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