rebase: bump github.com/prometheus/client_golang from 1.14.0 to 1.15.1

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.14.0 to 1.15.1.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/main/CHANGELOG.md)
- [Commits](https://github.com/prometheus/client_golang/compare/v1.14.0...v1.15.1)

---
updated-dependencies:
- dependency-name: github.com/prometheus/client_golang
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/github.com/prometheus/common/expfmt/decode.go

@@ -115,32 +115,28 @@ func (d *protoDecoder) Decode(v *dto.MetricFamily) error {
 // textDecoder implements the Decoder interface for the text protocol.
 type textDecoder struct {
 	r    io.Reader
-	p    TextParser
-	fams []*dto.MetricFamily
+	fams map[string]*dto.MetricFamily
+	err  error
 }
 
 // Decode implements the Decoder interface.
 func (d *textDecoder) Decode(v *dto.MetricFamily) error {
-	// TODO(fabxc): Wrap this as a line reader to make streaming safer.
-	if len(d.fams) == 0 {
-		// No cached metric families, read everything and parse metrics.
-		fams, err := d.p.TextToMetricFamilies(d.r)
-		if err != nil {
-			return err
-		}
-		if len(fams) == 0 {
-			return io.EOF
-		}
-		d.fams = make([]*dto.MetricFamily, 0, len(fams))
-		for _, f := range fams {
-			d.fams = append(d.fams, f)
+	if d.err == nil {
+		// Read all metrics in one shot.
+		var p TextParser
+		d.fams, d.err = p.TextToMetricFamilies(d.r)
+		// If we don't get an error, store io.EOF for the end.
+		if d.err == nil {
+			d.err = io.EOF
 		}
 	}
-
-	*v = *d.fams[0]
-	d.fams = d.fams[1:]
-
-	return nil
+	// Pick off one MetricFamily per Decode until there's nothing left.
+	for key, fam := range d.fams {
+		*v = *fam
+		delete(d.fams, key)
+		return nil
+	}
+	return d.err
 }
 
 // SampleDecoder wraps a Decoder to extract samples from the metric families

vendor/github.com/prometheus/common/expfmt/fuzz.go

@@ -21,8 +21,8 @@ import "bytes"
 
 // Fuzz text metric parser with with github.com/dvyukov/go-fuzz:
 //
-//     go-fuzz-build github.com/prometheus/common/expfmt
-//     go-fuzz -bin expfmt-fuzz.zip -workdir fuzz
+//	go-fuzz-build github.com/prometheus/common/expfmt
+//	go-fuzz -bin expfmt-fuzz.zip -workdir fuzz
 //
 // Further input samples should go in the folder fuzz/corpus.
 func Fuzz(in []byte) int {

vendor/github.com/prometheus/common/expfmt/openmetrics_create.go

@@ -46,20 +46,20 @@ import (
 // missing features and peculiarities to avoid complications when switching from
 // Prometheus to OpenMetrics or vice versa:
 //
-// - Counters are expected to have the `_total` suffix in their metric name. In
-//   the output, the suffix will be truncated from the `# TYPE` and `# HELP`
-//   line. A counter with a missing `_total` suffix is not an error. However,
-//   its type will be set to `unknown` in that case to avoid invalid OpenMetrics
-//   output.
+//   - Counters are expected to have the `_total` suffix in their metric name. In
+//     the output, the suffix will be truncated from the `# TYPE` and `# HELP`
+//     line. A counter with a missing `_total` suffix is not an error. However,
+//     its type will be set to `unknown` in that case to avoid invalid OpenMetrics
+//     output.
 //
-// - No support for the following (optional) features: `# UNIT` line, `_created`
-//   line, info type, stateset type, gaugehistogram type.
+//   - No support for the following (optional) features: `# UNIT` line, `_created`
+//     line, info type, stateset type, gaugehistogram type.
 //
-// - The size of exemplar labels is not checked (i.e. it's possible to create
-//   exemplars that are larger than allowed by the OpenMetrics specification).
+//   - The size of exemplar labels is not checked (i.e. it's possible to create
+//     exemplars that are larger than allowed by the OpenMetrics specification).
 //
-// - The value of Counters is not checked. (OpenMetrics doesn't allow counters
-//   with a `NaN` value.)
+//   - The value of Counters is not checked. (OpenMetrics doesn't allow counters
+//     with a `NaN` value.)
 func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily) (written int, err error) {
 	name := in.GetName()
 	if name == "" {

