Add a PingService and make sure we use the average of at least three pings

static/js/app.js

@@ -416,6 +416,93 @@ quayApp = angular.module('quay', quayDependencies, function($provide, cfpLoading
     }]);
 
 
+    $provide.factory('PingService', [function() {
+      var pingService = {};
+      var pingCache = {};
+
+      var reportPingResult = function($scope, url, ping, callback) {
+        // Lookup the cached ping data, if any.
+        var cached = pingCache[url];
+        if (!cached) {
+          cached = pingCache[url] = {
+            'pings': []
+          };
+        }
+
+        // If an error occurred, report it and done.
+        if (ping < 0) {
+          cached['pings'] = [-1];
+          $scope.$apply(function() {
+            callback(-1, false, -1);
+          });
+          return;
+        }
+
+        // Otherwise, add the current ping and determine the average.
+        cached['pings'].push(ping);
+
+        var sum = 0;
+        for (var i = 0; i < cached['pings'].length; ++i) {
+          sum += cached['pings'][i];
+        }
+
+        // Report the average ping.
+        $scope.$apply(function() {
+          callback(Math.floor(sum / cached['pings'].length), true, cached['pings'].length);
+        });
+
+        // Schedule another check if we've done less than three.
+        if (cached['pings'].length < 3) {
+          setTimeout(function() {
+            pingUrlInternal($scope, url, callback);
+          }, 1000);
+        }
+      };
+      
+      var pingUrlInternal = function($scope, url, callback) {
+        var path = url + '?cb=' + (Math.random() * 100);
+	var start = new Date();
+	var xhr = new XMLHttpRequest();
+	xhr.onerror = function() {
+          reportPingResult(url, -1, callback);
+	};
+
+	xhr.onreadystatechange = function () {
+	  if (xhr.readyState === xhr.HEADERS_RECEIVED) {
+	    if (xhr.status != 200) {
+              reportPingResult($scope, url, -1, callback);
+	      return;
+	    }
+
+            var ping = (new Date() - start);
+            reportPingResult($scope, url, ping, callback);
+	  }
+	};
+
+	xhr.open("GET", path);
+	xhr.send(null);
+      };
+
+      pingService.pingUrl = function($scope, url, callback) {
+        if (pingCache[url]) {
+          cached = pingCache[url];
+          $scope.$apply(function() {
+            callback(cached.result, cached.success);
+          });
+          return;
+        }
+
+        // Note: We do each in a callback after 1s to prevent it running when other code
+        // runs (which can skew the results).
+        setTimeout(function() {
+          pingUrlInternal($scope, url, callback);
+        }, 1000);
+      };
+      
+      return pingService;
+    }]);
+
+
     $provide.factory('TriggerDescriptionBuilder', ['UtilService', '$sanitize', function(UtilService, $sanitize) {
       var builderService = {};
 
@@ -4628,7 +4715,7 @@ quayApp.directive('locationView', function () {
     scope: {
       'location': '=location'
     },
-    controller: function($rootScope, $scope, $element, $http) {
+    controller: function($rootScope, $scope, $element, $http, PingService) {
       var LOCATIONS = {
 	'local_us': { 'country': 'US', 'data': 'quay-registry.s3.amazonaws.com', 'title': 'United States' },
 	'local_eu': { 'country': 'EU', 'data': 'quay-registry-eu.s3-eu-west-1.amazonaws.com', 'title': 'Europe' },
@@ -4671,47 +4758,13 @@ quayApp.directive('locationView', function () {
       };
 
       $scope.getLocationPing = function(location) {
-	if (!$rootScope.__CACHED_LOCATION_PINGS) {
+        var url = 'http://' + LOCATIONS[location]['data'] + '/okay.txt';
-	  $rootScope.__CACHED_LOCATION_PINGS = {};
+        PingService.pingUrl($scope, url, function(ping, success, count) {
+          if (count == 3 || !success) {
+            $scope.locationPing = success ? ping : -1;
           }
-
-	if ($rootScope.__CACHED_LOCATION_PINGS[location]) {
-	  $scope.locationPing = $rootScope.__CACHED_LOCATION_PINGS[location];
-	  return;
-	}
-
-	var conductPing = function() {
-	  var path = 'http://' + LOCATIONS[location]['data'] + '/okay.txt?cb=' + (Math.random() * 100);
-	  var start = new Date();
-	  var xhr = new XMLHttpRequest();
-	  xhr.onerror = function() {
-	    $scope.$apply(function() {
-	      $scope.locationPing = -1;
         });
       };
-	  xhr.onreadystatechange = function () {
-	    if (xhr.readyState === xhr.HEADERS_RECEIVED) {
-	      if (xhr.status != 200) {
-		$scope.$apply(function() {
-		  $scope.locationPing = -1;
-		});
-		return;
-	      }
-
-              var ping = (new Date() - start);
-	      $scope.$apply(function() {
-		$rootScope.__CACHED_LOCATION_PINGS[location] = $scope.locationPing = ping;
-	      });
-	    }
-	  };
-
-	  xhr.open("GET", path);
-	  xhr.send(null);
-	  return;
-	};
-
-	setTimeout(conductPing, 1000);
-      };
 
       $scope.$watch('location', function(location) {
 	if (!location) { return; }