From 1fc9c837263ec3094024bcfc7ef3b2cdb8c0a5cd Mon Sep 17 00:00:00 2001
From: Corey Goldberg <cgoldberg@gmail.com>
Date: Fri, 20 Feb 2015 11:57:51 -0500
Subject: [PATCH] Added listener and beacon for video cdn eval.

---
 .../xmodule/video_module/video_module.py      | 17 +++++++++++++
 .../courseware/tests/test_video_mongo.py      | 21 ++++++++++++++++
 lms/templates/video.html                      | 25 +++++++++++++++++++
 3 files changed, 63 insertions(+)

diff --git a/common/lib/xmodule/xmodule/video_module/video_module.py b/common/lib/xmodule/xmodule/video_module/video_module.py
index d6007513b7..f12347fd4f 100644
--- a/common/lib/xmodule/xmodule/video_module/video_module.py
+++ b/common/lib/xmodule/xmodule/video_module/video_module.py
@@ -16,6 +16,7 @@ Examples of html5 videos for manual testing:
 import copy
 import json
 import logging
+import random
 from collections import OrderedDict
 from operator import itemgetter
 
@@ -232,10 +233,26 @@ class VideoModule(VideoFields, VideoTranscriptsMixin, VideoStudentViewHandlers,
 
         track_url, transcript_language, sorted_languages = self.get_transcripts_for_student()
 
+        # CDN_VIDEO_URLS is only to be used here and will be deleted
+        # TODO(ali@edx.org): Delete this after the CDN experiment has completed.
+        if getattr(settings, 'PERFORMANCE_GRAPHITE_URL', '') != '' and \
+                self.system.user_location == 'CN' and \
+                getattr(settings, 'ENABLE_VIDEO_BEACON', False) and \
+                self.edx_video_id in getattr(settings, 'CDN_VIDEO_URLS', {}).keys():
+            cdn_urls = getattr(settings, 'CDN_VIDEO_URLS', {})[self.edx_video_id]
+            cdn_exp_group, sources[0] = random.choice(zip(range(len(cdn_urls)), cdn_urls))
+            cdn_eval = True
+        else:
+            cdn_eval = False
+            cdn_exp_group = None
+
         return self.system.render_template('video.html', {
             'ajax_url': self.system.ajax_url + '/save_user_state',
             'autoplay': settings.FEATURES.get('AUTOPLAY_VIDEOS', False),
             'branding_info': branding_info,
+            'cdn_eval': cdn_eval,
+            'cdn_eval_endpoint': getattr(settings, 'PERFORMANCE_GRAPHITE_URL', ''),
+            'cdn_exp_group': cdn_exp_group,
             # This won't work when we move to data that
             # isn't on the filesystem
             'data_dir': getattr(self, 'data_dir', None),
diff --git a/lms/djangoapps/courseware/tests/test_video_mongo.py b/lms/djangoapps/courseware/tests/test_video_mongo.py
index 789cc388d4..d1a59ef78a 100644
--- a/lms/djangoapps/courseware/tests/test_video_mongo.py
+++ b/lms/djangoapps/courseware/tests/test_video_mongo.py
@@ -29,6 +29,9 @@ class TestVideoYouTube(TestVideo):
             'ajax_url': self.item_descriptor.xmodule_runtime.ajax_url + '/save_user_state',
             'autoplay': settings.FEATURES.get('AUTOPLAY_VIDEOS', False),
             'branding_info': None,
+            'cdn_eval': False,
+            'cdn_eval_endpoint': getattr(settings, 'PERFORMANCE_GRAPHITE_URL', ''),
+            'cdn_exp_group': None,
             'data_dir': getattr(self, 'data_dir', None),
             'display_name': u'A Name',
             'end': 3610.0,
@@ -93,6 +96,9 @@ class TestVideoNonYouTube(TestVideo):
         expected_context = {
             'ajax_url': self.item_descriptor.xmodule_runtime.ajax_url + '/save_user_state',
             'branding_info': None,
+            'cdn_eval': False,
+            'cdn_eval_endpoint': getattr(settings, 'PERFORMANCE_GRAPHITE_URL', ''),
+            'cdn_exp_group': None,
             'data_dir': getattr(self, 'data_dir', None),
             'show_captions': 'true',
             'handout': None,
@@ -197,6 +203,9 @@ class TestGetHtmlMethod(BaseTestXmodule):
 
