traefik/vendor/github.com/prometheus/common/model/value.go
Emile Vauge aeb17182b4
Merge v1.2.1-master
Signed-off-by: Emile Vauge <emile@vauge.com>
2017-04-11 22:36:56 +02:00

416 lines
10 KiB
Go

// Copyright 2013 The Prometheus 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 model
import (
"encoding/json"
"fmt"
"math"
"sort"
"strconv"
"strings"
)
var (
// ZeroSamplePair is the pseudo zero-value of SamplePair used to signal a
// non-existing sample pair. It is a SamplePair with timestamp Earliest and
// value 0.0. Note that the natural zero value of SamplePair has a timestamp
// of 0, which is possible to appear in a real SamplePair and thus not
// suitable to signal a non-existing SamplePair.
ZeroSamplePair = SamplePair{Timestamp: Earliest}
// ZeroSample is the pseudo zero-value of Sample used to signal a
// non-existing sample. It is a Sample with timestamp Earliest, value 0.0,
// and metric nil. Note that the natural zero value of Sample has a timestamp
// of 0, which is possible to appear in a real Sample and thus not suitable
// to signal a non-existing Sample.
ZeroSample = Sample{Timestamp: Earliest}
)
// A SampleValue is a representation of a value for a given sample at a given
// time.
type SampleValue float64
// MarshalJSON implements json.Marshaler.
func (v SampleValue) MarshalJSON() ([]byte, error) {
return json.Marshal(v.String())
}
// UnmarshalJSON implements json.Unmarshaler.
func (v *SampleValue) UnmarshalJSON(b []byte) error {
if len(b) < 2 || b[0] != '"' || b[len(b)-1] != '"' {
return fmt.Errorf("sample value must be a quoted string")
}
f, err := strconv.ParseFloat(string(b[1:len(b)-1]), 64)
if err != nil {
return err
}
*v = SampleValue(f)
return nil
}
// Equal returns true if the value of v and o is equal or if both are NaN. Note
// that v==o is false if both are NaN. If you want the conventional float
// behavior, use == to compare two SampleValues.
func (v SampleValue) Equal(o SampleValue) bool {
if v == o {
return true
}
return math.IsNaN(float64(v)) && math.IsNaN(float64(o))
}
func (v SampleValue) String() string {
return strconv.FormatFloat(float64(v), 'f', -1, 64)
}
// SamplePair pairs a SampleValue with a Timestamp.
type SamplePair struct {
Timestamp Time
Value SampleValue
}
// MarshalJSON implements json.Marshaler.
func (s SamplePair) MarshalJSON() ([]byte, error) {
t, err := json.Marshal(s.Timestamp)
if err != nil {
return nil, err
}
v, err := json.Marshal(s.Value)
if err != nil {
return nil, err
}
return []byte(fmt.Sprintf("[%s,%s]", t, v)), nil
}
// UnmarshalJSON implements json.Unmarshaler.
func (s *SamplePair) UnmarshalJSON(b []byte) error {
v := [...]json.Unmarshaler{&s.Timestamp, &s.Value}
return json.Unmarshal(b, &v)
}
// Equal returns true if this SamplePair and o have equal Values and equal
// Timestamps. The sematics of Value equality is defined by SampleValue.Equal.
func (s *SamplePair) Equal(o *SamplePair) bool {
return s == o || (s.Value.Equal(o.Value) && s.Timestamp.Equal(o.Timestamp))
}
func (s SamplePair) String() string {
return fmt.Sprintf("%s @[%s]", s.Value, s.Timestamp)
}
// Sample is a sample pair associated with a metric.
type Sample struct {
Metric Metric `json:"metric"`
Value SampleValue `json:"value"`
Timestamp Time `json:"timestamp"`
}
// Equal compares first the metrics, then the timestamp, then the value. The
// sematics of value equality is defined by SampleValue.Equal.
func (s *Sample) Equal(o *Sample) bool {
if s == o {
return true
}
if !s.Metric.Equal(o.Metric) {
return false
}
if !s.Timestamp.Equal(o.Timestamp) {
return false
}
return s.Value.Equal(o.Value)
}
func (s Sample) String() string {
return fmt.Sprintf("%s => %s", s.Metric, SamplePair{
Timestamp: s.Timestamp,
Value: s.Value,
})
}
// MarshalJSON implements json.Marshaler.
func (s Sample) MarshalJSON() ([]byte, error) {
v := struct {
Metric Metric `json:"metric"`
Value SamplePair `json:"value"`
}{
Metric: s.Metric,
Value: SamplePair{
Timestamp: s.Timestamp,
Value: s.Value,
},
}
return json.Marshal(&v)
}
// UnmarshalJSON implements json.Unmarshaler.
func (s *Sample) UnmarshalJSON(b []byte) error {
v := struct {
Metric Metric `json:"metric"`
Value SamplePair `json:"value"`
}{
Metric: s.Metric,
Value: SamplePair{
Timestamp: s.Timestamp,
Value: s.Value,
},
}
if err := json.Unmarshal(b, &v); err != nil {
return err
}
s.Metric = v.Metric
s.Timestamp = v.Value.Timestamp
s.Value = v.Value.Value
return nil
}
// Samples is a sortable Sample slice. It implements sort.Interface.
type Samples []*Sample
func (s Samples) Len() int {
return len(s)
}
// Less compares first the metrics, then the timestamp.
