add shared sequence number

djih · djih · commit 71f3c31ee0d4 · 2015-09-21T20:02:13.000-07:00
diff --git a/amplitude.js b/amplitude.js
@@ -152,6 +152,7 @@ var DEFAULT_OPTIONS = {
 var LocalStorageKeys = {
   LAST_EVENT_ID: 'amplitude_lastEventId',
   LAST_IDENTIFY_ID: 'amplitude_lastIdentifyId',
+  LAST_SEQUENCE_NUMBER: 'amplitude_lastSequenceNumber',
   LAST_EVENT_TIME: 'amplitude_lastEventTime',
   SESSION_ID: 'amplitude_sessionId'
 };
@@ -168,6 +169,7 @@ var Amplitude = function() {
 
 Amplitude.prototype._eventId = 0;
 Amplitude.prototype._identifyId = 0;
+Amplitude.prototype._sequenceNumber = 0;
 Amplitude.prototype._sending = false;
 Amplitude.prototype._lastEventTime = null;
 Amplitude.prototype._sessionId = null;
@@ -244,6 +246,7 @@ Amplitude.prototype.init = function(apiKey, opt_userId, opt_config, callback) {
     this._sessionId = parseInt(localStorage.getItem(LocalStorageKeys.SESSION_ID)) || null;
     this._eventId = localStorage.getItem(LocalStorageKeys.LAST_EVENT_ID) || 0;
     this._identifyId = localStorage.getItem(LocalStorageKeys.LAST_IDENTIFY_ID) || 0;
+    this._sequenceNumber = localStorage.getItem(LocalStorageKeys.LAST_SEQUENCE_NUMBER) || 0;
     var now = new Date().getTime();
     if (!this._sessionId || !this._lastEventTime || now - this._lastEventTime > this.options.sessionTimeout) {
       this._newSession = true;
@@ -286,6 +289,11 @@ Amplitude.prototype.nextIdentifyId = function() {
   return this._identifyId;
 };
 
+Amplitude.prototype.nextSequenceNumber = function() {
+  this._sequenceNumber++;
+  return this._sequenceNumber;
+};
+
 // returns the number of unsent events and identifys
 Amplitude.prototype._unsentCount = function() {
   return this._unsentEvents.length + this._unsentIdentifys.length;
@@ -552,7 +560,8 @@ Amplitude.prototype._logEvent = function(eventType, eventProperties, apiProperti
       library: {
         name: 'amplitude-js',
         version: this.__VERSION__
-      }
+      },
+      sequence_number: this.nextSequenceNumber() // for ordering events and identifys
       // country: null
     };
 
@@ -722,14 +731,17 @@ Amplitude.prototype._mergeEventsAndIdentifys = function(numEvents) {
       event = this._unsentIdentifys[identifyIndex++];
       maxIdentifyId = event.event_id;
 
-    // case 3: need to compare timestamps
+    // case 3: need to compare sequence numbers
     } else {
-      if (this._unsentIdentifys[identifyIndex].timestamp <= this._unsentEvents[eventIndex].timestamp) {
-        event = this._unsentIdentifys[identifyIndex++];
-        maxIdentifyId = event.event_id;
-      } else {
+      // events logged before v2.5.0 won't have a sequence number, put those first
+      if (!('sequence_number' in this._unsentEvents[eventIndex]) ||
+          this._unsentEvents[eventIndex].sequence_number <
+          this._unsentIdentifys[identifyIndex].sequence_number) {
         event = this._unsentEvents[eventIndex++];
         maxEventId = event.event_id;
+      } else {
+        event = this._unsentIdentifys[identifyIndex++];
+        maxIdentifyId = event.event_id;
       }
     }
 
diff --git a/amplitude.min.js b/amplitude.min.js
diff --git a/src/amplitude.js b/src/amplitude.js
@@ -40,6 +40,7 @@ var DEFAULT_OPTIONS = {
 var LocalStorageKeys = {
   LAST_EVENT_ID: 'amplitude_lastEventId',
   LAST_IDENTIFY_ID: 'amplitude_lastIdentifyId',
+  LAST_SEQUENCE_NUMBER: 'amplitude_lastSequenceNumber',
   LAST_EVENT_TIME: 'amplitude_lastEventTime',
   SESSION_ID: 'amplitude_sessionId'
 };
@@ -56,6 +57,7 @@ var Amplitude = function() {
 
