TUN-8456: Update quic-go to 0.45 and collect mtu and congestion control metrics

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

@@ -14,6 +14,7 @@
 package expfmt
 
 import (
+	"bufio"
 	"fmt"
 	"io"
 	"math"
@@ -21,8 +22,8 @@ import (
 	"net/http"
 
 	dto "github.com/prometheus/client_model/go"
+	"google.golang.org/protobuf/encoding/protodelim"
 
-	"github.com/matttproud/golang_protobuf_extensions/pbutil"
 	"github.com/prometheus/common/model"
 )
 
@@ -44,7 +45,7 @@ func ResponseFormat(h http.Header) Format {
 
 	mediatype, params, err := mime.ParseMediaType(ct)
 	if err != nil {
-		return FmtUnknown
+		return fmtUnknown
 	}
 
 	const textType = "text/plain"
@@ -52,28 +53,28 @@ func ResponseFormat(h http.Header) Format {
 	switch mediatype {
 	case ProtoType:
 		if p, ok := params["proto"]; ok && p != ProtoProtocol {
-			return FmtUnknown
+			return fmtUnknown
 		}
 		if e, ok := params["encoding"]; ok && e != "delimited" {
-			return FmtUnknown
+			return fmtUnknown
 		}
-		return FmtProtoDelim
+		return fmtProtoDelim
 
 	case textType:
 		if v, ok := params["version"]; ok && v != TextVersion {
-			return FmtUnknown
+			return fmtUnknown
 		}
-		return FmtText
+		return fmtText
 	}
 
-	return FmtUnknown
+	return fmtUnknown
 }
 
 // NewDecoder returns a new decoder based on the given input format.
 // If the input format does not imply otherwise, a text format decoder is returned.
 func NewDecoder(r io.Reader, format Format) Decoder {
-	switch format {
-	case FmtProtoDelim:
+	switch format.FormatType() {
+	case TypeProtoDelim:
 		return &protoDecoder{r: r}
 	}
 	return &textDecoder{r: r}
@@ -86,8 +87,10 @@ type protoDecoder struct {
 
 // Decode implements the Decoder interface.
 func (d *protoDecoder) Decode(v *dto.MetricFamily) error {
-	_, err := pbutil.ReadDelimited(d.r, v)
-	if err != nil {
+	opts := protodelim.UnmarshalOptions{
+		MaxSize: -1,
+	}
+	if err := opts.UnmarshalFrom(bufio.NewReader(d.r), v); err != nil {
 		return err
 	}
 	if !model.IsValidMetricName(model.LabelValue(v.GetName())) {
@@ -115,32 +118,31 @@ 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.Name = fam.Name
+		v.Help = fam.Help
+		v.Type = fam.Type
+		v.Metric = fam.Metric
+		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/encode.go

@@ -18,9 +18,11 @@ import (
 	"io"
 	"net/http"
 
-	"github.com/golang/protobuf/proto" //nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
-	"github.com/matttproud/golang_protobuf_extensions/pbutil"
+	"google.golang.org/protobuf/encoding/protodelim"
+	"google.golang.org/protobuf/encoding/prototext"
+
 	"github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg"
+	"github.com/prometheus/common/model"
 
 	dto "github.com/prometheus/client_model/go"
 )
@@ -60,23 +62,32 @@ func (ec encoderCloser) Close() error {
 // as the support is still experimental. To include the option to negotiate
 // FmtOpenMetrics, use NegotiateOpenMetrics.
 func Negotiate(h http.Header) Format {
+	escapingScheme := Format(fmt.Sprintf("; escaping=%s", Format(model.NameEscapingScheme.String())))
 	for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
+		if escapeParam := ac.Params[model.EscapingKey]; escapeParam != "" {
+			switch Format(escapeParam) {
+			case model.AllowUTF8, model.EscapeUnderscores, model.EscapeDots, model.EscapeValues:
+				escapingScheme = Format(fmt.Sprintf("; escaping=%s", escapeParam))
+			default:
+				// If the escaping parameter is unknown, ignore it.
+			}
+		}
 		ver := ac.Params["version"]
 		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
 			switch ac.Params["encoding"] {
 			case "delimited":
-				return FmtProtoDelim
+				return fmtProtoDelim + escapingScheme
 			case "text":
-				return FmtProtoText
+				return fmtProtoText + escapingScheme
 			case "compact-text":
-				return FmtProtoCompact
+				return fmtProtoCompact + escapingScheme
 			}
 		}
 		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
-			return FmtText
+			return fmtText + escapingScheme
 		}
 	}
-	return FmtText
+	return fmtText + escapingScheme
 }
 
