Modernize invertergui: MQTT write support, HA integration, UI updates

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

@@ -45,7 +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"
@@ -53,36 +53,51 @@ 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.
+// NewDecoder returns a new decoder based on the given input format. Metric
+// names are validated based on the provided Format -- if the format requires
+// escaping, raditional Prometheues validity checking is used. Otherwise, names
+// are checked for UTF-8 validity. Supported formats include delimited protobuf
+// and Prometheus text format.  For historical reasons, this decoder fallbacks
+// to classic text decoding for any other format. This decoder does not fully
+// support OpenMetrics although it may often succeed due to the similarities
+// between the formats. This decoder may not support the latest features of
+// Prometheus text format and is not intended for high-performance applications.
+// See: https://github.com/prometheus/common/issues/812
 func NewDecoder(r io.Reader, format Format) Decoder {
+	scheme := model.LegacyValidation
+	if format.ToEscapingScheme() == model.NoEscaping {
+		scheme = model.UTF8Validation
+	}
 	switch format.FormatType() {
 	case TypeProtoDelim:
-		return &protoDecoder{r: r}
+		return &protoDecoder{r: bufio.NewReader(r), s: scheme}
+	case TypeProtoText, TypeProtoCompact:
+		return &errDecoder{err: fmt.Errorf("format %s not supported for decoding", format)}
 	}
-	return &textDecoder{r: r}
+	return &textDecoder{r: r, s: scheme}
 }
 
 // protoDecoder implements the Decoder interface for protocol buffers.
 type protoDecoder struct {
-	r io.Reader
+	r protodelim.Reader
+	s model.ValidationScheme
 }
 
 // Decode implements the Decoder interface.
@@ -90,10 +105,10 @@ func (d *protoDecoder) Decode(v *dto.MetricFamily) error {
 	opts := protodelim.UnmarshalOptions{
 		MaxSize: -1,
 	}
-	if err := opts.UnmarshalFrom(bufio.NewReader(d.r), v); err != nil {
+	if err := opts.UnmarshalFrom(d.r, v); err != nil {
 		return err
 	}
-	if !model.IsValidMetricName(model.LabelValue(v.GetName())) {
+	if !d.s.IsValidMetricName(v.GetName()) {
 		return fmt.Errorf("invalid metric name %q", v.GetName())
 	}
 	for _, m := range v.GetMetric() {
@@ -107,7 +122,7 @@ func (d *protoDecoder) Decode(v *dto.MetricFamily) error {
 			if !model.LabelValue(l.GetValue()).IsValid() {
 				return fmt.Errorf("invalid label value %q", l.GetValue())
 			}
-			if !model.LabelName(l.GetName()).IsValid() {
+			if !d.s.IsValidLabelName(l.GetName()) {
 				return fmt.Errorf("invalid label name %q", l.GetName())
 			}
 		}
@@ -115,10 +130,20 @@ func (d *protoDecoder) Decode(v *dto.MetricFamily) error {
 	return nil
 }
 
+// errDecoder is an error-state decoder that always returns the same error.
+type errDecoder struct {
+	err error
+}
+
+func (d *errDecoder) Decode(*dto.MetricFamily) error {
+	return d.err
+}
+
 // textDecoder implements the Decoder interface for the text protocol.
 type textDecoder struct {
 	r    io.Reader
 	fams map[string]*dto.MetricFamily
+	s    model.ValidationScheme
 	err  error
 }
 
@@ -126,7 +151,7 @@ type textDecoder struct {
 func (d *textDecoder) Decode(v *dto.MetricFamily) error {
 	if d.err == nil {
 		// Read all metrics in one shot.
-		var p TextParser
+		p := NewTextParser(d.s)
 		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 {
@@ -195,7 +220,7 @@ func extractSamples(f *dto.MetricFamily, o *DecodeOptions) (model.Vector, error)
 		return extractSummary(o, f), nil
 	case dto.MetricType_UNTYPED:
 		return extractUntyped(o, f), nil
-	case dto.MetricType_HISTOGRAM:
+	case dto.MetricType_HISTOGRAM, dto.MetricType_GAUGE_HISTOGRAM:
 		return extractHistogram(o, f), nil
 	}
 	return nil, fmt.Errorf("expfmt.extractSamples: unknown metric family type %v", f.GetType())
@@ -378,9 +403,13 @@ func extractHistogram(o *DecodeOptions, f *dto.MetricFamily) model.Vector {
 				infSeen = true
 			}
 
+			v := q.GetCumulativeCountFloat()
+			if v <= 0 {
+				v = float64(q.GetCumulativeCount())
+			}
 			samples = append(samples, &model.Sample{
 				Metric:    model.Metric(lset),
-				Value:     model.SampleValue(q.GetCumulativeCount()),
+				Value:     model.SampleValue(v),
 				Timestamp: timestamp,
 			})
 		}
@@ -403,9 +432,13 @@ func extractHistogram(o *DecodeOptions, f *dto.MetricFamily) model.Vector {
 		}
 		lset[model.MetricNameLabel] = model.LabelValue(f.GetName() + "_count")
 
+		v := m.Histogram.GetSampleCountFloat()
+		if v <= 0 {
+			v = float64(m.Histogram.GetSampleCount())
+		}
 		count := &model.Sample{
 			Metric:    model.Metric(lset),
-			Value:     model.SampleValue(m.Histogram.GetSampleCount()),
+			Value:     model.SampleValue(v),
 			Timestamp: timestamp,
 		}
 		samples = append(samples, count)

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

@@ -18,13 +18,12 @@ import (
 	"io"
 	"net/http"
 
+	"github.com/munnerz/goautoneg"
+	dto "github.com/prometheus/client_model/go"
 	"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"
 )
 
 // Encoder types encode metric families into an underlying wire protocol.
@@ -60,14 +59,14 @@ func (ec encoderCloser) Close() error {
 // appropriate accepted type is found, FmtText is returned (which is the
 // Prometheus text format). This function will never negotiate FmtOpenMetrics,
 // as the support is still experimental. To include the option to negotiate
-// FmtOpenMetrics, use NegotiateOpenMetrics.
+// FmtOpenMetrics, use NegotiateIncludingOpenMetrics.
 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))
+				escapingScheme = Format("; escaping=" + escapeParam)
 			default:
 				// If the escaping parameter is unknown, ignore it.
 			}
@@ -76,18 +75,18 @@ func Negotiate(h http.Header) Format {
 		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
 			switch ac.Params["encoding"] {
 			case "delimited":
-				return fmtProtoDelim + escapingScheme
+				return FmtProtoDelim + escapingScheme
 			case "text":
-				return fmtProtoText + escapingScheme
+				return FmtProtoText + escapingScheme
 			case "compact-text":
-				return fmtProtoCompact + escapingScheme
+				return FmtProtoCompact + escapingScheme
 			}
 		}
 		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
-			return fmtText + escapingScheme
+			return FmtText + escapingScheme
 		}
 	}
-	return fmtText + escapingScheme
+	return FmtText + escapingScheme
 }
 
