Update dependencies

33 files changed, 2249 insertions, 411 deletions

diff --git a/vendor/github.com/prometheus/client_golang/prometheus/counter.go b/vendor/github.com/prometheus/client_golang/prometheus/counter.go
index 72d5256..273db5f 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/counter.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/counter.go
@@ -70,16 +70,12 @@ func (c *counter) Add(v float64) {
 // if you want to count the same thing partitioned by various dimensions
 // (e.g. number of HTTP requests, partitioned by response code and
 // method). Create instances with NewCounterVec.
-//
-// CounterVec embeds MetricVec. See there for a full list of methods with
-// detailed documentation.
 type CounterVec struct {
-	*MetricVec
+	*metricVec
 }
 
 // NewCounterVec creates a new CounterVec based on the provided CounterOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -88,7 +84,7 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 		opts.ConstLabels,
 	)
 	return &CounterVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
+		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			result := &counter{value: value{
 				desc:       desc,
 				valType:    CounterValue,
@@ -100,22 +96,51 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Counter and not a
-// Metric so that no type conversion is required.
+// GetMetricWithLabelValues returns the Counter for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new Counter is created.
+//
+// It is possible to call this method without using the returned Counter to only
+// create the new Counter but leave it at its starting value 0. See also the
+// SummaryVec example.
+//
+// Keeping the Counter for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Counter from the CounterVec. In that case,
+// the Counter will still exist, but it will not be exported anymore, even if a
+// Counter with the same label values is created later.
+//
+// An error is returned if the number of label values is not the same as the
+// number of VariableLabels in Desc.
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the GaugeVec example.
 func (m *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+	metric, err := m.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Counter), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Counter and not a Metric so that no
-// type conversion is required.
+// GetMetricWith returns the Counter for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new Counter is created. Implications of
+// creating a Counter without using it and keeping the Counter for later use are
+// the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc.
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
 func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+	metric, err := m.metricVec.getMetricWith(labels)
 	if metric != nil {
 		return metric.(Counter), err
 	}
@@ -127,14 +152,14 @@ func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
 // error, WithLabelValues allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Add(42)
 func (m *CounterVec) WithLabelValues(lvs ...string) Counter {
-	return m.MetricVec.WithLabelValues(lvs...).(Counter)
+	return m.metricVec.withLabelValues(lvs...).(Counter)
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
 // returned an error. By not returning an error, With allows shortcuts like
 //     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
 func (m *CounterVec) With(labels Labels) Counter {
-	return m.MetricVec.With(labels).(Counter)
+	return m.metricVec.with(labels).(Counter)
 }
 
 // CounterFunc is a Counter whose value is determined at collect time by calling a
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/desc.go b/vendor/github.com/prometheus/client_golang/prometheus/desc.go
index 1835b16..920abc9 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/desc.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/desc.go
@@ -25,19 +25,6 @@ import (
 	dto "github.com/prometheus/client_model/go"
 )
 
-// reservedLabelPrefix is a prefix which is not legal in user-supplied
-// label names.
-const reservedLabelPrefix = "__"
-
-// Labels represents a collection of label name -> value mappings. This type is
-// commonly used with the With(Labels) and GetMetricWith(Labels) methods of
-// metric vector Collectors, e.g.:
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-//
-// The other use-case is the specification of constant label pairs in Opts or to
-// create a Desc.
-type Labels map[string]string
-
 // Desc is the descriptor used by every Prometheus Metric. It is essentially
 // the immutable meta-data of a Metric. The normal Metric implementations
 // included in this package manage their Desc under the hood. Users only have to
@@ -122,6 +109,12 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	for _, labelName := range labelNames {
 		labelValues = append(labelValues, constLabels[labelName])
 	}
+	// Validate the const label values. They can't have a wrong cardinality, so
+	// use in len(labelValues) as expectedNumberOfValues.
+	if err := validateLabelValues(labelValues, len(labelValues)); err != nil {
+		d.err = err
+		return d
+	}
 	// Now add the variable label names, but prefix them with something that
 	// cannot be in a regular label name. That prevents matching the label
 	// dimension with a different mix between preset and variable labels.
@@ -137,6 +130,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 		d.err = errors.New("duplicate label names")
 		return d
 	}
+
 	vh := hashNew()
 	for _, val := range labelValues {
 		vh = hashAdd(vh, val)
@@ -193,8 +187,3 @@ func (d *Desc) String() string {
 		d.variableLabels,
 	)
 }
-
-func checkLabelName(l string) bool {
-	return model.LabelName(l).IsValid() &&
-		!strings.HasPrefix(l, reservedLabelPrefix)
-}
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/doc.go b/vendor/github.com/prometheus/client_golang/prometheus/doc.go
index 1fdef9e..36ef155 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/doc.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/doc.go
@@ -26,6 +26,7 @@
 //    package main
 //
 //    import (
+//    	"log"
 //    	"net/http"
 //
 //    	"github.com/prometheus/client_golang/prometheus"
@@ -59,7 +60,7 @@
 //    	// The Handler function provides a default handler to expose metrics
 //    	// via an HTTP server. "/metrics" is the usual endpoint for that.
 //    	http.Handle("/metrics", promhttp.Handler())
-//      log.Fatal(http.ListenAndServe(":8080", nil))
+//    	log.Fatal(http.ListenAndServe(":8080", nil))
 //    }
 //
 //
@@ -144,7 +145,7 @@
 // registry.
 //
 // So far, everything we did operated on the so-called default registry, as it
-// can be found in the global DefaultRegistry variable. With NewRegistry, you
+// can be found in the global DefaultRegisterer variable. With NewRegistry, you
 // can create a custom registry, or you can even implement the Registerer or
 // Gatherer interfaces yourself. The methods Register and Unregister work in the
 // same way on a custom registry as the global functions Register and Unregister
@@ -152,11 +153,11 @@
 //
 // There are a number of uses for custom registries: You can use registries with
 // special properties, see NewPedanticRegistry. You can avoid global state, as
-// it is imposed by the DefaultRegistry. You can use multiple registries at the
-// same time to expose different metrics in different ways. You can use separate
-// registries for testing purposes.
+// it is imposed by the DefaultRegisterer. You can use multiple registries at
+// the same time to expose different metrics in different ways.  You can use
+// separate registries for testing purposes.
 //
-// Also note that the DefaultRegistry comes registered with a Collector for Go
+// Also note that the DefaultRegisterer comes registered with a Collector for Go
 // runtime metrics (via NewGoCollector) and a Collector for process metrics (via
 // NewProcessCollector). With a custom registry, you are in control and decide
 // yourself about the Collectors to register.
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/gauge.go b/vendor/github.com/prometheus/client_golang/prometheus/gauge.go
index 9ab5a3d..13064da 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/gauge.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/gauge.go
@@ -63,12 +63,11 @@ func NewGauge(opts GaugeOpts) Gauge {
 // (e.g. number of operations queued, partitioned by user and operation
 // type). Create instances with NewGaugeVec.
 type GaugeVec struct {
-	*MetricVec
+	*metricVec
 }
 
 // NewGaugeVec creates a new GaugeVec based on the provided GaugeOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -77,28 +76,57 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 		opts.ConstLabels,
 	)
 	return &GaugeVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
+		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			return newValue(desc, GaugeValue, 0, lvs...)
 		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Gauge and not a
-// Metric so that no type conversion is required.
+// GetMetricWithLabelValues returns the Gauge for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new Gauge is created.
+//
+// It is possible to call this method without using the returned Gauge to only
+// create the new Gauge but leave it at its starting value 0. See also the
+// SummaryVec example.
+//
+// Keeping the Gauge for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Gauge from the GaugeVec. In that case, the
+// Gauge will still exist, but it will not be exported anymore, even if a
+// Gauge with the same label values is created later. See also the CounterVec
+// example.
+//
+// An error is returned if the number of label values is not the same as the
+// number of VariableLabels in Desc.
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
 func (m *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+	metric, err := m.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Gauge), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Gauge and not a Metric so that no
-// type conversion is required.
+// GetMetricWith returns the Gauge for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new Gauge is created. Implications of
+// creating a Gauge without using it and keeping the Gauge for later use are
+// the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc.
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
 func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+	metric, err := m.metricVec.getMetricWith(labels)
 	if metric != nil {
 		return metric.(Gauge), err
 	}
@@ -110,14 +138,14 @@ func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
 // error, WithLabelValues allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Add(42)
 func (m *GaugeVec) WithLabelValues(lvs ...string) Gauge {
-	return m.MetricVec.WithLabelValues(lvs...).(Gauge)
+	return m.metricVec.withLabelValues(lvs...).(Gauge)
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
 // returned an error. By not returning an error, With allows shortcuts like
 //     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
 func (m *GaugeVec) With(labels Labels) Gauge {
-	return m.MetricVec.With(labels).(Gauge)
+	return m.metricVec.with(labels).(Gauge)
 }
 
 // GaugeFunc is a Gauge whose value is determined at collect time by calling a
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/go_collector.go b/vendor/github.com/prometheus/client_golang/prometheus/go_collector.go
index f967645..096454a 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/go_collector.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/go_collector.go
@@ -11,6 +11,7 @@ type goCollector struct {
 	goroutinesDesc *Desc
 	threadsDesc    *Desc
 	gcDesc         *Desc
+	goInfoDesc     *Desc
 
 	// metrics to describe and collect
 	metrics memStatsMetrics
@@ -26,12 +27,16 @@ func NewGoCollector() Collector {
 			nil, nil),
 		threadsDesc: NewDesc(
 			"go_threads",
-			"Number of OS threads created",
+			"Number of OS threads created.",
 			nil, nil),
 		gcDesc: NewDesc(
 			"go_gc_duration_seconds",
 			"A summary of the GC invocation durations.",
 			nil, nil),
+		goInfoDesc: NewDesc(
+			"go_info",
+			"Information about the Go environment.",
+			nil, Labels{"version": runtime.Version()}),
 		metrics: memStatsMetrics{
 			{
 				desc: NewDesc(
@@ -239,6 +244,7 @@ func (c *goCollector) Describe(ch chan<- *Desc) {
 	ch <- c.goroutinesDesc
 	ch <- c.threadsDesc
 	ch <- c.gcDesc
+	ch <- c.goInfoDesc
 	for _, i := range c.metrics {
 		ch <- i.desc
 	}
@@ -261,6 +267,8 @@ func (c *goCollector) Collect(ch chan<- Metric) {
 	quantiles[0.0] = stats.PauseQuantiles[0].Seconds()
 	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), float64(stats.PauseTotal.Seconds()), quantiles)
 
+	ch <- MustNewConstMetric(c.goInfoDesc, GaugeValue, 1)
+
 	ms := &runtime.MemStats{}
 	runtime.ReadMemStats(ms)
 	for _, i := range c.metrics {
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/histogram.go b/vendor/github.com/prometheus/client_golang/prometheus/histogram.go
index 9719e8f..6cc6e68 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/histogram.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/histogram.go
@@ -287,12 +287,11 @@ func (h *histogram) Write(out *dto.Metric) error {
 // (e.g. HTTP request latencies, partitioned by status code and method). Create
 // instances with NewHistogramVec.
 type HistogramVec struct {
-	*MetricVec
+	*metricVec
 }
 