func (s Samples) Less(i, j int) bool {
switch {
case s[i].Metric.Before(s[j].Metric):
return true
case s[j].Metric.Before(s[i].Metric):
return false
case s[i].Timestamp.Before(s[j].Timestamp):
return true
default:
return false
}
}
func (s Samples) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
// Equal compares two sets of samples and returns true if they are equal.
func (s Samples) Equal(o Samples) bool {
if len(s) != len(o) {
return false
}
for i, sample := range s {
if !sample.Equal(o[i]) {
return false
}
}
return true
}
// SampleStream is a stream of Values belonging to an attached COWMetric.
type SampleStream struct {
Metric Metric `json:"metric"`
Values []SamplePair `json:"values"`
}
func (ss SampleStream) String() string {
vals := make([]string, len(ss.Values))
for i, v := range ss.Values {
vals[i] = v.String()
}
return fmt.Sprintf("%s =>\n%s", ss.Metric, strings.Join(vals, "\n"))
}
// Value is a generic interface for values resulting from a query evaluation.
type Value interface {
Type() ValueType
String() string
}
func (Matrix) Type() ValueType { return ValMatrix }
func (Vector) Type() ValueType { return ValVector }
func (*Scalar) Type() ValueType { return ValScalar }
func (*String) Type() ValueType { return ValString }
type ValueType int
const (
ValNone ValueType = iota
ValScalar
ValVector
ValMatrix
ValString
)
// MarshalJSON implements json.Marshaler.
func (et ValueType) MarshalJSON() ([]byte, error) {
return json.Marshal(et.String())
}
func (et *ValueType) UnmarshalJSON(b []byte) error {
var s string
if err := json.Unmarshal(b, &s); err != nil {
return err
}
switch s {
case "<ValNone>":
*et = ValNone
case "scalar":
*et = ValScalar
case "vector":
*et = ValVector
case "matrix":
*et = ValMatrix
case "string":
*et = ValString
default:
return fmt.Errorf("unknown value type %q", s)
}
return nil
}
func (e ValueType) String() string {
switch e {
case ValNone:
return "<ValNone>"
case ValScalar:
return "scalar"
case ValVector:
return "vector"
case ValMatrix:
return "matrix"
case ValString:
return "string"
}
panic("ValueType.String: unhandled value type")
}
// Scalar is a scalar value evaluated at the set timestamp.
type Scalar struct {
Value SampleValue `json:"value"`
Timestamp Time `json:"timestamp"`
}
func (s Scalar) String() string {
return fmt.Sprintf("scalar: %v @[%v]", s.Value, s.Timestamp)
}
// MarshalJSON implements json.Marshaler.
func (s Scalar) MarshalJSON() ([]byte, error) {
v := strconv.FormatFloat(float64(s.Value), 'f', -1, 64)
return json.Marshal([...]interface{}{s.Timestamp, string(v)})
}
// UnmarshalJSON implements json.Unmarshaler.
func (s *Scalar) UnmarshalJSON(b []byte) error {
var f string
v := [...]interface{}{&s.Timestamp, &f}
if err := json.Unmarshal(b, &v); err != nil {
return err
}
value, err := strconv.ParseFloat(f, 64)
if err != nil {
return fmt.Errorf("error parsing sample value: %s", err)
}
s.Value = SampleValue(value)
return nil
}
// String is a string value evaluated at the set timestamp.
type String struct {
Value string `json:"value"`
Timestamp Time `json:"timestamp"`
}
func (s *String) String() string {
return s.Value
}
// MarshalJSON implements json.Marshaler.
func (s String) MarshalJSON() ([]byte, error) {
return json.Marshal([]interface{}{s.Timestamp, s.Value})
}
// UnmarshalJSON implements json.Unmarshaler.
func (s *String) UnmarshalJSON(b []byte) error {
v := [...]interface{}{&s.Timestamp, &s.Value}
return json.Unmarshal(b, &v)
}
// Vector is basically only an alias for Samples, but the
// contract is that in a Vector, all Samples have the same timestamp.
type Vector []*Sample
func (vec Vector) String() string {
entries := make([]string, len(vec))
for i, s := range vec {
entries[i] = s.String()
}
return strings.Join(entries, "\n")
}
func (vec Vector) Len() int { return len(vec) }
func (vec Vector) Swap(i, j int) { vec[i], vec[j] = vec[j], vec[i] }
// Less compares first the metrics, then the timestamp.
func (vec Vector) Less(i, j int) bool {
switch {
case vec[i].Metric.Before(vec[j].Metric):
return true
case vec[j].Metric.Before(vec[i].Metric):
return false
case vec[i].Timestamp.Before(vec[j].Timestamp):
return true
default:
return false
}
}
// Equal compares two sets of samples and returns true if they are equal.
func (vec Vector) Equal(o Vector) bool {
if len(vec) != len(o) {
return false
}
for i, sample := range vec {
if !sample.Equal(o[i]) {
return false
}
}
return true
}
// Matrix is a list of time series.
type Matrix []*SampleStream
func (m Matrix) Len() int { return len(m) }
func (m Matrix) Less(i, j int) bool { return m[i].Metric.Before(m[j].Metric) }
func (m Matrix) Swap(i, j int) { m[i], m[j] = m[j], m[i] }
func (mat Matrix) String() string {
matCp := make(Matrix, len(mat))
copy(matCp, mat)
sort.Sort(matCp)
strs := make([]string, len(matCp))
for i, ss := range matCp {
strs[i] = ss.String()
}
return strings.Join(strs, "\n")
}