diff --git a/vendor/github.com/prometheus/common/expfmt/decode.go b/vendor/github.com/prometheus/common/expfmt/decode.go
index c092723..7657f84 100644
--- a/vendor/github.com/prometheus/common/expfmt/decode.go
+++ b/vendor/github.com/prometheus/common/expfmt/decode.go
@@ -164,7 +164,7 @@
 }
 
 // ExtractSamples builds a slice of samples from the provided metric
-// families. If an error occurrs during sample extraction, it continues to
+// families. If an error occurs during sample extraction, it continues to
 // extract from the remaining metric families. The returned error is the last
 // error that has occurred.
 func ExtractSamples(o *DecodeOptions, fams ...*dto.MetricFamily) (model.Vector, error) {
diff --git a/vendor/github.com/prometheus/common/expfmt/encode.go b/vendor/github.com/prometheus/common/expfmt/encode.go
index 11839ed..bd4e347 100644
--- a/vendor/github.com/prometheus/common/expfmt/encode.go
+++ b/vendor/github.com/prometheus/common/expfmt/encode.go
@@ -30,17 +30,38 @@
 	Encode(*dto.MetricFamily) error
 }
 
-type encoder func(*dto.MetricFamily) error
-
-func (e encoder) Encode(v *dto.MetricFamily) error {
-	return e(v)
+// Closer is implemented by Encoders that need to be closed to finalize
+// encoding. (For example, OpenMetrics needs a final `# EOF` line.)
+//
+// Note that all Encoder implementations returned from this package implement
+// Closer, too, even if the Close call is a no-op. This happens in preparation
+// for adding a Close method to the Encoder interface directly in a (mildly
+// breaking) release in the future.
+type Closer interface {
+	Close() error
 }
 
-// Negotiate returns the Content-Type based on the given Accept header.
-// If no appropriate accepted type is found, FmtText is returned.
+type encoderCloser struct {
+	encode func(*dto.MetricFamily) error
+	close  func() error
+}
+
+func (ec encoderCloser) Encode(v *dto.MetricFamily) error {
+	return ec.encode(v)
+}
+
+func (ec encoderCloser) Close() error {
+	return ec.close()
+}
+
+// Negotiate returns the Content-Type based on the given Accept header. If no
+// 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.
 func Negotiate(h http.Header) Format {
 	for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
-		// Check for protocol buffer
+		ver := ac.Params["version"]
 		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
 			switch ac.Params["encoding"] {
 			case "delimited":
@@ -51,8 +72,6 @@
 				return FmtProtoCompact
 			}
 		}
-		// Check for text format.
-		ver := ac.Params["version"]
 		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
 			return FmtText
 		}
@@ -60,29 +79,84 @@
 	return FmtText
 }
 