vendor/github.com/prometheus/common/expfmt/text_create.go

@@ -17,7 +17,6 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math"
 	"strconv"
 	"strings"
@@ -44,7 +43,7 @@ const (
 var (
 	bufPool = sync.Pool{
 		New: func() interface{} {
-			return bufio.NewWriter(ioutil.Discard)
+			return bufio.NewWriter(io.Discard)
 		},
 	}
 	numBufPool = sync.Pool{

vendor/github.com/prometheus/common/expfmt/text_parse.go

@@ -142,9 +142,13 @@ func (p *TextParser) reset(in io.Reader) {
 func (p *TextParser) startOfLine() stateFn {
 	p.lineCount++
 	if p.skipBlankTab(); p.err != nil {
-		// End of input reached. This is the only case where
-		// that is not an error but a signal that we are done.
-		p.err = nil
+		// This is the only place that we expect to see io.EOF,
+		// which is not an error but the signal that we are done.
+		// Any other error that happens to align with the start of
+		// a line is still an error.
+		if p.err == io.EOF {
+			p.err = nil
+		}
 		return nil
 	}
 	switch p.currentByte {

vendor/github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg/autoneg.go

@@ -11,18 +11,18 @@ Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:
 
-    Redistributions of source code must retain the above copyright
-    notice, this list of conditions and the following disclaimer.
+	Redistributions of source code must retain the above copyright
+	notice, this list of conditions and the following disclaimer.
 
-    Redistributions in binary form must reproduce the above copyright
-    notice, this list of conditions and the following disclaimer in
-    the documentation and/or other materials provided with the
-    distribution.
+	Redistributions in binary form must reproduce the above copyright
+	notice, this list of conditions and the following disclaimer in
+	the documentation and/or other materials provided with the
+	distribution.
 
-    Neither the name of the Open Knowledge Foundation Ltd. nor the
-    names of its contributors may be used to endorse or promote
-    products derived from this software without specific prior written
-    permission.
+	Neither the name of the Open Knowledge Foundation Ltd. nor the
+	names of its contributors may be used to endorse or promote
+	products derived from this software without specific prior written
+	permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
@@ -35,8 +35,6 @@ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-
 */
 package goautoneg
 

vendor/github.com/prometheus/common/model/time.go

@@ -18,7 +18,6 @@ import (
 	"errors"
 	"fmt"
 	"math"
-	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -183,54 +182,78 @@ func (d *Duration) Type() string {
 	return "duration"
 }
 
-var durationRE = regexp.MustCompile("^(([0-9]+)y)?(([0-9]+)w)?(([0-9]+)d)?(([0-9]+)h)?(([0-9]+)m)?(([0-9]+)s)?(([0-9]+)ms)?$")
+func isdigit(c byte) bool { return c >= '0' && c <= '9' }
+
+// Units are required to go in order from biggest to smallest.
+// This guards against confusion from "1m1d" being 1 minute + 1 day, not 1 month + 1 day.
+var unitMap = map[string]struct {
+	pos  int
+	mult uint64
+}{
+	"ms": {7, uint64(time.Millisecond)},
+	"s":  {6, uint64(time.Second)},
+	"m":  {5, uint64(time.Minute)},
+	"h":  {4, uint64(time.Hour)},
+	"d":  {3, uint64(24 * time.Hour)},
+	"w":  {2, uint64(7 * 24 * time.Hour)},
+	"y":  {1, uint64(365 * 24 * time.Hour)},
+}
 
