124 lines
3.8 KiB
Go
124 lines
3.8 KiB
Go
// Copyright 2017, OpenCensus Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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package view
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import "time"
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// AggType represents the type of aggregation function used on a View.
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type AggType int
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// All available aggregation types.
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const (
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AggTypeNone AggType = iota // no aggregation; reserved for future use.
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AggTypeCount // the count aggregation, see Count.
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AggTypeSum // the sum aggregation, see Sum.
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AggTypeDistribution // the distribution aggregation, see Distribution.
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AggTypeLastValue // the last value aggregation, see LastValue.
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)
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func (t AggType) String() string {
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return aggTypeName[t]
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}
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var aggTypeName = map[AggType]string{
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AggTypeNone: "None",
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AggTypeCount: "Count",
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AggTypeSum: "Sum",
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AggTypeDistribution: "Distribution",
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AggTypeLastValue: "LastValue",
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}
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// Aggregation represents a data aggregation method. Use one of the functions:
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// Count, Sum, or Distribution to construct an Aggregation.
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type Aggregation struct {
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Type AggType // Type is the AggType of this Aggregation.
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Buckets []float64 // Buckets are the bucket endpoints if this Aggregation represents a distribution, see Distribution.
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newData func(time.Time) AggregationData
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}
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var (
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aggCount = &Aggregation{
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Type: AggTypeCount,
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newData: func(t time.Time) AggregationData {
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return &CountData{Start: t}
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},
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}
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aggSum = &Aggregation{
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Type: AggTypeSum,
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newData: func(t time.Time) AggregationData {
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return &SumData{Start: t}
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},
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}
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)
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// Count indicates that data collected and aggregated
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// with this method will be turned into a count value.
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// For example, total number of accepted requests can be
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// aggregated by using Count.
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func Count() *Aggregation {
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return aggCount
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}
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// Sum indicates that data collected and aggregated
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// with this method will be summed up.
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// For example, accumulated request bytes can be aggregated by using
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// Sum.
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func Sum() *Aggregation {
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return aggSum
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}
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// Distribution indicates that the desired aggregation is
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// a histogram distribution.
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//
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// A distribution aggregation may contain a histogram of the values in the
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// population. The bucket boundaries for that histogram are described
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// by the bounds. This defines len(bounds)+1 buckets.
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//
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// If len(bounds) >= 2 then the boundaries for bucket index i are:
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//
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// [-infinity, bounds[i]) for i = 0
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// [bounds[i-1], bounds[i]) for 0 < i < length
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// [bounds[i-1], +infinity) for i = length
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//
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// If len(bounds) is 0 then there is no histogram associated with the
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// distribution. There will be a single bucket with boundaries
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// (-infinity, +infinity).
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//
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// If len(bounds) is 1 then there is no finite buckets, and that single
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// element is the common boundary of the overflow and underflow buckets.
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func Distribution(bounds ...float64) *Aggregation {
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agg := &Aggregation{
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Type: AggTypeDistribution,
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Buckets: bounds,
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}
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agg.newData = func(t time.Time) AggregationData {
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return newDistributionData(agg, t)
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}
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return agg
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}
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// LastValue only reports the last value recorded using this
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// aggregation. All other measurements will be dropped.
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func LastValue() *Aggregation {
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return &Aggregation{
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Type: AggTypeLastValue,
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newData: func(_ time.Time) AggregationData {
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return &LastValueData{}
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},
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}
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}
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