Add rate() function resistant to counter reset

This commit is contained in:
Alexander Zobnin
2017-06-26 11:26:13 +03:00
parent fa12b04650
commit d6b36772b6
12 changed files with 130 additions and 6 deletions

View File

@@ -4,7 +4,8 @@
* This module contains functions for working with time series.
*
* datapoints - array of points where point is [value, timestamp]. In almost all cases (if other wasn't
* explicitly said) we assume datapoints are sorted by timestamp.
* explicitly said) we assume datapoints are sorted by timestamp. Timestamp is the number of milliseconds
* since 1 January 1970 00:00:00 UTC.
*
*/
@@ -168,6 +169,10 @@ function scale(datapoints, factor) {
});
}
/**
* Simple delta. Calculate value delta between points.
* @param {*} datapoints
*/
function delta(datapoints) {
let newSeries = [];
let deltaValue;
@@ -178,6 +183,32 @@ function delta(datapoints) {
return newSeries;
}
/**
* Calculates rate per second. Resistant to counter reset.
* @param {*} datapoints
*/
function rate(datapoints) {
let newSeries = [];
let point, point_prev;
let valueDelta = 0;
let timeDelta = 0;
for (let i = 1; i < datapoints.length; i++) {
point = datapoints[i];
point_prev = datapoints[i - 1];
// Convert ms to seconds
timeDelta = (point[POINT_TIMESTAMP] - point_prev[POINT_TIMESTAMP]) / 1000;
// Handle counter reset - use previous value
if (point[POINT_VALUE] >= point_prev[POINT_VALUE]) {
valueDelta = (point[POINT_VALUE] - point_prev[POINT_VALUE]) / timeDelta;
}
newSeries.push([valueDelta, point[POINT_TIMESTAMP]]);
}
return newSeries;
}
function SUM(values) {
var sum = 0;
_.each(values, function (value) {
@@ -297,6 +328,7 @@ const exportedFunctions = {
sumSeries,
scale,
delta,
rate,
SUM,
COUNT,
AVERAGE,