 // ParseDuration parses a string into a time.Duration, assuming that a year
 // always has 365d, a week always has 7d, and a day always has 24h.
-func ParseDuration(durationStr string) (Duration, error) {
-	switch durationStr {
+func ParseDuration(s string) (Duration, error) {
+	switch s {
 	case "0":
 		// Allow 0 without a unit.
 		return 0, nil
 	case "":
 		return 0, errors.New("empty duration string")
 	}
-	matches := durationRE.FindStringSubmatch(durationStr)
-	if matches == nil {
-		return 0, fmt.Errorf("not a valid duration string: %q", durationStr)
-	}
-	var dur time.Duration
 
-	// Parse the match at pos `pos` in the regex and use `mult` to turn that
-	// into ms, then add that value to the total parsed duration.
-	var overflowErr error
-	m := func(pos int, mult time.Duration) {
-		if matches[pos] == "" {
-			return
+	orig := s
+	var dur uint64
+	lastUnitPos := 0
+
+	for s != "" {
+		if !isdigit(s[0]) {
+			return 0, fmt.Errorf("not a valid duration string: %q", orig)
 		}
-		n, _ := strconv.Atoi(matches[pos])
+		// Consume [0-9]*
+		i := 0
+		for ; i < len(s) && isdigit(s[i]); i++ {
+		}
+		v, err := strconv.ParseUint(s[:i], 10, 0)
+		if err != nil {
+			return 0, fmt.Errorf("not a valid duration string: %q", orig)
+		}
+		s = s[i:]
 
+		// Consume unit.
+		for i = 0; i < len(s) && !isdigit(s[i]); i++ {
+		}
+		if i == 0 {
+			return 0, fmt.Errorf("not a valid duration string: %q", orig)
+		}
+		u := s[:i]
+		s = s[i:]
+		unit, ok := unitMap[u]
+		if !ok {
+			return 0, fmt.Errorf("unknown unit %q in duration %q", u, orig)
+		}
+		if unit.pos <= lastUnitPos { // Units must go in order from biggest to smallest.
+			return 0, fmt.Errorf("not a valid duration string: %q", orig)
+		}
+		lastUnitPos = unit.pos
 		// Check if the provided duration overflows time.Duration (> ~ 290years).
-		if n > int((1<<63-1)/mult/time.Millisecond) {
-			overflowErr = errors.New("duration out of range")
+		if v > 1<<63/unit.mult {
+			return 0, errors.New("duration out of range")
 		}
-		d := time.Duration(n) * time.Millisecond
-		dur += d * mult
-
-		if dur < 0 {
-			overflowErr = errors.New("duration out of range")
+		dur += v * unit.mult
+		if dur > 1<<63-1 {
+			return 0, errors.New("duration out of range")
 		}
 	}
-
-	m(2, 1000*60*60*24*365) // y
-	m(4, 1000*60*60*24*7)   // w
-	m(6, 1000*60*60*24)     // d
-	m(8, 1000*60*60)        // h
-	m(10, 1000*60)          // m
-	m(12, 1000)             // s
-	m(14, 1)                // ms
-
-	return Duration(dur), overflowErr
+	return Duration(dur), nil
 }
 
 func (d Duration) String() string {

vendor/github.com/prometheus/common/model/value.go

@@ -16,20 +16,12 @@ 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
@@ -38,82 +30,14 @@ var (
 	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 semantics 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.
+// Sample is a sample pair associated with a metric. A single sample must either
+// define Value or Histogram but not both. Histogram == nil implies the Value
+// field is used, otherwise it should be ignored.
 type Sample struct {
-	Metric    Metric      `json:"metric"`
-	Value     SampleValue `json:"value"`
-	Timestamp Time        `json:"timestamp"`
+	Metric    Metric           `json:"metric"`
+	Value     SampleValue      `json:"value"`
+	Timestamp Time             `json:"timestamp"`
+	Histogram *SampleHistogram `json:"histogram"`
 }
 