 // NegotiateIncludingOpenMetrics works like Negotiate but includes
@@ -100,7 +99,7 @@ func NegotiateIncludingOpenMetrics(h http.Header) Format {
 		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))
+				escapingScheme = Format("; escaping=" + escapeParam)
 			default:
 				// If the escaping parameter is unknown, ignore it.
 			}
@@ -109,26 +108,26 @@ func NegotiateIncludingOpenMetrics(h http.Header) Format {
 		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
 			switch ac.Params["encoding"] {
 			case "delimited":
-				return fmtProtoDelim + escapingScheme
+				return FmtProtoDelim + escapingScheme
 			case "text":
-				return fmtProtoText + escapingScheme
+				return FmtProtoText + escapingScheme
 			case "compact-text":
-				return fmtProtoCompact + escapingScheme
+				return FmtProtoCompact + escapingScheme
 			}
 		}
 		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
-			return fmtText + escapingScheme
+			return FmtText + escapingScheme
 		}
 		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
+				return FmtOpenMetrics_1_0_0 + escapingScheme
 			default:
-				return fmtOpenMetrics_0_0_1 + escapingScheme
+				return FmtOpenMetrics_0_0_1 + escapingScheme
 			}
 		}
 	}
-	return fmtText + escapingScheme
+	return FmtText + escapingScheme
 }
 
 // NewEncoder returns a new encoder based on content type negotiation. All
@@ -152,7 +151,7 @@ func NewEncoder(w io.Writer, format Format, options ...EncoderOption) Encoder {
 	case TypeProtoDelim:
 		return encoderCloser{
 			encode: func(v *dto.MetricFamily) error {
-				_, err := protodelim.MarshalTo(w, v)
+				_, err := protodelim.MarshalTo(w, model.EscapeMetricFamily(v, escapingScheme))
 				return err
 			},
 			close: func() error { return nil },

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

@@ -15,6 +15,7 @@
 package expfmt
 
 import (
+	"errors"
 	"strings"
 
 	"github.com/prometheus/common/model"
@@ -31,24 +32,36 @@ type Format string
 // 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`
+	TextVersion   = "0.0.4"
+	ProtoType     = `application/vnd.google.protobuf`
+	ProtoProtocol = `io.prometheus.client.MetricFamily`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoCompact) instead.
+	ProtoFmt        = ProtoType + "; proto=" + ProtoProtocol + ";"
+	OpenMetricsType = `application/openmetrics-text`
+	//nolint:revive // Allow for underscores.
 	OpenMetricsVersion_0_0_1 = "0.0.1"
+	//nolint:revive // Allow for underscores.
 	OpenMetricsVersion_1_0_0 = "1.0.0"
 
-	// 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`
+	// The Content-Type values for the different wire protocols. Do not do direct
+	// comparisons to these constants, instead use the comparison functions.
+	//
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeUnknown) instead.
+	FmtUnknown Format = `<unknown>`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeTextPlain) instead.
+	FmtText Format = `text/plain; version=` + TextVersion + `; charset=utf-8`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoDelim) instead.
+	FmtProtoDelim Format = ProtoFmt + ` encoding=delimited`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoText) instead.
+	FmtProtoText Format = ProtoFmt + ` encoding=text`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoCompact) instead.
+	FmtProtoCompact Format = ProtoFmt + ` encoding=compact-text`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeOpenMetrics) instead.
+	//nolint:revive // Allow for underscores.
+	FmtOpenMetrics_1_0_0 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_1_0_0 + `; charset=utf-8`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeOpenMetrics) instead.
+	//nolint:revive // Allow for underscores.
+	FmtOpenMetrics_0_0_1 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_0_0_1 + `; charset=utf-8`
 )
 
 const (
@@ -63,7 +76,7 @@ const (
 type FormatType int
 
 const (
-	TypeUnknown = iota
+	TypeUnknown FormatType = iota
 	TypeProtoCompact
 	TypeProtoDelim
 	TypeProtoText
@@ -73,31 +86,63 @@ const (
 
 // 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.
+// encode.go. If a type has more than one version, the latest version will be
+// returned.
 func NewFormat(t FormatType) Format {
 	switch t {
 	case TypeProtoCompact:
-		return fmtProtoCompact
+		return FmtProtoCompact
 	case TypeProtoDelim:
-		return fmtProtoDelim
+		return FmtProtoDelim
 	case TypeProtoText:
-		return fmtProtoText
+		return FmtProtoText
 	case TypeTextPlain:
-		return fmtText
+		return FmtText
 	case TypeOpenMetrics:
-		return fmtOpenMetrics_1_0_0
+		return FmtOpenMetrics_1_0_0
 	default:
-		return fmtUnknown
+		return FmtUnknown
 	}
 }
 
+// NewOpenMetricsFormat generates a new OpenMetrics format matching the
+// specified version number.
+func NewOpenMetricsFormat(version string) (Format, error) {
+	if version == OpenMetricsVersion_0_0_1 {
+		return FmtOpenMetrics_0_0_1, nil
+	}
+	if version == OpenMetricsVersion_1_0_0 {
+		return FmtOpenMetrics_1_0_0, nil
+	}
+	return FmtUnknown, errors.New("unknown open metrics version string")
+}
+
+// WithEscapingScheme returns a copy of Format with the specified escaping
+// scheme appended to the end. If an escaping scheme already exists it is
+// removed.
+func (f Format) WithEscapingScheme(s model.EscapingScheme) Format {
+	var terms []string
+	for _, p := range strings.Split(string(f), ";") {
+		toks := strings.Split(p, "=")
+		if len(toks) != 2 {
+			trimmed := strings.TrimSpace(p)
+			if len(trimmed) > 0 {
+				terms = append(terms, trimmed)
+			}
+			continue
+		}
+		key := strings.TrimSpace(toks[0])
+		if key != model.EscapingKey {
+			terms = append(terms, strings.TrimSpace(p))
+		}
+	}
+	terms = append(terms, model.EscapingKey+"="+s.String())
+	return Format(strings.Join(terms, "; "))
+}
+
 // 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 {
@@ -148,8 +193,8 @@ func (f Format) FormatType() FormatType {
 // 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), ";") {
+func (f Format) ToEscapingScheme() model.EscapingScheme {
+	for _, p := range strings.Split(string(f), ";") {
 		toks := strings.Split(p, "=")
 		if len(toks) != 2 {
 			continue

