Functions reference

Functions Variables

There are some built-in template variables available for using in functions:

  • $__range_ms - panel time range in ms
  • $__range_s - panel time range in seconds
  • $__range - panel time range, string representation (30s, 1m, 1h)
  • $__range_series - invoke function over all series values

Examples:

groupBy($__range, avg)
percentile($__range_series, 95) - 95th percentile over all values

Transform

groupBy

groupBy(interval, function)

Takes each timeseries and consolidate its points fallen in the given interval into one point using function, which can be one of: avg, min, max, median.

Examples:

groupBy(10m, avg)
groupBy(1h, median)

scale

scale(factor)

Takes timeseries and multiplies each point by the given factor.

Examples:

scale(100)
scale(0.01)

delta

delta()

Converts absolute values to delta. This function just calculate difference between values. For the per-second calculation use rate().

rate

rate()

Calculates the per-second rate of increase of the time series. Resistant to counter reset. Suitable for converting of growing counters into the per-sercond rate.

movingAverage

movingAverage(windowSize)

Graphs the moving average of a metric over a fixed number of past points, specified by windowSize param.

Examples:

movingAverage(60)
calculates moving average over 60 points (if metric has 1 second resolution it matches 1 minute window)

exponentialMovingAverage

exponentialMovingAverage(windowSize)

Takes a series of values and a window size and produces an exponential moving average utilizing the following formula:
ema(current) = constant * (Current Value) + (1 - constant) * ema(previous)

The Constant is calculated as:
constant = 2 / (windowSize + 1)

If windowSize < 1 (0.1, for instance), Constant wouldn't be calculated and will be taken directly from windowSize (Constant = windowSize).

It's a bit tricky to graph EMA from the first point of series (not from Nth = windowSize). In order to do it, plugin should fetch previous N points first and calculate simple moving average for it. To avoid it, plugin uses this hack: assume, previous N points have the same average values as first N (windowSize). So you should keep this fact in mind and don't rely on first N points interval.

Examples:

movingAverage(60)
calculates moving average over 60 points (if metric has 1 second resolution it matches 1 minute window)

percentile

percentile(interval, N)

Takes a series of values and a window size and consolidate all its points fallen in the given interval into one point by Nth percentile.

Examples:

percentile(1h, 99)
percentile($__range_series, 95) - 95th percentile over all series values

removeAboveValue

removeAboveValue(N)

Replaces series values with null if value > N

Examples:

removeAboveValue(1)

removeBelowValue

removeBelowValue(N)

Replaces series values with null if value < N

transformNull

transformNull(N)

Replaces null values with N

Aggregate

aggregateBy

aggregateBy(interval, function)

Takes all timeseries and consolidate all its points fallen in the given interval into one point using function, which can be one of: avg, min, max, median.

Examples:

aggregateBy(10m, avg)
aggregateBy(1h, median)

sumSeries

sumSeries()

This will add metrics together and return the sum at each datapoint. This method required interpolation of each timeseries so it may cause high CPU load. Try to combine it with groupBy() function to reduce load.

percentileAgg

percentileAgg(interval, N)

Takes all timeseries and consolidate all its points fallen in the given interval into one point by Nth percentile.

Examples:

percentileAgg(1h, 99)
percentileAgg($__range_series, 95) - 95th percentile over all values

average

average(interval)

Deprecated, use aggregateBy(interval, avg) instead.

min

min(interval)

Deprecated, use aggregateBy(interval, min) instead.

max

max(interval)

Deprecated, use aggregateBy(interval, max) instead.

Filter

top

top(N, value)

Returns top N series, sorted by value, which can be one of: avg, min, max, median.

Examples:

top(10, avg)
top(5, max)

bottom

bottom(N, value)

Returns bottom N series, sorted by value, which can be one of: avg, min, max, median.

Examples:

bottom(5, avg)

trendValue

trendValue(valueType)

Specifying type of trend value returned by Zabbix when trends are used (avg, min or max).

Time

timeShift

timeShift(interval)

Draws the selected metrics shifted in time. If no sign is given, a minus sign ( - ) is implied which will shift the metric back in time. If a plus sign ( + ) is given, the metric will be shifted forward in time. Examples:

timeShift(24h)  - shift metric back in 24h hours
timeShift(-24h) - the same result as for timeShift(24h)
timeShift(+1d)  - shift metric forward in 1 day

Alias

Following template variables available for using in setAlias() and replaceAlias() functions:

  • $__zbx_item, $__zbx_item_name - item name
  • $__zbx_item_key - item key
  • $__zbx_host_name - visible name of the host
  • $__zbx_host - technical name of the host

Examples:

setAlias($__zbx_host_name: $__zbx_item) -> backend01: CPU user time
setAlias(Item key: $__zbx_item_key) -> Item key: system.cpu.load[percpu,avg1]
setAlias($__zbx_host_name) -> backend01

setAlias

setAlias(alias)

Returns given alias instead of the metric name.

Examples:

setAlias(load)

setAliasByRegex

setAliasByRegex(regex)

Returns part of the metric name matched by regex.

Examples:

setAlias(Zabbix busy [a-zA-Z]+)

replaceAlias

replaceAlias(pattern, newAlias)

Replace metric name using pattern. Pattern is regex or regular string. If regex is used, following special replacement patterns are supported:

Pattern Inserts
$$ Inserts a "$".
$& Inserts the matched substring.
$` Inserts the portion of the string that precedes the matched substring.
$' Inserts the portion of the string that follows the matched substring.
$n Where n is a non-negative integer less than 100, inserts the nth parenthesized submatch string, provided the first argument was a RegExp object.

For more details see String.prototype.replace() function.

Examples:

CPU system time
replaceAlias(/CPU (.*) time/, $1) -> system

backend01: CPU system time
replaceAlias(/CPU (.*) time/, $1) -> backend01: system

backend01: CPU system time
replaceAlias(/.*CPU (.*) time/, $1) -> system

backend01: CPU system time
replaceAlias(/(.*): CPU (.*) time/, $1 - $2) -> backend01 - system

Special

consolidateBy

consolidateBy(consolidationFunc)

When a graph is drawn where width of the graph size in pixels is smaller than the number of datapoints to be graphed, plugin consolidates the values to to prevent line overlap. The consolidateBy() function changes the consolidation function from the default of average to one of sum, min, max or count.

Valid function names are sum, avg, min, max and count.