 // NegotiateIncludingOpenMetrics works like Negotiate but includes
@@ -84,26 +95,40 @@ func Negotiate(h http.Header) Format {
 // temporary and will disappear once FmtOpenMetrics is fully supported and as
 // such may be negotiated by the normal Negotiate function.
 func NegotiateIncludingOpenMetrics(h http.Header) Format {
+	escapingScheme := Format(fmt.Sprintf("; escaping=%s", Format(model.NameEscapingScheme.String())))
 	for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
+		if escapeParam := ac.Params[model.EscapingKey]; escapeParam != "" {
+			switch Format(escapeParam) {
+			case model.AllowUTF8, model.EscapeUnderscores, model.EscapeDots, model.EscapeValues:
+				escapingScheme = Format(fmt.Sprintf("; escaping=%s", escapeParam))
+			default:
+				// If the escaping parameter is unknown, ignore it.
+			}
+		}
 		ver := ac.Params["version"]
 		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
 			switch ac.Params["encoding"] {
 			case "delimited":
-				return FmtProtoDelim
+				return fmtProtoDelim + escapingScheme
 			case "text":
-				return FmtProtoText
+				return fmtProtoText + escapingScheme
 			case "compact-text":
-				return FmtProtoCompact
+				return fmtProtoCompact + escapingScheme
 			}
 		}
 		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
-			return FmtText
+			return fmtText + escapingScheme
 		}
-		if ac.Type+"/"+ac.SubType == OpenMetricsType && (ver == OpenMetricsVersion || ver == "") {
-			return FmtOpenMetrics
+		if ac.Type+"/"+ac.SubType == OpenMetricsType && (ver == OpenMetricsVersion_0_0_1 || ver == OpenMetricsVersion_1_0_0 || ver == "") {
+			switch ver {
+			case OpenMetricsVersion_1_0_0:
+				return fmtOpenMetrics_1_0_0 + escapingScheme
+			default:
+				return fmtOpenMetrics_0_0_1 + escapingScheme
+			}
 		}
 	}
-	return FmtText
+	return fmtText + escapingScheme
 }
 
 // NewEncoder returns a new encoder based on content type negotiation. All
@@ -112,44 +137,48 @@ func NegotiateIncludingOpenMetrics(h http.Header) Format {
 // for FmtOpenMetrics, but a future (breaking) release will add the Close method
 // to the Encoder interface directly. The current version of the Encoder
 // interface is kept for backwards compatibility.
+// In cases where the Format does not allow for UTF-8 names, the global
+// NameEscapingScheme will be applied.
 func NewEncoder(w io.Writer, format Format) Encoder {
-	switch format {
-	case FmtProtoDelim:
+	escapingScheme := format.ToEscapingScheme()
+
+	switch format.FormatType() {
+	case TypeProtoDelim:
 		return encoderCloser{
 			encode: func(v *dto.MetricFamily) error {
-				_, err := pbutil.WriteDelimited(w, v)
+				_, err := protodelim.MarshalTo(w, v)
 				return err
 			},
 			close: func() error { return nil },
 		}
-	case FmtProtoCompact:
+	case TypeProtoCompact:
 		return encoderCloser{
 			encode: func(v *dto.MetricFamily) error {
-				_, err := fmt.Fprintln(w, v.String())
+				_, err := fmt.Fprintln(w, model.EscapeMetricFamily(v, escapingScheme).String())
 				return err
 			},
 			close: func() error { return nil },
 		}
-	case FmtProtoText:
+	case TypeProtoText:
 		return encoderCloser{
 			encode: func(v *dto.MetricFamily) error {
-				_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
+				_, err := fmt.Fprintln(w, prototext.Format(model.EscapeMetricFamily(v, escapingScheme)))
 				return err
 			},
 			close: func() error { return nil },
 		}
-	case FmtText:
+	case TypeTextPlain:
 		return encoderCloser{
 			encode: func(v *dto.MetricFamily) error {
-				_, err := MetricFamilyToText(w, v)
+				_, err := MetricFamilyToText(w, model.EscapeMetricFamily(v, escapingScheme))
 				return err
 			},
 			close: func() error { return nil },
 		}
-	case FmtOpenMetrics:
+	case TypeOpenMetrics:
 		return encoderCloser{
 			encode: func(v *dto.MetricFamily) error {
-				_, err := MetricFamilyToOpenMetrics(w, v)
+				_, err := MetricFamilyToOpenMetrics(w, model.EscapeMetricFamily(v, escapingScheme))
 				return err
 			},
 			close: func() error {

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

@@ -14,28 +14,154 @@
 // Package expfmt contains tools for reading and writing Prometheus metrics.
 package expfmt
 
+import (
+	"strings"
+
+	"github.com/prometheus/common/model"
+)
+
 // Format specifies the HTTP content type of the different wire protocols.
 type Format string
 
-// Constants to assemble the Content-Type values for the different wire protocols.
+// Constants to assemble the Content-Type values for the different wire
+// protocols. The Content-Type strings here are all for the legacy exposition
+// formats, where valid characters for metric names and label names are limited.
+// Support for arbitrary UTF-8 characters in those names is already partially
+// implemented in this module (see model.ValidationScheme), but to actually use
+// it on the wire, new content-type strings will have to be agreed upon and
+// added here.
 const (
-	TextVersion        = "0.0.4"
-	ProtoType          = `application/vnd.google.protobuf`
-	ProtoProtocol      = `io.prometheus.client.MetricFamily`
-	ProtoFmt           = ProtoType + "; proto=" + ProtoProtocol + ";"
-	OpenMetricsType    = `application/openmetrics-text`
-	OpenMetricsVersion = "0.0.1"
+	TextVersion              = "0.0.4"
+	ProtoType                = `application/vnd.google.protobuf`
+	ProtoProtocol            = `io.prometheus.client.MetricFamily`
+	protoFmt                 = ProtoType + "; proto=" + ProtoProtocol + ";"
+	OpenMetricsType          = `application/openmetrics-text`
+	OpenMetricsVersion_0_0_1 = "0.0.1"
+	OpenMetricsVersion_1_0_0 = "1.0.0"
 
