+function DropSubscriptionEvent() {}
+
+function EventStorePersistentSubscriptionBase(
+    subscriptionId, streamId,
+    eventAppeared, subscriptionDropped,
+    userCredentials, log, verboseLogging, settings, bufferSize, autoAck
+) {
+  bufferSize = bufferSize === undefined ? 10 : bufferSize;
+  autoAck = autoAck === undefined ? true : autoAck;
+
+  this._subscriptionId = subscriptionId;
+  this._streamId = streamId;
+  this._eventAppeared = eventAppeared;
+  this._subscriptionDropped = subscriptionDropped;
+  this._userCredentials = userCredentials;
+  this._log = log;
+  this._verbose = verboseLogging;
+  this._settings = settings;
+  this._bufferSize = bufferSize;
+  this._autoAck = autoAck;
+
+  this._subscription = null;
+  this._dropData = null;
+  this._queue = [];
+  this._isProcessing = false;
+  this._isDropped = false;
+}
+
+EventStorePersistentSubscriptionBase.prototype.start = function() {
+  this._stopped = false;
+
+  var self = this;
+  this._startSubscription(this._subscriptionId, this._streamId, this._bufferSize, this._userCredentials,
+                          this._onEventAppeared.bind(this), this._onSubscriptionDropped.bind(this), this._settings)
+      .then(function(subscription) {
+        self._subscription = subscription;
+      });
+};
+
+EventStorePersistentSubscriptionBase.prototype._startSubscription = function() {
+  throw new Error("EventStorePersistentSubscriptionBase._startSubscription abstract method called." +
+                  this.constructor.name);
+};
+
+/**
+ * @param {ResolvedEvent[]|ResolvedEvent} events
+ */
+EventStorePersistentSubscriptionBase.prototype.acknowledge = function(events) {
+  ensure.notNull(events, "events");
+
+  if (this._subscription === null) throw new Error("Invalid operation. Subscription is not active yet.");
+  if (!Array.isArray(events))
+    events = [events];
+  var ids = events.map(function(x) { return x.originalEvent.eventId; });
+  this._subscription.notifyEventsProcessed(ids);
+};
+
+/**
+ * @param {ResolvedEvent[]|ResolvedEvent} events
+ * @param {number} action One of PersistentSubscriptionNakEventAction
+ * @param {string} reason
+ */
+EventStorePersistentSubscriptionBase.prototype.fail = function(events, action, reason) {
+  ensure.notNull(events, "events");
+  PersistentSubscriptionNakEventAction.isValid(action);
+  ensure.notNull(reason, "reason");
+
+  if (this._subscription === null) throw new Error("Invalid operation. Subscription is not active yet.");
+  if (!Array.isArray(events))
+    events = [events];
+  var ids = events.map(function(x) { return x.originalEvent.eventId; });
+  this._subscription.notifyEventsFailed(ids, action, reason);
+};
+
+EventStorePersistentSubscriptionBase.prototype.stop = function() {
+  if (this._verbose) this._log.debug("Persistent Subscription to %s: requesting stop...", this._streamId);
+  this._enqueueSubscriptionDropNotification(SubscriptionDropReason.UserInitiated, null);
+  //TODO figure out timeout with Promise still running
+  //if (!_stopped.Wait(timeout))
