feat(RPM): add average server response time

The collector sends average response time with the existing rpm metrics
RisingStack · Nov 17, 2015 · ce3e36c · ce3e36c
1 parent 7bb687e
commit ce3e36c
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Showing 2 changed files with 22 additions and 6 deletions.
diff --git a/lib/providers/httpTransaction/index.js b/lib/providers/httpTransaction/index.js
@@ -27,6 +27,8 @@ function HttpTransaction(eventBus, options) {
   this.traces = [];
   this.rpmMetrics = {};
   this.totalRequestCount = 0;
+  this.avgResponseTime = 0;
+  this.avgRequestCount = 0;
 
   this.on(HttpTransaction.CLIENT_RECV, this.onClientReceive);
   this.on(HttpTransaction.CLIENT_SEND, this.onClientSend);
@@ -160,9 +162,15 @@ HttpTransaction.prototype.onServerSend = function (data) {
   }
 
   this.collectStatusCode(trace);
+  this.avgResponseTime = this.calculateAvgResponseTime(trace.responseTime);
   delete this.partials[data.id];
 };
 
+HttpTransaction.prototype.calculateAvgResponseTime = function (responseTime) {
+  return (this.avgResponseTime * this.avgRequestCount) +
+    responseTime / this.avgRequestCount++ || null;
+};
+
 HttpTransaction.prototype.collectStatusCode = function (trace) {
   if (!this.rpmMetrics[trace.statusCode]) {
     this.rpmMetrics[trace.statusCode] = 1;
@@ -209,13 +217,17 @@ HttpTransaction.prototype.report = function (data) {
 
 HttpTransaction.prototype._sendRpm = function () {
   debug('sending rpm metrics to the trace service');
-  if (Object.keys(this.rpmMetrics).length > 0) {
-    var dataBag = {};
-    dataBag.requests = cloneDeep(this.rpmMetrics);
-    dataBag.timestamp = new Date().toISOString();
+  if (Object.keys(this.rpmMetrics).length > 0 || this.avgResponseTime) {
+    var dataBag = {
+      requests: cloneDeep(this.rpmMetrics),
+      timestamp: new Date().toISOString(),
+      avgResponseTime: this.avgResponseTime
+    };
 
     this.eventBus.emit(this.eventBus.RPM_METRICS, dataBag);
     this.rpmMetrics = {};
+    this.avgRequestCount = 0;
+    this.avgResponseTime = 0;
   }
 };
 

diff --git a/lib/providers/httpTransaction/wraps/http.Server.prototype.js b/lib/providers/httpTransaction/wraps/http.Server.prototype.js
@@ -15,6 +15,7 @@ function wrapListener(listener, collector, config) {
 
   return function (request, response) {
     var mustCollect;
+    var serverRecieveTime;
 
     var headers = request.headers;
 
@@ -42,12 +43,13 @@ function wrapListener(listener, collector, config) {
     }
 
     var method = request.method;
+    serverRecieveTime = microtime.now();
 
     var collectorDataBag = {
       id: requestId,
       host: headers.host,
       url: requestUrl.pathname,
-      time: microtime.now(),
+      time: serverRecieveTime,
       method: method,
       headers: headers
     };
@@ -64,6 +66,7 @@ function wrapListener(listener, collector, config) {
      * @method instrumentedFinish
      */
     function instrumentedFinish () {
+      var responseTime = serverSendTime - serverRecieveTime;
 
       var collectorDataBag = {
         mustCollect: mustCollect,
@@ -72,7 +75,8 @@ function wrapListener(listener, collector, config) {
         url: requestUrl.pathname,
         time: serverSendTime,
         headers: headers,
-        statusCode: response.statusCode
+        statusCode: response.statusCode,
+        responseTime: responseTime
       };
 
       // Collect request ended