-	// The Content-Type values for the different wire protocols.
-	FmtUnknown      Format = `<unknown>`
-	FmtText         Format = `text/plain; version=` + TextVersion + `; charset=utf-8`
-	FmtProtoDelim   Format = ProtoFmt + ` encoding=delimited`
-	FmtProtoText    Format = ProtoFmt + ` encoding=text`
-	FmtProtoCompact Format = ProtoFmt + ` encoding=compact-text`
-	FmtOpenMetrics  Format = OpenMetricsType + `; version=` + OpenMetricsVersion + `; charset=utf-8`
+	// The Content-Type values for the different wire protocols. Note that these
+	// values are now unexported. If code was relying on comparisons to these
+	// constants, instead use FormatType().
+	fmtUnknown           Format = `<unknown>`
+	fmtText              Format = `text/plain; version=` + TextVersion + `; charset=utf-8`
+	fmtProtoDelim        Format = protoFmt + ` encoding=delimited`
+	fmtProtoText         Format = protoFmt + ` encoding=text`
+	fmtProtoCompact      Format = protoFmt + ` encoding=compact-text`
+	fmtOpenMetrics_1_0_0 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_1_0_0 + `; charset=utf-8`
+	fmtOpenMetrics_0_0_1 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_0_0_1 + `; charset=utf-8`
 )
 
 const (
 	hdrContentType = "Content-Type"
 	hdrAccept      = "Accept"
 )
+
+// FormatType is a Go enum representing the overall category for the given
+// Format. As the number of Format permutations increases, doing basic string
+// comparisons are not feasible, so this enum captures the most useful
+// high-level attribute of the Format string.
+type FormatType int
+
+const (
+	TypeUnknown = iota
+	TypeProtoCompact
+	TypeProtoDelim
+	TypeProtoText
+	TypeTextPlain
+	TypeOpenMetrics
+)
+
+// NewFormat generates a new Format from the type provided. Mostly used for
+// tests, most Formats should be generated as part of content negotiation in
+// encode.go.
+func NewFormat(t FormatType) Format {
+	switch t {
+	case TypeProtoCompact:
+		return fmtProtoCompact
+	case TypeProtoDelim:
+		return fmtProtoDelim
+	case TypeProtoText:
+		return fmtProtoText
+	case TypeTextPlain:
+		return fmtText
+	case TypeOpenMetrics:
+		return fmtOpenMetrics_1_0_0
+	default:
+		return fmtUnknown
+	}
+}
+
+// FormatType deduces an overall FormatType for the given format.
+func (f Format) FormatType() FormatType {
+	toks := strings.Split(string(f), ";")
+	if len(toks) < 2 {
+		return TypeUnknown
+	}
+
+	params := make(map[string]string)
+	for i, t := range toks {
+		if i == 0 {
+			continue
+		}
+		args := strings.Split(t, "=")
+		if len(args) != 2 {
+			continue
+		}
+		params[strings.TrimSpace(args[0])] = strings.TrimSpace(args[1])
+	}
+
+	switch strings.TrimSpace(toks[0]) {
+	case ProtoType:
+		if params["proto"] != ProtoProtocol {
+			return TypeUnknown
+		}
+		switch params["encoding"] {
+		case "delimited":
+			return TypeProtoDelim
+		case "text":
+			return TypeProtoText
+		case "compact-text":
+			return TypeProtoCompact
+		default:
+			return TypeUnknown
+		}
+	case OpenMetricsType:
+		if params["charset"] != "utf-8" {
+			return TypeUnknown
+		}
+		return TypeOpenMetrics
+	case "text/plain":
+		v, ok := params["version"]
+		if !ok {
+			return TypeTextPlain
+		}
+		if v == TextVersion {
+			return TypeTextPlain
+		}
+		return TypeUnknown
+	default:
+		return TypeUnknown
+	}
+}
+
+// ToEscapingScheme returns an EscapingScheme depending on the Format. Iff the
+// Format contains a escaping=allow-utf-8 term, it will select NoEscaping. If a valid
+// "escaping" term exists, that will be used. Otherwise, the global default will
+// be returned.
+func (format Format) ToEscapingScheme() model.EscapingScheme {
+	for _, p := range strings.Split(string(format), ";") {
+		toks := strings.Split(p, "=")
+		if len(toks) != 2 {
+			continue
+		}
+		key, value := strings.TrimSpace(toks[0]), strings.TrimSpace(toks[1])
+		if key == model.EscapingKey {
+			scheme, err := model.ToEscapingScheme(value)
+			if err != nil {
+				return model.NameEscapingScheme
+			}
+			return scheme
+		}
+	}
+	return model.NameEscapingScheme
+}