 // NewHistogramVec creates a new HistogramVec based on the provided HistogramOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -301,30 +300,60 @@ func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
 		opts.ConstLabels,
 	)
 	return &HistogramVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
+		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			return newHistogram(desc, opts, lvs...)
 		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Histogram and not a
-// Metric so that no type conversion is required.
-func (m *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Histogram, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Histogram for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new Histogram is created.
+//
+// It is possible to call this method without using the returned Histogram to only
+// create the new Histogram but leave it at its starting value, a Histogram without
+// any observations.
+//
+// Keeping the Histogram for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Histogram from the HistogramVec. In that case, the
+// Histogram will still exist, but it will not be exported anymore, even if a
+// Histogram with the same label values is created later. See also the CounterVec
+// example.
+//
+// An error is returned if the number of label values is not the same as the
+// number of VariableLabels in Desc.
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the GaugeVec example.
+func (m *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
+	metric, err := m.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
-		return metric.(Histogram), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Histogram and not a Metric so that no
-// type conversion is required.
-func (m *HistogramVec) GetMetricWith(labels Labels) (Histogram, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Histogram for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new Histogram is created. Implications of
+// creating a Histogram without using it and keeping the Histogram for later use
+// are the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc.
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (m *HistogramVec) GetMetricWith(labels Labels) (Observer, error) {
+	metric, err := m.metricVec.getMetricWith(labels)
 	if metric != nil {
-		return metric.(Histogram), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
@@ -333,15 +362,15 @@ func (m *HistogramVec) GetMetricWith(labels Labels) (Histogram, error) {
 // GetMetricWithLabelValues would have returned an error. By not returning an
 // error, WithLabelValues allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Observe(42.21)
-func (m *HistogramVec) WithLabelValues(lvs ...string) Histogram {
-	return m.MetricVec.WithLabelValues(lvs...).(Histogram)
+func (m *HistogramVec) WithLabelValues(lvs ...string) Observer {
+	return m.metricVec.withLabelValues(lvs...).(Observer)
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
 // returned an error. By not returning an error, With allows shortcuts like
 //     myVec.With(Labels{"code": "404", "method": "GET"}).Observe(42.21)
-func (m *HistogramVec) With(labels Labels) Histogram {
-	return m.MetricVec.With(labels).(Histogram)
+func (m *HistogramVec) With(labels Labels) Observer {
+	return m.metricVec.with(labels).(Observer)
 }
 
 type constHistogram struct {
@@ -401,8 +430,8 @@ func NewConstHistogram(
 	buckets map[float64]uint64,
 	labelValues ...string,
 ) (Metric, error) {
-	if len(desc.variableLabels) != len(labelValues) {
-		return nil, errInconsistentCardinality
+	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
+		return nil, err
 	}
 	return &constHistogram{
 		desc:       desc,
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/http.go b/vendor/github.com/prometheus/client_golang/prometheus/http.go
index d74fb48..bfee5c6 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/http.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/http.go
@@ -62,7 +62,8 @@ func giveBuf(buf *bytes.Buffer) {
 //
 // Deprecated: Please note the issues described in the doc comment of
 // InstrumentHandler. You might want to consider using promhttp.Handler instead
-// (which is not instrumented).
+// (which is not instrumented, but can be instrumented with the tooling provided
+// in package promhttp).
 func Handler() http.Handler {
 	return InstrumentHandler("prometheus", UninstrumentedHandler())
 }
@@ -95,7 +96,7 @@ func UninstrumentedHandler() http.Handler {
 			closer.Close()
 		}
 		if lastErr != nil && buf.Len() == 0 {
-			http.Error(w, "No metrics encoded, last error:\n\n"+err.Error(), http.StatusInternalServerError)
+			http.Error(w, "No metrics encoded, last error:\n\n"+lastErr.Error(), http.StatusInternalServerError)
 			return
 		}
 		header := w.Header()
@@ -158,7 +159,8 @@ func nowSeries(t ...time.Time) nower {
 // value. http_requests_total is a metric vector partitioned by HTTP method
 // (label name "method") and HTTP status code (label name "code").
 //
-// Deprecated: InstrumentHandler has several issues:
+// Deprecated: InstrumentHandler has several issues. Use the tooling provided in
+// package promhttp instead. The issues are the following:
 //
 // - It uses Summaries rather than Histograms. Summaries are not useful if
 // aggregation across multiple instances is required.
@@ -174,10 +176,6 @@ func nowSeries(t ...time.Time) nower {
 //
 // - It has additional issues with HTTP/2, cf.
 // https://github.com/prometheus/client_golang/issues/272.
-//
-// Upcoming versions of this package will provide ways of instrumenting HTTP
-// handlers that are more flexible and have fewer issues. Please prefer direct
-// instrumentation in the meantime.
 func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFunc {
 	return InstrumentHandlerFunc(handlerName, handler.ServeHTTP)
 }
@@ -187,7 +185,7 @@ func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFun
 // issues).
 //
 // Deprecated: InstrumentHandlerFunc is deprecated for the same reasons as
-// InstrumentHandler is.
+// InstrumentHandler is. Use the tooling provided in package promhttp instead.
 func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
 	return InstrumentHandlerFuncWithOpts(
 		SummaryOpts{
@@ -226,7 +224,7 @@ func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWri
 // SummaryOpts.
 //
 // Deprecated: InstrumentHandlerWithOpts is deprecated for the same reasons as
-// InstrumentHandler is.
+// InstrumentHandler is. Use the tooling provided in package promhttp instead.
 func InstrumentHandlerWithOpts(opts SummaryOpts, handler http.Handler) http.HandlerFunc {
 	return InstrumentHandlerFuncWithOpts(opts, handler.ServeHTTP)
 }
@@ -237,7 +235,7 @@ func InstrumentHandlerWithOpts(opts SummaryOpts, handler http.Handler) http.Hand
 // SummaryOpts are used.
 //
 // Deprecated: InstrumentHandlerFuncWithOpts is deprecated for the same reasons
-// as InstrumentHandler is.
+// as InstrumentHandler is. Use the tooling provided in package promhttp instead.
 func InstrumentHandlerFuncWithOpts(opts SummaryOpts, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
 	reqCnt := NewCounterVec(
 		CounterOpts{
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/labels.go b/vendor/github.com/prometheus/client_golang/prometheus/labels.go
new file mode 100644
index 0000000..2502e37
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/labels.go
@@ -0,0 +1,57 @@
+package prometheus
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/prometheus/common/model"
+)
+
+// Labels represents a collection of label name -> value mappings. This type is
+// commonly used with the With(Labels) and GetMetricWith(Labels) methods of
+// metric vector Collectors, e.g.:
+//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
+//
+// The other use-case is the specification of constant label pairs in Opts or to
+// create a Desc.
+type Labels map[string]string
+
+// reservedLabelPrefix is a prefix which is not legal in user-supplied
+// label names.
+const reservedLabelPrefix = "__"
+
+var errInconsistentCardinality = errors.New("inconsistent label cardinality")
+
+func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
+	if len(labels) != expectedNumberOfValues {
+		return errInconsistentCardinality
+	}
+
+	for name, val := range labels {
+		if !utf8.ValidString(val) {
+			return fmt.Errorf("label %s: value %q is not valid UTF-8", name, val)
+		}
+	}
+
+	return nil
+}
+
+func validateLabelValues(vals []string, expectedNumberOfValues int) error {
+	if len(vals) != expectedNumberOfValues {
+		return errInconsistentCardinality
+	}
+
+	for _, val := range vals {
+		if !utf8.ValidString(val) {
+			return fmt.Errorf("label value %q is not valid UTF-8", val)
+		}
+	}
+
+	return nil
+}
+
+func checkLabelName(l string) bool {
+	return model.LabelName(l).IsValid() && !strings.HasPrefix(l, reservedLabelPrefix)
+}
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/observer.go b/vendor/github.com/prometheus/client_golang/prometheus/observer.go
new file mode 100644
index 0000000..b0520e8
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/observer.go
@@ -0,0 +1,50 @@
+// Copyright 2017 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 prometheus
+
+// Observer is the interface that wraps the Observe method, which is used by
+// Histogram and Summary to add observations.
+type Observer interface {
+	Observe(float64)
+}
+
+// The ObserverFunc type is an adapter to allow the use of ordinary
+// functions as Observers. If f is a function with the appropriate
+// signature, ObserverFunc(f) is an Observer that calls f.
+//
+// This adapter is usually used in connection with the Timer type, and there are
+// two general use cases:
+//
+// The most common one is to use a Gauge as the Observer for a Timer.
+// See the "Gauge" Timer example.
+//
+// The more advanced use case is to create a function that dynamically decides
+// which Observer to use for observing the duration. See the "Complex" Timer
+// example.
+type ObserverFunc func(float64)
+
+// Observe calls f(value). It implements Observer.
+func (f ObserverFunc) Observe(value float64) {
+	f(value)
+}
+
+// ObserverVec is an interface implemented by `HistogramVec` and `SummaryVec`.
+type ObserverVec interface {
+	GetMetricWith(Labels) (Observer, error)
+	GetMetricWithLabelValues(lvs ...string) (Observer, error)
+	With(Labels) Observer
+	WithLabelValues(...string) Observer
+
+	Collector
+}
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator.go
new file mode 100644
index 0000000..5ee095b
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator.go
@@ -0,0 +1,199 @@
+// Copyright 2017 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 promhttp
+
+import (
+	"bufio"
+	"io"
+	"net"
+	"net/http"
+)
+
+const (
+	closeNotifier = 1 << iota
+	flusher
+	hijacker
+	readerFrom
+	pusher
+)
+
+type delegator interface {
+	http.ResponseWriter
+
+	Status() int
+	Written() int64
+}
+
+type responseWriterDelegator struct {
+	http.ResponseWriter
+
+	handler, method    string
+	status             int
+	written            int64
+	wroteHeader        bool
+	observeWriteHeader func(int)
+}
+
+func (r *responseWriterDelegator) Status() int {
+	return r.status
+}
+
+func (r *responseWriterDelegator) Written() int64 {
+	return r.written
+}
+
+func (r *responseWriterDelegator) WriteHeader(code int) {
+	r.status = code
+	r.wroteHeader = true
+	r.ResponseWriter.WriteHeader(code)
+	if r.observeWriteHeader != nil {
+		r.observeWriteHeader(code)
+	}
+}
+
+func (r *responseWriterDelegator) Write(b []byte) (int, error) {
+	if !r.wroteHeader {
+		r.WriteHeader(http.StatusOK)
+	}
+	n, err := r.ResponseWriter.Write(b)
+	r.written += int64(n)
+	return n, err
+}
+
+type closeNotifierDelegator struct{ *responseWriterDelegator }
+type flusherDelegator struct{ *responseWriterDelegator }
+type hijackerDelegator struct{ *responseWriterDelegator }
+type readerFromDelegator struct{ *responseWriterDelegator }
+
+func (d *closeNotifierDelegator) CloseNotify() <-chan bool {
+	return d.ResponseWriter.(http.CloseNotifier).CloseNotify()
+}
+func (d *flusherDelegator) Flush() {
+	d.ResponseWriter.(http.Flusher).Flush()
+}
+func (d *hijackerDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return d.ResponseWriter.(http.Hijacker).Hijack()
+}
+func (d *readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
+	if !d.wroteHeader {
+		d.WriteHeader(http.StatusOK)
+	}
+	n, err := d.ResponseWriter.(io.ReaderFrom).ReadFrom(re)
+	d.written += n
+	return n, err
+}
+
+var pickDelegator = make([]func(*responseWriterDelegator) delegator, 32)
+
+func init() {
+	// TODO(beorn7): Code generation would help here.
+	pickDelegator[0] = func(d *responseWriterDelegator) delegator { // 0
+		return d
+	}
+	pickDelegator[closeNotifier] = func(d *responseWriterDelegator) delegator { // 1
+		return closeNotifierDelegator{d}
+	}
+	pickDelegator[flusher] = func(d *responseWriterDelegator) delegator { // 2
+		return flusherDelegator{d}
+	}
+	pickDelegator[flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 3
+		return struct {
+			*responseWriterDelegator
+			http.Flusher
+			http.CloseNotifier
+		}{d, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[hijacker] = func(d *responseWriterDelegator) delegator { // 4
+		return hijackerDelegator{d}
+	}
+	pickDelegator[hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 5
+		return struct {
+			*responseWriterDelegator
+			http.Hijacker
+			http.CloseNotifier
+		}{d, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 6
+		return struct {
+			*responseWriterDelegator
+			http.Hijacker
+			http.Flusher
+		}{d, &hijackerDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 7
+		return struct {
+			*responseWriterDelegator
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom] = func(d *responseWriterDelegator) delegator { // 8
+		return readerFromDelegator{d}
+	}
+	pickDelegator[readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 9
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.CloseNotifier
+		}{d, &readerFromDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 10
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Flusher
+		}{d, &readerFromDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 11
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Flusher
+			http.CloseNotifier
+		}{d, &readerFromDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 12
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 13
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+			http.CloseNotifier
+		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 14
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 15
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+}
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_1_8.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_1_8.go
new file mode 100644
index 0000000..f4d386f
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_1_8.go
@@ -0,0 +1,181 @@
+// Copyright 2017 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.
+
+// +build go1.8
+
+package promhttp
+
+import (
+	"io"
+	"net/http"
+)
+
+type pusherDelegator struct{ *responseWriterDelegator }
+
+func (d *pusherDelegator) Push(target string, opts *http.PushOptions) error {
+	return d.ResponseWriter.(http.Pusher).Push(target, opts)
+}
+
+func init() {
+	pickDelegator[pusher] = func(d *responseWriterDelegator) delegator { // 16
+		return pusherDelegator{d}
+	}
+	pickDelegator[pusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 17
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+flusher] = func(d *responseWriterDelegator) delegator { // 18
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+		}{d, &pusherDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[pusher+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 19
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker] = func(d *responseWriterDelegator) delegator { // 20
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+		}{d, &pusherDelegator{d}, &hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 21
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 22
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+		}{d, &pusherDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { //23
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom] = func(d *responseWriterDelegator) delegator { // 24
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 25
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 26
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 27
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 28
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 29
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}, &closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 30
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 31
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, &pusherDelegator{d}, &readerFromDelegator{d}, &hijackerDelegator{d}, &flusherDelegator{d}, &closeNotifierDelegator{d}}
+	}
+}
+
+func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
+	d := &responseWriterDelegator{
+		ResponseWriter:     w,
+		observeWriteHeader: observeWriteHeaderFunc,
+	}
+
+	id := 0
+	if _, ok := w.(http.CloseNotifier); ok {
+		id += closeNotifier
+	}
+	if _, ok := w.(http.Flusher); ok {
+		id += flusher
+	}
+	if _, ok := w.(http.Hijacker); ok {
+		id += hijacker
+	}
+	if _, ok := w.(io.ReaderFrom); ok {
+		id += readerFrom
+	}
+	if _, ok := w.(http.Pusher); ok {
+		id += pusher
+	}
+
+	return pickDelegator[id](d)
+}
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_pre_1_8.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_pre_1_8.go
new file mode 100644
index 0000000..8bb9b8b
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator_pre_1_8.go
@@ -0,0 +1,44 @@
+// Copyright 2017 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.
+
+// +build !go1.8
+
+package promhttp
+
+import (
+	"io"
+	"net/http"
+)
+
+func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
+	d := &responseWriterDelegator{
+		ResponseWriter:     w,
+		observeWriteHeader: observeWriteHeaderFunc,
+	}
+
+	id := 0
+	if _, ok := w.(http.CloseNotifier); ok {
+		id += closeNotifier
+	}
+	if _, ok := w.(http.Flusher); ok {
+		id += flusher
+	}
+	if _, ok := w.(http.Hijacker); ok {
+		id += hijacker
+	}
+	if _, ok := w.(io.ReaderFrom); ok {
+		id += readerFrom
+	}
+
+	return pickDelegator[id](d)
+}
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go
index b6dd5a2..2d67f24 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go
@@ -11,21 +11,24 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Copyright (c) 2013, The Prometheus Authors
-// All rights reserved.
+// Package promhttp provides tooling around HTTP servers and clients.
 //
-// Use of this source code is governed by a BSD-style license that can be found
-// in the LICENSE file.
-
-// Package promhttp contains functions to create http.Handler instances to
-// expose Prometheus metrics via HTTP. In later versions of this package, it
-// will also contain tooling to instrument instances of http.Handler and
-// http.RoundTripper.
+// First, the package allows the creation of http.Handler instances to expose
+// Prometheus metrics via HTTP. promhttp.Handler acts on the
+// prometheus.DefaultGatherer. With HandlerFor, you can create a handler for a
+// custom registry or anything that implements the Gatherer interface. It also
+// allows the creation of handlers that act differently on errors or allow to
+// log errors.
+//
+// Second, the package provides tooling to instrument instances of http.Handler
+// via middleware. Middleware wrappers follow the naming scheme
+// InstrumentHandlerX, where X describes the intended use of the middleware.
+// See each function's doc comment for specific details.
 //
-// promhttp.Handler acts on the prometheus.DefaultGatherer. With HandlerFor,
-// you can create a handler for a custom registry or anything that implements
-// the Gatherer interface. It also allows to create handlers that act
-// differently on errors or allow to log errors.
+// Finally, the package allows for an http.RoundTripper to be instrumented via
+// middleware. Middleware wrappers follow the naming scheme
+// InstrumentRoundTripperX, where X describes the intended use of the
+// middleware. See each function's doc comment for specific details.
 package promhttp
 