 Amplitude.prototype._eventId = 0;
 Amplitude.prototype._identifyId = 0;
+Amplitude.prototype._sequenceNumber = 0;
 Amplitude.prototype._sending = false;
 Amplitude.prototype._lastEventTime = null;
 Amplitude.prototype._sessionId = null;
@@ -132,6 +134,7 @@ Amplitude.prototype.init = function(apiKey, opt_userId, opt_config, callback) {
     this._sessionId = parseInt(localStorage.getItem(LocalStorageKeys.SESSION_ID)) || null;
     this._eventId = localStorage.getItem(LocalStorageKeys.LAST_EVENT_ID) || 0;
     this._identifyId = localStorage.getItem(LocalStorageKeys.LAST_IDENTIFY_ID) || 0;
+    this._sequenceNumber = localStorage.getItem(LocalStorageKeys.LAST_SEQUENCE_NUMBER) || 0;
     var now = new Date().getTime();
     if (!this._sessionId || !this._lastEventTime || now - this._lastEventTime > this.options.sessionTimeout) {
       this._newSession = true;
@@ -174,6 +177,11 @@ Amplitude.prototype.nextIdentifyId = function() {
   return this._identifyId;
 };
 
+Amplitude.prototype.nextSequenceNumber = function() {
+  this._sequenceNumber++;
+  return this._sequenceNumber;
+};
+
 // returns the number of unsent events and identifys
 Amplitude.prototype._unsentCount = function() {
   return this._unsentEvents.length + this._unsentIdentifys.length;
@@ -440,7 +448,8 @@ Amplitude.prototype._logEvent = function(eventType, eventProperties, apiProperti
       library: {
         name: 'amplitude-js',
         version: this.__VERSION__
-      }
+      },
+      sequence_number: this.nextSequenceNumber() // for ordering events and identifys
       // country: null
     };
 
@@ -610,14 +619,17 @@ Amplitude.prototype._mergeEventsAndIdentifys = function(numEvents) {
       event = this._unsentIdentifys[identifyIndex++];
       maxIdentifyId = event.event_id;
 
-    // case 3: need to compare timestamps
+    // case 3: need to compare sequence numbers
     } else {
-      if (this._unsentIdentifys[identifyIndex].timestamp <= this._unsentEvents[eventIndex].timestamp) {
-        event = this._unsentIdentifys[identifyIndex++];
-        maxIdentifyId = event.event_id;
-      } else {
+      // events logged before v2.5.0 won't have a sequence number, put those first
+      if (!('sequence_number' in this._unsentEvents[eventIndex]) ||
+          this._unsentEvents[eventIndex].sequence_number <
+          this._unsentIdentifys[identifyIndex].sequence_number) {
         event = this._unsentEvents[eventIndex++];
         maxEventId = event.event_id;
+      } else {
+        event = this._unsentIdentifys[identifyIndex++];
+        maxIdentifyId = event.event_id;
       }
     }
 
diff --git a/test/amplitude.js b/test/amplitude.js
@@ -716,6 +716,7 @@ describe('Amplitude', function() {
         assert.isTrue('$add' in events[i].user_properties);
         assert.deepEqual(events[i].user_properties['$add'], {'photoCount': 1});
         assert.equal(events[i].event_id, i+1);
+        assert.equal(events[i].sequence_number, i+1);
       }
 
       // send response and check that remove events works properly
@@ -746,6 +747,7 @@ describe('Amplitude', function() {
       for (var i = 0; i < 3; i++) {
         assert.equal(events[i].event_type, 'test');
         assert.equal(events[i].event_id, i+1);
+        assert.equal(events[i].sequence_number, i+1);
       }
 
       // send response and check that remove events works properly
@@ -773,14 +775,16 @@ describe('Amplitude', function() {
       var events = JSON.parse(querystring.parse(server.requests[0].requestBody).e);
       assert.lengthOf(events, 2);
 
-      // if identify and event have same timestamp, identify comes first
-      assert.equal(events[0].event_type, '$identify');
+      // event should come before identify - maintain order using sequence number
+      assert.equal(events[0].event_type, 'test');
       assert.equal(events[0].event_id, 1);
-      assert.isTrue('$add' in events[0].user_properties);
-      assert.deepEqual(events[0].user_properties['$add'], {'photoCount': 1});
-      assert.equal(events[1].event_type, 'test');
+      assert.deepEqual(events[0].user_properties, {});
+      assert.equal(events[0].sequence_number, 1);
+      assert.equal(events[1].event_type, '$identify');
       assert.equal(events[1].event_id, 1);
-      assert.deepEqual(events[1].user_properties, {});
+      assert.isTrue('$add' in events[1].user_properties);
+      assert.deepEqual(events[1].user_properties['$add'], {'photoCount': 1});
+      assert.equal(events[1].sequence_number, 2);
 