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

@@ -13,11 +13,14 @@
 
 // Build only when actually fuzzing
 //go:build gofuzz
-// +build gofuzz
 
 package expfmt
 
-import "bytes"
+import (
+	"bytes"
+
+	"github.com/prometheus/common/model"
+)
 
 // Fuzz text metric parser with with github.com/dvyukov/go-fuzz:
 //
@@ -26,9 +29,8 @@ import "bytes"
 //
 // Further input samples should go in the folder fuzz/corpus.
 func Fuzz(in []byte) int {
-	parser := TextParser{}
+	parser := NewTextParser(model.UTF8Validation)
 	_, err := parser.TextToMetricFamilies(bytes.NewReader(in))
-
 	if err != nil {
 		return 0
 	}

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

@@ -22,11 +22,10 @@ import (
 	"strconv"
 	"strings"
 
+	dto "github.com/prometheus/client_model/go"
 	"google.golang.org/protobuf/types/known/timestamppb"
 
 	"github.com/prometheus/common/model"
-
-	dto "github.com/prometheus/client_model/go"
 )
 
 type encoderOption struct {
@@ -38,7 +37,7 @@ type EncoderOption func(*encoderOption)
 
 // WithCreatedLines is an EncoderOption that configures the OpenMetrics encoder
 // to include _created lines (See
-// https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#counter-1).
+// https://github.com/prometheus/OpenMetrics/blob/v1.0.0/specification/OpenMetrics.md#counter-1).
 // Created timestamps can improve the accuracy of series reset detection, but
 // come with a bandwidth cost.
 //
@@ -102,7 +101,7 @@ func WithUnit() EncoderOption {
 //
 //   - According to the OM specs, the `# UNIT` line is optional, but if populated,
 //     the unit has to be present in the metric name as its suffix:
-//     (see https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#unit).
+//     (see https://github.com/prometheus/OpenMetrics/blob/v1.0.0/specification/OpenMetrics.md#unit).
 //     However, in order to accommodate any potential scenario where such a change in the
 //     metric name is not desirable, the users are here given the choice of either explicitly
 //     opt in, in case they wish for the unit to be included in the output AND in the metric name
@@ -152,8 +151,8 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 	if metricType == dto.MetricType_COUNTER && strings.HasSuffix(compliantName, "_total") {
 		compliantName = name[:len(name)-6]
 	}
-	if toOM.withUnit && in.Unit != nil && !strings.HasSuffix(compliantName, fmt.Sprintf("_%s", *in.Unit)) {
-		compliantName = compliantName + fmt.Sprintf("_%s", *in.Unit)
+	if toOM.withUnit && in.Unit != nil && !strings.HasSuffix(compliantName, "_"+*in.Unit) {
+		compliantName = compliantName + "_" + *in.Unit
 	}
 
 	// Comments, first HELP, then TYPE.
@@ -161,38 +160,38 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 		n, err = w.WriteString("# HELP ")
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 		n, err = writeName(w, compliantName)
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 		err = w.WriteByte(' ')
 		written++
 		if err != nil {
-			return
+			return written, err
 		}
 		n, err = writeEscapedString(w, *in.Help, true)
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 		err = w.WriteByte('\n')
 		written++
 		if err != nil {
-			return
+			return written, err
 		}
 	}
 	n, err = w.WriteString("# TYPE ")
 	written += n
 	if err != nil {
-		return
+		return written, err
 	}
 	n, err = writeName(w, compliantName)
 	written += n
 	if err != nil {
-		return
+		return written, err
 	}
 	switch metricType {
 	case dto.MetricType_COUNTER:
@@ -209,51 +208,53 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 		n, err = w.WriteString(" unknown\n")
 	case dto.MetricType_HISTOGRAM:
 		n, err = w.WriteString(" histogram\n")
+	case dto.MetricType_GAUGE_HISTOGRAM:
+		n, err = w.WriteString(" gaugehistogram\n")
 	default:
 		return written, fmt.Errorf("unknown metric type %s", metricType.String())
 	}
 	written += n
 	if err != nil {
-		return
+		return written, err
 	}
 	if toOM.withUnit && in.Unit != nil {
 		n, err = w.WriteString("# UNIT ")
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 		n, err = writeName(w, compliantName)
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 
 		err = w.WriteByte(' ')
 		written++
 		if err != nil {
-			return
+			return written, err
 		}
 		n, err = writeEscapedString(w, *in.Unit, true)
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 		err = w.WriteByte('\n')
 		written++
 		if err != nil {
-			return
+			return written, err
 		}
 	}
 
