Added DataProcessingService for timeseries post-processing.

plugins/datasource-zabbix/dataProcessingService.js

@@ -0,0 +1,99 @@
+define([
+  'angular',
+  'lodash',
+  'moment'
+],
+function (angular, _, moment) {
+  'use strict';
+
+  var module = angular.module('grafana.services');
+
+  module.service('DataProcessingService', function() {
+
+    /**
+     * Downsample datapoints series
+     */
+    this.downsampleSeries = function(datapoints, time_to, ms_interval, func) {
+      var downsampledSeries = [];
+      var timeWindow = {
+        from: time_to * 1000 - ms_interval,
+        to: time_to * 1000
+      };
+
+      var points_sum = 0;
+      var points_num = 0;
+      var value_avg = 0;
+      var frame = [];
+
+      for (var i = datapoints.length - 1; i >= 0; i -= 1) {
+        if (timeWindow.from < datapoints[i][1] && datapoints[i][1] <= timeWindow.to) {
+          points_sum += datapoints[i][0];
+          points_num++;
+          frame.push(datapoints[i][0]);
+        }
+        else {
+          value_avg = points_num ? points_sum / points_num : 0;
+
+          if (func === "max") {
+            downsampledSeries.push([_.max(frame), timeWindow.to]);
+          }
+          else if (func === "min") {
+            downsampledSeries.push([_.min(frame), timeWindow.to]);
+          }
+
+          // avg by default
+          else {
+            downsampledSeries.push([value_avg, timeWindow.to]);
+          }
+
+          // Shift time window
+          timeWindow.to = timeWindow.from;
+          timeWindow.from -= ms_interval;
+
+          points_sum = 0;
+          points_num = 0;
+          frame = [];
+
+          // Process point again
+          i++;
+        }
+      }
+      return downsampledSeries.reverse();
+    };
+
+    /**
+     * Group points by given time interval
+     * datapoints: [[<value>, <unixtime>], ...]
+     */
+    this.groupBy = function(datapoints, ms_interval, groupByCallback) {
+      var frames = _.groupBy(datapoints, function(point) {
+        var group_time = Number(moment.utc(point[1]).startOf('minute').valueOf());
+        group_time = Math.ceil(point[1] / ms_interval) * ms_interval;
+        return group_time;
+      });
+
+      // frame: { '<unixtime>': [[<value>, <unixtime>], ...] }
+      // return [{ '<unixtime>': <value> }, { '<unixtime>': <value> }, ...]
+      var grouped = _.mapValues(frames, function(frame) {
+        var points = _.map(frame, function(point) {
+          return point[0];
+        });
+        return groupByCallback(points);
+      });
+
+      // Convert points to Grafana format
+      return _.map(grouped, function(value, timestamp) {
+        return [Number(value), Number(timestamp)];
+      });
+    };
+
+    this.AVERAGE = function(values) {
+      var sum = 0;
+      _.each(values, function(value) {
+        sum += value;
+      });
+      return sum / values.length;
+    };
+
+  });
+});