functions: simple moving average

dist/test/datasource-zabbix/dataProcessor.js

@@ -31,6 +31,9 @@ var rate = _timeseries2.default.rate;
 var scale = function scale(factor, datapoints) {
   return _timeseries2.default.scale_perf(datapoints, factor);
 };
+var simpleMovingAverage = function simpleMovingAverage(n, datapoints) {
+  return _timeseries2.default.simpleMovingAverage(datapoints, n);
+};
 
 var SUM = _timeseries2.default.SUM;
 var COUNT = _timeseries2.default.COUNT;
@@ -121,6 +124,7 @@ var metricFunctions = {
   scale: scale,
   delta: delta,
   rate: rate,
+  simpleMovingAverage: simpleMovingAverage,
   aggregateBy: aggregateByWrapper,
   average: _lodash2.default.partial(aggregateWrapper, AVERAGE),
   min: _lodash2.default.partial(aggregateWrapper, MIN),

dist/test/datasource-zabbix/metricFunctions.js

@@ -73,6 +73,13 @@ addFuncDef({
   defaultParams: []
 });
 
+addFuncDef({
+  name: 'simpleMovingAverage',
+  category: 'Transform',
+  params: [{ name: 'factor', type: 'int', options: [6, 10, 60, 600] }],
+  defaultParams: [10]
+});
+
 // Aggregate
 
 addFuncDef({

dist/test/datasource-zabbix/timeseries.js

@@ -234,6 +234,49 @@ function rate(datapoints) {
   return newSeries;
 }
 
+function simpleMovingAverage(datapoints, n) {
+  var sma = [];
+  var w_sum = void 0;
+  var w_avg = null;
+  var w_count = 0;
+
+  // Initial window
+  for (var j = n; j > 0; j--) {
+    if (datapoints[n - j][POINT_VALUE] !== null) {
+      w_avg += datapoints[n - j][POINT_VALUE];
+      w_count++;
+    }
+  }
+  if (w_count > 0) {
+    w_avg = w_avg / w_count;
+  } else {
+    w_avg = null;
+  }
+  sma.push([w_avg, datapoints[n - 1][POINT_TIMESTAMP]]);
+
+  for (var i = n; i < datapoints.length; i++) {
+    // Insert next value
+    if (datapoints[i][POINT_VALUE] !== null) {
+      w_sum = w_avg * w_count;
+      w_avg = (w_sum + datapoints[i][POINT_VALUE]) / (w_count + 1);
+      w_count++;
+    }
+    // Remove left side point
+    if (datapoints[i - n][POINT_VALUE] !== null) {
+      w_sum = w_avg * w_count;
+      if (w_count > 1) {
+        w_avg = (w_sum - datapoints[i - n][POINT_VALUE]) / (w_count - 1);
+        w_count--;
+      } else {
+        w_avg = null;
+        w_count = 0;
+      }
+    }
+    sma.push([w_avg, datapoints[i][POINT_TIMESTAMP]]);
+  }
+  return sma;
+}
+
 function COUNT(values) {
   return values.length;
 }
@@ -367,6 +410,7 @@ var exportedFunctions = {
   scale_perf: scale_perf,
   delta: delta,
   rate: rate,
+  simpleMovingAverage: simpleMovingAverage,
   SUM: SUM,
   COUNT: COUNT,
   AVERAGE: AVERAGE,