 	var createdTsBytesWritten int
 
 	// Finally the samples, one line for each.
+	if metricType == dto.MetricType_COUNTER && strings.HasSuffix(name, "_total") {
+		compliantName += "_total"
+	}
 	for _, metric := range in.Metric {
 		switch metricType {
 		case dto.MetricType_COUNTER:
-			if strings.HasSuffix(name, "_total") {
-				compliantName = compliantName + "_total"
-			}
 			if metric.Counter == nil {
 				return written, fmt.Errorf(
 					"expected counter in metric %s %s", compliantName, metric,
@@ -305,7 +306,7 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 				)
 				written += n
 				if err != nil {
-					return
+					return written, err
 				}
 			}
 			n, err = writeOpenMetricsSample(
@@ -315,7 +316,7 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 			)
 			written += n
 			if err != nil {
-				return
+				return written, err
 			}
 			n, err = writeOpenMetricsSample(
 				w, compliantName, "_count", metric, "", 0,
@@ -326,7 +327,7 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 				createdTsBytesWritten, err = writeOpenMetricsCreated(w, compliantName, "", metric, "", 0, metric.Summary.GetCreatedTimestamp())
 				n += createdTsBytesWritten
 			}
-		case dto.MetricType_HISTOGRAM:
+		case dto.MetricType_HISTOGRAM, dto.MetricType_GAUGE_HISTOGRAM:
 			if metric.Histogram == nil {
 				return written, fmt.Errorf(
 					"expected histogram in metric %s %s", compliantName, metric,
@@ -334,6 +335,12 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 			}
 			infSeen := false
 			for _, b := range metric.Histogram.Bucket {
+				if b.GetCumulativeCountFloat() > 0 {
+					return written, fmt.Errorf(
+						"OpenMetrics v1.0 does not support float histogram %s %s",
+						compliantName, metric,
+					)
+				}
 				n, err = writeOpenMetricsSample(
 					w, compliantName, "_bucket", metric,
 					model.BucketLabel, b.GetUpperBound(),
@@ -342,7 +349,7 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 				)
 				written += n
 				if err != nil {
-					return
+					return written, err
 				}
 				if math.IsInf(b.GetUpperBound(), +1) {
 					infSeen = true
@@ -355,9 +362,12 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 					0, metric.Histogram.GetSampleCount(), true,
 					nil,
 				)
+				// We do not check for a float sample count here
+				// because we will check for it below (and error
+				// out if needed).
 				written += n
 				if err != nil {
-					return
+					return written, err
 				}
 			}
 			n, err = writeOpenMetricsSample(
@@ -367,7 +377,13 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 			)
 			written += n
 			if err != nil {
-				return
+				return written, err
+			}
+			if metric.Histogram.GetSampleCountFloat() > 0 {
+				return written, fmt.Errorf(
+					"OpenMetrics v1.0 does not support float histogram %s %s",
+					compliantName, metric,
+				)
 			}
 			n, err = writeOpenMetricsSample(
 				w, compliantName, "_count", metric, "", 0,
@@ -385,10 +401,10 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 		}
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 	}
-	return
+	return written, err
 }
 
 // FinalizeOpenMetrics writes the final `# EOF\n` line required by OpenMetrics.
@@ -477,7 +493,7 @@ func writeOpenMetricsNameAndLabelPairs(
 	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)) {
+		if !model.LegacyValidation.IsValidMetricName(name) {
 			metricInsideBraces = true
 			err := w.WriteByte(separator)
 			written++
@@ -641,11 +657,11 @@ func writeExemplar(w enhancedWriter, e *dto.Exemplar) (int, error) {
 		if err != nil {
 			return written, err
 		}
-		err = (*e).Timestamp.CheckValid()
+		err = e.Timestamp.CheckValid()
 		if err != nil {
 			return written, err
 		}
-		ts := (*e).Timestamp.AsTime()
+		ts := e.Timestamp.AsTime()
 		// TODO(beorn7): Format this directly from components of ts to
 		// avoid overflow/underflow and precision issues of the float
 		// conversion.

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

@@ -22,9 +22,9 @@ import (
 	"strings"
 	"sync"
 
-	"github.com/prometheus/common/model"
-
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/common/model"
 )
 
 // enhancedWriter has all the enhanced write functions needed here. bufio.Writer
@@ -108,38 +108,38 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 		n, err = w.WriteString("# HELP ")
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 		n, err = writeName(w, name)
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 		err = w.WriteByte(' ')
 		written++
 		if err != nil {
-			return
+			return written, err
 		}
 		n, err = writeEscapedString(w, *in.Help, false)
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 		err = w.WriteByte('\n')
 		written++
 		if err != nil {
-			return
+			return written, err
 		}
 	}
 	n, err = w.WriteString("# TYPE ")
 	written += n
 	if err != nil {
-		return
+		return written, err
 	}
 	n, err = writeName(w, name)
 	written += n
 	if err != nil {
-		return
+		return written, err
 	}
 	metricType := in.GetType()
 	switch metricType {
@@ -151,14 +151,17 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 		n, err = w.WriteString(" summary\n")
 	case dto.MetricType_UNTYPED:
 		n, err = w.WriteString(" untyped\n")
-	case dto.MetricType_HISTOGRAM:
+	case dto.MetricType_HISTOGRAM, dto.MetricType_GAUGE_HISTOGRAM:
+		// The classic Prometheus text format has no notion of a gauge
+		// histogram. We render a gauge histogram in the same way as a
+		// regular histogram.
 		n, err = w.WriteString(" histogram\n")
 	default:
 		return written, fmt.Errorf("unknown metric type %s", metricType.String())
 	}
 	written += n
 	if err != nil {
-		return
+		return written, err
 	}
 
 	// Finally the samples, one line for each.
@@ -208,7 +211,7 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 				)
 				written += n
 				if err != nil {
-					return
+					return written, err
 				}
 			}
 			n, err = writeSample(
@@ -217,13 +220,13 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 			)
 			written += n
 			if err != nil {
-				return
+				return written, err
 			}
 			n, err = writeSample(
 				w, name, "_count", metric, "", 0,
 				float64(metric.Summary.GetSampleCount()),
 			)
-		case dto.MetricType_HISTOGRAM:
+		case dto.MetricType_HISTOGRAM, dto.MetricType_GAUGE_HISTOGRAM:
 			if metric.Histogram == nil {
 				return written, fmt.Errorf(
 					"expected histogram in metric %s %s", name, metric,
@@ -231,28 +234,36 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 			}
 			infSeen := false
 			for _, b := range metric.Histogram.Bucket {
+				v := b.GetCumulativeCountFloat()
+				if v == 0 {
+					v = float64(b.GetCumulativeCount())
+				}
 				n, err = writeSample(
 					w, name, "_bucket", metric,
 					model.BucketLabel, b.GetUpperBound(),
-					float64(b.GetCumulativeCount()),
+					v,
 				)
 				written += n
 				if err != nil {
-					return
+					return written, err
 				}
 				if math.IsInf(b.GetUpperBound(), +1) {
 					infSeen = true
 				}
 			}
 			if !infSeen {
+				v := metric.Histogram.GetSampleCountFloat()
+				if v == 0 {
+					v = float64(metric.Histogram.GetSampleCount())
+				}
 				n, err = writeSample(
 					w, name, "_bucket", metric,
 					model.BucketLabel, math.Inf(+1),
-					float64(metric.Histogram.GetSampleCount()),
+					v,
 				)
 				written += n
 				if err != nil {
-					return
+					return written, err
 				}
 			}
 			n, err = writeSample(
@@ -261,12 +272,13 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 			)
 			written += n
 			if err != nil {
-				return
+				return written, err
 			}
-			n, err = writeSample(
-				w, name, "_count", metric, "", 0,
-				float64(metric.Histogram.GetSampleCount()),
-			)
+			v := metric.Histogram.GetSampleCountFloat()
+			if v == 0 {
+				v = float64(metric.Histogram.GetSampleCount())
+			}
+			n, err = writeSample(w, name, "_count", metric, "", 0, v)
 		default:
 			return written, fmt.Errorf(
 				"unexpected type in metric %s %s", name, metric,
@@ -274,10 +286,10 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err e
 		}
 		written += n
 		if err != nil {
-			return
+			return written, err
 		}
 	}
-	return
+	return written, err
 }
 