 import (
@@ -125,7 +128,7 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
 			closer.Close()
 		}
 		if lastErr != nil && buf.Len() == 0 {
-			http.Error(w, "No metrics encoded, last error:\n\n"+err.Error(), http.StatusInternalServerError)
+			http.Error(w, "No metrics encoded, last error:\n\n"+lastErr.Error(), http.StatusInternalServerError)
 			return
 		}
 		header := w.Header()
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client.go
new file mode 100644
index 0000000..65f9425
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client.go
@@ -0,0 +1,98 @@
+// Copyright 2017 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 promhttp
+
+import (
+	"net/http"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// The RoundTripperFunc type is an adapter to allow the use of ordinary
+// functions as RoundTrippers. If f is a function with the appropriate
+// signature, RountTripperFunc(f) is a RoundTripper that calls f.
+type RoundTripperFunc func(req *http.Request) (*http.Response, error)
+
+// RoundTrip implements the RoundTripper interface.
+func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) {
+	return rt(r)
+}
+
+// InstrumentRoundTripperInFlight is a middleware that wraps the provided
+// http.RoundTripper. It sets the provided prometheus.Gauge to the number of
+// requests currently handled by the wrapped http.RoundTripper.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripper) RoundTripperFunc {
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		gauge.Inc()
+		defer gauge.Dec()
+		return next.RoundTrip(r)
+	})
+}
+
+// InstrumentRoundTripperCounter is a middleware that wraps the provided
+// http.RoundTripper to observe the request result with the provided CounterVec.
+// The CounterVec must have zero, one, or two labels. The only allowed label
+// names are "code" and "method". The function panics if any other instance
+// labels are provided. Partitioning of the CounterVec happens by HTTP status
+// code and/or HTTP method if the respective instance label names are present
+// in the CounterVec. For unpartitioned counting, use a CounterVec with
+// zero labels.
+//
+// If the wrapped RoundTripper panics or returns a non-nil error, the Counter
+// is not incremented.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper) RoundTripperFunc {
+	code, method := checkLabels(counter)
+
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		resp, err := next.RoundTrip(r)
+		if err == nil {
+			counter.With(labels(code, method, r.Method, resp.StatusCode)).Inc()
+		}
+		return resp, err
+	})
+}
+
+// InstrumentRoundTripperDuration is a middleware that wraps the provided
+// http.RoundTripper to observe the request duration with the provided ObserverVec.
+// The ObserverVec must have zero, one, or two labels. The only allowed label
+// names are "code" and "method". The function panics if any other instance
+// labels are provided. The Observe method of the Observer in the ObserverVec
+// is called with the request duration in seconds. Partitioning happens by HTTP
+// status code and/or HTTP method if the respective instance label names are
+// present in the ObserverVec. For unpartitioned observations, use an
+// ObserverVec with zero labels. Note that partitioning of Histograms is
+// expensive and should be used judiciously.
+//
+// If the wrapped RoundTripper panics or returns a non-nil error, no values are
+// reported.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundTripper) RoundTripperFunc {
+	code, method := checkLabels(obs)
+
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		start := time.Now()
+		resp, err := next.RoundTrip(r)
+		if err == nil {
+			obs.With(labels(code, method, r.Method, resp.StatusCode)).Observe(time.Since(start).Seconds())
+		}
+		return resp, err
+	})
+}
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client_1_8.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client_1_8.go
new file mode 100644
index 0000000..0bd80c3
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client_1_8.go
@@ -0,0 +1,144 @@
+// Copyright 2017 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.
+
+// +build go1.8
+
+package promhttp
+
+import (
+	"context"
+	"crypto/tls"
+	"net/http"
+	"net/http/httptrace"
+	"time"
+)
+
+// InstrumentTrace is used to offer flexibility in instrumenting the available
+// httptrace.ClientTrace hook functions. Each function is passed a float64
+// representing the time in seconds since the start of the http request. A user
+// may choose to use separately buckets Histograms, or implement custom
+// instance labels on a per function basis.
+type InstrumentTrace struct {
+	GotConn              func(float64)
+	PutIdleConn          func(float64)
+	GotFirstResponseByte func(float64)
+	Got100Continue       func(float64)
+	DNSStart             func(float64)
+	DNSDone              func(float64)
+	ConnectStart         func(float64)
+	ConnectDone          func(float64)
+	TLSHandshakeStart    func(float64)
+	TLSHandshakeDone     func(float64)
+	WroteHeaders         func(float64)
+	Wait100Continue      func(float64)
+	WroteRequest         func(float64)
+}
+
+// InstrumentRoundTripperTrace is a middleware that wraps the provided
+// RoundTripper and reports times to hook functions provided in the
+// InstrumentTrace struct. Hook functions that are not present in the provided
+// InstrumentTrace struct are ignored. Times reported to the hook functions are
+// time since the start of the request. Only with Go1.9+, those times are
+// guaranteed to never be negative. (Earlier Go versions are not using a
+// monotonic clock.) Note that partitioning of Histograms is expensive and
+// should be used judiciously.
+//
+// For hook functions that receive an error as an argument, no observations are
+// made in the event of a non-nil error value.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		start := time.Now()
+
+		trace := &httptrace.ClientTrace{
+			GotConn: func(_ httptrace.GotConnInfo) {
+				if it.GotConn != nil {
+					it.GotConn(time.Since(start).Seconds())
+				}
+			},
+			PutIdleConn: func(err error) {
+				if err != nil {
+					return
+				}
+				if it.PutIdleConn != nil {
+					it.PutIdleConn(time.Since(start).Seconds())
+				}
+			},
+			DNSStart: func(_ httptrace.DNSStartInfo) {
+				if it.DNSStart != nil {
+					it.DNSStart(time.Since(start).Seconds())
+				}
+			},
+			DNSDone: func(_ httptrace.DNSDoneInfo) {
+				if it.DNSStart != nil {
+					it.DNSStart(time.Since(start).Seconds())
+				}
+			},
+			ConnectStart: func(_, _ string) {
+				if it.ConnectStart != nil {
+					it.ConnectStart(time.Since(start).Seconds())
+				}
+			},
+			ConnectDone: func(_, _ string, err error) {
+				if err != nil {
+					return
+				}
+				if it.ConnectDone != nil {
+					it.ConnectDone(time.Since(start).Seconds())
+				}
+			},
+			GotFirstResponseByte: func() {
+				if it.GotFirstResponseByte != nil {
+					it.GotFirstResponseByte(time.Since(start).Seconds())
+				}
+			},
+			Got100Continue: func() {
+				if it.Got100Continue != nil {
+					it.Got100Continue(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeStart: func() {
+				if it.TLSHandshakeStart != nil {
+					it.TLSHandshakeStart(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeDone: func(_ tls.ConnectionState, err error) {
+				if err != nil {
+					return
+				}
+				if it.TLSHandshakeDone != nil {
+					it.TLSHandshakeDone(time.Since(start).Seconds())
+				}
+			},
+			WroteHeaders: func() {
+				if it.WroteHeaders != nil {
+					it.WroteHeaders(time.Since(start).Seconds())
+				}
+			},
+			Wait100Continue: func() {
+				if it.Wait100Continue != nil {
+					it.Wait100Continue(time.Since(start).Seconds())
+				}
+			},
+			WroteRequest: func(_ httptrace.WroteRequestInfo) {
+				if it.WroteRequest != nil {
+					it.WroteRequest(time.Since(start).Seconds())
+				}
+			},
+		}
+		r = r.WithContext(httptrace.WithClientTrace(context.Background(), trace))
+
+		return next.RoundTrip(r)
+	})
+}
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go
new file mode 100644
index 0000000..3d145ad
--- /dev/null
+++ b/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go
@@ -0,0 +1,440 @@
+// Copyright 2017 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 promhttp
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// magicString is used for the hacky label test in checkLabels. Remove once fixed.
+const magicString = "zZgWfBxLqvG8kc8IMv3POi2Bb0tZI3vAnBx+gBaFi9FyPzB/CzKUer1yufDa"
+
+// InstrumentHandlerInFlight is a middleware that wraps the provided
+// http.Handler. It sets the provided prometheus.Gauge to the number of
+// requests currently handled by the wrapped http.Handler.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		g.Inc()
+		defer g.Dec()
+		next.ServeHTTP(w, r)
+	})
+}
+
+// InstrumentHandlerDuration is a middleware that wraps the provided
+// http.Handler to observe the request duration with the provided ObserverVec.
+// The ObserverVec must have zero, one, or two labels. The only allowed label
+// names are "code" and "method". The function panics if any other instance
+// labels are provided. The Observe method of the Observer in the ObserverVec
+// is called with the request duration in seconds. Partitioning happens by HTTP
+// status code and/or HTTP method if the respective instance label names are
+// present in the ObserverVec. For unpartitioned observations, use an
+// ObserverVec with zero labels. Note that partitioning of Histograms is
+// expensive and should be used judiciously.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, no values are reported.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(obs)
+
+	if code {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			now := time.Now()
+			d := newDelegator(w, nil)
+			next.ServeHTTP(d, r)
+
+			obs.With(labels(code, method, r.Method, d.Status())).Observe(time.Since(now).Seconds())
