Function: diffps

The diffps() function calculates the rate of change per second of a numeric metric between its current value and its value from the previous check. It is specifically designed for counter-type metrics that continuously increase, providing an interval-independent measure of activity.

he function can be applied to both float and integer metrics. The returned value will be a float, as it represents a rate over time.

Dependency

The diffps() function requires a previous value for the metric to compute the difference. Therefore this expression will only start if a previous value is available.

Syntax:

<numeric_metric>.diffps()

Example:

// Calculate the number of new errors per second since the last check
var.error_rate_per_second = item.error_count.diffps()

case var.error_rate_per_second > 0.0:
    return WARNING, "Errors detected at rate: @var.error_rate_per_second /s"