 // writeSample writes a single sample in text format to w, given the metric
@@ -354,7 +366,7 @@ func writeNameAndLabelPairs(
 	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)) {
+		if !model.LegacyValidation.IsValidMetricName(name) {
 			metricInsideBraces = true
 			err := w.WriteByte(separator)
 			written++
@@ -498,7 +510,7 @@ func writeInt(w enhancedWriter, i int64) (int, error) {
 // 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)) {
+	if model.LegacyValidation.IsValidMetricName(name) {
 		return w.WriteString(name)
 	}
 	var written int

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

@@ -22,9 +22,9 @@ import (
 	"math"
 	"strconv"
 	"strings"
+	"unicode/utf8"
 
 	dto "github.com/prometheus/client_model/go"
-
 	"google.golang.org/protobuf/proto"
 
 	"github.com/prometheus/common/model"
@@ -48,8 +48,10 @@ func (e ParseError) Error() string {
 	return fmt.Sprintf("text format parsing error in line %d: %s", e.Line, e.Msg)
 }
 
-// TextParser is used to parse the simple and flat text-based exchange format. Its
-// zero value is ready to use.
+// TextParser is used to parse the simple and flat text-based exchange format.
+//
+// TextParser instances must be created with NewTextParser, the zero value of
+// TextParser is invalid.
 type TextParser struct {
 	metricFamiliesByName map[string]*dto.MetricFamily
 	buf                  *bufio.Reader // Where the parsed input is read through.
@@ -60,6 +62,7 @@ type TextParser struct {
 	currentMF            *dto.MetricFamily
 	currentMetric        *dto.Metric
 	currentLabelPair     *dto.LabelPair
+	currentLabelPairs    []*dto.LabelPair // Temporarily stores label pairs while parsing a metric line.
 
 	// The remaining member variables are only used for summaries/histograms.
 	currentLabels map[string]string // All labels including '__name__' but excluding 'quantile'/'le'
@@ -74,6 +77,17 @@ type TextParser struct {
 	// count and sum of that summary/histogram.
 	currentIsSummaryCount, currentIsSummarySum     bool
 	currentIsHistogramCount, currentIsHistogramSum bool
+	// These indicate if the metric name from the current line being parsed is inside
+	// braces and if that metric name was found respectively.
+	currentMetricIsInsideBraces, currentMetricInsideBracesIsPresent bool
+	// scheme sets the desired ValidationScheme for names. Defaults to the invalid
+	// UnsetValidation.
+	scheme model.ValidationScheme
+}
+
+// NewTextParser returns a new TextParser with the provided nameValidationScheme.
+func NewTextParser(nameValidationScheme model.ValidationScheme) TextParser {
+	return TextParser{scheme: nameValidationScheme}
 }
 
 // TextToMetricFamilies reads 'in' as the simple and flat text-based exchange
@@ -117,11 +131,47 @@ func (p *TextParser) TextToMetricFamilies(in io.Reader) (map[string]*dto.MetricF
 	if p.err != nil && errors.Is(p.err, io.EOF) {
 		p.parseError("unexpected end of input stream")
 	}
+	for _, histogramMetric := range p.histograms {
+		normalizeHistogram(histogramMetric.GetHistogram())
+	}
 	return p.metricFamiliesByName, p.err
 }
 
+// normalizeHistogram makes sure that all the buckets and the count in each
+// histogram is either completely float or completely integer.
+func normalizeHistogram(histogram *dto.Histogram) {
+	if histogram == nil {
+		return
+	}
+	anyFloats := false
+	if histogram.GetSampleCountFloat() != 0 {
+		anyFloats = true
+	} else {
+		for _, b := range histogram.GetBucket() {
+			if b.GetCumulativeCountFloat() != 0 {
+				anyFloats = true
+				break
+			}
+		}
+	}
+	if !anyFloats {
+		return
+	}
+	if histogram.GetSampleCountFloat() == 0 {
+		histogram.SampleCountFloat = proto.Float64(float64(histogram.GetSampleCount()))
+		histogram.SampleCount = nil
+	}
+	for _, b := range histogram.GetBucket() {
+		if b.GetCumulativeCountFloat() == 0 {
+			b.CumulativeCountFloat = proto.Float64(float64(b.GetCumulativeCount()))
+			b.CumulativeCount = nil
+		}
+	}
+}
+
 func (p *TextParser) reset(in io.Reader) {
 	p.metricFamiliesByName = map[string]*dto.MetricFamily{}
+	p.currentLabelPairs = nil
 	if p.buf == nil {
 		p.buf = bufio.NewReader(in)
 	} else {
@@ -137,12 +187,15 @@ func (p *TextParser) reset(in io.Reader) {
 	}
 	p.currentQuantile = math.NaN()
 	p.currentBucket = math.NaN()
+	p.currentMF = nil
 }
 