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

@@ -35,6 +35,18 @@ import (
 // sanity checks. If the input contains duplicate metrics or invalid metric or
 // label names, the conversion will result in invalid text format output.
 //
+// If metric names conform to the legacy validation pattern, they will be placed
+// outside the brackets in the traditional way, like `foo{}`. If the metric name
+// fails the legacy validation check, it will be placed quoted inside the
+// brackets: `{"foo"}`. As stated above, the input is assumed to be santized and
+// no error will be thrown in this case.
+//
+// Similar to metric names, if label names conform to the legacy validation
+// pattern, they will be unquoted as normal, like `foo{bar="baz"}`. If the label
+// name fails the legacy validation check, it will be quoted:
+// `foo{"bar"="baz"}`. As stated above, the input is assumed to be santized and
+// no error will be thrown in this case.
+//
 // This function fulfills the type 'expfmt.encoder'.
 //
 // Note that OpenMetrics requires a final `# EOF` line. Since this function acts
@@ -46,20 +58,20 @@ 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 == "" {
@@ -98,7 +110,7 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily) (written int
 		if err != nil {
 			return
 		}
-		n, err = w.WriteString(shortName)
+		n, err = writeName(w, shortName)
 		written += n
 		if err != nil {
 			return
@@ -124,7 +136,7 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily) (written int
 	if err != nil {
 		return
 	}
-	n, err = w.WriteString(shortName)
+	n, err = writeName(w, shortName)
 	written += n
 	if err != nil {
 		return
@@ -303,21 +315,9 @@ func writeOpenMetricsSample(
 	floatValue float64, intValue uint64, useIntValue bool,
 	exemplar *dto.Exemplar,
 ) (int, error) {
-	var written int
-	n, err := w.WriteString(name)
-	written += n
-	if err != nil {
-		return written, err
-	}
-	if suffix != "" {
-		n, err = w.WriteString(suffix)
-		written += n
-		if err != nil {
-			return written, err
-		}
-	}
-	n, err = writeOpenMetricsLabelPairs(
-		w, metric.Label, additionalLabelName, additionalLabelValue,
+	written := 0
+	n, err := writeOpenMetricsNameAndLabelPairs(
+		w, name+suffix, metric.Label, additionalLabelName, additionalLabelValue,
 	)
 	written += n
 	if err != nil {
@@ -365,27 +365,58 @@ func writeOpenMetricsSample(
 	return written, nil
 }
 
-// writeOpenMetricsLabelPairs works like writeOpenMetrics but formats the float
-// in OpenMetrics style.
-func writeOpenMetricsLabelPairs(
+// writeOpenMetricsNameAndLabelPairs works like writeOpenMetricsSample but
+// formats the float in OpenMetrics style.
+func writeOpenMetricsNameAndLabelPairs(
 	w enhancedWriter,
+	name string,
 	in []*dto.LabelPair,
 	additionalLabelName string, additionalLabelValue float64,
 ) (int, error) {
-	if len(in) == 0 && additionalLabelName == "" {
-		return 0, nil
-	}
 	var (
-		written   int
-		separator byte = '{'
+		written            int
+		separator          byte = '{'
+		metricInsideBraces      = false
 	)
+
+	if name != "" {
+		// If the name does not pass the legacy validity check, we must put the
+		// metric name inside the braces, quoted.
+		if !model.IsValidLegacyMetricName(model.LabelValue(name)) {
+			metricInsideBraces = true
+			err := w.WriteByte(separator)
+			written++
+			if err != nil {
+				return written, err
+			}
+			separator = ','
+		}
+
+		n, err := writeName(w, name)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+
+	if len(in) == 0 && additionalLabelName == "" {
+		if metricInsideBraces {
+			err := w.WriteByte('}')
+			written++
+			if err != nil {
+				return written, err
+			}
+		}
+		return written, nil
+	}
+
 	for _, lp := range in {
 		err := w.WriteByte(separator)
 		written++
 		if err != nil {
 			return written, err
 		}
-		n, err := w.WriteString(lp.GetName())
+		n, err := writeName(w, lp.GetName())
 		written += n
 		if err != nil {
 			return written, err
@@ -451,7 +482,7 @@ func writeExemplar(w enhancedWriter, e *dto.Exemplar) (int, error) {
 	if err != nil {
 		return written, err
 	}
-	n, err = writeOpenMetricsLabelPairs(w, e.Label, "", 0)
+	n, err = writeOpenMetricsNameAndLabelPairs(w, "", e.Label, "", 0)
 	written += n
 	if err != nil {
 		return written, err

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{
@@ -63,6 +62,18 @@ var (
 // contains duplicate metrics or invalid metric or label names, the conversion
 // will result in invalid text format output.
 //
+// If metric names conform to the legacy validation pattern, they will be placed
+// outside the brackets in the traditional way, like `foo{}`. If the metric name
+// fails the legacy validation check, it will be placed quoted inside the
+// brackets: `{"foo"}`. As stated above, the input is assumed to be santized and
+// no error will be thrown in this case.
+//
+// Similar to metric names, if label names conform to the legacy validation
+// pattern, they will be unquoted as normal, like `foo{bar="baz"}`. If the label
+// name fails the legacy validation check, it will be quoted:
+// `foo{"bar"="baz"}`. As stated above, the input is assumed to be santized and
+// no error will be thrown in this case.
+//
 // This method fulfills the type 'prometheus.encoder'.
 func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err error) {
 	// Fail-fast checks.
@@ -99,7 +110,7 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 		if err != nil {
 			return
 		}
-		n, err = w.WriteString(name)
+		n, err = writeName(w, name)
 		written += n
 		if err != nil {
 			return
@@ -125,7 +136,7 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 	if err != nil {
 		return
 	}
-	n, err = w.WriteString(name)
+	n, err = writeName(w, name)
 	written += n
 	if err != nil {
 		return
@@ -281,21 +292,9 @@ func writeSample(
 	additionalLabelName string, additionalLabelValue float64,
 	value float64,
 ) (int, error) {
-	var written int
-	n, err := w.WriteString(name)
-	written += n
-	if err != nil {
-		return written, err
-	}
-	if suffix != "" {
-		n, err = w.WriteString(suffix)
-		written += n
-		if err != nil {
-			return written, err
-		}
-	}
-	n, err = writeLabelPairs(
-		w, metric.Label, additionalLabelName, additionalLabelValue,
+	written := 0
+	n, err := writeNameAndLabelPairs(
+		w, name+suffix, metric.Label, additionalLabelName, additionalLabelValue,
 	)
 	written += n
 	if err != nil {
@@ -331,32 +330,64 @@ func writeSample(
 	return written, nil
 }
 