       // send response and check that remove events works properly
       server.respondWith('success');
@@ -819,18 +823,72 @@ describe('Amplitude', function() {
       // verify the correct coalescing
       assert.equal(events[0].event_type, 'test1');
       assert.deepEqual(events[0].user_properties, {});
+      assert.equal(events[0].sequence_number, 1);
       assert.equal(events[1].event_type, '$identify');
       assert.isTrue('$add' in events[1].user_properties);
       assert.deepEqual(events[1].user_properties['$add'], {'photoCount': 1});
+      assert.equal(events[1].sequence_number, 2);
       assert.equal(events[2].event_type, 'test2');
       assert.deepEqual(events[2].user_properties, {});
+      assert.equal(events[2].sequence_number, 3);
       assert.equal(events[3].event_type, 'test3');
       assert.deepEqual(events[3].user_properties, {});
-      assert.equal(events[4].event_type, '$identify');
-      assert.isTrue('$add' in events[4].user_properties);
-      assert.deepEqual(events[4].user_properties['$add'], {'photoCount': 2});
-      assert.equal(events[5].event_type, 'test4');
-      assert.deepEqual(events[5].user_properties, {});
+      assert.equal(events[3].sequence_number, 4);
+      assert.equal(events[4].event_type, 'test4');
+      assert.deepEqual(events[4].user_properties, {});
+      assert.equal(events[4].sequence_number, 5);
+      assert.equal(events[5].event_type, '$identify');
+      assert.isTrue('$add' in events[5].user_properties);
+      assert.deepEqual(events[5].user_properties['$add'], {'photoCount': 2});
+      assert.equal(events[5].sequence_number, 6);
+
+      // send response and check that remove events works properly
+      server.respondWith('success');
+      server.respond();
+      assert.equal(amplitude._unsentCount(), 0);
+      assert.lengthOf(amplitude._unsentEvents, 0);
+      assert.lengthOf(amplitude._unsentIdentifys, 0);
+    });
+
+    it('should merged events supporting backwards compatability', function() {
+      // events logged before v2.5.0 won't have sequence number, should get priority
+      amplitude.init(apiKey, null, {batchEvents: true, eventUploadThreshold: 3});
+      assert.equal(amplitude._unsentCount(), 0);
+
+      amplitude.identify(new Identify().add('photoCount', 1));
+      amplitude.logEvent('test');
+      delete amplitude._unsentEvents[0].sequence_number; // delete sequence number to simulate old event
+      amplitude._sequenceNumber = 1; // reset sequence number
+      amplitude.identify(new Identify().add('photoCount', 2));
+
+      // verify some internal counters
+      assert.equal(amplitude._eventId, 1);
+      assert.equal(amplitude._identifyId, 2);
+      assert.equal(amplitude._unsentCount(), 3);
+      assert.lengthOf(amplitude._unsentEvents, 1);
+      assert.lengthOf(amplitude._unsentIdentifys, 2);
+
+      assert.lengthOf(server.requests, 1);
+      var events = JSON.parse(querystring.parse(server.requests[0].requestBody).e);
+      assert.lengthOf(events, 3);
+
+      // event should come before identify - prioritize events with no sequence number
+      assert.equal(events[0].event_type, 'test');
+      assert.equal(events[0].event_id, 1);
+      assert.deepEqual(events[0].user_properties, {});
+      assert.isFalse('sequence_number' in events[0]);
+
+      assert.equal(events[1].event_type, '$identify');
+      assert.equal(events[1].event_id, 1);
+      assert.isTrue('$add' in events[1].user_properties);
+      assert.deepEqual(events[1].user_properties['$add'], {'photoCount': 1});
+      assert.equal(events[1].sequence_number, 1);
+
+      assert.equal(events[2].event_type, '$identify');
+      assert.equal(events[2].event_id, 2);
+      assert.isTrue('$add' in events[2].user_properties);
+      assert.deepEqual(events[2].user_properties['$add'], {'photoCount': 2});
+      assert.equal(events[2].sequence_number, 2);
 
       // send response and check that remove events works properly
       server.respondWith('success');