+    //throw new TimeoutException(string.Format("Could not stop {0} in time.", GetType().Name));
+};
+
+EventStorePersistentSubscriptionBase.prototype._enqueueSubscriptionDropNotification = function(reason, error) {
+  // if drop data was already set -- no need to enqueue drop again, somebody did that already
+  if (!this._dropData) {
+    this._dropData = {reason: reason, error: error};
+    this._enqueue(new DropSubscriptionEvent());
+  }
+};
+
+EventStorePersistentSubscriptionBase.prototype._onSubscriptionDropped = function(subscription, reason, exception) {
+  this._enqueueSubscriptionDropNotification(reason, exception);
+};
+
+EventStorePersistentSubscriptionBase.prototype._onEventAppeared = function(subscription, resolvedEvent) {
+  this._enqueue(resolvedEvent);
+};
+
+EventStorePersistentSubscriptionBase.prototype._enqueue = function(resolvedEvent) {
+  this._queue.push(resolvedEvent);
+  if (!this._isProcessing) {
+    this._isProcessing = true;
+    setImmediate(this._processQueue.bind(this));
+  }
+};
+
+EventStorePersistentSubscriptionBase.prototype._processQueue = function() {
+  //do
+  //{
+    var e = this._queue.shift();
+    while (e)
+    {
+      if (e instanceof DropSubscriptionEvent) // drop subscription artificial ResolvedEvent
+      {
+        if (this._dropData === null) throw new Error("Drop reason not specified.");
+        this._dropSubscription(this._dropData.reason, this._dropData.error);
+        return;
+      }
+      if (this._dropData !== null)
+      {
+        this._dropSubscription(this._dropData.reason, this._dropData.error);
+        return;
+      }
+      try
+      {
+        this._eventAppeared(this, e);
+        if(this._autoAck)
+          this._subscription.notifyEventsProcessed([e.originalEvent.eventId]);
+        if (this._verbose)
+          this._log.debug("Persistent Subscription to %s: processed event (%s, %d, %s @ %d).",
+              this._streamId, e.originalEvent.eventStreamId, e.originalEvent.eventNumber, e.originalEvent.eventType,
+              e.originalEventNumber);
+      }
+      catch (err)
+      {
+        //TODO GFY should we autonak here?
+        this._dropSubscription(SubscriptionDropReason.EventHandlerException, err);
+        return;
+      }
+      e = this._queue.shift();
+    }
+    this._isProcessing = false;
+  //} while (_queue.Count > 0 && Interlocked.CompareExchange(ref _isProcessing, 1, 0) == 0);
+};
+
+EventStorePersistentSubscriptionBase.prototype._dropSubscription = function(reason, error) {
+  if (!this._isDropped)
+  {
+    this._isDropped = true;
+    if (this._verbose)
+      this._log.debug("Persistent Subscription to %s: dropping subscription, reason: %s %s.",
+                      this._streamId, reason, error);
+
+    if (this._subscription !== null)
+      this._subscription.unsubscribe();
+    if (this._subscriptionDropped !== null)
+      this._subscriptionDropped(this, reason, error);
+    this._stopped = true;
+  }
+};
+
+module.exports = EventStorePersistentSubscriptionBase;