-// writeLabelPairs converts a slice of LabelPair proto messages plus the
-// explicitly given additional label pair into text formatted as required by the
-// text format and writes it to 'w'. An empty slice in combination with an empty
-// string 'additionalLabelName' results in nothing being written. Otherwise, the
-// label pairs are written, escaped as required by the text format, and enclosed
-// in '{...}'. The function returns the number of bytes written and any error
-// encountered.
-func writeLabelPairs(
+// writeNameAndLabelPairs converts a slice of LabelPair proto messages plus the
+// explicitly given metric name and additional label pair into text formatted as
+// required by the text format and writes it to 'w'. An empty slice in
+// combination with an empty string 'additionalLabelName' results in nothing
+// being written. Otherwise, the label pairs are written, escaped as required by
+// the text format, and enclosed in '{...}'. The function returns the number of
+// bytes written and any error encountered. If the metric name is not
+// legacy-valid, it will be put inside the brackets as well. Legacy-invalid
+// label names will also be quoted.
+func writeNameAndLabelPairs(
 	w enhancedWriter,
+	name string,
 	in []*dto.LabelPair,
 	additionalLabelName string, additionalLabelValue float64,
 ) (int, error) {
-	if len(in) == 0 && additionalLabelName == "" {
-		return 0, nil
-	}
 	var (
-		written   int
-		separator byte = '{'
+		written            int
+		separator          byte = '{'
+		metricInsideBraces      = false
 	)
+
+	if name != "" {
+		// If the name does not pass the legacy validity check, we must put the
+		// metric name inside the braces.
+		if !model.IsValidLegacyMetricName(model.LabelValue(name)) {
+			metricInsideBraces = true
+			err := w.WriteByte(separator)
+			written++
+			if err != nil {
+				return written, err
+			}
+			separator = ','
+		}
+		n, err := writeName(w, name)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+
+	if len(in) == 0 && additionalLabelName == "" {
+		if metricInsideBraces {
+			err := w.WriteByte('}')
+			written++
+			if err != nil {
+				return written, err
+			}
+		}
+		return written, nil
+	}
+
 	for _, lp := range in {
 		err := w.WriteByte(separator)
 		written++
 		if err != nil {
 			return written, err
 		}
-		n, err := w.WriteString(lp.GetName())
+		n, err := writeName(w, lp.GetName())
 		written += n
 		if err != nil {
 			return written, err
@@ -463,3 +494,27 @@ func writeInt(w enhancedWriter, i int64) (int, error) {
 	numBufPool.Put(bp)
 	return written, err
 }
+
+// writeName writes a string as-is if it complies with the legacy naming
+// scheme, or escapes it in double quotes if not.
+func writeName(w enhancedWriter, name string) (int, error) {
+	if model.IsValidLegacyMetricName(model.LabelValue(name)) {
+		return w.WriteString(name)
+	}
+	var written int
+	var err error
+	err = w.WriteByte('"')
+	written++
+	if err != nil {
+		return written, err
+	}
+	var n int
+	n, err = writeEscapedString(w, name, true)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	err = w.WriteByte('"')
+	written++
+	return written, err
+}

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

@@ -16,6 +16,7 @@ package expfmt
 import (
 	"bufio"
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -24,7 +25,8 @@ import (
 
 	dto "github.com/prometheus/client_model/go"
 
-	"github.com/golang/protobuf/proto" //nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
+	"google.golang.org/protobuf/proto"
+
 	"github.com/prometheus/common/model"
 )
 
@@ -112,7 +114,7 @@ func (p *TextParser) TextToMetricFamilies(in io.Reader) (map[string]*dto.MetricF
 	// stream. Turn this error into something nicer and more
 	// meaningful. (io.EOF is often used as a signal for the legitimate end
 	// of an input stream.)
-	if p.err == io.EOF {
+	if p.err != nil && errors.Is(p.err, io.EOF) {
 		p.parseError("unexpected end of input stream")
 	}
 	return p.metricFamiliesByName, p.err
@@ -142,9 +144,13 @@ 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 errors.Is(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/alert.go

@@ -90,13 +90,13 @@ func (a *Alert) Validate() error {
 		return fmt.Errorf("start time must be before end time")
 	}
 	if err := a.Labels.Validate(); err != nil {
-		return fmt.Errorf("invalid label set: %s", err)
+		return fmt.Errorf("invalid label set: %w", err)
 	}
 	if len(a.Labels) == 0 {
 		return fmt.Errorf("at least one label pair required")
 	}
 	if err := a.Annotations.Validate(); err != nil {
-		return fmt.Errorf("invalid annotations: %s", err)
+		return fmt.Errorf("invalid annotations: %w", err)
 	}
 	return nil
 }

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

@@ -97,17 +97,25 @@ var LabelNameRE = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$")
 // therewith.
 type LabelName string
 
-// IsValid is true iff the label name matches the pattern of LabelNameRE. This
-// method, however, does not use LabelNameRE for the check but a much faster
-// hardcoded implementation.
+// IsValid returns true iff name matches the pattern of LabelNameRE for legacy
+// names, and iff it's valid UTF-8 if NameValidationScheme is set to
+// UTF8Validation. For the legacy matching, it does not use LabelNameRE for the
+// check but a much faster hardcoded implementation.
 func (ln LabelName) IsValid() bool {
 	if len(ln) == 0 {
 		return false
 	}
-	for i, b := range ln {
-		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || (b >= '0' && b <= '9' && i > 0)) {
-			return false
+	switch NameValidationScheme {
+	case LegacyValidation:
+		for i, b := range ln {
+			if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || (b >= '0' && b <= '9' && i > 0)) {
+				return false
+			}
 		}
+	case UTF8Validation:
+		return utf8.ValidString(string(ln))
+	default:
+		panic(fmt.Sprintf("Invalid name validation scheme requested: %d", NameValidationScheme))
 	}
 	return true
 }
@@ -164,7 +172,7 @@ func (l LabelNames) String() string {
 // A LabelValue is an associated value for a LabelName.
 type LabelValue string
 