-// NewEncoder returns a new encoder based on content type negotiation.
+// NegotiateIncludingOpenMetrics works like Negotiate but includes
+// FmtOpenMetrics as an option for the result. Note that this function is
+// 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 {
+	for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
+		ver := ac.Params["version"]
+		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
+			switch ac.Params["encoding"] {
+			case "delimited":
+				return FmtProtoDelim
+			case "text":
+				return FmtProtoText
+			case "compact-text":
+				return FmtProtoCompact
+			}
+		}
+		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
+			return FmtText
+		}
+		if ac.Type+"/"+ac.SubType == OpenMetricsType && (ver == OpenMetricsVersion || ver == "") {
+			return FmtOpenMetrics
+		}
+	}
+	return FmtText
+}
+
+// NewEncoder returns a new encoder based on content type negotiation. All
+// Encoder implementations returned by NewEncoder also implement Closer, and
+// callers should always call the Close method. It is currently only required
+// 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.
 func NewEncoder(w io.Writer, format Format) Encoder {
 	switch format {
 	case FmtProtoDelim:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := pbutil.WriteDelimited(w, v)
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := pbutil.WriteDelimited(w, v)
+				return err
+			},
+			close: func() error { return nil },
+		}
 	case FmtProtoCompact:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := fmt.Fprintln(w, v.String())
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := fmt.Fprintln(w, v.String())
+				return err
+			},
+			close: func() error { return nil },
+		}
 	case FmtProtoText:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
+				return err
+			},
+			close: func() error { return nil },
+		}
 	case FmtText:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := MetricFamilyToText(w, v)
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := MetricFamilyToText(w, v)
+				return err
+			},
+			close: func() error { return nil },
+		}
+	case FmtOpenMetrics:
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := MetricFamilyToOpenMetrics(w, v)
+				return err
+			},
+			close: func() error {
+				_, err := FinalizeOpenMetrics(w)
+				return err
+			},
+		}
 	}
-	panic("expfmt.NewEncoder: unknown format")
+	panic(fmt.Errorf("expfmt.NewEncoder: unknown format %q", format))
 }
diff --git a/vendor/github.com/prometheus/common/expfmt/expfmt.go b/vendor/github.com/prometheus/common/expfmt/expfmt.go
index c71bcb9..0f176fa 100644
--- a/vendor/github.com/prometheus/common/expfmt/expfmt.go
+++ b/vendor/github.com/prometheus/common/expfmt/expfmt.go
@@ -19,10 +19,12 @@
 
 // Constants to assemble the Content-Type values for the different wire protocols.
 const (
-	TextVersion   = "0.0.4"
-	ProtoType     = `application/vnd.google.protobuf`
-	ProtoProtocol = `io.prometheus.client.MetricFamily`
-	ProtoFmt      = ProtoType + "; proto=" + ProtoProtocol + ";"
+	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"
 
 	// The Content-Type values for the different wire protocols.
 	FmtUnknown      Format = `<unknown>`
@@ -30,6 +32,7 @@
 	FmtProtoDelim   Format = ProtoFmt + ` encoding=delimited`
 	FmtProtoText    Format = ProtoFmt + ` encoding=text`
 	FmtProtoCompact Format = ProtoFmt + ` encoding=compact-text`
+	FmtOpenMetrics  Format = OpenMetricsType + `; version=` + OpenMetricsVersion + `; charset=utf-8`
 )
 