 // startOfLine represents the state where the next byte read from p.buf is the
 // start of a line (or whitespace leading up to it).
 func (p *TextParser) startOfLine() stateFn {
 	p.lineCount++
+	p.currentMetricIsInsideBraces = false
+	p.currentMetricInsideBracesIsPresent = false
 	if p.skipBlankTab(); 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.
@@ -158,6 +211,9 @@ func (p *TextParser) startOfLine() stateFn {
 		return p.startComment
 	case '\n':
 		return p.startOfLine // Empty line, start the next one.
+	case '{':
+		p.currentMetricIsInsideBraces = true
+		return p.readingLabels
 	}
 	return p.readingMetricName
 }
@@ -206,6 +262,9 @@ func (p *TextParser) startComment() stateFn {
 		return nil
 	}
 	p.setOrCreateCurrentMF()
+	if p.err != nil {
+		return nil
+	}
 	if p.skipBlankTab(); p.err != nil {
 		return nil // Unexpected end of input.
 	}
@@ -234,6 +293,9 @@ func (p *TextParser) readingMetricName() stateFn {
 		return nil
 	}
 	p.setOrCreateCurrentMF()
+	if p.err != nil {
+		return nil
+	}
 	// Now is the time to fix the type if it hasn't happened yet.
 	if p.currentMF.Type == nil {
 		p.currentMF.Type = dto.MetricType_UNTYPED.Enum()
@@ -256,7 +318,9 @@ func (p *TextParser) readingLabels() stateFn {
 	// Summaries/histograms are special. We have to reset the
 	// currentLabels map, currentQuantile and currentBucket before starting to
 	// read labels.
-	if p.currentMF.GetType() == dto.MetricType_SUMMARY || p.currentMF.GetType() == dto.MetricType_HISTOGRAM {
+	if p.currentMF.GetType() == dto.MetricType_SUMMARY ||
+		p.currentMF.GetType() == dto.MetricType_HISTOGRAM ||
+		p.currentMF.GetType() == dto.MetricType_GAUGE_HISTOGRAM {
 		p.currentLabels = map[string]string{}
 		p.currentLabels[string(model.MetricNameLabel)] = p.currentMF.GetName()
 		p.currentQuantile = math.NaN()
@@ -275,6 +339,8 @@ func (p *TextParser) startLabelName() stateFn {
 		return nil // Unexpected end of input.
 	}
 	if p.currentByte == '}' {
+		p.currentMetric.Label = append(p.currentMetric.Label, p.currentLabelPairs...)
+		p.currentLabelPairs = nil
 		if p.skipBlankTab(); p.err != nil {
 			return nil // Unexpected end of input.
 		}
@@ -287,34 +353,81 @@ func (p *TextParser) startLabelName() stateFn {
 		p.parseError(fmt.Sprintf("invalid label name for metric %q", p.currentMF.GetName()))
 		return nil
 	}
-	p.currentLabelPair = &dto.LabelPair{Name: proto.String(p.currentToken.String())}
-	if p.currentLabelPair.GetName() == string(model.MetricNameLabel) {
-		p.parseError(fmt.Sprintf("label name %q is reserved", model.MetricNameLabel))
-		return nil
-	}
-	// Special summary/histogram treatment. Don't add 'quantile' and 'le'
-	// labels to 'real' labels.
-	if !(p.currentMF.GetType() == dto.MetricType_SUMMARY && p.currentLabelPair.GetName() == model.QuantileLabel) &&
-		!(p.currentMF.GetType() == dto.MetricType_HISTOGRAM && p.currentLabelPair.GetName() == model.BucketLabel) {
-		p.currentMetric.Label = append(p.currentMetric.Label, p.currentLabelPair)
-	}
 	if p.skipBlankTabIfCurrentBlankTab(); p.err != nil {
 		return nil // Unexpected end of input.
 	}
 	if p.currentByte != '=' {
+		if p.currentMetricIsInsideBraces {
+			if p.currentMetricInsideBracesIsPresent {
+				p.parseError(fmt.Sprintf("multiple metric names for metric %q", p.currentMF.GetName()))
+				return nil
+			}
+			switch p.currentByte {
+			case ',':
+				p.setOrCreateCurrentMF()
+				if p.err != nil {
+					return nil
+				}
+				if p.currentMF.Type == nil {
+					p.currentMF.Type = dto.MetricType_UNTYPED.Enum()
+				}
+				p.currentMetric = &dto.Metric{}
+				p.currentMetricInsideBracesIsPresent = true
+				return p.startLabelName
+			case '}':
+				p.setOrCreateCurrentMF()
+				if p.err != nil {
+					p.currentLabelPairs = nil
+					return nil
+				}
+				if p.currentMF.Type == nil {
+					p.currentMF.Type = dto.MetricType_UNTYPED.Enum()
+				}
+				p.currentMetric = &dto.Metric{}
+				p.currentMetric.Label = append(p.currentMetric.Label, p.currentLabelPairs...)
+				p.currentLabelPairs = nil
+				if p.skipBlankTab(); p.err != nil {
+					return nil // Unexpected end of input.
+				}
+				return p.readingValue
+			default:
+				p.parseError(fmt.Sprintf("unexpected end of metric name %q", p.currentByte))
+				return nil
+			}
+		}
 		p.parseError(fmt.Sprintf("expected '=' after label name, found %q", p.currentByte))
+		p.currentLabelPairs = nil
 		return nil
 	}
+	p.currentLabelPair = &dto.LabelPair{Name: proto.String(p.currentToken.String())}
+	if p.currentLabelPair.GetName() == string(model.MetricNameLabel) {
+		p.parseError(fmt.Sprintf("label name %q is reserved", model.MetricNameLabel))
+		p.currentLabelPairs = nil
+		return nil
+	}
+	if !p.scheme.IsValidLabelName(p.currentLabelPair.GetName()) {
+		p.parseError(fmt.Sprintf("invalid label name %q", p.currentLabelPair.GetName()))
+		p.currentLabelPairs = nil
+		return nil
+	}
+	// Special summary/histogram treatment. Don't add 'quantile' and 'le'
+	// labels to 'real' labels.
+	if (p.currentMF.GetType() != dto.MetricType_SUMMARY || p.currentLabelPair.GetName() != model.QuantileLabel) &&
+		((p.currentMF.GetType() != dto.MetricType_HISTOGRAM &&
+			p.currentMF.GetType() != dto.MetricType_GAUGE_HISTOGRAM) ||
+			p.currentLabelPair.GetName() != model.BucketLabel) {
+		p.currentLabelPairs = append(p.currentLabelPairs, p.currentLabelPair)
+	}
 	// Check for duplicate label names.
 	labels := make(map[string]struct{})
-	for _, l := range p.currentMetric.Label {
+	for _, l := range p.currentLabelPairs {
 		lName := l.GetName()
-		if _, exists := labels[lName]; !exists {
-			labels[lName] = struct{}{}
-		} else {
+		if _, exists := labels[lName]; exists {
 			p.parseError(fmt.Sprintf("duplicate label names for metric %q", p.currentMF.GetName()))
+			p.currentLabelPairs = nil
 			return nil
 		}
+		labels[lName] = struct{}{}
 	}
 	return p.startLabelValue
 }
@@ -345,6 +458,7 @@ func (p *TextParser) startLabelValue() stateFn {
 			if p.currentQuantile, p.err = parseFloat(p.currentLabelPair.GetValue()); p.err != nil {
 				// Create a more helpful error message.
 				p.parseError(fmt.Sprintf("expected float as value for 'quantile' label, got %q", p.currentLabelPair.GetValue()))
+				p.currentLabelPairs = nil
 				return nil
 			}
 		} else {
@@ -352,7 +466,7 @@ func (p *TextParser) startLabelValue() stateFn {
 		}
 	}
 	// Similar special treatment of histograms.
-	if p.currentMF.GetType() == dto.MetricType_HISTOGRAM {
+	if p.currentMF.GetType() == dto.MetricType_HISTOGRAM || p.currentMF.GetType() == dto.MetricType_GAUGE_HISTOGRAM {
 		if p.currentLabelPair.GetName() == model.BucketLabel {
 			if p.currentBucket, p.err = parseFloat(p.currentLabelPair.GetValue()); p.err != nil {
 				// Create a more helpful error message.
@@ -371,12 +485,19 @@ func (p *TextParser) startLabelValue() stateFn {
 		return p.startLabelName
 