         expected_context = {
             'branding_info': None,
+            'cdn_eval': False,
+            'cdn_eval_endpoint': getattr(settings, 'PERFORMANCE_GRAPHITE_URL', ''),
+            'cdn_exp_group': None,
             'data_dir': getattr(self, 'data_dir', None),
             'show_captions': 'true',
             'handout': None,
@@ -314,6 +323,9 @@ class TestGetHtmlMethod(BaseTestXmodule):
 
         initial_context = {
             'branding_info': None,
+            'cdn_eval': False,
+            'cdn_eval_endpoint': getattr(settings, 'PERFORMANCE_GRAPHITE_URL', ''),
+            'cdn_exp_group': None,
             'data_dir': getattr(self, 'data_dir', None),
             'show_captions': 'true',
             'handout': None,
@@ -454,6 +466,9 @@ class TestGetHtmlMethod(BaseTestXmodule):
         # Video found for edx_video_id
         initial_context = {
             'branding_info': None,
+            'cdn_eval': False,
+            'cdn_eval_endpoint': getattr(settings, 'PERFORMANCE_GRAPHITE_URL', ''),
+            'cdn_exp_group': None,
             'data_dir': getattr(self, 'data_dir', None),
             'show_captions': 'true',
             'handout': None,
@@ -572,6 +587,9 @@ class TestGetHtmlMethod(BaseTestXmodule):
         # Video found for edx_video_id
         initial_context = {
             'branding_info': None,
+            'cdn_eval': False,
+            'cdn_eval_endpoint': getattr(settings, 'PERFORMANCE_GRAPHITE_URL', ''),
+            'cdn_exp_group': None,
             'data_dir': getattr(self, 'data_dir', None),
             'show_captions': 'true',
             'handout': None,
@@ -691,6 +709,9 @@ class TestGetHtmlMethod(BaseTestXmodule):
                 'logo_tag': 'Video hosted by XuetangX.com',
                 'url': 'http://www.xuetangx.com'
             },
+            'cdn_eval': False,
+            'cdn_eval_endpoint': getattr(settings, 'PERFORMANCE_GRAPHITE_URL', ''),
+            'cdn_exp_group': None,
             'data_dir': getattr(self, 'data_dir', None),
             'show_captions': 'true',
             'handout': None,
diff --git a/lms/templates/video.html b/lms/templates/video.html
index 772e797dd1..cc73172e9a 100644
--- a/lms/templates/video.html
+++ b/lms/templates/video.html
@@ -150,3 +150,28 @@
     % endif
   </ul>
 </div>
+% if cdn_eval:
+<script>
+  function sendMetricToGraphite(metricName, value) {
+    var url = "${cdn_eval_endpoint}";
+    var request = new XMLHttpRequest();
+    request.open("POST", url, true);  // send asynchronously
+    request.send(metricName + " " + value);
+  };
+  var cdnStartTime, beaconSent = false;
+  function initializeCDNExperiment() {
+    cdnStartTime = Date.now();
+    $("#video_${id}").bind("html5:canplaythrough", null, function() {
+      if (!beaconSent) {
+        timeElapsed = Date.now() - cdnStartTime;
+        sendMetricToGraphite("loadtime_${cdn_exp_group}", timeElapsed);
+      }
+      beaconSent = true;
+    });
+  }
+  $("#video_${id}").bind("initialize", null, initializeCDNExperiment);
+  if ($("#video_${id}").hasClass("is-initialized")) {
+    initializeCDNExperiment();
+  }
+</script>
+% endif;