 // Equal compares first the metrics, then the timestamp, then the value. The
@@ -129,11 +53,19 @@ func (s *Sample) Equal(o *Sample) bool {
 	if !s.Timestamp.Equal(o.Timestamp) {
 		return false
 	}
-
+	if s.Histogram != nil {
+		return s.Histogram.Equal(o.Histogram)
+	}
 	return s.Value.Equal(o.Value)
 }
 
 func (s Sample) String() string {
+	if s.Histogram != nil {
+		return fmt.Sprintf("%s => %s", s.Metric, SampleHistogramPair{
+			Timestamp: s.Timestamp,
+			Histogram: s.Histogram,
+		})
+	}
 	return fmt.Sprintf("%s => %s", s.Metric, SamplePair{
 		Timestamp: s.Timestamp,
 		Value:     s.Value,
@@ -142,6 +74,19 @@ func (s Sample) String() string {
 
 // MarshalJSON implements json.Marshaler.
 func (s Sample) MarshalJSON() ([]byte, error) {
+	if s.Histogram != nil {
+		v := struct {
+			Metric    Metric              `json:"metric"`
+			Histogram SampleHistogramPair `json:"histogram"`
+		}{
+			Metric: s.Metric,
+			Histogram: SampleHistogramPair{
+				Timestamp: s.Timestamp,
+				Histogram: s.Histogram,
+			},
+		}
+		return json.Marshal(&v)
+	}
 	v := struct {
 		Metric Metric     `json:"metric"`
 		Value  SamplePair `json:"value"`
@@ -152,21 +97,25 @@ func (s Sample) MarshalJSON() ([]byte, error) {
 			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    Metric              `json:"metric"`
+		Value     SamplePair          `json:"value"`
+		Histogram SampleHistogramPair `json:"histogram"`
 	}{
 		Metric: s.Metric,
 		Value: SamplePair{
 			Timestamp: s.Timestamp,
 			Value:     s.Value,
 		},
+		Histogram: SampleHistogramPair{
+			Timestamp: s.Timestamp,
+			Histogram: s.Histogram,
+		},
 	}
 
 	if err := json.Unmarshal(b, &v); err != nil {
@@ -174,8 +123,13 @@ func (s *Sample) UnmarshalJSON(b []byte) error {
 	}
 
 	s.Metric = v.Metric
-	s.Timestamp = v.Value.Timestamp
-	s.Value = v.Value.Value
+	if v.Histogram.Histogram != nil {
+		s.Timestamp = v.Histogram.Timestamp
+		s.Histogram = v.Histogram.Histogram
+	} else {
+		s.Timestamp = v.Value.Timestamp
+		s.Value = v.Value.Value
+	}
 
 	return nil
 }
@@ -221,80 +175,76 @@ func (s Samples) Equal(o Samples) bool {
 
 // SampleStream is a stream of Values belonging to an attached COWMetric.
 type SampleStream struct {
-	Metric Metric       `json:"metric"`
-	Values []SamplePair `json:"values"`
+	Metric     Metric                `json:"metric"`
+	Values     []SamplePair          `json:"values"`
+	Histograms []SampleHistogramPair `json:"histograms"`
 }
 