src/messages/messages.proto

@@ -35,12 +35,12 @@ message EventRecord {
 }
 
 message ResolvedIndexedEvent {
-	optional EventRecord event = 1;
+	required EventRecord event = 1;
 	optional EventRecord link = 2;
 }
 
 message ResolvedEvent {
-	optional EventRecord event = 1;
+	required EventRecord event = 1;
 	optional EventRecord link = 2;
 	required int64 commit_position = 3;
 	required int64 prepare_position = 4;
@@ -195,6 +195,119 @@ message ReadAllEventsCompleted {
 	optional string error = 7;
 }
 
+message CreatePersistentSubscription {
+	required string subscription_group_name = 1;
+	required string event_stream_id = 2;
+	required bool resolve_link_tos = 3;
+	required int32 start_from = 4;
+	required int32 message_timeout_milliseconds = 5;
+	required bool record_statistics = 6;
+	required int32 live_buffer_size = 7;
+	required int32 read_batch_size = 8;
+	required int32 buffer_size = 9;
+	required int32 max_retry_count = 10;
+	required bool prefer_round_robin = 11;
+	required int32 checkpoint_after_time = 12;
+	required int32 checkpoint_max_count = 13;
+	required int32 checkpoint_min_count = 14;
+	required int32 subscriber_max_count = 15;
+	optional string named_consumer_strategy = 16;
+}
+
+message DeletePersistentSubscription {
+	required string subscription_group_name = 1;
+	required string event_stream_id = 2;
+}
+
+message UpdatePersistentSubscription {
+	required string subscription_group_name = 1;
+	required string event_stream_id = 2;
+	required bool resolve_link_tos = 3;
+	required int32 start_from = 4;
+	required int32 message_timeout_milliseconds = 5;
+	required bool record_statistics = 6;
+	required int32 live_buffer_size = 7;
+	required int32 read_batch_size = 8;
+	required int32 buffer_size = 9;
+	required int32 max_retry_count = 10;
+	required bool prefer_round_robin = 11;
+	required int32 checkpoint_after_time = 12;
+	required int32 checkpoint_max_count = 13;
+	required int32 checkpoint_min_count = 14;
+	required int32 subscriber_max_count = 15;
+	optional string named_consumer_strategy = 16;
+}
+
+message UpdatePersistentSubscriptionCompleted {
+	enum UpdatePersistentSubscriptionResult {
+		Success = 0;
+		DoesNotExist = 1;
+		Fail = 2;
+		AccessDenied=3;
+	}
+	required UpdatePersistentSubscriptionResult result = 1 [default = Success];
+	optional string reason = 2;
+}
+
+message CreatePersistentSubscriptionCompleted {
+	enum CreatePersistentSubscriptionResult {
+		Success = 0;
+		AlreadyExists = 1;
+		Fail = 2;
+		AccessDenied=3;
+	}
+	required CreatePersistentSubscriptionResult result = 1 [default = Success];
+	optional string reason = 2;
+}
+
+message DeletePersistentSubscriptionCompleted {
+	enum DeletePersistentSubscriptionResult {
+		Success = 0;
+		DoesNotExist = 1;
+		Fail = 2;
+		AccessDenied = 3;
+	}
+	required DeletePersistentSubscriptionResult result = 1 [default = Success];
+	optional string reason = 2;
+}
+
+message ConnectToPersistentSubscription {
+	required string subscription_id = 1;
+	required string event_stream_id = 2;
+	required int32 allowed_in_flight_messages = 3;
+
+}
+
+message PersistentSubscriptionAckEvents {
+	required string subscription_id = 1;
+	repeated bytes processed_event_ids = 2;
+}
+
+message PersistentSubscriptionNakEvents {
+	enum NakAction {
+		Unknown = 0;
+		Park = 1;
+		Retry = 2;
+		Skip = 3;
+		Stop = 4;
+	}
+
+	required string subscription_id = 1;
+	repeated bytes processed_event_ids = 2;
+	optional string message = 3;
+	required NakAction action = 4 [default = Unknown];
+}
+
+message PersistentSubscriptionConfirmation {
+	required int64 last_commit_position = 1;
+	required string subscription_id = 2;
+	optional int32 last_event_number = 3;
+}
+
+message PersistentSubscriptionStreamEventAppeared {
+	required ResolvedIndexedEvent event = 1;
+}
+
 message SubscribeToStream {
 	required string event_stream_id = 1;
 	required bool resolve_link_tos = 2;
@@ -217,6 +330,9 @@ message SubscriptionDropped {
 	enum SubscriptionDropReason {
 		Unsubscribed = 0;
 		AccessDenied = 1;
+		NotFound=2;
+		PersistentSubscriptionDeleted=3;
+		SubscriberMaxCountReached=4;
 	}
 
 	optional SubscriptionDropReason reason = 1 [default = Unsubscribed];

src/persistentEventStoreSubscription.js

@@ -0,0 +1,25 @@
+var util = require('util');
+
+var EventStoreSubscription = require('./eventStoreSubscription');
+
+
+function PersistentEventStoreSubscription(subscriptionOperation, streamId, lastCommitPosition, lastEventNumber) {
+  EventStoreSubscription.call(this, streamId, lastCommitPosition, lastEventNumber);
+
+  this._subscriptionOperation = subscriptionOperation;
+}
+util.inherits(PersistentEventStoreSubscription, EventStoreSubscription);
+
+PersistentEventStoreSubscription.prototype.unsubscribe = function() {
+  this._subscriptionOperation.unsubscribe();
+};
+
+PersistentEventStoreSubscription.prototype.notifyEventsProcessed = function(processedEvents) {
+  this._subscriptionOperation.notifyEventsProcessed(processedEvents);
+};
+
+PersistentEventStoreSubscription.prototype.notifyEventsFailed = function(processedEvents, action, reason) {
+  this._subscriptionOperation.notifyEventsFailed(processedEvents, action, reason);
+};
+
+module.exports = PersistentEventStoreSubscription;

