Functions reference
===================

Transform
---------

### groupBy

```
groupBy(interval, function)
```

Takes each timeseries and consolidate its points falled in 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.

Aggregate
---------

### aggregateBy
```
aggregateBy(interval, function)
```

Takes all timeseries and consolidate all its points falled in 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.

### 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)
```


## Trends

### 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

### 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 detais see [String.prototype.replace()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/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
```