+		})
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		now := time.Now()
+		next.ServeHTTP(w, r)
+		obs.With(labels(code, method, r.Method, 0)).Observe(time.Since(now).Seconds())
+	})
+}
+
+// InstrumentHandlerCounter is a middleware that wraps the provided
+// http.Handler to observe the request result with the provided CounterVec.
+// The CounterVec must have zero, one, or two labels. The only allowed label
+// names are "code" and "method". The function panics if any other instance
+// labels are provided. Partitioning of the CounterVec happens by HTTP status
+// code and/or HTTP method if the respective instance label names are present
+// in the CounterVec. For unpartitioned counting, use a CounterVec with
+// zero labels.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, the Counter is not incremented.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(counter)
+
+	if code {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			d := newDelegator(w, nil)
+			next.ServeHTTP(d, r)
+			counter.With(labels(code, method, r.Method, d.Status())).Inc()
+		})
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		next.ServeHTTP(w, r)
+		counter.With(labels(code, method, r.Method, 0)).Inc()
+	})
+}
+
+// InstrumentHandlerTimeToWriteHeader is a middleware that wraps the provided
+// http.Handler to observe with the provided ObserverVec the request duration
+// until the response headers are written. The ObserverVec must have zero, one,
+// or two labels. The only allowed label names are "code" and "method". The
+// function panics if any other instance labels are provided. The Observe
+// method of the Observer in the ObserverVec is called with the request
+// duration in seconds. Partitioning happens by HTTP status code and/or HTTP
+// method if the respective instance label names are present in the
+// ObserverVec. For unpartitioned observations, use an ObserverVec with zero
+// labels. Note that partitioning of Histograms is expensive and should be used
+// judiciously.
+//
+// If the wrapped Handler panics before calling WriteHeader, no value is
+// reported.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(obs)
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		now := time.Now()
+		d := newDelegator(w, func(status int) {
+			obs.With(labels(code, method, r.Method, status)).Observe(time.Since(now).Seconds())
+		})
+		next.ServeHTTP(d, r)
+	})
+}
+
+// InstrumentHandlerRequestSize is a middleware that wraps the provided
+// http.Handler to observe the request size with the provided ObserverVec.
+// The ObserverVec must have zero, one, or two labels. The only allowed label
+// names are "code" and "method". The function panics if any other instance
+// labels are provided. The Observe method of the Observer in the ObserverVec
+// is called with the request size in bytes. Partitioning happens by HTTP
+// status code and/or HTTP method if the respective instance label names are
+// present in the ObserverVec. For unpartitioned observations, use an
+// ObserverVec with zero labels. Note that partitioning of Histograms is
+// expensive and should be used judiciously.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, no values are reported.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(obs)
+
+	if code {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			d := newDelegator(w, nil)
+			next.ServeHTTP(d, r)
+			size := computeApproximateRequestSize(r)
+			obs.With(labels(code, method, r.Method, d.Status())).Observe(float64(size))
+		})
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		next.ServeHTTP(w, r)
+		size := computeApproximateRequestSize(r)
+		obs.With(labels(code, method, r.Method, 0)).Observe(float64(size))
+	})
+}
+
+// InstrumentHandlerResponseSize is a middleware that wraps the provided
+// http.Handler to observe the response size with the provided ObserverVec.
+// The ObserverVec must have zero, one, or two labels. The only allowed label
+// names are "code" and "method". The function panics if any other instance
+// labels are provided. The Observe method of the Observer in the ObserverVec
+// is called with the response size in bytes. Partitioning happens by HTTP
+// status code and/or HTTP method if the respective instance label names are
+// present in the ObserverVec. For unpartitioned observations, use an
+// ObserverVec with zero labels. Note that partitioning of Histograms is
+// expensive and should be used judiciously.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, no values are reported.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler) http.Handler {
+	code, method := checkLabels(obs)
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		d := newDelegator(w, nil)
+		next.ServeHTTP(d, r)
+		obs.With(labels(code, method, r.Method, d.Status())).Observe(float64(d.Written()))
+	})
+}
+
+func checkLabels(c prometheus.Collector) (code bool, method bool) {
+	// TODO(beorn7): Remove this hacky way to check for instance labels
+	// once Descriptors can have their dimensionality queried.
+	var (
+		desc *prometheus.Desc
+		pm   dto.Metric
+	)
+
+	descc := make(chan *prometheus.Desc, 1)
+	c.Describe(descc)
+
+	select {
+	case desc = <-descc:
+	default:
+		panic("no description provided by collector")
+	}
+	select {
+	case <-descc:
+		panic("more than one description provided by collector")
+	default:
+	}
+
+	close(descc)
+
+	if _, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0); err == nil {
+		return
+	}
+	if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString); err == nil {
+		if err := m.Write(&pm); err != nil {
+			panic("error checking metric for labels")
+		}
+		for _, label := range pm.Label {
+			name, value := label.GetName(), label.GetValue()
+			if value != magicString {
+				continue
+			}
+			switch name {
+			case "code":
+				code = true
+			case "method":
+				method = true
+			default:
+				panic("metric partitioned with non-supported labels")
+			}
+			return
+		}
+		panic("previously set label not found – this must never happen")
+	}
+	if m, err := prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, magicString, magicString); err == nil {
+		if err := m.Write(&pm); err != nil {
+			panic("error checking metric for labels")
+		}
+		for _, label := range pm.Label {
+			name, value := label.GetName(), label.GetValue()
+			if value != magicString {
+				continue
+			}
+			if name == "code" || name == "method" {
+				continue
+			}
+			panic("metric partitioned with non-supported labels")
+		}
+		code = true
+		method = true
+		return
+	}
+	panic("metric partitioned with non-supported labels")
+}
+
+// emptyLabels is a one-time allocation for non-partitioned metrics to avoid
+// unnecessary allocations on each request.
+var emptyLabels = prometheus.Labels{}
+
+func labels(code, method bool, reqMethod string, status int) prometheus.Labels {
+	if !(code || method) {
+		return emptyLabels
+	}
+	labels := prometheus.Labels{}
+
+	if code {
+		labels["code"] = sanitizeCode(status)
+	}
+	if method {
+		labels["method"] = sanitizeMethod(reqMethod)
+	}
+
+	return labels
+}
+
+func computeApproximateRequestSize(r *http.Request) int {
+	s := 0
+	if r.URL != nil {
+		s += len(r.URL.String())
+	}
+
+	s += len(r.Method)
+	s += len(r.Proto)
+	for name, values := range r.Header {
+		s += len(name)
+		for _, value := range values {
+			s += len(value)
+		}
+	}
+	s += len(r.Host)
+
+	// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
+
+	if r.ContentLength != -1 {
+		s += int(r.ContentLength)
+	}
+	return s
+}
+
+func sanitizeMethod(m string) string {
+	switch m {
+	case "GET", "get":
+		return "get"
+	case "PUT", "put":
+		return "put"
+	case "HEAD", "head":
+		return "head"
+	case "POST", "post":
+		return "post"
+	case "DELETE", "delete":
+		return "delete"
+	case "CONNECT", "connect":
+		return "connect"
+	case "OPTIONS", "options":
+		return "options"
+	case "NOTIFY", "notify":
+		return "notify"
+	default:
+		return strings.ToLower(m)
+	}
+}
+
+// If the wrapped http.Handler has not set a status code, i.e. the value is
+// currently 0, santizeCode will return 200, for consistency with behavior in
+// the stdlib.
+func sanitizeCode(s int) string {
+	switch s {
+	case 100:
+		return "100"
+	case 101:
+		return "101"
+
+	case 200, 0:
+		return "200"
+	case 201:
+		return "201"
+	case 202:
+		return "202"
+	case 203:
+		return "203"
+	case 204:
+		return "204"
+	case 205:
+		return "205"
+	case 206:
+		return "206"
+
+	case 300:
+		return "300"
+	case 301:
+		return "301"
+	case 302:
+		return "302"
+	case 304:
+		return "304"
+	case 305:
+		return "305"
+	case 307:
+		return "307"
+
+	case 400:
+		return "400"
+	case 401:
+		return "401"
+	case 402:
+		return "402"
+	case 403:
+		return "403"
+	case 404:
+		return "404"
+	case 405:
+		return "405"
+	case 406:
+		return "406"
+	case 407:
+		return "407"
+	case 408:
+		return "408"
+	case 409:
+		return "409"
+	case 410:
+		return "410"
+	case 411:
+		return "411"
+	case 412:
+		return "412"
+	case 413:
+		return "413"
+	case 414:
+		return "414"
+	case 415:
+		return "415"
+	case 416:
+		return "416"
+	case 417:
+		return "417"
+	case 418:
+		return "418"
+
+	case 500:
+		return "500"
+	case 501:
+		return "501"
+	case 502:
+		return "502"
+	case 503:
+		return "503"
+	case 504:
+		return "504"
+	case 505:
+		return "505"
+
+	case 428:
+		return "428"
+	case 429:
+		return "429"
+	case 431:
+		return "431"
+	case 511:
+		return "511"
+
+	default:
+		return strconv.Itoa(s)
+	}
+}
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/registry.go b/vendor/github.com/prometheus/client_golang/prometheus/registry.go
index 8c6b5bd..c84a442 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/registry.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/registry.go
@@ -20,6 +20,7 @@ import (
 	"os"
 	"sort"
 	"sync"
+	"unicode/utf8"
 
