Merge pull request #277 from dynmeth/master

Added median calculation to timer_data

lib/process_metrics.js

@@ -64,6 +64,9 @@ var process_metrics = function (metrics, flushInterval, ts, flushCallback) {
            sumOfDiffs += (values[i] - mean) * (values[i] - mean);
         }
 
+        var mid = Math.floor(count/2);
+        var median = (count % 2) ? values[mid] : (values[mid-1] + values[mid])/2;
+
         var stddev = Math.sqrt(sumOfDiffs / count);
         current_timer_data["std"] = stddev;
         current_timer_data["upper"] = max;
@@ -72,6 +75,7 @@ var process_metrics = function (metrics, flushInterval, ts, flushCallback) {
         current_timer_data["count_ps"] = timer_counters[key] / (flushInterval / 1000);
         current_timer_data["sum"] = sum;
         current_timer_data["mean"] = mean;
+        current_timer_data["median"] = median;
 
         // note: values bigger than the upper limit of the last bin are ignored, by design
         conf = histogram || [];

test/process_metrics_tests.js

@@ -46,7 +46,7 @@ module.exports = {
     test.done();
   },
   timers_single_time: function(test) {
-    test.expect(7);
+    test.expect(8);
     this.metrics.timers['a'] = [100];
     this.metrics.timer_counters['a'] = 1;
     pm.process_metrics(this.metrics, 100, this.time_stamp, function(){});
@@ -58,10 +58,11 @@ module.exports = {
     test.equal(10, timer_data.count_ps);
     test.equal(100, timer_data.sum);
     test.equal(100, timer_data.mean);
+    test.equal(100, timer_data.median);
     test.done();
   },
     timers_multiple_times: function(test) {
-    test.expect(7);
+    test.expect(8);
     this.metrics.timers['a'] = [100, 200, 300];
     this.metrics.timer_counters['a'] = 3;
     pm.process_metrics(this.metrics, 100, this.time_stamp, function(){});
@@ -73,6 +74,7 @@ module.exports = {
     test.equal(30, timer_data.count_ps);
     test.equal(600, timer_data.sum);
     test.equal(200, timer_data.mean);
+    test.equal(200, timer_data.median);
     test.done();
   },
     timers_single_time_single_percentile: function(test) {
@@ -190,5 +192,13 @@ module.exports = {
     statsd_metrics = this.metrics.statsd_metrics;
     test.notEqual(undefined, statsd_metrics["processing_time"]);
     test.done();
+  },
+    timers_multiple_times_even: function(test) {
+    test.expect(1);
+    this.metrics.timers['a'] = [300, 200, 400, 100];
+    pm.process_metrics(this.metrics, 100, this.time_stamp, function(){});
+    timer_data = this.metrics.timer_data['a'];
+    test.equal(250, timer_data.median);
+    test.done();
   }
 }