src/persistentSubscriptionNakEventAction.js

@@ -0,0 +1,14 @@
+const PersistentSubscriptionNakEventAction = {
+  Unknown: 0,
+  Park: 1,
+  Retry: 2,
+  Skip: 3,
+  Stop: 4
+};
+
+module.exports = PersistentSubscriptionNakEventAction;
+module.exports.isValid = function(value) {
+  for(var k in PersistentSubscriptionNakEventAction)
+    if (PersistentSubscriptionNakEventAction[k] === value) return true;
+  return false;
+};

src/persistentSubscriptionSettings.js

@@ -0,0 +1,26 @@
+var SystemConsumerStrategies = require('./systemConsumerStrategies');
+
+function PersistentSubscriptionSettings(
+  resolveLinkTos, startFrom, extraStatistics, messageTimeout,
+  maxRetryCount, liveBufferSize, readBatchSize, historyBufferSize,
+  checkPointAfter, minCheckPointCount, maxCheckPointCount,
+  maxSubscriberCount, namedConsumerStrategy
+) {
+  this.resolveLinkTos = resolveLinkTos;
+  this.startFrom = startFrom;
+  this.extraStatistics = extraStatistics;
+  this.messageTimeout = messageTimeout;
+  this.maxRetryCount = maxRetryCount;
+  this.liveBufferSize = liveBufferSize;
+  this.readBatchSize = readBatchSize;
+  this.historyBufferSize = historyBufferSize;
+  this.checkPointAfter = checkPointAfter;
+  this.minCheckPointCount = minCheckPointCount;
+  this.maxCheckPointCount = maxCheckPointCount;
+  this.maxSubscriberCount = maxSubscriberCount;
+  this.namedConsumerStrategy = namedConsumerStrategy;
+}
+
+module.exports.create = function() {
+  return new PersistentSubscriptionSettings(false, -1, false, 30000, 500, 500, 10, 20, 2000, 10, 1000, 0, SystemConsumerStrategies.RoundRobin);
+};

src/results.js

@@ -285,6 +285,57 @@ function RawStreamMetadataResult(stream, isStreamDeleted, metastreamVersion, str
   });
 }
 
+const PersistentSubscriptionCreateStatus = {
+  Success: 'success',
+  NotFound: 'notFound',
+  Failure: 'failure'
+};
+
+/**
+ * @param {string} status
+ * @constructor
+ * @property {string} status
+ */
+function PersistentSubscriptionCreateResult(status) {
+  Object.defineProperties(this, {
+    status: {enumerable: true, value: status}
+  });
+}
+
+const PersistentSubscriptionUpdateStatus = {
+  Success: 'success',
+  NotFound: 'notFound',
+  Failure: 'failure',
+  AccessDenied: 'accessDenied'
+};
+
+/**
+ * @param {string} status
+ * @constructor
+ * @property {string} status
+ */
+function PersistentSubscriptionUpdateResult(status) {
+  Object.defineProperties(this, {
+    status: {enumerable: true, value: status}
+  });
+}
+
+const PersistentSubscriptionDeleteStatus = {
+  Success: 'success',
+  Failure: 'failure'
+};
+
+/**
+ * @param {string} status
+ * @constructor
+ * @property {string} status
+ */
+function PersistentSubscriptionDeleteResult(status) {
+  Object.defineProperties(this, {
+    status: {enumerable: true, value: status}
+  });
+}
+
 // Exports Constructors
 module.exports.Position = Position;
 module.exports.toNumber = toNumber;
@@ -296,3 +347,9 @@ module.exports.StreamEventsSlice = StreamEventsSlice;
 module.exports.AllEventsSlice = AllEventsSlice;
 module.exports.DeleteResult = DeleteResult;
 module.exports.RawStreamMetadataResult = RawStreamMetadataResult;
+module.exports.PersistentSubscriptionCreateResult = PersistentSubscriptionCreateResult;
+module.exports.PersistentSubscriptionCreateStatus = PersistentSubscriptionCreateStatus;
+module.exports.PersistentSubscriptionUpdateResult = PersistentSubscriptionUpdateResult;
+module.exports.PersistentSubscriptionUpdateStatus = PersistentSubscriptionUpdateStatus;
+module.exports.PersistentSubscriptionDeleteResult = PersistentSubscriptionDeleteResult;
+module.exports.PersistentSubscriptionDeleteStatus = PersistentSubscriptionDeleteStatus;