 	"github.com/golang/protobuf/proto"
 
@@ -80,7 +81,7 @@ func NewPedanticRegistry() *Registry {
 
 // Registerer is the interface for the part of a registry in charge of
 // registering and unregistering. Users of custom registries should use
-// Registerer as type for registration purposes (rather then the Registry type
+// Registerer as type for registration purposes (rather than the Registry type
 // directly). In that way, they are free to use custom Registerer implementation
 // (e.g. for testing purposes).
 type Registerer interface {
@@ -655,7 +656,7 @@ func normalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily)
 
 // checkMetricConsistency checks if the provided Metric is consistent with the
 // provided MetricFamily. It also hashed the Metric labels and the MetricFamily
-// name. If the resulting hash is alread in the provided metricHashes, an error
+// name. If the resulting hash is already in the provided metricHashes, an error
 // is returned. If not, it is added to metricHashes. The provided dimHashes maps
 // MetricFamily names to their dimHash (hashed sorted label names). If dimHashes
 // doesn't yet contain a hash for the provided MetricFamily, it is
@@ -679,6 +680,12 @@ func checkMetricConsistency(
 		)
 	}
 
+	for _, labelPair := range dtoMetric.GetLabel() {
+		if !utf8.ValidString(*labelPair.Value) {
+			return fmt.Errorf("collected metric's label %s is not utf8: %#v", *labelPair.Name, *labelPair.Value)
+		}
+	}
+
 	// Is the metric unique (i.e. no other metric with the same name and the same label values)?
 	h := hashNew()
 	h = hashAdd(h, metricFamily.GetName())
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/summary.go b/vendor/github.com/prometheus/client_golang/prometheus/summary.go
index 82b8850..21c031e 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/summary.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/summary.go
@@ -36,7 +36,10 @@ const quantileLabel = "quantile"
 //
 // A typical use-case is the observation of request latencies. By default, a
 // Summary provides the median, the 90th and the 99th percentile of the latency
-// as rank estimations.
+// as rank estimations. However, the default behavior will change in the
+// upcoming v0.10 of the library. There will be no rank estiamtions at all by
+// default. For a sane transition, it is recommended to set the desired rank
+// estimations explicitly.
 //
 // Note that the rank estimations cannot be aggregated in a meaningful way with
 // the Prometheus query language (i.e. you cannot average or add them). If you
@@ -78,8 +81,10 @@ const (
 )
 
 // SummaryOpts bundles the options for creating a Summary metric. It is
-// mandatory to set Name and Help to a non-empty string. All other fields are
-// optional and can safely be left at their zero value.
+// mandatory to set Name and Help to a non-empty string. While all other fields
+// are optional and can safely be left at their zero value, it is recommended to
+// explicitly set the Objectives field to the desired value as the default value
+// will change in the upcoming v0.10 of the library.
 type SummaryOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Summary (created by joining these components with
@@ -399,12 +404,11 @@ func (s quantSort) Less(i, j int) bool {
 // (e.g. HTTP request latencies, partitioned by status code and method). Create
 // instances with NewSummaryVec.
 type SummaryVec struct {
-	*MetricVec
+	*metricVec
 }
 
 // NewSummaryVec creates a new SummaryVec based on the provided SummaryOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -413,30 +417,60 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
 		opts.ConstLabels,
 	)
 	return &SummaryVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
+		metricVec: newMetricVec(desc, func(lvs ...string) Metric {
 			return newSummary(desc, opts, lvs...)
 		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Summary and not a
-// Metric so that no type conversion is required.
-func (m *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Summary, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Summary for the given slice of label
+// values (same order as the VariableLabels in Desc). If that combination of
+// label values is accessed for the first time, a new Summary is created.
+//
+// It is possible to call this method without using the returned Summary to only
+// create the new Summary but leave it at its starting value, a Summary without
+// any observations.
+//
+// Keeping the Summary for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Summary from the SummaryVec. In that case, the
+// Summary will still exist, but it will not be exported anymore, even if a
+// Summary with the same label values is created later. See also the CounterVec
+// example.
+//
+// An error is returned if the number of label values is not the same as the
+// number of VariableLabels in Desc.
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the GaugeVec example.
+func (m *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
+	metric, err := m.metricVec.getMetricWithLabelValues(lvs...)
 	if metric != nil {
-		return metric.(Summary), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Summary and not a Metric so that no
-// type conversion is required.
-func (m *SummaryVec) GetMetricWith(labels Labels) (Summary, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Summary for the given Labels map (the label names
+// must match those of the VariableLabels in Desc). If that label map is
+// accessed for the first time, a new Summary is created. Implications of
+// creating a Summary without using it and keeping the Summary for later use are
+// the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the VariableLabels in Desc.
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (m *SummaryVec) GetMetricWith(labels Labels) (Observer, error) {
+	metric, err := m.metricVec.getMetricWith(labels)
 	if metric != nil {
-		return metric.(Summary), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
@@ -445,15 +479,15 @@ func (m *SummaryVec) GetMetricWith(labels Labels) (Summary, error) {
 // GetMetricWithLabelValues would have returned an error. By not returning an
 // error, WithLabelValues allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Observe(42.21)
-func (m *SummaryVec) WithLabelValues(lvs ...string) Summary {
-	return m.MetricVec.WithLabelValues(lvs...).(Summary)
+func (m *SummaryVec) WithLabelValues(lvs ...string) Observer {
+	return m.metricVec.withLabelValues(lvs...).(Observer)
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
 // returned an error. By not returning an error, With allows shortcuts like
 //     myVec.With(Labels{"code": "404", "method": "GET"}).Observe(42.21)
-func (m *SummaryVec) With(labels Labels) Summary {
-	return m.MetricVec.With(labels).(Summary)
+func (m *SummaryVec) With(labels Labels) Observer {
+	return m.metricVec.with(labels).(Observer)
 }
 
 type constSummary struct {
@@ -514,8 +548,8 @@ func NewConstSummary(
 	quantiles map[float64]float64,
 	labelValues ...string,
 ) (Metric, error) {
-	if len(desc.variableLabels) != len(labelValues) {
-		return nil, errInconsistentCardinality
+	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
+		return nil, err
 	}
 	return &constSummary{
 		desc:       desc,
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/timer.go b/vendor/github.com/prometheus/client_golang/prometheus/timer.go
index f4cac5a..b8fc5f1 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/timer.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/timer.go
@@ -15,32 +15,6 @@ package prometheus
 
 import "time"
 
-// Observer is the interface that wraps the Observe method, which is used by
-// Histogram and Summary to add observations.
-type Observer interface {
-	Observe(float64)
-}
-
-// The ObserverFunc type is an adapter to allow the use of ordinary
-// functions as Observers. If f is a function with the appropriate
-// signature, ObserverFunc(f) is an Observer that calls f.
-//
-// This adapter is usually used in connection with the Timer type, and there are
-// two general use cases:
-//
-// The most common one is to use a Gauge as the Observer for a Timer.
-// See the "Gauge" Timer example.
-//
-// The more advanced use case is to create a function that dynamically decides
-// which Observer to use for observing the duration. See the "Complex" Timer
-// example.
-type ObserverFunc func(float64)
-
-// Observe calls f(value). It implements Observer.
-func (f ObserverFunc) Observe(value float64) {
-	f(value)
-}
-
 // Timer is a helper type to time functions. Use NewTimer to create new
 // instances.
 type Timer struct {
@@ -67,6 +41,9 @@ func NewTimer(o Observer) *Timer {
 // NewTimer. It calls the Observe method of the Observer provided during
 // construction with the duration in seconds as an argument. ObserveDuration is
 // usually called with a defer statement.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
 func (t *Timer) ObserveDuration() {
 	if t.observer != nil {
 		t.observer.Observe(time.Since(t.begin).Seconds())
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/untyped.go b/vendor/github.com/prometheus/client_golang/prometheus/untyped.go
index 065501d..0f9ce63 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/untyped.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/untyped.go
@@ -13,113 +13,12 @@
 
 package prometheus
 
-// Untyped is a Metric that represents a single numerical value that can
-// arbitrarily go up and down.
-//
-// An Untyped metric works the same as a Gauge. The only difference is that to
-// no type information is implied.
-//
-// To create Untyped instances, use NewUntyped.
-//
-// Deprecated: The Untyped type is deprecated because it doesn't make sense in
-// direct instrumentation. If you need to mirror an external metric of unknown
-// type (usually while writing exporters), Use MustNewConstMetric to create an
-// untyped metric instance on the fly.
-type Untyped interface {
-	Metric
-	Collector
-
-	// Set sets the Untyped metric to an arbitrary value.
-	Set(float64)
-	// Inc increments the Untyped metric by 1.
-	Inc()
-	// Dec decrements the Untyped metric by 1.
-	Dec()
-	// Add adds the given value to the Untyped metric. (The value can be
-	// negative, resulting in a decrease.)
-	Add(float64)
-	// Sub subtracts the given value from the Untyped metric. (The value can
-	// be negative, resulting in an increase.)
-	Sub(float64)
-}
-
 // UntypedOpts is an alias for Opts. See there for doc comments.
 type UntypedOpts Opts
 
-// NewUntyped creates a new Untyped metric from the provided UntypedOpts.
-func NewUntyped(opts UntypedOpts) Untyped {
-	return newValue(NewDesc(
-		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
-		opts.Help,
-		nil,
-		opts.ConstLabels,
-	), UntypedValue, 0)
-}
-
-// UntypedVec is a Collector that bundles a set of Untyped metrics that all
-// share the same Desc, but have different values for their variable
-// labels. This is used if you want to count the same thing partitioned by
-// various dimensions. Create instances with NewUntypedVec.
-type UntypedVec struct {
-	*MetricVec
-}
-
-// NewUntypedVec creates a new UntypedVec based on the provided UntypedOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
-func NewUntypedVec(opts UntypedOpts, labelNames []string) *UntypedVec {
-	desc := NewDesc(
-		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
-		opts.Help,
-		labelNames,
-		opts.ConstLabels,
-	)
-	return &UntypedVec{
-		MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
-			return newValue(desc, UntypedValue, 0, lvs...)
-		}),
-	}
-}
-
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns an Untyped and not a
-// Metric so that no type conversion is required.
-func (m *UntypedVec) GetMetricWithLabelValues(lvs ...string) (Untyped, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
-	if metric != nil {
-		return metric.(Untyped), err
-	}
-	return nil, err
-}
-
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns an Untyped and not a Metric so that no
-// type conversion is required.
-func (m *UntypedVec) GetMetricWith(labels Labels) (Untyped, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
-	if metric != nil {
-		return metric.(Untyped), err
-	}
-	return nil, err
-}
-
-// WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
-//     myVec.WithLabelValues("404", "GET").Add(42)
-func (m *UntypedVec) WithLabelValues(lvs ...string) Untyped {
-	return m.MetricVec.WithLabelValues(lvs...).(Untyped)
-}
-
-// With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-func (m *UntypedVec) With(labels Labels) Untyped {
-	return m.MetricVec.With(labels).(Untyped)
-}
-
-// UntypedFunc is an Untyped whose value is determined at collect time by
-// calling a provided function.
+// UntypedFunc works like GaugeFunc but the collected metric is of type
+// "Untyped". UntypedFunc is useful to mirror an external metric of unknown
+// type.
 //
 // To create UntypedFunc instances, use NewUntypedFunc.
 type UntypedFunc interface {
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/value.go b/vendor/github.com/prometheus/client_golang/prometheus/value.go
index ff75ce5..4a9cca6 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/value.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/value.go
@@ -14,7 +14,6 @@
 package prometheus
 
 import (
-	"errors"
 	"fmt"
 	"math"
 	"sort"
@@ -37,8 +36,6 @@ const (
 	UntypedValue
 )
 
-var errInconsistentCardinality = errors.New("inconsistent label cardinality")
-
 // value is a generic metric for simple values. It implements Metric, Collector,
 // Counter, Gauge, and Untyped. Its effective type is determined by
 // ValueType. This is a low-level building block used by the library to back the
@@ -158,8 +155,8 @@ func (v *valueFunc) Write(out *dto.Metric) error {
 // the Collect method. NewConstMetric returns an error if the length of
 // labelValues is not consistent with the variable labels in Desc.
 func NewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues ...string) (Metric, error) {
-	if len(desc.variableLabels) != len(labelValues) {
-		return nil, errInconsistentCardinality
+	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
+		return nil, err
 	}
 	return &constMetric{
 		desc:       desc,
diff --git a/vendor/github.com/prometheus/client_golang/prometheus/vec.go b/vendor/github.com/prometheus/client_golang/prometheus/vec.go
index 7f3eef9..65d13fe 100644
--- a/vendor/github.com/prometheus/client_golang/prometheus/vec.go
+++ b/vendor/github.com/prometheus/client_golang/prometheus/vec.go
@@ -20,12 +20,12 @@ import (
 	"github.com/prometheus/common/model"
 )
 