 	case '}':
+		if p.currentMF == nil {
+			p.parseError("invalid metric name")
+			return nil
+		}
+		p.currentMetric.Label = append(p.currentMetric.Label, p.currentLabelPairs...)
+		p.currentLabelPairs = nil
 		if p.skipBlankTab(); p.err != nil {
 			return nil // Unexpected end of input.
 		}
 		return p.readingValue
 	default:
 		p.parseError(fmt.Sprintf("unexpected end of label value %q", p.currentLabelPair.GetValue()))
+		p.currentLabelPairs = nil
 		return nil
 	}
 }
@@ -387,7 +508,8 @@ func (p *TextParser) readingValue() stateFn {
 	// When we are here, we have read all the labels, so for the
 	// special case of a summary/histogram, we can finally find out
 	// if the metric already exists.
-	if p.currentMF.GetType() == dto.MetricType_SUMMARY {
+	switch p.currentMF.GetType() {
+	case dto.MetricType_SUMMARY:
 		signature := model.LabelsToSignature(p.currentLabels)
 		if summary := p.summaries[signature]; summary != nil {
 			p.currentMetric = summary
@@ -395,7 +517,7 @@ func (p *TextParser) readingValue() stateFn {
 			p.summaries[signature] = p.currentMetric
 			p.currentMF.Metric = append(p.currentMF.Metric, p.currentMetric)
 		}
-	} else if p.currentMF.GetType() == dto.MetricType_HISTOGRAM {
+	case dto.MetricType_HISTOGRAM, dto.MetricType_GAUGE_HISTOGRAM:
 		signature := model.LabelsToSignature(p.currentLabels)
 		if histogram := p.histograms[signature]; histogram != nil {
 			p.currentMetric = histogram
@@ -403,7 +525,7 @@ func (p *TextParser) readingValue() stateFn {
 			p.histograms[signature] = p.currentMetric
 			p.currentMF.Metric = append(p.currentMF.Metric, p.currentMetric)
 		}
-	} else {
+	default:
 		p.currentMF.Metric = append(p.currentMF.Metric, p.currentMetric)
 	}
 	if p.readTokenUntilWhitespace(); p.err != nil {
@@ -441,24 +563,38 @@ func (p *TextParser) readingValue() stateFn {
 				},
 			)
 		}
-	case dto.MetricType_HISTOGRAM:
+	case dto.MetricType_HISTOGRAM, dto.MetricType_GAUGE_HISTOGRAM:
 		// *sigh*
 		if p.currentMetric.Histogram == nil {
 			p.currentMetric.Histogram = &dto.Histogram{}
 		}
 		switch {
 		case p.currentIsHistogramCount:
-			p.currentMetric.Histogram.SampleCount = proto.Uint64(uint64(value))
+			if uintValue := uint64(value); value == float64(uintValue) {
+				p.currentMetric.Histogram.SampleCount = proto.Uint64(uintValue)
+			} else {
+				if value < 0 {
+					p.parseError(fmt.Sprintf("negative count for histogram %q", p.currentMF.GetName()))
+					return nil
+				}
+				p.currentMetric.Histogram.SampleCountFloat = proto.Float64(value)
+			}
 		case p.currentIsHistogramSum:
 			p.currentMetric.Histogram.SampleSum = proto.Float64(value)
 		case !math.IsNaN(p.currentBucket):
-			p.currentMetric.Histogram.Bucket = append(
-				p.currentMetric.Histogram.Bucket,
-				&dto.Bucket{
-					UpperBound:      proto.Float64(p.currentBucket),
-					CumulativeCount: proto.Uint64(uint64(value)),
-				},
-			)
+			b := &dto.Bucket{
+				UpperBound: proto.Float64(p.currentBucket),
+			}
+			if uintValue := uint64(value); value == float64(uintValue) {
+				b.CumulativeCount = proto.Uint64(uintValue)
+			} else {
+				if value < 0 {
+					p.parseError(fmt.Sprintf("negative bucket population for histogram %q", p.currentMF.GetName()))
+					return nil
+				}
+				b.CumulativeCountFloat = proto.Float64(value)
+			}
+			p.currentMetric.Histogram.Bucket = append(p.currentMetric.Histogram.Bucket, b)
 		}
 	default:
 		p.err = fmt.Errorf("unexpected type for metric name %q", p.currentMF.GetName())
@@ -521,10 +657,18 @@ func (p *TextParser) readingType() stateFn {
 	if p.readTokenUntilNewline(false); p.err != nil {
 		return nil // Unexpected end of input.
 	}
-	metricType, ok := dto.MetricType_value[strings.ToUpper(p.currentToken.String())]
+	typ := strings.ToUpper(p.currentToken.String()) // Tolerate any combination of upper and lower case.
+	metricType, ok := dto.MetricType_value[typ]     // Tolerate "gauge_histogram" (not originally part of the text format).
 	if !ok {
-		p.parseError(fmt.Sprintf("unknown metric type %q", p.currentToken.String()))
-		return nil
+		// We also want to tolerate "gaugehistogram" to mark a gauge
+		// histogram, because that string is used in OpenMetrics. Note,
+		// however, that gauge histograms do not officially exist in the
+		// classic text format.
+		if typ != "GAUGEHISTOGRAM" {
+			p.parseError(fmt.Sprintf("unknown metric type %q", p.currentToken.String()))
+			return nil
+		}
+		metricType = int32(dto.MetricType_GAUGE_HISTOGRAM)
 	}
 	p.currentMF.Type = dto.MetricType(metricType).Enum()
 	return p.startOfLine
@@ -585,6 +729,8 @@ func (p *TextParser) readTokenUntilNewline(recognizeEscapeSequence bool) {
 				p.currentToken.WriteByte(p.currentByte)
 			case 'n':
 				p.currentToken.WriteByte('\n')
+			case '"':
+				p.currentToken.WriteByte('"')
 			default:
 				p.parseError(fmt.Sprintf("invalid escape sequence '\\%c'", p.currentByte))
 				return
@@ -610,13 +756,45 @@ func (p *TextParser) readTokenUntilNewline(recognizeEscapeSequence bool) {
