feat(cluster-time): track incoming cluster time gossiping

This is the first part of the requirement to "gossip the cluster
time" by tracking the clusterTime provided on incoming server
responses.

NODE-1088

Author: mbroadst

lib/connection/pool.js

@@ -65,9 +65,13 @@ var _id = 0;
  * @fires Pool#parseError
  * @return {Pool} A cursor instance
  */
-var Pool = function(options) {
+var Pool = function(topology, options) {
   // Add event listener
   EventEmitter.call(this);
+
+  // Store topology for later use
+  this.topology = topology;
+
   // Add the options
   this.options = assign(
     {
@@ -104,9 +108,6 @@ var Pool = function(options) {
     options
   );
 
-  // console.log("=================================== pool options")
-  // console.dir(this.options)
-
   // Identification information
   this.id = _id++;
   // Current reconnect retries
@@ -269,9 +270,6 @@ function reauthenticate(pool, connection, cb) {
 
 function connectionFailureHandler(self, event) {
   return function(err) {
-    // console.log("========== connectionFailureHandler :: " + event)
-    // console.dir(err)
-
     if (this._connectionFailHandled) return;
     this._connectionFailHandled = true;
     // Destroy the connection
@@ -323,7 +321,6 @@ function connectionFailureHandler(self, event) {
 
 function attemptReconnect(self) {
   return function() {
-    // console.log("========================= attemptReconnect")
     self.emit('attemptReconnect', self);
     if (self.state === DESTROYED || self.state === DESTROYING) return;
 
@@ -542,6 +539,12 @@ function messageHandler(self) {
           return handleOperationCallback(self, workItem.cb, new MongoError(err));
         }
 
+        // Look for clusterTime, and update it if necessary
+        if (message.documents[0] && message.documents[0].hasOwnProperty('$clusterTime')) {
+          const $clusterTime = message.documents[0].$clusterTime;
+          self.topology.clusterTime = $clusterTime;
+        }
+
         // Establish if we have an error
         if (
           workItem.command &&

lib/topologies/mongos.js

@@ -40,7 +40,8 @@ var MongoCR = require('../auth/mongocr'),
   Plain = require('../auth/plain'),
   GSSAPI = require('../auth/gssapi'),
   SSPI = require('../auth/sspi'),
-  ScramSHA1 = require('../auth/scram');
+  ScramSHA1 = require('../auth/scram'),
+  resolveClusterTime = require('./shared').resolveClusterTime;
 
 //
 // States
@@ -230,6 +231,9 @@ var Mongos = function(seedlist, options) {
     servers: []
   };
 
+  // Highest clusterTime seen in responses from the current deployment
+  this.clusterTime = null;
+
   // Add event listener
   EventEmitter.call(this);
 };
@@ -283,7 +287,9 @@ Mongos.prototype.connect = function(options) {
   var servers = this.s.seedlist.map(function(x) {
     return new Server(
       assign(
-        {},
+        {
+          clusterTimeWatcher: clusterTime => resolveClusterTime(self, clusterTime)
+        },
         self.s.options,
         x,
         {
@@ -606,7 +612,9 @@ function reconnectProxies(self, proxies, callback) {
       // Create a new server instance
       var server = new Server(
         assign(
-          {},
+          {
+            clusterTimeWatcher: clusterTime => resolveClusterTime(self, clusterTime)
+          },
           self.s.options,
           {
             host: _server.name.split(':')[0],

lib/topologies/replset.js

@@ -14,7 +14,8 @@ var inherits = require('util').inherits,
   clone = require('./shared').clone,
   Timeout = require('./shared').Timeout,
   Interval = require('./shared').Interval,
-  createClientInfo = require('./shared').createClientInfo;
+  createClientInfo = require('./shared').createClientInfo,
+  resolveClusterTime = require('./shared').resolveClusterTime;
 
 var MongoCR = require('../auth/mongocr'),
   X509 = require('../auth/x509'),
@@ -252,6 +253,9 @@ var ReplSet = function(seedlist, options) {
   this.ismaster = null;
   // Contains the intervalId
   this.intervalIds = [];
+
+  // Highest clusterTime seen in responses from the current deployment
+  this.clusterTime = null;
 };
 