-// MetricVec is a Collector to bundle metrics of the same name that
-// differ in their label values. MetricVec is usually not used directly but as a
-// building block for implementations of vectors of a given metric
-// type. GaugeVec, CounterVec, SummaryVec, and UntypedVec are examples already
-// provided in this package.
-type MetricVec struct {
+// metricVec is a Collector to bundle metrics of the same name that differ in
+// their label values. metricVec is not used directly (and therefore
+// unexported). It is used as a building block for implementations of vectors of
+// a given metric type, like GaugeVec, CounterVec, SummaryVec, HistogramVec, and
+// UntypedVec.
+type metricVec struct {
 	mtx      sync.RWMutex // Protects the children.
 	children map[uint64][]metricWithLabelValues
 	desc     *Desc
@@ -35,10 +35,9 @@ type MetricVec struct {
 	hashAddByte func(h uint64, b byte) uint64
 }
 
-// newMetricVec returns an initialized MetricVec. The concrete value is
-// returned for embedding into another struct.
-func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *MetricVec {
-	return &MetricVec{
+// newMetricVec returns an initialized metricVec.
+func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *metricVec {
+	return &metricVec{
 		children:    map[uint64][]metricWithLabelValues{},
 		desc:        desc,
 		newMetric:   newMetric,
@@ -56,12 +55,12 @@ type metricWithLabelValues struct {
 
 // Describe implements Collector. The length of the returned slice
 // is always one.
-func (m *MetricVec) Describe(ch chan<- *Desc) {
+func (m *metricVec) Describe(ch chan<- *Desc) {
 	ch <- m.desc
 }
 
 // Collect implements Collector.
-func (m *MetricVec) Collect(ch chan<- Metric) {
+func (m *metricVec) Collect(ch chan<- Metric) {
 	m.mtx.RLock()
 	defer m.mtx.RUnlock()
 
@@ -72,31 +71,7 @@ func (m *MetricVec) Collect(ch chan<- Metric) {
 	}
 }
 
-// GetMetricWithLabelValues returns the Metric for the given slice of label
-// values (same order as the VariableLabels in Desc). If that combination of
-// label values is accessed for the first time, a new Metric is created.
-//
-// It is possible to call this method without using the returned Metric to only
-// create the new Metric but leave it at its start value (e.g. a Summary or
-// Histogram without any observations). See also the SummaryVec example.
-//
-// Keeping the Metric for later use is possible (and should be considered if
-// performance is critical), but keep in mind that Reset, DeleteLabelValues and
-// Delete can be used to delete the Metric from the MetricVec. In that case, the
-// Metric will still exist, but it will not be exported anymore, even if a
-// Metric with the same label values is created later. See also the CounterVec
-// example.
-//
-// An error is returned if the number of label values is not the same as the
-// number of VariableLabels in Desc.
-//
-// Note that for more than one label value, this method is prone to mistakes
-// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
-// an alternative to avoid that type of mistake. For higher label numbers, the
-// latter has a much more readable (albeit more verbose) syntax, but it comes
-// with a performance overhead (for creating and processing the Labels map).
-// See also the GaugeVec example.
-func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
+func (m *metricVec) getMetricWithLabelValues(lvs ...string) (Metric, error) {
 	h, err := m.hashLabelValues(lvs)
 	if err != nil {
 		return nil, err
@@ -105,19 +80,7 @@ func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
 	return m.getOrCreateMetricWithLabelValues(h, lvs), nil
 }
 
-// GetMetricWith returns the Metric for the given Labels map (the label names
-// must match those of the VariableLabels in Desc). If that label map is
-// accessed for the first time, a new Metric is created. Implications of
-// creating a Metric without using it and keeping the Metric for later use are
-// the same as for GetMetricWithLabelValues.
-//
-// An error is returned if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in Desc.
-//
-// This method is used for the same purpose as
-// GetMetricWithLabelValues(...string). See there for pros and cons of the two
-// methods.
-func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) {
+func (m *metricVec) getMetricWith(labels Labels) (Metric, error) {
 	h, err := m.hashLabels(labels)
 	if err != nil {
 		return nil, err
@@ -126,22 +89,16 @@ func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) {
 	return m.getOrCreateMetricWithLabels(h, labels), nil
 }
 
-// WithLabelValues works as GetMetricWithLabelValues, but panics if an error
-// occurs. The method allows neat syntax like:
-//     httpReqs.WithLabelValues("404", "POST").Inc()
-func (m *MetricVec) WithLabelValues(lvs ...string) Metric {
-	metric, err := m.GetMetricWithLabelValues(lvs...)
+func (m *metricVec) withLabelValues(lvs ...string) Metric {
+	metric, err := m.getMetricWithLabelValues(lvs...)
 	if err != nil {
 		panic(err)
 	}
 	return metric
 }
 
-// With works as GetMetricWith, but panics if an error occurs. The method allows
-// neat syntax like:
-//     httpReqs.With(Labels{"status":"404", "method":"POST"}).Inc()
-func (m *MetricVec) With(labels Labels) Metric {
-	metric, err := m.GetMetricWith(labels)
+func (m *metricVec) with(labels Labels) Metric {
+	metric, err := m.getMetricWith(labels)
 	if err != nil {
 		panic(err)
 	}
@@ -153,8 +110,8 @@ func (m *MetricVec) With(labels Labels) Metric {
 // returns true if a metric was deleted.
 //
 // It is not an error if the number of label values is not the same as the
-// number of VariableLabels in Desc.  However, such inconsistent label count can
-// never match an actual Metric, so the method will always return false in that
+// number of VariableLabels in Desc. However, such inconsistent label count can
+// never match an actual metric, so the method will always return false in that
 // case.
 //
 // Note that for more than one label value, this method is prone to mistakes
@@ -163,7 +120,7 @@ func (m *MetricVec) With(labels Labels) Metric {
 // latter has a much more readable (albeit more verbose) syntax, but it comes
 // with a performance overhead (for creating and processing the Labels map).
 // See also the CounterVec example.
-func (m *MetricVec) DeleteLabelValues(lvs ...string) bool {
+func (m *metricVec) DeleteLabelValues(lvs ...string) bool {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
 
@@ -178,13 +135,13 @@ func (m *MetricVec) DeleteLabelValues(lvs ...string) bool {
 // passed in as labels. It returns true if a metric was deleted.
 //
 // It is not an error if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in the Desc of the MetricVec. However, such
-// inconsistent Labels can never match an actual Metric, so the method will
-// always return false in that case.
+// with those of the VariableLabels in Desc. However, such inconsistent Labels
+// can never match an actual metric, so the method will always return false in
+// that case.
 //
 // This method is used for the same purpose as DeleteLabelValues(...string). See
 // there for pros and cons of the two methods.
-func (m *MetricVec) Delete(labels Labels) bool {
+func (m *metricVec) Delete(labels Labels) bool {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
 
@@ -199,7 +156,7 @@ func (m *MetricVec) Delete(labels Labels) bool {
 // deleteByHashWithLabelValues removes the metric from the hash bucket h. If
 // there are multiple matches in the bucket, use lvs to select a metric and
 // remove only that metric.
-func (m *MetricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool {
+func (m *metricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool {
 	metrics, ok := m.children[h]
 	if !ok {
 		return false
@@ -221,7 +178,7 @@ func (m *MetricVec) deleteByHashWithLabelValues(h uint64, lvs []string) bool {
 // deleteByHashWithLabels removes the metric from the hash bucket h. If there
 // are multiple matches in the bucket, use lvs to select a metric and remove
 // only that metric.
-func (m *MetricVec) deleteByHashWithLabels(h uint64, labels Labels) bool {
+func (m *metricVec) deleteByHashWithLabels(h uint64, labels Labels) bool {
 	metrics, ok := m.children[h]
 	if !ok {
 		return false
@@ -240,7 +197,7 @@ func (m *MetricVec) deleteByHashWithLabels(h uint64, labels Labels) bool {
 }
 
 // Reset deletes all metrics in this vector.
-func (m *MetricVec) Reset() {
+func (m *metricVec) Reset() {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
 
@@ -249,10 +206,11 @@ func (m *MetricVec) Reset() {
 	}
 }
 
-func (m *MetricVec) hashLabelValues(vals []string) (uint64, error) {
-	if len(vals) != len(m.desc.variableLabels) {
-		return 0, errInconsistentCardinality
+func (m *metricVec) hashLabelValues(vals []string) (uint64, error) {
+	if err := validateLabelValues(vals, len(m.desc.variableLabels)); err != nil {
+		return 0, err
 	}
+
 	h := hashNew()
 	for _, val := range vals {
 		h = m.hashAdd(h, val)
@@ -261,10 +219,11 @@ func (m *MetricVec) hashLabelValues(vals []string) (uint64, error) {
 	return h, nil
 }
 
-func (m *MetricVec) hashLabels(labels Labels) (uint64, error) {
-	if len(labels) != len(m.desc.variableLabels) {
-		return 0, errInconsistentCardinality
+func (m *metricVec) hashLabels(labels Labels) (uint64, error) {
+	if err := validateValuesInLabels(labels, len(m.desc.variableLabels)); err != nil {
+		return 0, err
 	}
+
 	h := hashNew()
 	for _, label := range m.desc.variableLabels {
 		val, ok := labels[label]
@@ -281,9 +240,9 @@ func (m *MetricVec) hashLabels(labels Labels) (uint64, error) {
 // or creates it and returns the new one.
 //
 // This function holds the mutex.
-func (m *MetricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) Metric {
+func (m *metricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string) Metric {
 	m.mtx.RLock()
-	metric, ok := m.getMetricWithLabelValues(hash, lvs)
+	metric, ok := m.getMetricWithHashAndLabelValues(hash, lvs)
 	m.mtx.RUnlock()
 	if ok {
 		return metric
@@ -291,7 +250,7 @@ func (m *MetricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string)
 
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
-	metric, ok = m.getMetricWithLabelValues(hash, lvs)
+	metric, ok = m.getMetricWithHashAndLabelValues(hash, lvs)
 	if !ok {
 		// Copy to avoid allocation in case wo don't go down this code path.
 		copiedLVs := make([]string, len(lvs))
@@ -306,9 +265,9 @@ func (m *MetricVec) getOrCreateMetricWithLabelValues(hash uint64, lvs []string)
 // or creates it and returns the new one.
 //
 // This function holds the mutex.
-func (m *MetricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metric {
+func (m *metricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metric {
 	m.mtx.RLock()
-	metric, ok := m.getMetricWithLabels(hash, labels)
+	metric, ok := m.getMetricWithHashAndLabels(hash, labels)
 	m.mtx.RUnlock()
 	if ok {
 		return metric
@@ -316,7 +275,7 @@ func (m *MetricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metr
 
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
-	metric, ok = m.getMetricWithLabels(hash, labels)
+	metric, ok = m.getMetricWithHashAndLabels(hash, labels)
 	if !ok {
 		lvs := m.extractLabelValues(labels)
 		metric = m.newMetric(lvs...)
@@ -325,9 +284,9 @@ func (m *MetricVec) getOrCreateMetricWithLabels(hash uint64, labels Labels) Metr
 	return metric
 }
 
-// getMetricWithLabelValues gets a metric while handling possible collisions in
-// the hash space. Must be called while holding read mutex.
-func (m *MetricVec) getMetricWithLabelValues(h uint64, lvs []string) (Metric, bool) {
+// getMetricWithHashAndLabelValues gets a metric while handling possible
+// collisions in the hash space. Must be called while holding the read mutex.
+func (m *metricVec) getMetricWithHashAndLabelValues(h uint64, lvs []string) (Metric, bool) {
 	metrics, ok := m.children[h]
 	if ok {
 		if i := m.findMetricWithLabelValues(metrics, lvs); i < len(metrics) {
@@ -337,9 +296,9 @@ func (m *MetricVec) getMetricWithLabelValues(h uint64, lvs []string) (Metric, bo
 	return nil, false
 }
 
-// getMetricWithLabels gets a metric while handling possible collisions in
+// getMetricWithHashAndLabels gets a metric while handling possible collisions in
 // the hash space. Must be called while holding read mutex.
-func (m *MetricVec) getMetricWithLabels(h uint64, labels Labels) (Metric, bool) {
+func (m *metricVec) getMetricWithHashAndLabels(h uint64, labels Labels) (Metric, bool) {
 	metrics, ok := m.children[h]
 	if ok {
 		if i := m.findMetricWithLabels(metrics, labels); i < len(metrics) {
@@ -351,7 +310,7 @@ func (m *MetricVec) getMetricWithLabels(h uint64, labels Labels) (Metric, bool)
 