 // but not into p.currentToken.
 func (p *TextParser) readTokenAsMetricName() {
 	p.currentToken.Reset()
+	// A UTF-8 metric name must be quoted and may have escaped characters.
+	quoted := false
+	escaped := false
 	if !isValidMetricNameStart(p.currentByte) {
 		return
 	}
-	for {
-		p.currentToken.WriteByte(p.currentByte)
+	for p.err == nil {
+		if escaped {
+			switch p.currentByte {
+			case '\\':
+				p.currentToken.WriteByte(p.currentByte)
+			case 'n':
+				p.currentToken.WriteByte('\n')
+			case '"':
+				p.currentToken.WriteByte('"')
+			default:
+				p.parseError(fmt.Sprintf("invalid escape sequence '\\%c'", p.currentByte))
+				return
+			}
+			escaped = false
+		} else {
+			switch p.currentByte {
+			case '"':
+				quoted = !quoted
+				if !quoted {
+					p.currentByte, p.err = p.buf.ReadByte()
+					return
+				}
+			case '\n':
+				p.parseError(fmt.Sprintf("metric name %q contains unescaped new-line", p.currentToken.String()))
+				return
+			case '\\':
+				escaped = true
+			default:
+				p.currentToken.WriteByte(p.currentByte)
+			}
+		}
 		p.currentByte, p.err = p.buf.ReadByte()
-		if p.err != nil || !isValidMetricNameContinuation(p.currentByte) {
+		if !isValidMetricNameContinuation(p.currentByte, quoted) || (!quoted && p.currentByte == ' ') {
 			return
 		}
 	}
@@ -628,13 +806,45 @@ func (p *TextParser) readTokenAsMetricName() {
 // but not into p.currentToken.
 func (p *TextParser) readTokenAsLabelName() {
 	p.currentToken.Reset()
+	// A UTF-8 label name must be quoted and may have escaped characters.
+	quoted := false
+	escaped := false
 	if !isValidLabelNameStart(p.currentByte) {
 		return
 	}
-	for {
-		p.currentToken.WriteByte(p.currentByte)
+	for p.err == nil {
+		if escaped {
+			switch p.currentByte {
+			case '\\':
+				p.currentToken.WriteByte(p.currentByte)
+			case 'n':
+				p.currentToken.WriteByte('\n')
+			case '"':
+				p.currentToken.WriteByte('"')
+			default:
+				p.parseError(fmt.Sprintf("invalid escape sequence '\\%c'", p.currentByte))
+				return
+			}
+			escaped = false
+		} else {
+			switch p.currentByte {
+			case '"':
+				quoted = !quoted
+				if !quoted {
+					p.currentByte, p.err = p.buf.ReadByte()
+					return
+				}
+			case '\n':
+				p.parseError(fmt.Sprintf("label name %q contains unescaped new-line", p.currentToken.String()))
+				return
+			case '\\':
+				escaped = true
+			default:
+				p.currentToken.WriteByte(p.currentByte)
+			}
+		}
 		p.currentByte, p.err = p.buf.ReadByte()
-		if p.err != nil || !isValidLabelNameContinuation(p.currentByte) {
+		if !isValidLabelNameContinuation(p.currentByte, quoted) || (!quoted && p.currentByte == '=') {
 			return
 		}
 	}
@@ -660,6 +870,7 @@ func (p *TextParser) readTokenAsLabelValue() {
 				p.currentToken.WriteByte('\n')
 			default:
 				p.parseError(fmt.Sprintf("invalid escape sequence '\\%c'", p.currentByte))
+				p.currentLabelPairs = nil
 				return
 			}
 			escaped = false
@@ -685,6 +896,10 @@ func (p *TextParser) setOrCreateCurrentMF() {
 	p.currentIsHistogramCount = false
 	p.currentIsHistogramSum = false
 	name := p.currentToken.String()
+	if !p.scheme.IsValidMetricName(name) {
+		p.parseError(fmt.Sprintf("invalid metric name %q", name))
+		return
+	}
 	if p.currentMF = p.metricFamiliesByName[name]; p.currentMF != nil {
 		return
 	}
@@ -703,7 +918,8 @@ func (p *TextParser) setOrCreateCurrentMF() {
 	}
 	histogramName := histogramMetricName(name)
 	if p.currentMF = p.metricFamiliesByName[histogramName]; p.currentMF != nil {
-		if p.currentMF.GetType() == dto.MetricType_HISTOGRAM {
+		if p.currentMF.GetType() == dto.MetricType_HISTOGRAM ||
+			p.currentMF.GetType() == dto.MetricType_GAUGE_HISTOGRAM {
 			if isCount(name) {
 				p.currentIsHistogramCount = true
 			}
@@ -718,19 +934,19 @@ func (p *TextParser) setOrCreateCurrentMF() {
 }
 
 func isValidLabelNameStart(b byte) bool {
-	return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_'
+	return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == '"'
 }
 
-func isValidLabelNameContinuation(b byte) bool {
-	return isValidLabelNameStart(b) || (b >= '0' && b <= '9')
+func isValidLabelNameContinuation(b byte, quoted bool) bool {
+	return isValidLabelNameStart(b) || (b >= '0' && b <= '9') || (quoted && utf8.ValidString(string(b)))
 }
 
 func isValidMetricNameStart(b byte) bool {
 	return isValidLabelNameStart(b) || b == ':'
 }
 
-func isValidMetricNameContinuation(b byte) bool {
-	return isValidLabelNameContinuation(b) || b == ':'
+func isValidMetricNameContinuation(b byte, quoted bool) bool {
+	return isValidLabelNameContinuation(b, quoted) || b == ':'
 }
 
 func isBlankOrTab(b byte) bool {
@@ -775,7 +991,7 @@ func histogramMetricName(name string) string {
 
 func parseFloat(s string) (float64, error) {
 	if strings.ContainsAny(s, "pP_") {
-		return 0, fmt.Errorf("unsupported character in float")
+		return 0, errors.New("unsupported character in float")
 	}
 	return strconv.ParseFloat(s, 64)
 }