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prometheus/model/metric.go

142 lines
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// Copyright 2013 Prometheus Team
// 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 model
import (
"crypto/md5"
"encoding/hex"
"fmt"
"sort"
"time"
)
const (
// XXX: Re-evaluate down the road.
reservedDelimiter = `"`
)
// A Fingerprint is a simplified representation of an entity---e.g., a hash of
// an entire Metric.
type Fingerprint string
// A LabelName is a key for a LabelSet or Metric. It has a value associated
// therewith.
type LabelName string
// A LabelValue is an associated value for a LabelName.
type LabelValue string
// A LabelSet is a collection of LabelName and LabelValue pairs. The LabelSet
// may be fully-qualified down to the point where it may resolve to a single
// Metric in the data store or not. All operations that occur within the realm
// of a LabelSet can emit a vector of Metric entities to which the LabelSet may
// match.
type LabelSet map[LabelName]LabelValue
// A Metric is similar to a LabelSet, but the key difference is that a Metric is
// a singleton and refers to one and only one stream of samples.
type Metric map[LabelName]LabelValue
type Fingerprints []Fingerprint
func (f Fingerprints) Len() int {
return len(f)
}
func (f Fingerprints) Less(i, j int) bool {
return sort.StringsAreSorted([]string{string(f[i]), string(f[j])})
}
func (f Fingerprints) Swap(i, j int) {
f[i], f[j] = f[j], f[i]
}
// Fingerprint generates a fingerprint for this given Metric.
func (m Metric) Fingerprint() Fingerprint {
labelLength := len(m)
labelNames := make([]string, 0, labelLength)
for labelName := range m {
labelNames = append(labelNames, string(labelName))
}
sort.Strings(labelNames)
summer := md5.New()
for _, labelName := range labelNames {
summer.Write([]byte(labelName))
summer.Write([]byte(reservedDelimiter))
summer.Write([]byte(m[LabelName(labelName)]))
}
return Fingerprint(hex.EncodeToString(summer.Sum(nil)))
}
// A SampleValue is a representation of a value for a given sample at a given
// time. It is presently float32 due to that being the representation that
// Protocol Buffers provide of floats in Go. This is a smell and should be
// remedied down the road.
type SampleValue float32
func (v SampleValue) MarshalJSON() ([]byte, error) {
return []byte(fmt.Sprintf("\"%f\"", v)), nil
}
func (s SamplePair) MarshalJSON() ([]byte, error) {
return []byte(fmt.Sprintf("{\"Value\": \"%f\", \"Timestamp\": %d}", s.Value, s.Timestamp.Unix())), nil
}
type Sample struct {
Metric Metric
Value SampleValue
Timestamp time.Time
}
type SamplePair struct {
Value SampleValue
Timestamp time.Time
}
type Values []SamplePair
func (v Values) Len() int {
return len(v)
}
func (v Values) Less(i, j int) bool {
return v[i].Timestamp.Before(v[j].Timestamp)
}
func (v Values) Swap(i, j int) {
v[i], v[j] = v[j], v[i]
}
type SampleSet struct {
Metric Metric
Values Values
}
type Interval struct {
OldestInclusive time.Time
NewestInclusive time.Time
}
// PENDING DELETION BELOW THIS LINE
type Samples struct {
Value SampleValue
Timestamp time.Time
}