-// IsValid returns true iff the string is a valid UTF8.
+// IsValid returns true iff the string is a valid UTF-8.
 func (lv LabelValue) IsValid() bool {
 	return utf8.ValidString(string(lv))
 }

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

@@ -0,0 +1,28 @@
+// Copyright 2023 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
+
+// MetricType represents metric type values.
+type MetricType string
+
+const (
+	MetricTypeCounter        = MetricType("counter")
+	MetricTypeGauge          = MetricType("gauge")
+	MetricTypeHistogram      = MetricType("histogram")
+	MetricTypeGaugeHistogram = MetricType("gaugehistogram")
+	MetricTypeSummary        = MetricType("summary")
+	MetricTypeInfo           = MetricType("info")
+	MetricTypeStateset       = MetricType("stateset")
+	MetricTypeUnknown        = MetricType("unknown")
+)

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

@@ -18,15 +18,84 @@ import (
 	"regexp"
 	"sort"
 	"strings"
+	"unicode/utf8"
+
+	dto "github.com/prometheus/client_model/go"
+	"google.golang.org/protobuf/proto"
 )
 
 var (
-	// MetricNameRE is a regular expression matching valid metric
-	// names. Note that the IsValidMetricName function performs the same
-	// check but faster than a match with this regular expression.
-	MetricNameRE = regexp.MustCompile(`^[a-zA-Z_:][a-zA-Z0-9_:]*$`)
+	// NameValidationScheme determines the method of name validation to be used by
+	// all calls to IsValidMetricName() and LabelName IsValid(). Setting UTF-8 mode
+	// in isolation from other components that don't support UTF-8 may result in
+	// bugs or other undefined behavior. This value is intended to be set by
+	// UTF-8-aware binaries as part of their startup. To avoid need for locking,
+	// this value should be set once, ideally in an init(), before multiple
+	// goroutines are started.
+	NameValidationScheme = LegacyValidation
+
+	// NameEscapingScheme defines the default way that names will be
+	// escaped when presented to systems that do not support UTF-8 names. If the
+	// Content-Type "escaping" term is specified, that will override this value.
+	NameEscapingScheme = ValueEncodingEscaping
 )
 
+// ValidationScheme is a Go enum for determining how metric and label names will
+// be validated by this library.
+type ValidationScheme int
+
+const (
+	// LegacyValidation is a setting that requirets that metric and label names
+	// conform to the original Prometheus character requirements described by
+	// MetricNameRE and LabelNameRE.
+	LegacyValidation ValidationScheme = iota
+
+	// UTF8Validation only requires that metric and label names be valid UTF-8
+	// strings.
+	UTF8Validation
+)
+
+type EscapingScheme int
+
+const (
+	// NoEscaping indicates that a name will not be escaped. Unescaped names that
+	// do not conform to the legacy validity check will use a new exposition
+	// format syntax that will be officially standardized in future versions.
+	NoEscaping EscapingScheme = iota
+
+	// UnderscoreEscaping replaces all legacy-invalid characters with underscores.
+	UnderscoreEscaping
+
+	// DotsEscaping is similar to UnderscoreEscaping, except that dots are
+	// converted to `_dot_` and pre-existing underscores are converted to `__`.
+	DotsEscaping
+
+	// ValueEncodingEscaping prepends the name with `U__` and replaces all invalid
+	// characters with the unicode value, surrounded by underscores. Single
+	// underscores are replaced with double underscores.
+	ValueEncodingEscaping
+)
+
+const (
+	// EscapingKey is the key in an Accept or Content-Type header that defines how
+	// metric and label names that do not conform to the legacy character
+	// requirements should be escaped when being scraped by a legacy prometheus
+	// system. If a system does not explicitly pass an escaping parameter in the
+	// Accept header, the default NameEscapingScheme will be used.
+	EscapingKey = "escaping"
+
+	// Possible values for Escaping Key:
+	AllowUTF8         = "allow-utf-8" // No escaping required.
+	EscapeUnderscores = "underscores"
+	EscapeDots        = "dots"
+	EscapeValues      = "values"
+)
+
+// MetricNameRE is a regular expression matching valid metric
+// names. Note that the IsValidMetricName function performs the same
+// check but faster than a match with this regular expression.
+var MetricNameRE = regexp.MustCompile(`^[a-zA-Z_:][a-zA-Z0-9_:]*$`)
+
 // 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 LabelSet
@@ -86,17 +155,302 @@ func (m Metric) FastFingerprint() Fingerprint {
 	return LabelSet(m).FastFingerprint()
 }
 
