| // 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. |
| // |
| // A 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{} |
| }, |
| } |
| } |