 func (ss SampleStream) String() string {
-	vals := make([]string, len(ss.Values))
+	valuesLength := len(ss.Values)
+	vals := make([]string, valuesLength+len(ss.Histograms))
 	for i, v := range ss.Values {
 		vals[i] = v.String()
 	}
+	for i, v := range ss.Histograms {
+		vals[i+valuesLength] = 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 (ss SampleStream) MarshalJSON() ([]byte, error) {
+	if len(ss.Histograms) > 0 && len(ss.Values) > 0 {
+		v := struct {
+			Metric     Metric                `json:"metric"`
+			Values     []SamplePair          `json:"values"`
+			Histograms []SampleHistogramPair `json:"histograms"`
+		}{
+			Metric:     ss.Metric,
+			Values:     ss.Values,
+			Histograms: ss.Histograms,
+		}
+		return json.Marshal(&v)
+	} else if len(ss.Histograms) > 0 {
+		v := struct {
+			Metric     Metric                `json:"metric"`
+			Histograms []SampleHistogramPair `json:"histograms"`
+		}{
+			Metric:     ss.Metric,
+			Histograms: ss.Histograms,
+		}
+		return json.Marshal(&v)
+	} else {
+		v := struct {
+			Metric Metric       `json:"metric"`
+			Values []SamplePair `json:"values"`
+		}{
+			Metric: ss.Metric,
+			Values: ss.Values,
+		}
+		return json.Marshal(&v)
+	}
 }
 
-func (Matrix) Type() ValueType  { return ValMatrix }
-func (Vector) Type() ValueType  { return ValVector }
-func (*Scalar) Type() ValueType { return ValScalar }
-func (*String) Type() ValueType { return ValString }
+func (ss *SampleStream) UnmarshalJSON(b []byte) error {
+	v := struct {
+		Metric     Metric                `json:"metric"`
+		Values     []SamplePair          `json:"values"`
+		Histograms []SampleHistogramPair `json:"histograms"`
+	}{
+		Metric:     ss.Metric,
+		Values:     ss.Values,
+		Histograms: ss.Histograms,
+	}
 
-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 {
+	if err := json.Unmarshal(b, &v); 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")
+	ss.Metric = v.Metric
+	ss.Values = v.Values
+	ss.Histograms = v.Histograms
+
+	return nil
 }
 
 // Scalar is a scalar value evaluated at the set timestamp.

vendor/github.com/prometheus/common/model/value_float.go

@@ -0,0 +1,100 @@
+// 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"
+	"strconv"
+)
+
+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}
+)
+
+// 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
+}
+
+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 semantics 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)
+}

