Histogram class Null safety

Histogram allows aggregatable distributions of events, such as request latencies.

Inheritance

Constructors

Histogram({required String name, required String help, List<String> labelNames = const [], List<double> buckets = defaultBuckets, Collect<Histogram>? collectCallback})
Construct a new Histogram with a name, help text, optional labelNames and optional upper bounds for the buckets. If labelNames are provided, use labels(...) to assign label values. buckets have to be sorted in ascending order. If no buckets are provided the defaultBuckets are used instead. The optional collectCallback is called at the beginning of collect and allows to update the value of the histogram before collecting it.
Histogram.exponential({required String name, required String help, required double start, required double factor, required int count, List<String> labelNames = const [], Collect<Collector>? collectCallback})
Construct a new Histogram with a name, help text, and optional labelNames. The count buckets are exponential distributed starting at start with a distance growing exponentially by factor. If labelNames are provided, use labels(...) to assign label values. The optional collectCallback is called at the beginning of collect and allows to update the value of the histogram before collecting it.
Histogram.linear({required String name, required String help, required double start, required double width, required int count, List<String> labelNames = const [], Collect<Collector>? collectCallback})
Construct a new Histogram with a name, help text, and optional labelNames. The count buckets are linear distributed starting at start with a distance of width. If labelNames are provided, use labels(...) to assign label values. The optional collectCallback is called at the beginning of collect and allows to update the value of the histogram before collecting it.

Properties

buckets List<double>
The upper bounds of the buckets.
final
bucketValues List<double>
Access the values in the buckets of a histogram without labels.
read-only
collectCallback Collect<Histogram>?
Optional callback called in collect before samples are collected.
final
count double
Access the count of elements in a histogram without labels.
read-only
hashCode int
The hash code for this object.
read-onlyinherited
help String
The help text of the metric.
finalinherited
labelNames List<String>
The unmodifiable list of labelNames assigned to this metric.
finalinherited
name String
The name of the metric.
finalinherited
runtimeType Type
A representation of the runtime type of the object.
read-onlyinherited
sum double
Access the total sum of the elements in a histogram without labels.
read-only

Methods

clear() → void
Remove all Child metrics.
inherited
collect() Future<Iterable<MetricFamilySamples>>
collect all metrics and samples that are part of this Collector.
override
collectNames() Iterable<String>
Collect all metric names, including child metrics.
override
labels(List<String> labelValues) HistogramChild
Create a Child metric and assign the labelValues. The size of the labelValues has to match the labelNames of the metric.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
observe(double v) → void
Observe a new value v and store it in the corresponding buckets of a histogram without labels.
observeDuration<T>(Future<T> f) Future<T>
Observe the duration of the Future f and store it in the corresponding buckets of a histogram without labels.
observeDurationSync<T>(T callback()) → T
Observe the duration of callback and store it in the corresponding buckets of a histogram without labels.
register([CollectorRegistry? registry]) → void
Register the Collector at a registry. If no registry is provided, the CollectorRegistry.defaultRegistry is used.
inherited
remove(List<String> labelValues) → void
Remove a Child metric based on it's label values.
inherited
toString() String
A string representation of this object.
inherited

Operators

operator ==(Object other) bool
The equality operator.
inherited

Constants

defaultBuckets → const List<double>
The default upper bounds for histogram buckets.
<double>[.005, .01, .025, .05, .075, .1, .25, .5, .75, 1, 2.5, 5, 7.5, 10]
leLabel → const String
Name of the 'le' label.
'le'