 const (
diff --git a/vendor/github.com/prometheus/common/expfmt/openmetrics_create.go b/vendor/github.com/prometheus/common/expfmt/openmetrics_create.go
new file mode 100644
index 0000000..8a9313a
--- /dev/null
+++ b/vendor/github.com/prometheus/common/expfmt/openmetrics_create.go
@@ -0,0 +1,527 @@
+// Copyright 2020 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 expfmt
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"math"
+	"strconv"
+	"strings"
+
+	"github.com/golang/protobuf/ptypes"
+	"github.com/prometheus/common/model"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// MetricFamilyToOpenMetrics converts a MetricFamily proto message into the
+// OpenMetrics text format and writes the resulting lines to 'out'. It returns
+// the number of bytes written and any error encountered. The output will have
+// the same order as the input, no further sorting is performed. Furthermore,
+// this function assumes the input is already sanitized and does not perform any
+// sanity checks. If the input contains duplicate metrics or invalid metric or
+// label names, the conversion will result in invalid text format output.
+//
+// This function fulfills the type 'expfmt.encoder'.
+//
+// Note that OpenMetrics requires a final `# EOF` line. Since this function acts
+// on individual metric families, it is the responsibility of the caller to
+// append this line to 'out' once all metric families have been written.
+// Conveniently, this can be done by calling FinalizeOpenMetrics.
+//
+// The output should be fully OpenMetrics compliant. However, there are a few
+// 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.
+//
+// - 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 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 == "" {
+		return 0, fmt.Errorf("MetricFamily has no name: %s", in)
+	}
+
+	// Try the interface upgrade. If it doesn't work, we'll use a
+	// bufio.Writer from the sync.Pool.
+	w, ok := out.(enhancedWriter)
+	if !ok {
+		b := bufPool.Get().(*bufio.Writer)
+		b.Reset(out)
+		w = b
+		defer func() {
+			bErr := b.Flush()
+			if err == nil {
+				err = bErr
+			}
+			bufPool.Put(b)
+		}()
+	}
+
+	var (
+		n          int
+		metricType = in.GetType()
+		shortName  = name
+	)
+	if metricType == dto.MetricType_COUNTER && strings.HasSuffix(shortName, "_total") {
+		shortName = name[:len(name)-6]
+	}
+
+	// Comments, first HELP, then TYPE.
+	if in.Help != nil {
+		n, err = w.WriteString("# HELP ")
+		written += n
+		if err != nil {
+			return
+		}
+		n, err = w.WriteString(shortName)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return
+		}
+		n, err = writeEscapedString(w, *in.Help, true)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte('\n')
+		written++
+		if err != nil {
+			return
+		}
+	}
+	n, err = w.WriteString("# TYPE ")
+	written += n
+	if err != nil {
+		return
+	}
+	n, err = w.WriteString(shortName)
+	written += n
+	if err != nil {
+		return
+	}
+	switch metricType {
+	case dto.MetricType_COUNTER:
+		if strings.HasSuffix(name, "_total") {
+			n, err = w.WriteString(" counter\n")
+		} else {
+			n, err = w.WriteString(" unknown\n")
+		}
+	case dto.MetricType_GAUGE:
+		n, err = w.WriteString(" gauge\n")
+	case dto.MetricType_SUMMARY:
+		n, err = w.WriteString(" summary\n")
+	case dto.MetricType_UNTYPED:
+		n, err = w.WriteString(" unknown\n")
+	case dto.MetricType_HISTOGRAM:
+		n, err = w.WriteString(" histogram\n")
+	default:
+		return written, fmt.Errorf("unknown metric type %s", metricType.String())
+	}
+	written += n
+	if err != nil {
+		return
+	}
+
+	// Finally the samples, one line for each.
+	for _, metric := range in.Metric {
+		switch metricType {
+		case dto.MetricType_COUNTER:
+			if metric.Counter == nil {
+				return written, fmt.Errorf(
+					"expected counter in metric %s %s", name, metric,
+				)
+			}
+			// Note that we have ensured above that either the name
+			// ends on `_total` or that the rendered type is
+			// `unknown`. Therefore, no `_total` must be added here.