-// IsValidMetricName returns true iff name matches the pattern of MetricNameRE.
+// IsValidMetricName returns true iff name matches the pattern of MetricNameRE
+// for legacy names, and iff it's valid UTF-8 if the UTF8Validation scheme is
+// selected.
+func IsValidMetricName(n LabelValue) bool {
+	switch NameValidationScheme {
+	case LegacyValidation:
+		return IsValidLegacyMetricName(n)
+	case UTF8Validation:
+		if len(n) == 0 {
+			return false
+		}
+		return utf8.ValidString(string(n))
+	default:
+		panic(fmt.Sprintf("Invalid name validation scheme requested: %d", NameValidationScheme))
+	}
+}
+
+// IsValidLegacyMetricName is similar to IsValidMetricName but always uses the
+// legacy validation scheme regardless of the value of NameValidationScheme.
 // This function, however, does not use MetricNameRE for the check but a much
 // faster hardcoded implementation.
-func IsValidMetricName(n LabelValue) bool {
+func IsValidLegacyMetricName(n LabelValue) bool {
 	if len(n) == 0 {
 		return false
 	}
 	for i, b := range n {
-		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == ':' || (b >= '0' && b <= '9' && i > 0)) {
+		if !isValidLegacyRune(b, i) {
 			return false
 		}
 	}
 	return true
 }
+
+// EscapeMetricFamily escapes the given metric names and labels with the given
+// escaping scheme. Returns a new object that uses the same pointers to fields
+// when possible and creates new escaped versions so as not to mutate the
+// input.
+func EscapeMetricFamily(v *dto.MetricFamily, scheme EscapingScheme) *dto.MetricFamily {
+	if v == nil {
+		return nil
+	}
+
+	if scheme == NoEscaping {
+		return v
+	}
+
+	out := &dto.MetricFamily{
+		Help: v.Help,
+		Type: v.Type,
+	}
+
+	// If the name is nil, copy as-is, don't try to escape.
+	if v.Name == nil || IsValidLegacyMetricName(LabelValue(v.GetName())) {
+		out.Name = v.Name
+	} else {
+		out.Name = proto.String(EscapeName(v.GetName(), scheme))
+	}
+	for _, m := range v.Metric {
+		if !metricNeedsEscaping(m) {
+			out.Metric = append(out.Metric, m)
+			continue
+		}
+
+		escaped := &dto.Metric{
+			Gauge:       m.Gauge,
+			Counter:     m.Counter,
+			Summary:     m.Summary,
+			Untyped:     m.Untyped,
+			Histogram:   m.Histogram,
+			TimestampMs: m.TimestampMs,
+		}
+
+		for _, l := range m.Label {
+			if l.GetName() == MetricNameLabel {
+				if l.Value == nil || IsValidLegacyMetricName(LabelValue(l.GetValue())) {
+					escaped.Label = append(escaped.Label, l)
+					continue
+				}
+				escaped.Label = append(escaped.Label, &dto.LabelPair{
+					Name:  proto.String(MetricNameLabel),
+					Value: proto.String(EscapeName(l.GetValue(), scheme)),
+				})
+				continue
+			}
+			if l.Name == nil || IsValidLegacyMetricName(LabelValue(l.GetName())) {
+				escaped.Label = append(escaped.Label, l)
+				continue
+			}
+			escaped.Label = append(escaped.Label, &dto.LabelPair{
+				Name:  proto.String(EscapeName(l.GetName(), scheme)),
+				Value: l.Value,
+			})
+		}
+		out.Metric = append(out.Metric, escaped)
+	}
+	return out
+}
+
+func metricNeedsEscaping(m *dto.Metric) bool {
+	for _, l := range m.Label {
+		if l.GetName() == MetricNameLabel && !IsValidLegacyMetricName(LabelValue(l.GetValue())) {
+			return true
+		}
+		if !IsValidLegacyMetricName(LabelValue(l.GetName())) {
+			return true
+		}
+	}
+	return false
+}
+
+const (
+	lowerhex = "0123456789abcdef"
+)
+
+// EscapeName escapes the incoming name according to the provided escaping
+// scheme. Depending on the rules of escaping, this may cause no change in the
+// string that is returned. (Especially NoEscaping, which by definition is a
+// noop). This function does not do any validation of the name.
+func EscapeName(name string, scheme EscapingScheme) string {
+	if len(name) == 0 {
+		return name
+	}
+	var escaped strings.Builder
+	switch scheme {
+	case NoEscaping:
+		return name
+	case UnderscoreEscaping:
+		if IsValidLegacyMetricName(LabelValue(name)) {
+			return name
+		}
+		for i, b := range name {
+			if isValidLegacyRune(b, i) {
+				escaped.WriteRune(b)
+			} else {
+				escaped.WriteRune('_')
+			}
+		}
+		return escaped.String()
+	case DotsEscaping:
+		// Do not early return for legacy valid names, we still escape underscores.
+		for i, b := range name {
+			if b == '_' {
+				escaped.WriteString("__")
+			} else if b == '.' {
+				escaped.WriteString("_dot_")
+			} else if isValidLegacyRune(b, i) {
+				escaped.WriteRune(b)
+			} else {
+				escaped.WriteRune('_')
+			}
+		}
+		return escaped.String()
+	case ValueEncodingEscaping:
+		if IsValidLegacyMetricName(LabelValue(name)) {
+			return name
+		}
+		escaped.WriteString("U__")
+		for i, b := range name {
+			if isValidLegacyRune(b, i) {
+				escaped.WriteRune(b)
+			} else if !utf8.ValidRune(b) {
+				escaped.WriteString("_FFFD_")
+			} else if b < 0x100 {
+				escaped.WriteRune('_')
+				for s := 4; s >= 0; s -= 4 {
+					escaped.WriteByte(lowerhex[b>>uint(s)&0xF])
+				}
+				escaped.WriteRune('_')
+			} else if b < 0x10000 {
+				escaped.WriteRune('_')
+				for s := 12; s >= 0; s -= 4 {
+					escaped.WriteByte(lowerhex[b>>uint(s)&0xF])
+				}
+				escaped.WriteRune('_')
+			}
+		}
+		return escaped.String()
+	default:
+		panic(fmt.Sprintf("invalid escaping scheme %d", scheme))
+	}
+}
+
+// lower function taken from strconv.atoi
+func lower(c byte) byte {
+	return c | ('x' - 'X')
+}
+
+// UnescapeName unescapes the incoming name according to the provided escaping
+// scheme if possible. Some schemes are partially or totally non-roundtripable.
+// If any error is enountered, returns the original input.
+func UnescapeName(name string, scheme EscapingScheme) string {
+	if len(name) == 0 {
+		return name
+	}
+	switch scheme {
+	case NoEscaping:
+		return name
+	case UnderscoreEscaping:
+		// It is not possible to unescape from underscore replacement.
+		return name
+	case DotsEscaping:
+		name = strings.ReplaceAll(name, "_dot_", ".")
+		name = strings.ReplaceAll(name, "__", "_")
+		return name
+	case ValueEncodingEscaping:
+		escapedName, found := strings.CutPrefix(name, "U__")
+		if !found {
+			return name
+		}
+
+		var unescaped strings.Builder
+	TOP:
+		for i := 0; i < len(escapedName); i++ {
+			// All non-underscores are treated normally.
+			if escapedName[i] != '_' {
+				unescaped.WriteByte(escapedName[i])
+				continue
+			}
+			i++
+			if i >= len(escapedName) {
+				return name
+			}
+			// A double underscore is a single underscore.
+			if escapedName[i] == '_' {
+				unescaped.WriteByte('_')
+				continue
+			}
+			// We think we are in a UTF-8 code, process it.
+			var utf8Val uint
+			for j := 0; i < len(escapedName); j++ {
+				// This is too many characters for a utf8 value.
+				if j > 4 {
+					return name
+				}
+				// Found a closing underscore, convert to a rune, check validity, and append.
+				if escapedName[i] == '_' {
+					utf8Rune := rune(utf8Val)
+					if !utf8.ValidRune(utf8Rune) {
+						return name
+					}
+					unescaped.WriteRune(utf8Rune)
+					continue TOP
+				}
+				r := lower(escapedName[i])
+				utf8Val *= 16
+				if r >= '0' && r <= '9' {
+					utf8Val += uint(r) - '0'
+				} else if r >= 'a' && r <= 'f' {
+					utf8Val += uint(r) - 'a' + 10
+				} else {
+					return name
+				}
+				i++
+			}
+			// Didn't find closing underscore, invalid.
+			return name
+		}
+		return unescaped.String()
+	default:
+		panic(fmt.Sprintf("invalid escaping scheme %d", scheme))
+	}
+}
+
+func isValidLegacyRune(b rune, i int) bool {
+	return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == ':' || (b >= '0' && b <= '9' && i > 0)
+}
+
+func (e EscapingScheme) String() string {
+	switch e {
+	case NoEscaping:
+		return AllowUTF8
+	case UnderscoreEscaping:
+		return EscapeUnderscores
+	case DotsEscaping:
+		return EscapeDots
+	case ValueEncodingEscaping:
+		return EscapeValues
+	default:
+		panic(fmt.Sprintf("unknown format scheme %d", e))
+	}
+}
+
+func ToEscapingScheme(s string) (EscapingScheme, error) {
+	if s == "" {
+		return NoEscaping, fmt.Errorf("got empty string instead of escaping scheme")
+	}
+	switch s {
+	case AllowUTF8:
+		return NoEscaping, nil
+	case EscapeUnderscores:
+		return UnderscoreEscaping, nil
+	case EscapeDots:
+		return DotsEscaping, nil
+	case EscapeValues:
+		return ValueEncodingEscaping, nil
+	default:
+		return NoEscaping, fmt.Errorf("unknown format scheme " + s)
+	}
+}