 // findMetricWithLabelValues returns the index of the matching metric or
 // len(metrics) if not found.
-func (m *MetricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, lvs []string) int {
+func (m *metricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, lvs []string) int {
 	for i, metric := range metrics {
 		if m.matchLabelValues(metric.values, lvs) {
 			return i
@@ -362,7 +321,7 @@ func (m *MetricVec) findMetricWithLabelValues(metrics []metricWithLabelValues, l
 
 // findMetricWithLabels returns the index of the matching metric or len(metrics)
 // if not found.
-func (m *MetricVec) findMetricWithLabels(metrics []metricWithLabelValues, labels Labels) int {
+func (m *metricVec) findMetricWithLabels(metrics []metricWithLabelValues, labels Labels) int {
 	for i, metric := range metrics {
 		if m.matchLabels(metric.values, labels) {
 			return i
@@ -371,7 +330,7 @@ func (m *MetricVec) findMetricWithLabels(metrics []metricWithLabelValues, labels
 	return len(metrics)
 }
 
-func (m *MetricVec) matchLabelValues(values []string, lvs []string) bool {
+func (m *metricVec) matchLabelValues(values []string, lvs []string) bool {
 	if len(values) != len(lvs) {
 		return false
 	}
@@ -383,7 +342,7 @@ func (m *MetricVec) matchLabelValues(values []string, lvs []string) bool {
 	return true
 }
 
-func (m *MetricVec) matchLabels(values []string, labels Labels) bool {
+func (m *metricVec) matchLabels(values []string, labels Labels) bool {
 	if len(labels) != len(values) {
 		return false
 	}
@@ -395,7 +354,7 @@ func (m *MetricVec) matchLabels(values []string, labels Labels) bool {
 	return true
 }
 
-func (m *MetricVec) extractLabelValues(labels Labels) []string {
+func (m *metricVec) extractLabelValues(labels Labels) []string {
 	labelValues := make([]string, len(labels))
 	for i, k := range m.desc.variableLabels {
 		labelValues[i] = labels[k]
diff --git a/vendor/github.com/prometheus/common/expfmt/text_parse.go b/vendor/github.com/prometheus/common/expfmt/text_parse.go
index ef9a150..54bcfde 100644
--- a/vendor/github.com/prometheus/common/expfmt/text_parse.go
+++ b/vendor/github.com/prometheus/common/expfmt/text_parse.go
@@ -315,6 +315,10 @@ func (p *TextParser) startLabelValue() stateFn {
 	if p.readTokenAsLabelValue(); p.err != nil {
 		return nil
 	}
+	if !model.LabelValue(p.currentToken.String()).IsValid() {
+		p.parseError(fmt.Sprintf("invalid label value %q", p.currentToken.String()))
+		return nil
+	}
 	p.currentLabelPair.Value = proto.String(p.currentToken.String())
 	// Special treatment of summaries:
 	// - Quantile labels are special, will result in dto.Quantile later.
diff --git a/vendor/github.com/prometheus/common/model/time.go b/vendor/github.com/prometheus/common/model/time.go
index 548968a..7e87f1a 100644
--- a/vendor/github.com/prometheus/common/model/time.go
+++ b/vendor/github.com/prometheus/common/model/time.go
@@ -163,9 +163,21 @@ func (t *Time) UnmarshalJSON(b []byte) error {
 // This type should not propagate beyond the scope of input/output processing.
 type Duration time.Duration
 
+// Set implements pflag/flag.Value
+func (d *Duration) Set(s string) error {
+	var err error
+	*d, err = ParseDuration(s)
+	return err
+}
+
+// Type implements pflag.Value
+func (d *Duration) Type() string {
+	return "duration"
+}
+
 var durationRE = regexp.MustCompile("^([0-9]+)(y|w|d|h|m|s|ms)$")
 
-// StringToDuration parses a string into a time.Duration, assuming that a year
+// 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) {
 	matches := durationRE.FindStringSubmatch(durationStr)
diff --git a/vendor/github.com/prometheus/procfs/Makefile b/vendor/github.com/prometheus/procfs/Makefile
index c264a49..dd48afd 100644
--- a/vendor/github.com/prometheus/procfs/Makefile
+++ b/vendor/github.com/prometheus/procfs/Makefile
@@ -1,6 +1,18 @@
-ci:
+ci: fmt lint test
+
+fmt:
 	! gofmt -l *.go | read nothing
 	go vet
-	go test -v ./...
+
+lint:
 	go get github.com/golang/lint/golint
 	golint *.go
+
+test: sysfs/fixtures/.unpacked
+	go test -v ./...
+
+sysfs/fixtures/.unpacked: sysfs/fixtures.ttar
+	./ttar -C sysfs -x -f sysfs/fixtures.ttar
+	touch $@
+
+.PHONY: fmt lint test ci
diff --git a/vendor/github.com/prometheus/procfs/ipvs.go b/vendor/github.com/prometheus/procfs/ipvs.go
index e7012f7..696d114 100644
--- a/vendor/github.com/prometheus/procfs/ipvs.go
+++ b/vendor/github.com/prometheus/procfs/ipvs.go
@@ -33,6 +33,8 @@ type IPVSBackendStatus struct {
 	LocalAddress net.IP
 	// The local (virtual) port.
 	LocalPort uint16
+	// The local firewall mark
+	LocalMark string
 	// The transport protocol (TCP, UDP).
 	Proto string
 	// The remote (real) IP address.
@@ -142,6 +144,7 @@ func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
 		status       []IPVSBackendStatus
 		scanner      = bufio.NewScanner(file)
 		proto        string
+		localMark    string
 		localAddress net.IP
 		localPort    uint16
 		err          error
@@ -160,10 +163,19 @@ func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
 				continue
 			}
 			proto = fields[0]
+			localMark = ""
 			localAddress, localPort, err = parseIPPort(fields[1])
 			if err != nil {
 				return nil, err
 			}
+		case fields[0] == "FWM":
+			if len(fields) < 2 {
+				continue
+			}
+			proto = fields[0]
+			localMark = fields[1]
+			localAddress = nil
+			localPort = 0
 		case fields[0] == "->":
 			if len(fields) < 6 {
 				continue
@@ -187,6 +199,7 @@ func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
 			status = append(status, IPVSBackendStatus{
 				LocalAddress:  localAddress,
 				LocalPort:     localPort,
+				LocalMark:     localMark,
 				RemoteAddress: remoteAddress,
 				RemotePort:    remotePort,
 				Proto:         proto,
@@ -200,22 +213,31 @@ func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
 }
 
 func parseIPPort(s string) (net.IP, uint16, error) {
-	tmp := strings.SplitN(s, ":", 2)
-
-	if len(tmp) != 2 {
-		return nil, 0, fmt.Errorf("invalid IP:Port: %s", s)
-	}
+	var (
+		ip  net.IP
+		err error
+	)
 
-	if len(tmp[0]) != 8 && len(tmp[0]) != 32 {
-		return nil, 0, fmt.Errorf("invalid IP: %s", tmp[0])
+	switch len(s) {
+	case 13:
+		ip, err = hex.DecodeString(s[0:8])
+		if err != nil {
+			return nil, 0, err
+		}
+	case 46:
+		ip = net.ParseIP(s[1:40])
+		if ip == nil {
+			return nil, 0, fmt.Errorf("invalid IPv6 address: %s", s[1:40])
+		}
+	default:
+		return nil, 0, fmt.Errorf("unexpected IP:Port: %s", s)
 	}
 
-	ip, err := hex.DecodeString(tmp[0])
-	if err != nil {
-		return nil, 0, err
+	portString := s[len(s)-4:]
+	if len(portString) != 4 {
+		return nil, 0, fmt.Errorf("unexpected port string format: %s", portString)
 	}
-
-	port, err := strconv.ParseUint(tmp[1], 16, 16)
+	port, err := strconv.ParseUint(portString, 16, 16)
 	if err != nil {
 		return nil, 0, err
 	}
diff --git a/vendor/github.com/prometheus/procfs/mountstats.go b/vendor/github.com/prometheus/procfs/mountstats.go
index fe8f1f6..6b2b0ba 100644
--- a/vendor/github.com/prometheus/procfs/mountstats.go
+++ b/vendor/github.com/prometheus/procfs/mountstats.go
@@ -523,15 +523,19 @@ func parseNFSTransportStats(ss []string, statVersion string) (*NFSTransportStats
 	}
 
 	// Allocate enough for v1.1 stats since zero value for v1.1 stats will be okay
-	// in a v1.0 response
-	ns := make([]uint64, 0, fieldTransport11Len)
-	for _, s := range ss {
+	// in a v1.0 response.
+	//
+	// Note: slice length must be set to length of v1.1 stats to avoid a panic when
+	// only v1.0 stats are present.
+	// See: https://github.com/prometheus/node_exporter/issues/571.
+	ns := make([]uint64, fieldTransport11Len)
+	for i, s := range ss {
 		n, err := strconv.ParseUint(s, 10, 64)
 		if err != nil {
 			return nil, err
 		}
 
-		ns = append(ns, n)
+		ns[i] = n
 	}
 
 	return &NFSTransportStats{
diff --git a/vendor/github.com/prometheus/procfs/proc_limits.go b/vendor/github.com/prometheus/procfs/proc_limits.go
index 2df997c..b684a5b 100644
--- a/vendor/github.com/prometheus/procfs/proc_limits.go
+++ b/vendor/github.com/prometheus/procfs/proc_limits.go
@@ -13,46 +13,46 @@ import (
 // http://man7.org/linux/man-pages/man2/getrlimit.2.html.
 type ProcLimits struct {
 	// CPU time limit in seconds.
-	CPUTime int
+	CPUTime int64
 	// Maximum size of files that the process may create.
-	FileSize int
+	FileSize int64
 	// Maximum size of the process's data segment (initialized data,
 	// uninitialized data, and heap).
-	DataSize int
+	DataSize int64
 	// Maximum size of the process stack in bytes.
-	StackSize int
+	StackSize int64
 	// Maximum size of a core file.
-	CoreFileSize int
+	CoreFileSize int64
 	// Limit of the process's resident set in pages.
-	ResidentSet int
+	ResidentSet int64
 	// Maximum number of processes that can be created for the real user ID of
 	// the calling process.
-	Processes int
+	Processes int64
 	// Value one greater than the maximum file descriptor number that can be
 	// opened by this process.
-	OpenFiles int
+	OpenFiles int64
 	// Maximum number of bytes of memory that may be locked into RAM.
-	LockedMemory int
+	LockedMemory int64
 	// Maximum size of the process's virtual memory address space in bytes.
-	AddressSpace int
+	AddressSpace int64
 	// Limit on the combined number of flock(2) locks and fcntl(2) leases that
 	// this process may establish.
-	FileLocks int
+	FileLocks int64
 	// Limit of signals that may be queued for the real user ID of the calling
 	// process.
-	PendingSignals int
+	PendingSignals int64
 	// Limit on the number of bytes that can be allocated for POSIX message
 	// queues for the real user ID of the calling process.
-	MsqqueueSize int
+	MsqqueueSize int64
 	// Limit of the nice priority set using setpriority(2) or nice(2).
-	NicePriority int
+	NicePriority int64
 	// Limit of the real-time priority set using sched_setscheduler(2) or
 	// sched_setparam(2).
-	RealtimePriority int
+	RealtimePriority int64
 	// Limit (in microseconds) on the amount of CPU time that a process
 	// scheduled under a real-time scheduling policy may consume without making
 	// a blocking system call.
-	RealtimeTimeout int
+	RealtimeTimeout int64
 }
 
 const (
@@ -125,13 +125,13 @@ func (p Proc) NewLimits() (ProcLimits, error) {
 	return l, s.Err()
 }
 