+			n, err = writeOpenMetricsSample(
+				w, name, "", metric, "", 0,
+				metric.Counter.GetValue(), 0, false,
+				metric.Counter.Exemplar,
+			)
+		case dto.MetricType_GAUGE:
+			if metric.Gauge == nil {
+				return written, fmt.Errorf(
+					"expected gauge in metric %s %s", name, metric,
+				)
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "", metric, "", 0,
+				metric.Gauge.GetValue(), 0, false,
+				nil,
+			)
+		case dto.MetricType_UNTYPED:
+			if metric.Untyped == nil {
+				return written, fmt.Errorf(
+					"expected untyped in metric %s %s", name, metric,
+				)
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "", metric, "", 0,
+				metric.Untyped.GetValue(), 0, false,
+				nil,
+			)
+		case dto.MetricType_SUMMARY:
+			if metric.Summary == nil {
+				return written, fmt.Errorf(
+					"expected summary in metric %s %s", name, metric,
+				)
+			}
+			for _, q := range metric.Summary.Quantile {
+				n, err = writeOpenMetricsSample(
+					w, name, "", metric,
+					model.QuantileLabel, q.GetQuantile(),
+					q.GetValue(), 0, false,
+					nil,
+				)
+				written += n
+				if err != nil {
+					return
+				}
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_sum", metric, "", 0,
+				metric.Summary.GetSampleSum(), 0, false,
+				nil,
+			)
+			written += n
+			if err != nil {
+				return
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_count", metric, "", 0,
+				0, metric.Summary.GetSampleCount(), true,
+				nil,
+			)
+		case dto.MetricType_HISTOGRAM:
+			if metric.Histogram == nil {
+				return written, fmt.Errorf(
+					"expected histogram in metric %s %s", name, metric,
+				)
+			}
+			infSeen := false
+			for _, b := range metric.Histogram.Bucket {
+				n, err = writeOpenMetricsSample(
+					w, name, "_bucket", metric,
+					model.BucketLabel, b.GetUpperBound(),
+					0, b.GetCumulativeCount(), true,
+					b.Exemplar,
+				)
+				written += n
+				if err != nil {
+					return
+				}
+				if math.IsInf(b.GetUpperBound(), +1) {
+					infSeen = true
+				}
+			}
+			if !infSeen {
+				n, err = writeOpenMetricsSample(
+					w, name, "_bucket", metric,
+					model.BucketLabel, math.Inf(+1),
+					0, metric.Histogram.GetSampleCount(), true,
+					nil,
+				)
+				written += n
+				if err != nil {
+					return
+				}
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_sum", metric, "", 0,
+				metric.Histogram.GetSampleSum(), 0, false,
+				nil,
+			)
+			written += n
+			if err != nil {
+				return
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_count", metric, "", 0,
+				0, metric.Histogram.GetSampleCount(), true,
+				nil,
+			)
+		default:
+			return written, fmt.Errorf(
+				"unexpected type in metric %s %s", name, metric,
+			)
+		}
+		written += n
+		if err != nil {
+			return
+		}
+	}
+	return
+}
+
+// FinalizeOpenMetrics writes the final `# EOF\n` line required by OpenMetrics.
+func FinalizeOpenMetrics(w io.Writer) (written int, err error) {
+	return w.Write([]byte("# EOF\n"))
+}
+
+// writeOpenMetricsSample writes a single sample in OpenMetrics text format to
+// w, given the metric name, the metric proto message itself, optionally an
+// additional label name with a float64 value (use empty string as label name if
+// not required), the value (optionally as float64 or uint64, determined by
+// useIntValue), and optionally an exemplar (use nil if not required). The
+// function returns the number of bytes written and any error encountered.
+func writeOpenMetricsSample(
+	w enhancedWriter,
+	name, suffix string,
+	metric *dto.Metric,
+	additionalLabelName string, additionalLabelValue float64,
+	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 += n
+	if err != nil {
+		return written, err
+	}
+	err = w.WriteByte(' ')
+	written++
+	if err != nil {
+		return written, err
+	}
+	if useIntValue {
+		n, err = writeUint(w, intValue)
+	} else {
+		n, err = writeOpenMetricsFloat(w, floatValue)
+	}
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if metric.TimestampMs != nil {