 inherits(ReplSet, EventEmitter);
@@ -377,7 +381,9 @@ function connectNewServers(self, servers, callback) {
       // Create a new server instance
       var server = new Server(
         assign(
-          {},
+          {
+            clusterTimeWatcher: clusterTime => resolveClusterTime(self, clusterTime)
+          },
           self.s.options,
           {
             host: _server.split(':')[0],
@@ -956,7 +962,9 @@ ReplSet.prototype.connect = function(options) {
   var servers = this.s.seedlist.map(function(x) {
     return new Server(
       assign(
-        {},
+        {
+          clusterTimeWatcher: clusterTime => resolveClusterTime(self, clusterTime)
+        },
         self.s.options,
         x,
         {

lib/topologies/server.js

@@ -154,6 +154,14 @@ var Server = function(options) {
     compression: { compressors: createCompressionInfo(options) }
   };
 
+  // special case for Mongos and ReplSet deployments
+  if (options.clusterTimeWatcher) {
+    this.s.clusterTimeWatcher = options.clusterTimeWatcher;
+  } else {
+    // otherwise this is a single deployment and we need to track the clusterTime here
+    this.s.clusterTime = null;
+  }
+
   // Curent ismaster
   this.ismaster = null;
   // Current ping time
@@ -203,6 +211,24 @@ Object.defineProperty(Server.prototype, 'logicalSessionTimeoutMinutes', {
   }
 });
 
+// In single server deployments we track the clusterTime directly on the topology, however
+// in Mongos and ReplSet deployments we instead need to delegate the clusterTime up to the
+// tracking objects so we can ensure we are gossiping the maximum time received from the
+// server.
+Object.defineProperty(Server.prototype, 'clusterTime', {
+  enumerable: true,
+  set: function(clusterTime) {
+    if (this.s.clusterTimeWatcher) {
+      this.s.clusterTimeWatcher(clusterTime);
+    } else {
+      this.s.clusterTime = clusterTime;
+    }
+  },
+  get: function() {
+    return this.s.clusterTime || null;
+  }
+});
+
 Server.enableServerAccounting = function() {
   serverAccounting = true;
   servers = {};
@@ -503,7 +529,7 @@ Server.prototype.connect = function(options) {
   }
 
   // Create a pool
-  self.s.pool = new Pool(assign(self.s.options, options, { bson: this.s.bson }));
+  self.s.pool = new Pool(this, assign(self.s.options, options, { bson: this.s.bson }));
 
   // Set up listeners
   self.s.pool.on('close', eventHandler(self, 'close'));

lib/topologies/shared.js

@@ -354,6 +354,23 @@ function diff(previous, current) {
   return diff;
 }
 
+/**
+ * Shared function to determine clusterTime for a given topology
+ *
+ * @param {*} topology
+ * @param {*} clusterTime
+ */
+function resolveClusterTime(topology, $clusterTime) {
+  if (topology.clusterTime == null) {
+    topology.clusterTime = $clusterTime;
+  } else {
+    if ($clusterTime.clusterTime.greaterThan(topology.clusterTime.clusterTime)) {
+      topology.clusterTime = $clusterTime;
+    }
+  }
+}
+
+module.exports.resolveClusterTime = resolveClusterTime;
 module.exports.inquireServerState = inquireServerState;
 module.exports.getTopologyType = getTopologyType;
 module.exports.emitServerDescriptionChanged = emitServerDescriptionChanged;

test/tests/functional/pool_tests.js

@@ -17,7 +17,7 @@ describe('Pool tests', function() {
       Connection.enableConnectionAccounting();
 
       // Attempt to connect
-      var pool = new Pool({
+      var pool = new Pool(null, {
         host: this.configuration.host,
         port: this.configuration.port,
         bson: new Bson(),
@@ -45,7 +45,7 @@ describe('Pool tests', function() {
       Connection.enableConnectionAccounting();
 
       // Attempt to connect
-      var pool = new Pool({
+      var pool = new Pool(null, {
         host: this.configuration.host,
         port: this.configuration.port,
         bson: new Bson()
@@ -85,7 +85,7 @@ describe('Pool tests', function() {
       var index = 0;
 