src/subscriptionDropReason.js

@@ -3,6 +3,9 @@ const SubscriptionDropReason = {
   CatchUpError: 'catchUpError',
   ConnectionClosed: 'connectionClosed',
   EventHandlerException: 'eventHandlerException',
+  MaxSubscribersReached: 'maxSubscribersReached',
+  NotFound: 'notFound',
+  PersistentSubscriptionDeleted: 'persistentSubscriptionDeleted',
   ProcessingQueueOverflow: 'processingQueueOverflow',
   ServerError: 'serverError',
   SubscribingError: 'subscribingError',

src/systemConsumerStrategies.js

@@ -0,0 +1,7 @@
+const SystemConsumerStrategies = {
+  DispatchToSingle: 'DispatchToSingle',
+  RoundRobin: 'RoundRobin',
+  Pinned: 'Pinned'
+};
+
+module.exports = SystemConsumerStrategies;

src/systemData/tcpCommand.js

@@ -52,6 +52,17 @@ const TcpCommand = {
   StreamEventAppeared: 0xC2,
   UnsubscribeFromStream: 0xC3,
   SubscriptionDropped: 0xC4,
+  ConnectToPersistentSubscription: 0xC5,
+  PersistentSubscriptionConfirmation: 0xC6,
+  PersistentSubscriptionStreamEventAppeared: 0xC7,
+  CreatePersistentSubscription: 0xC8,
+  CreatePersistentSubscriptionCompleted: 0xC9,
+  DeletePersistentSubscription: 0xCA,
+  DeletePersistentSubscriptionCompleted: 0xCB,
+  PersistentSubscriptionAckEvents: 0xCC,
+  PersistentSubscriptionNakEvents: 0xCD,
+  UpdatePersistentSubscription: 0xCE,
+  UpdatePersistentSubscriptionCompleted: 0xCF,
 
   ScavengeDatabase: 0xD0,
   ScavengeDatabaseCompleted: 0xD1,

test/client_test.js

@@ -281,7 +281,36 @@ module.exports = {
           test.done(err);
         });
   },
-  //TODO: Persistent Subscription
+  'Test Create Persistent Subscription': function(test) {
+    var settings = client.PersistentSubscriptionSettings.create();
+    this.conn.createPersistentSubscription(testStreamName, 'consumer-1', settings, userCredentialsForAll)
+        .then(function(result) {
+          test.done();
+        })
+        .catch(function(err) {
+          test.done(err);
+        });
+  },
+  //TODO: Update Persistent Subscription
+  'Test ConnectTo Persistent Subscription': function(test) {
+    function eventAppeared(s, e) {
+      s.stop();
+    }
+    function subscriptionDropped(connection, reason, error) {
+      test.done(error);
+    }
+    var subscription = this.conn.connectToPersistentSubscription(testStreamName, 'consumer-1', eventAppeared, subscriptionDropped);
+    this.conn.appendToStream(testStreamName, client.expectedVersion.any, [createRandomEvent()]);
+  },
+  'Test Delete Persistent Subscription': function(test) {
+    this.conn.deletePersistentSubscription(testStreamName, 'consumer-1', userCredentialsForAll)
+        .then(function(result) {
+          test.done();
+        })
+        .catch(function(err) {
+          test.done(err);
+        });
+  },
   'Test Delete Stream': function(test) {
     this.conn.deleteStream(testStreamName, client.expectedVersion.any)
         .then(function(result) {