mirror of
https://github.com/restic/restic.git
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195 lines
5.3 KiB
Go
195 lines
5.3 KiB
Go
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// 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 (
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"bytes"
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"errors"
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"fmt"
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"reflect"
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"sort"
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"sync/atomic"
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"time"
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"go.opencensus.io/exemplar"
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"go.opencensus.io/stats"
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"go.opencensus.io/stats/internal"
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"go.opencensus.io/tag"
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)
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// View allows users to aggregate the recorded stats.Measurements.
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// Views need to be passed to the Register function to be before data will be
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// collected and sent to Exporters.
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type View struct {
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Name string // Name of View. Must be unique. If unset, will default to the name of the Measure.
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Description string // Description is a human-readable description for this view.
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// TagKeys are the tag keys describing the grouping of this view.
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// A single Row will be produced for each combination of associated tag values.
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TagKeys []tag.Key
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// Measure is a stats.Measure to aggregate in this view.
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Measure stats.Measure
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// Aggregation is the aggregation function tp apply to the set of Measurements.
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Aggregation *Aggregation
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}
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// WithName returns a copy of the View with a new name. This is useful for
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// renaming views to cope with limitations placed on metric names by various
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// backends.
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func (v *View) WithName(name string) *View {
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vNew := *v
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vNew.Name = name
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return &vNew
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}
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// same compares two views and returns true if they represent the same aggregation.
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func (v *View) same(other *View) bool {
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if v == other {
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return true
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}
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if v == nil {
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return false
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}
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return reflect.DeepEqual(v.Aggregation, other.Aggregation) &&
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v.Measure.Name() == other.Measure.Name()
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}
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var ErrNegativeBucketBounds = errors.New("negative bucket bounds not supported")
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// canonicalize canonicalizes v by setting explicit
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// defaults for Name and Description and sorting the TagKeys
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func (v *View) canonicalize() error {
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if v.Measure == nil {
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return fmt.Errorf("cannot register view %q: measure not set", v.Name)
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}
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if v.Aggregation == nil {
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return fmt.Errorf("cannot register view %q: aggregation not set", v.Name)
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}
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if v.Name == "" {
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v.Name = v.Measure.Name()
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}
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if v.Description == "" {
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v.Description = v.Measure.Description()
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}
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if err := checkViewName(v.Name); err != nil {
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return err
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}
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sort.Slice(v.TagKeys, func(i, j int) bool {
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return v.TagKeys[i].Name() < v.TagKeys[j].Name()
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})
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sort.Float64s(v.Aggregation.Buckets)
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for _, b := range v.Aggregation.Buckets {
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if b < 0 {
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return ErrNegativeBucketBounds
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}
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}
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return nil
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}
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// viewInternal is the internal representation of a View.
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type viewInternal struct {
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view *View // view is the canonicalized View definition associated with this view.
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subscribed uint32 // 1 if someone is subscribed and data need to be exported, use atomic to access
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collector *collector
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}
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func newViewInternal(v *View) (*viewInternal, error) {
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return &viewInternal{
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view: v,
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collector: &collector{make(map[string]AggregationData), v.Aggregation},
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}, nil
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}
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func (v *viewInternal) subscribe() {
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atomic.StoreUint32(&v.subscribed, 1)
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}
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func (v *viewInternal) unsubscribe() {
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atomic.StoreUint32(&v.subscribed, 0)
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}
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// isSubscribed returns true if the view is exporting
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// data by subscription.
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func (v *viewInternal) isSubscribed() bool {
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return atomic.LoadUint32(&v.subscribed) == 1
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}
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func (v *viewInternal) clearRows() {
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v.collector.clearRows()
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}
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func (v *viewInternal) collectedRows() []*Row {
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return v.collector.collectedRows(v.view.TagKeys)
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}
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func (v *viewInternal) addSample(m *tag.Map, e *exemplar.Exemplar) {
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if !v.isSubscribed() {
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return
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}
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sig := string(encodeWithKeys(m, v.view.TagKeys))
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v.collector.addSample(sig, e)
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}
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// A Data is a set of rows about usage of the single measure associated
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// with the given view. Each row is specific to a unique set of tags.
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type Data struct {
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View *View
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Start, End time.Time
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Rows []*Row
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}
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// Row is the collected value for a specific set of key value pairs a.k.a tags.
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type Row struct {
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Tags []tag.Tag
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Data AggregationData
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}
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func (r *Row) String() string {
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var buffer bytes.Buffer
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buffer.WriteString("{ ")
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buffer.WriteString("{ ")
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for _, t := range r.Tags {
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buffer.WriteString(fmt.Sprintf("{%v %v}", t.Key.Name(), t.Value))
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}
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buffer.WriteString(" }")
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buffer.WriteString(fmt.Sprintf("%v", r.Data))
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buffer.WriteString(" }")
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return buffer.String()
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}
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// Equal returns true if both rows are equal. Tags are expected to be ordered
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// by the key name. Even both rows have the same tags but the tags appear in
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// different orders it will return false.
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func (r *Row) Equal(other *Row) bool {
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if r == other {
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return true
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}
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return reflect.DeepEqual(r.Tags, other.Tags) && r.Data.equal(other.Data)
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}
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func checkViewName(name string) error {
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if len(name) > internal.MaxNameLength {
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return fmt.Errorf("view name cannot be larger than %v", internal.MaxNameLength)
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}
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if !internal.IsPrintable(name) {
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return fmt.Errorf("view name needs to be an ASCII string")
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}
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return nil
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}
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