       // Attempt to connect
-      var pool = new Pool({
+      var pool = new Pool(null, {
         host: this.configuration.host,
         port: this.configuration.port,
         bson: new Bson()
@@ -205,7 +205,7 @@ describe('Pool tests', function() {
       this.timeout(0);
 
       // Attempt to connect
-      var pool = new Pool({
+      var pool = new Pool(null, {
         host: this.configuration.host,
         port: this.configuration.port,
         socketTimeout: 3000,
@@ -242,7 +242,7 @@ describe('Pool tests', function() {
       Connection.enableConnectionAccounting();
 
       // Attempt to connect
-      var pool = new Pool({
+      var pool = new Pool(null, {
         host: this.configuration.host,
         port: this.configuration.port,
         socketTimeout: 3000,
@@ -300,7 +300,7 @@ describe('Pool tests', function() {
       Connection.enableConnectionAccounting();
 
       // Attempt to connect
-      var pool = new Pool({
+      var pool = new Pool(null, {
         host: this.configuration.host,
         port: this.configuration.port,
         socketTimeout: 3000,
@@ -382,7 +382,7 @@ describe('Pool tests', function() {
       Connection.enableConnectionAccounting();
 
       // Attempt to connect
-      var pool = new Pool({
+      var pool = new Pool(null, {
         host: this.configuration.host,
         port: this.configuration.port,
         socketTimeout: 3000,
@@ -459,7 +459,7 @@ describe('Pool tests', function() {
       Connection.enableConnectionAccounting();
 
       // Attempt to connect
-      var pool = new Pool({
+      var pool = new Pool(null, {
         host: this.configuration.host,
         port: this.configuration.port,
         socketTimeout: 1000,
@@ -526,7 +526,7 @@ describe('Pool tests', function() {
               expect(createUserRes).to.exist;
               expect(createUserErr).to.be.null;
               // Attempt to connect
-              var pool = new Pool({
+              var pool = new Pool(null, {
                 host: self.configuration.host,
                 port: self.configuration.port,
                 bson: new Bson()
@@ -606,7 +606,7 @@ describe('Pool tests', function() {
                     expect(createAdminUserErr).to.be.null;
 
                     // Attempt to connect
-                    var pool = new Pool({
+                    var pool = new Pool(null, {
                       host: self.configuration.host,
                       port: self.configuration.port,
                       bson: new Bson()
@@ -812,7 +812,7 @@ describe('Pool tests', function() {
                   expect(createAdminUserErr).to.be.null;
 
                   // Attempt to connect
-                  var pool = new Pool({
+                  var pool = new Pool(null, {
                     host: self.configuration.host,
                     port: self.configuration.port,
                     bson: new Bson()
@@ -936,7 +936,7 @@ describe('Pool tests', function() {
                   expect(createAdminUserRes).to.exist;
                   expect(createAdminUserErr).to.be.null;
                   // Attempt to connect
-                  var pool = new Pool({
+                  var pool = new Pool(null, {
                     host: self.configuration.host,
                     port: self.configuration.port,
                     bson: new Bson()
@@ -1030,7 +1030,7 @@ describe('Pool tests', function() {
                   expect(createAdminUserRes).to.exist;
 
                   // Attempt to connect
-                  var pool = new Pool({
+                  var pool = new Pool(null, {
                     host: self.configuration.host,
                     port: self.configuration.port,
                     bson: new Bson()
@@ -1098,7 +1098,7 @@ describe('Pool tests', function() {
       Connection.enableConnectionAccounting();
 
       // Attempt to connect
-      var pool = new Pool({
+      var pool = new Pool(null, {
         host: this.configuration.host,
         port: this.configuration.port,
         bson: new Bson(),

test/tests/functional/shared.js

@@ -17,7 +17,7 @@ function executeCommand(configuration, db, cmd, options, cb) {
   var port = options.port || configuration.port;
 
   // Attempt to connect
-  var pool = new Pool({
+  var pool = new Pool(null, {
     host: host,
     port: port,
     bson: new bson()
@@ -60,7 +60,7 @@ function locateAuthMethod(configuration, cb) {
   var cmd = { ismaster: true };
 
   // Attempt to connect
-  var pool = new Pool({
+  var pool = new Pool(null, {
     host: configuration.host,
     port: configuration.port,
     bson: new bson()