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return written, err
+		}
+		// TODO(beorn7): Format this directly without converting to a float first.
+		n, err = writeOpenMetricsFloat(w, float64(*metric.TimestampMs)/1000)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	if exemplar != nil {
+		n, err = writeExemplar(w, exemplar)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	err = w.WriteByte('\n')
+	written++
+	if err != nil {
+		return written, err
+	}
+	return written, nil
+}
+
+// writeOpenMetricsLabelPairs works like writeOpenMetrics but formats the float
+// in OpenMetrics style.
+func writeOpenMetricsLabelPairs(
+	w enhancedWriter,
+	in []*dto.LabelPair,
+	additionalLabelName string, additionalLabelValue float64,
+) (int, error) {
+	if len(in) == 0 && additionalLabelName == "" {
+		return 0, nil
+	}
+	var (
+		written   int
+		separator byte = '{'
+	)
+	for _, lp := range in {
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(lp.GetName())
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeEscapedString(w, lp.GetValue(), true)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
+		separator = ','
+	}
+	if additionalLabelName != "" {
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(additionalLabelName)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeOpenMetricsFloat(w, additionalLabelValue)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
+	}
+	err := w.WriteByte('}')
+	written++
+	if err != nil {
+		return written, err
+	}
+	return written, nil
+}
+
+// writeExemplar writes the provided exemplar in OpenMetrics format to w. The
+// function returns the number of bytes written and any error encountered.
+func writeExemplar(w enhancedWriter, e *dto.Exemplar) (int, error) {
+	written := 0
+	n, err := w.WriteString(" # ")
+	written += n
+	if err != nil {
+		return written, err
+	}
+	n, err = writeOpenMetricsLabelPairs(w, e.Label, "", 0)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	err = w.WriteByte(' ')
+	written++
+	if err != nil {
+		return written, err
+	}
+	n, err = writeOpenMetricsFloat(w, e.GetValue())
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if e.Timestamp != nil {
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return written, err
+		}
+		ts, err := ptypes.Timestamp((*e).Timestamp)
+		if err != nil {
+			return written, err
+		}
+		// TODO(beorn7): Format this directly from components of ts to
+		// avoid overflow/underflow and precision issues of the float
+		// conversion.
+		n, err = writeOpenMetricsFloat(w, float64(ts.UnixNano())/1e9)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	return written, nil
+}
+
+// writeOpenMetricsFloat works like writeFloat but appends ".0" if the resulting
+// number would otherwise contain neither a "." nor an "e".
+func writeOpenMetricsFloat(w enhancedWriter, f float64) (int, error) {
+	switch {
+	case f == 1:
+		return w.WriteString("1.0")
+	case f == 0:
+		return w.WriteString("0.0")
+	case f == -1:
+		return w.WriteString("-1.0")
+	case math.IsNaN(f):
+		return w.WriteString("NaN")
+	case math.IsInf(f, +1):
+		return w.WriteString("+Inf")
+	case math.IsInf(f, -1):
+		return w.WriteString("-Inf")
+	default:
+		bp := numBufPool.Get().(*[]byte)
+		*bp = strconv.AppendFloat((*bp)[:0], f, 'g', -1, 64)
+		if !bytes.ContainsAny(*bp, "e.") {
+			*bp = append(*bp, '.', '0')
+		}
+		written, err := w.Write(*bp)
+		numBufPool.Put(bp)
+		return written, err
+	}
+}
+
+// writeUint is like writeInt just for uint64.
+func writeUint(w enhancedWriter, u uint64) (int, error) {
+	bp := numBufPool.Get().(*[]byte)
+	*bp = strconv.AppendUint((*bp)[:0], u, 10)
+	written, err := w.Write(*bp)
+	numBufPool.Put(bp)
+	return written, err
+}
diff --git a/vendor/github.com/prometheus/common/expfmt/text_create.go b/vendor/github.com/prometheus/common/expfmt/text_create.go
index 8e473d0..5ba503b 100644
--- a/vendor/github.com/prometheus/common/expfmt/text_create.go
+++ b/vendor/github.com/prometheus/common/expfmt/text_create.go
@@ -14,9 +14,10 @@
 package expfmt
 