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

@@ -22,10 +22,8 @@ import (
 // when calculating their combined hash value (aka signature aka fingerprint).
 const SeparatorByte byte = 255
 
-var (
-	// cache the signature of an empty label set.
-	emptyLabelSignature = hashNew()
-)
+// cache the signature of an empty label set.
+var emptyLabelSignature = hashNew()
 
 // LabelsToSignature returns a quasi-unique signature (i.e., fingerprint) for a
 // given label set. (Collisions are possible but unlikely if the number of label

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

@@ -81,7 +81,7 @@ func (s *Silence) Validate() error {
 	}
 	for _, m := range s.Matchers {
 		if err := m.Validate(); err != nil {
-			return fmt.Errorf("invalid matcher: %s", err)
+			return fmt.Errorf("invalid matcher: %w", err)
 		}
 	}
 	if s.StartsAt.IsZero() {

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

@@ -16,104 +16,26 @@ 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.
+var ZeroSample = Sample{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 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 +51,19 @@ 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 +72,19 @@ 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 +95,25 @@ 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 +121,13 @@ 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 +173,76 @@ 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.
@@ -324,7 +272,7 @@ func (s *Scalar) UnmarshalJSON(b []byte) error {
 
 	value, err := strconv.ParseFloat(f, 64)
 	if err != nil {
-		return fmt.Errorf("error parsing sample value: %s", err)
+		return fmt.Errorf("error parsing sample value: %w", err)
 	}
 	s.Value = SampleValue(value)
 	return nil

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

@@ -0,0 +1,98 @@
+// 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"
+)
+
+// 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.
+var 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")
+}