// NewAggregate takes a named aggregating function `[float64] => float64` and makes it into a MetricFunction.
func NewAggregate(name string, aggregator func([]float64) float64) function.MetricFunction {
return function.MetricFunction{
Name: name,
MinArguments: 1,
MaxArguments: 1,
AllowsGroupBy: true,
Compute: func(context *function.EvaluationContext, args []function.Expression, groups function.Groups) (function.Value, error) {
argument := args[0]
value, err := argument.Evaluate(context)
if err != nil {
return nil, err
}
seriesList, err := value.ToSeriesList(context.Timerange)
if err != nil {
return nil, err
}
result := aggregate.AggregateBy(seriesList, aggregator, groups.List, groups.Collapses)
groupNames := make([]string, len(groups.List))
for i, group := range groups.List {
groupNames[i] += group
}
if len(groups.List) == 0 {
result.Query = fmt.Sprintf("%s(%s)", name, value.GetName())
} else {
verbName := "group"
if groups.Collapses {
verbName = "collapse"
}
result.Query = fmt.Sprintf("%s(%s %s by %s)", name, value.GetName(), verbName, strings.Join(groupNames, ", "))
}
result.Name = result.Query
return result, nil
},
}
}
// NewAggregate takes a named aggregating function `[float64] => float64` and makes it into a MetricFunction.
func NewAggregate(name string, aggregator func([]float64) float64) function.MetricFunction {
return function.MetricFunction{
Name: name,
MinArguments: 1,
MaxArguments: 1,
AllowsGroupBy: true,
Compute: func(context function.EvaluationContext, args []function.Expression, groups []string) (function.Value, error) {
argument := args[0]
value, err := argument.Evaluate(context)
if err != nil {
return nil, err
}
seriesList, err := value.ToSeriesList(context.Timerange)
if err != nil {
return nil, err
}
result := aggregate.AggregateBy(seriesList, aggregator, groups)
groupNames := make([]string, len(groups))
for i, group := range groups {
groupNames[i] += group
}
if len(groups) == 0 {
result.Name = fmt.Sprintf("%s(%s)", name, value.GetName())
} else {
result.Name = fmt.Sprintf("%s(%s group by %s)", name, value.GetName(), strings.Join(groupNames, ", "))
}
return function.SeriesListValue(result), nil
},
}
}