 import (
-	"bytes"
+	"bufio"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"math"
 	"strconv"
 	"strings"
@@ -27,7 +28,7 @@
 	dto "github.com/prometheus/client_model/go"
 )
 
-// enhancedWriter has all the enhanced write functions needed here. bytes.Buffer
+// enhancedWriter has all the enhanced write functions needed here. bufio.Writer
 // implements it.
 type enhancedWriter interface {
 	io.Writer
@@ -37,14 +38,13 @@
 }
 
 const (
-	initialBufSize    = 512
 	initialNumBufSize = 24
 )
 
 var (
 	bufPool = sync.Pool{
 		New: func() interface{} {
-			return bytes.NewBuffer(make([]byte, 0, initialBufSize))
+			return bufio.NewWriter(ioutil.Discard)
 		},
 	}
 	numBufPool = sync.Pool{
@@ -75,16 +75,14 @@
 	}
 
 	// Try the interface upgrade. If it doesn't work, we'll use a
-	// bytes.Buffer from the sync.Pool and write out its content to out in a
-	// single go in the end.
+	// bufio.Writer from the sync.Pool.
 	w, ok := out.(enhancedWriter)
 	if !ok {
-		b := bufPool.Get().(*bytes.Buffer)
-		b.Reset()
+		b := bufPool.Get().(*bufio.Writer)
+		b.Reset(out)
 		w = b
 		defer func() {
-			bWritten, bErr := out.Write(b.Bytes())
-			written = bWritten
+			bErr := b.Flush()
 			if err == nil {
 				err = bErr
 			}
@@ -425,9 +423,8 @@
 func writeEscapedString(w enhancedWriter, v string, includeDoubleQuote bool) (int, error) {
 	if includeDoubleQuote {
 		return quotedEscaper.WriteString(w, v)
-	} else {
-		return escaper.WriteString(w, v)
 	}
+	return escaper.WriteString(w, v)
 }
 
 // writeFloat is equivalent to fmt.Fprint with a float64 argument but hardcodes
diff --git a/vendor/github.com/prometheus/common/expfmt/text_parse.go b/vendor/github.com/prometheus/common/expfmt/text_parse.go
index ec3d86b..b6079b3 100644
--- a/vendor/github.com/prometheus/common/expfmt/text_parse.go
+++ b/vendor/github.com/prometheus/common/expfmt/text_parse.go
@@ -299,6 +299,17 @@
 		p.parseError(fmt.Sprintf("expected '=' after label name, found %q", p.currentByte))
 		return nil
 	}
+	// Check for duplicate label names.
+	labels := make(map[string]struct{})
+	for _, l := range p.currentMetric.Label {
+		lName := l.GetName()
+		if _, exists := labels[lName]; !exists {
+			labels[lName] = struct{}{}
+		} else {
+			p.parseError(fmt.Sprintf("duplicate label names for metric %q", p.currentMF.GetName()))
+			return nil
+		}
+	}
 	return p.startLabelValue
 }
 
@@ -325,7 +336,7 @@
 	// - Other labels have to be added to currentLabels for signature calculation.
 	if p.currentMF.GetType() == dto.MetricType_SUMMARY {
 		if p.currentLabelPair.GetName() == model.QuantileLabel {
-			if p.currentQuantile, p.err = strconv.ParseFloat(p.currentLabelPair.GetValue(), 64); p.err != nil {
+			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()))
 				return nil
@@ -337,7 +348,7 @@
 	// Similar special treatment of histograms.
 	if p.currentMF.GetType() == dto.MetricType_HISTOGRAM {
 		if p.currentLabelPair.GetName() == model.BucketLabel {
-			if p.currentBucket, p.err = strconv.ParseFloat(p.currentLabelPair.GetValue(), 64); p.err != nil {
+			if p.currentBucket, p.err = parseFloat(p.currentLabelPair.GetValue()); p.err != nil {
 				// Create a more helpful error message.
 				p.parseError(fmt.Sprintf("expected float as value for 'le' label, got %q", p.currentLabelPair.GetValue()))
 				return nil
@@ -392,7 +403,7 @@
 	if p.readTokenUntilWhitespace(); p.err != nil {
 		return nil // Unexpected end of input.
 	}
-	value, err := strconv.ParseFloat(p.currentToken.String(), 64)
+	value, err := parseFloat(p.currentToken.String())
 	if err != nil {
 		// Create a more helpful error message.
 		p.parseError(fmt.Sprintf("expected float as value, got %q", p.currentToken.String()))
@@ -755,3 +766,10 @@
 		return name
 	}
 }
+
+func parseFloat(s string) (float64, error) {
+	if strings.ContainsAny(s, "pP_") {
+		return 0, fmt.Errorf("unsupported character in float")
+	}
+	return strconv.ParseFloat(s, 64)
+}