peridot/vendor/go.opencensus.io/stats/view/collector.go

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2022-07-07 20:11:50 +00:00
// 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
import (
"sort"
"time"
"go.opencensus.io/internal/tagencoding"
"go.opencensus.io/tag"
)
type collector struct {
// signatures holds the aggregations values for each unique tag signature
// (values for all keys) to its aggregator.
signatures map[string]AggregationData
// Aggregation is the description of the aggregation to perform for this
// view.
a *Aggregation
}
func (c *collector) addSample(s string, v float64, attachments map[string]interface{}, t time.Time) {
aggregator, ok := c.signatures[s]
if !ok {
aggregator = c.a.newData()
c.signatures[s] = aggregator
}
aggregator.addSample(v, attachments, t)
}
// collectRows returns a snapshot of the collected Row values.
func (c *collector) collectedRows(keys []tag.Key) []*Row {
rows := make([]*Row, 0, len(c.signatures))
for sig, aggregator := range c.signatures {
tags := decodeTags([]byte(sig), keys)
row := &Row{Tags: tags, Data: aggregator.clone()}
rows = append(rows, row)
}
return rows
}
func (c *collector) clearRows() {
c.signatures = make(map[string]AggregationData)
}
// encodeWithKeys encodes the map by using values
// only associated with the keys provided.
func encodeWithKeys(m *tag.Map, keys []tag.Key) []byte {
vb := &tagencoding.Values{
Buffer: make([]byte, len(keys)),
}
for _, k := range keys {
v, _ := m.Value(k)
vb.WriteValue([]byte(v))
}
return vb.Bytes()
}
// decodeTags decodes tags from the buffer and
// orders them by the keys.
func decodeTags(buf []byte, keys []tag.Key) []tag.Tag {
vb := &tagencoding.Values{Buffer: buf}
var tags []tag.Tag
for _, k := range keys {
v := vb.ReadValue()
if v != nil {
tags = append(tags, tag.Tag{Key: k, Value: string(v)})
}
}
vb.ReadIndex = 0
sort.Slice(tags, func(i, j int) bool { return tags[i].Key.Name() < tags[j].Key.Name() })
return tags
}