vendor/github.com/prometheus/common/model/value_histogram.go

@@ -0,0 +1,178 @@
+// 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"
+	"strconv"
+	"strings"
+)
+
+type FloatString float64
+
+func (v FloatString) String() string {
+	return strconv.FormatFloat(float64(v), 'f', -1, 64)
+}
+
+func (v FloatString) MarshalJSON() ([]byte, error) {
+	return json.Marshal(v.String())
+}
+
+func (v *FloatString) UnmarshalJSON(b []byte) error {
+	if len(b) < 2 || b[0] != '"' || b[len(b)-1] != '"' {
+		return fmt.Errorf("float value must be a quoted string")
+	}
+	f, err := strconv.ParseFloat(string(b[1:len(b)-1]), 64)
+	if err != nil {
+		return err
+	}
+	*v = FloatString(f)
+	return nil
+}
+
+type HistogramBucket struct {
+	Boundaries int32
+	Lower      FloatString
+	Upper      FloatString
+	Count      FloatString
+}
+
+func (s HistogramBucket) MarshalJSON() ([]byte, error) {
+	b, err := json.Marshal(s.Boundaries)
+	if err != nil {
+		return nil, err
+	}
+	l, err := json.Marshal(s.Lower)
+	if err != nil {
+		return nil, err
+	}
+	u, err := json.Marshal(s.Upper)
+	if err != nil {
+		return nil, err
+	}
+	c, err := json.Marshal(s.Count)
+	if err != nil {
+		return nil, err
+	}
+	return []byte(fmt.Sprintf("[%s,%s,%s,%s]", b, l, u, c)), nil
+}
+
+func (s *HistogramBucket) UnmarshalJSON(buf []byte) error {
+	tmp := []interface{}{&s.Boundaries, &s.Lower, &s.Upper, &s.Count}
+	wantLen := len(tmp)
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if gotLen := len(tmp); gotLen != wantLen {
+		return fmt.Errorf("wrong number of fields: %d != %d", gotLen, wantLen)
+	}
+	return nil
+}
+
+func (s *HistogramBucket) Equal(o *HistogramBucket) bool {
+	return s == o || (s.Boundaries == o.Boundaries && s.Lower == o.Lower && s.Upper == o.Upper && s.Count == o.Count)
+}
+
+func (b HistogramBucket) String() string {
+	var sb strings.Builder
+	lowerInclusive := b.Boundaries == 1 || b.Boundaries == 3
+	upperInclusive := b.Boundaries == 0 || b.Boundaries == 3
+	if lowerInclusive {
+		sb.WriteRune('[')
+	} else {
+		sb.WriteRune('(')
+	}
+	fmt.Fprintf(&sb, "%g,%g", b.Lower, b.Upper)
+	if upperInclusive {
+		sb.WriteRune(']')
+	} else {
+		sb.WriteRune(')')
+	}
+	fmt.Fprintf(&sb, ":%v", b.Count)
+	return sb.String()
+}
+
+type HistogramBuckets []*HistogramBucket
+
+func (s HistogramBuckets) Equal(o HistogramBuckets) bool {
+	if len(s) != len(o) {
+		return false
+	}
+
+	for i, bucket := range s {
+		if !bucket.Equal(o[i]) {
+			return false
+		}
+	}
+	return true
+}
+
+type SampleHistogram struct {
+	Count   FloatString      `json:"count"`
+	Sum     FloatString      `json:"sum"`
+	Buckets HistogramBuckets `json:"buckets"`
+}
+
+func (s SampleHistogram) String() string {
+	return fmt.Sprintf("Count: %f, Sum: %f, Buckets: %v", s.Count, s.Sum, s.Buckets)
+}
+
+func (s *SampleHistogram) Equal(o *SampleHistogram) bool {
+	return s == o || (s.Count == o.Count && s.Sum == o.Sum && s.Buckets.Equal(o.Buckets))
+}
+
+type SampleHistogramPair struct {
+	Timestamp Time
+	// Histogram should never be nil, it's only stored as pointer for efficiency.
+	Histogram *SampleHistogram
+}
+
+func (s SampleHistogramPair) MarshalJSON() ([]byte, error) {
+	if s.Histogram == nil {
+		return nil, fmt.Errorf("histogram is nil")
+	}
+	t, err := json.Marshal(s.Timestamp)
+	if err != nil {
+		return nil, err
+	}
+	v, err := json.Marshal(s.Histogram)
+	if err != nil {
+		return nil, err
+	}
+	return []byte(fmt.Sprintf("[%s,%s]", t, v)), nil
+}
+
+func (s *SampleHistogramPair) UnmarshalJSON(buf []byte) error {
+	tmp := []interface{}{&s.Timestamp, &s.Histogram}
+	wantLen := len(tmp)
+	if err := json.Unmarshal(buf, &tmp); err != nil {
+		return err
+	}
+	if gotLen := len(tmp); gotLen != wantLen {
+		return fmt.Errorf("wrong number of fields: %d != %d", gotLen, wantLen)
+	}
+	if s.Histogram == nil {
+		return fmt.Errorf("histogram is null")
+	}
+	return nil
+}
+
+func (s SampleHistogramPair) String() string {
+	return fmt.Sprintf("%s @[%s]", s.Histogram, s.Timestamp)
+}
+
+func (s *SampleHistogramPair) Equal(o *SampleHistogramPair) bool {
+	return s == o || (s.Histogram.Equal(o.Histogram) && s.Timestamp.Equal(o.Timestamp))
+}

vendor/github.com/prometheus/common/model/value_type.go

@@ -0,0 +1,83 @@
+// 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"
+)
+
+// 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")
+}