From 06b3110ea0db116631b1e1da90eef4e663b3dc39 Mon Sep 17 00:00:00 2001
From: Christine Lytwynec <clytwynec@edx.org>
Date: Tue, 24 Mar 2015 17:16:37 -0400
Subject: [PATCH] onload performance beacon for LMS pages

---
 lms/envs/aws.py         |  1 +
 lms/envs/common.py      |  9 ++++++++-
 lms/templates/main.html | 30 ++++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/lms/envs/aws.py b/lms/envs/aws.py
index 38bb7b7e7c..8f3ab9ca9d 100644
--- a/lms/envs/aws.py
+++ b/lms/envs/aws.py
@@ -557,6 +557,7 @@ XBLOCK_SETTINGS = ENV_TOKENS.get('XBLOCK_SETTINGS', {})
 
 ##### CDN EXPERIMENT/MONITORING FLAGS #####
 CDN_VIDEO_URLS = ENV_TOKENS.get('CDN_VIDEO_URLS', CDN_VIDEO_URLS)
+ONLOAD_BEACON_SAMPLE_RATE = ENV_TOKENS.get('ONLOAD_BEACON_SAMPLE_RATE', ONLOAD_BEACON_SAMPLE_RATE)
 
 ##### ECOMMERCE API CONFIGURATION SETTINGS #####
 ECOMMERCE_API_URL = ENV_TOKENS.get('ECOMMERCE_API_URL', ECOMMERCE_API_URL)
diff --git a/lms/envs/common.py b/lms/envs/common.py
index 80b97bff69..7ea0fa32be 100644
--- a/lms/envs/common.py
+++ b/lms/envs/common.py
@@ -352,6 +352,9 @@ FEATURES = {
     # enable beacons for video timing statistics
     'ENABLE_VIDEO_BEACON': False,
 
+    # enable beacons for lms onload event statistics
+    'ENABLE_ONLOAD_BEACON': False,
+
     # Certificates Web/HTML Views
     'CERTIFICATES_HTML_VIEW': False,
 }
@@ -2074,9 +2077,13 @@ SEARCH_ENGINE = None
 # Use the LMS specific result processor
 SEARCH_RESULT_PROCESSOR = "lms.lib.courseware_search.lms_result_processor.LmsSearchResultProcessor"
 
-##### CDN EXPERIMENT/MONITORING FLAGS #####
+### PERFORMANCE EXPERIMENT SETTINGS ###
+# CDN experiment/monitoring flags
 CDN_VIDEO_URLS = {}
 
+# Page onload event sampling rate (min 0.0, max 1.0)
+ONLOAD_BEACON_SAMPLE_RATE = 0.0
+
 # The configuration visibility of account fields.
 ACCOUNT_VISIBILITY_CONFIGURATION = {
     # Default visibility level for accounts without a specified value
diff --git a/lms/templates/main.html b/lms/templates/main.html
index 5fbc3dffcb..e82d0432db 100644
--- a/lms/templates/main.html
+++ b/lms/templates/main.html
@@ -182,3 +182,33 @@
     )
   ) if course_id and enrollment_action else ""
 }</%def>
+
+# Performance beacon for onload times
+% if settings.FEATURES.get('ENABLE_ONLOAD_BEACON', False):
+<script>
+  (function () {
+    var sample_rate = ${settings.ONLOAD_BEACON_SAMPLE_RATE};
+    var roll = Math.floor(Math.random() * 100)/100;
+    var onloadBeaconSent = false;
+
+    if(roll < sample_rate){
+      $(window).load(function() {
+        setTimeout(function(){
+          var t = window.performance.timing;
+
+          var data = {
+            event: "onload",
+            value: t.loadEventEnd - t.navigationStart,
+            page: window.location.href,
+          };
+
+          if (!onloadBeaconSent) {
+            $.ajax({method: "POST", url: "/performance", data: data});
+          }
+          onloadBeaconSent = true;
+        }, 0);
+      });
+    }
+  }());
+</script>
+% endif