-func parseInt(s string) (int, error) {
+func parseInt(s string) (int64, error) {
 	if s == limitsUnlimited {
 		return -1, nil
 	}
-	i, err := strconv.ParseInt(s, 10, 32)
+	i, err := strconv.ParseInt(s, 10, 64)
 	if err != nil {
 		return 0, fmt.Errorf("couldn't parse value %s: %s", s, err)
 	}
-	return int(i), nil
+	return i, nil
 }
diff --git a/vendor/github.com/prometheus/procfs/stat.go b/vendor/github.com/prometheus/procfs/stat.go
index 1ca217e..701f4df 100644
--- a/vendor/github.com/prometheus/procfs/stat.go
+++ b/vendor/github.com/prometheus/procfs/stat.go
@@ -3,15 +3,66 @@ package procfs
 import (
 	"bufio"
 	"fmt"
+	"io"
 	"os"
 	"strconv"
 	"strings"
 )
 
+// CPUStat shows how much time the cpu spend in various stages.
+type CPUStat struct {
+	User      float64
+	Nice      float64
+	System    float64
+	Idle      float64
+	Iowait    float64
+	IRQ       float64
+	SoftIRQ   float64
+	Steal     float64
+	Guest     float64
+	GuestNice float64
+}
+
+// SoftIRQStat represent the softirq statistics as exported in the procfs stat file.
+// A nice introduction can be found at https://0xax.gitbooks.io/linux-insides/content/interrupts/interrupts-9.html
+// It is possible to get per-cpu stats by reading /proc/softirqs
+type SoftIRQStat struct {
+	Hi          uint64
+	Timer       uint64
+	NetTx       uint64
+	NetRx       uint64
+	Block       uint64
+	BlockIoPoll uint64
+	Tasklet     uint64
+	Sched       uint64
+	Hrtimer     uint64
+	Rcu         uint64
+}
+
 // Stat represents kernel/system statistics.
 type Stat struct {
 	// Boot time in seconds since the Epoch.
-	BootTime int64
+	BootTime uint64
+	// Summed up cpu statistics.
+	CPUTotal CPUStat
+	// Per-CPU statistics.
+	CPU []CPUStat
+	// Number of times interrupts were handled, which contains numbered and unnumbered IRQs.
+	IRQTotal uint64
+	// Number of times a numbered IRQ was triggered.
+	IRQ []uint64
+	// Number of times a context switch happened.
+	ContextSwitches uint64
+	// Number of times a process was created.
+	ProcessCreated uint64
+	// Number of processes currently running.
+	ProcessesRunning uint64
+	// Number of processes currently blocked (waiting for IO).
+	ProcessesBlocked uint64
+	// Number of times a softirq was scheduled.
+	SoftIRQTotal uint64
+	// Detailed softirq statistics.
+	SoftIRQ SoftIRQStat
 }
 
 // NewStat returns kernel/system statistics read from /proc/stat.
@@ -24,33 +75,145 @@ func NewStat() (Stat, error) {
 	return fs.NewStat()
 }
 
+// Parse a cpu statistics line and returns the CPUStat struct plus the cpu id (or -1 for the overall sum).
+func parseCPUStat(line string) (CPUStat, int64, error) {
+	cpuStat := CPUStat{}
+	var cpu string
+
+	count, err := fmt.Sscanf(line, "%s %f %f %f %f %f %f %f %f %f %f",
+		&cpu,
+		&cpuStat.User, &cpuStat.Nice, &cpuStat.System, &cpuStat.Idle,
+		&cpuStat.Iowait, &cpuStat.IRQ, &cpuStat.SoftIRQ, &cpuStat.Steal,
+		&cpuStat.Guest, &cpuStat.GuestNice)
+
+	if err != nil && err != io.EOF {
+		return CPUStat{}, -1, fmt.Errorf("couldn't parse %s (cpu): %s", line, err)
+	}
+	if count == 0 {
+		return CPUStat{}, -1, fmt.Errorf("couldn't parse %s (cpu): 0 elements parsed", line)
+	}
+
+	cpuStat.User /= userHZ
+	cpuStat.Nice /= userHZ
+	cpuStat.System /= userHZ
+	cpuStat.Idle /= userHZ
+	cpuStat.Iowait /= userHZ
+	cpuStat.IRQ /= userHZ
+	cpuStat.SoftIRQ /= userHZ
+	cpuStat.Steal /= userHZ
+	cpuStat.Guest /= userHZ
+	cpuStat.GuestNice /= userHZ
+
+	if cpu == "cpu" {
+		return cpuStat, -1, nil
+	}
+
+	cpuID, err := strconv.ParseInt(cpu[3:], 10, 64)
+	if err != nil {
+		return CPUStat{}, -1, fmt.Errorf("couldn't parse %s (cpu/cpuid): %s", line, err)
+	}
+
+	return cpuStat, cpuID, nil
+}
+
+// Parse a softirq line.
+func parseSoftIRQStat(line string) (SoftIRQStat, uint64, error) {
+	softIRQStat := SoftIRQStat{}
+	var total uint64
+	var prefix string
+
+	_, err := fmt.Sscanf(line, "%s %d %d %d %d %d %d %d %d %d %d %d",
+		&prefix, &total,
+		&softIRQStat.Hi, &softIRQStat.Timer, &softIRQStat.NetTx, &softIRQStat.NetRx,
+		&softIRQStat.Block, &softIRQStat.BlockIoPoll,
+		&softIRQStat.Tasklet, &softIRQStat.Sched,
+		&softIRQStat.Hrtimer, &softIRQStat.Rcu)
+
+	if err != nil {
+		return SoftIRQStat{}, 0, fmt.Errorf("couldn't parse %s (softirq): %s", line, err)
+	}
+
+	return softIRQStat, total, nil
+}
+
 // NewStat returns an information about current kernel/system statistics.
 func (fs FS) NewStat() (Stat, error) {
+	// See https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+
 	f, err := os.Open(fs.Path("stat"))
 	if err != nil {
 		return Stat{}, err
 	}
 	defer f.Close()
 
-	s := bufio.NewScanner(f)
-	for s.Scan() {
-		line := s.Text()
-		if !strings.HasPrefix(line, "btime") {
+	stat := Stat{}
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		parts := strings.Fields(scanner.Text())
+		// require at least <key> <value>
+		if len(parts) < 2 {
 			continue
 		}
-		fields := strings.Fields(line)
-		if len(fields) != 2 {
-			return Stat{}, fmt.Errorf("couldn't parse %s line %s", f.Name(), line)
-		}
-		i, err := strconv.ParseInt(fields[1], 10, 32)
-		if err != nil {
-			return Stat{}, fmt.Errorf("couldn't parse %s: %s", fields[1], err)
+		switch {
+		case parts[0] == "btime":
+			if stat.BootTime, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
+				return Stat{}, fmt.Errorf("couldn't parse %s (btime): %s", parts[1], err)
+			}
+		case parts[0] == "intr":
+			if stat.IRQTotal, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
+				return Stat{}, fmt.Errorf("couldn't parse %s (intr): %s", parts[1], err)
+			}
+			numberedIRQs := parts[2:]
+			stat.IRQ = make([]uint64, len(numberedIRQs))
+			for i, count := range numberedIRQs {
+				if stat.IRQ[i], err = strconv.ParseUint(count, 10, 64); err != nil {
+					return Stat{}, fmt.Errorf("couldn't parse %s (intr%d): %s", count, i, err)
+				}
+			}
+		case parts[0] == "ctxt":
+			if stat.ContextSwitches, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
+				return Stat{}, fmt.Errorf("couldn't parse %s (ctxt): %s", parts[1], err)
+			}
+		case parts[0] == "processes":
+			if stat.ProcessCreated, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
+				return Stat{}, fmt.Errorf("couldn't parse %s (processes): %s", parts[1], err)
+			}
+		case parts[0] == "procs_running":
+			if stat.ProcessesRunning, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
+				return Stat{}, fmt.Errorf("couldn't parse %s (procs_running): %s", parts[1], err)
+			}
+		case parts[0] == "procs_blocked":
+			if stat.ProcessesBlocked, err = strconv.ParseUint(parts[1], 10, 64); err != nil {
+				return Stat{}, fmt.Errorf("couldn't parse %s (procs_blocked): %s", parts[1], err)
+			}
+		case parts[0] == "softirq":
+			softIRQStats, total, err := parseSoftIRQStat(line)
+			if err != nil {
+				return Stat{}, err
+			}
+			stat.SoftIRQTotal = total
+			stat.SoftIRQ = softIRQStats
+		case strings.HasPrefix(parts[0], "cpu"):
+			cpuStat, cpuID, err := parseCPUStat(line)
+			if err != nil {
+				return Stat{}, err
+			}
+			if cpuID == -1 {
+				stat.CPUTotal = cpuStat
+			} else {
+				for int64(len(stat.CPU)) <= cpuID {
+					stat.CPU = append(stat.CPU, CPUStat{})
+				}
+				stat.CPU[cpuID] = cpuStat
+			}
 		}
-		return Stat{BootTime: i}, nil
 	}
-	if err := s.Err(); err != nil {
+
+	if err := scanner.Err(); err != nil {
 		return Stat{}, fmt.Errorf("couldn't parse %s: %s", f.Name(), err)
 	}
 
-	return Stat{}, fmt.Errorf("couldn't parse %s, missing btime", f.Name())
+	return stat, nil
 }
diff --git a/vendor/github.com/prometheus/procfs/ttar b/vendor/github.com/prometheus/procfs/ttar
new file mode 100755
index 0000000..8227a4a
--- /dev/null
+++ b/vendor/github.com/prometheus/procfs/ttar
@@ -0,0 +1,264 @@
+#!/usr/bin/env bash
+# Purpose: plain text tar format
+# Limitations: - only suitable for text files, directories, and symlinks
+#              - stores only filename, content, and mode
+#              - not designed for untrusted input
+
+# Note: must work with bash version 3.2 (macOS)
+
+set -o errexit -o nounset
+
+# Sanitize environment (for instance, standard sorting of glob matches)
+export LC_ALL=C
+
+path=""
+CMD=""
+
+function usage {
+    bname=$(basename "$0")
+    cat << USAGE
+Usage:   $bname [-C <DIR>] -c -f <ARCHIVE> <FILE...> (create archive)
+         $bname            -t -f <ARCHIVE>           (list archive contents)
+         $bname [-C <DIR>] -x -f <ARCHIVE>           (extract archive)
+
+Options:
+         -C <DIR>                                    (change directory)
+
+Example: Change to sysfs directory, create ttar file from fixtures directory
+         $bname -C sysfs -c -f sysfs/fixtures.ttar fixtures/
+USAGE
+exit "$1"
+}
+
+function vecho {
+    if [ "${VERBOSE:-}" == "yes" ]; then
+        echo >&7 "$@"
+    fi
+}
+
+function set_cmd {
+    if [ -n "$CMD" ]; then
+        echo "ERROR: more than one command given"
+        echo
+        usage 2
+    fi
+    CMD=$1
+}
+
+while getopts :cf:htxvC: opt; do
+    case $opt in
+        c)
+            set_cmd "create"
+            ;;
+        f)
+            ARCHIVE=$OPTARG
+            ;;
+        h)
+            usage 0
+            ;;
+        t)
+            set_cmd "list"
+            ;;
+        x)
+            set_cmd "extract"
+            ;;
+        v)
+            VERBOSE=yes
+            exec 7>&1
+            ;;
+        C)
+            CDIR=$OPTARG
+            ;;
+        *)
+            echo >&2 "ERROR: invalid option -$OPTARG"
+            echo
+            usage 1
+            ;;
+    esac
+done
+
+# Remove processed options from arguments
+shift $(( OPTIND - 1 ));
+
+if [ "${CMD:-}" == "" ]; then
+    echo >&2 "ERROR: no command given"
+    echo
+    usage 1
+elif [ "${ARCHIVE:-}" == "" ]; then
+    echo >&2 "ERROR: no archive name given"
+    echo
+    usage 1
+fi
+
+function list {
+    local path=""
+    local size=0
+    local line_no=0
+    local ttar_file=$1
+    if [ -n "${2:-}" ]; then
+        echo >&2 "ERROR: too many arguments."
+        echo
+        usage 1
+    fi
+    if [ ! -e "$ttar_file" ]; then
+        echo >&2 "ERROR: file not found ($ttar_file)"
+        echo
+        usage 1
+    fi
+    while read -r line; do
+        line_no=$(( line_no + 1 ))
+        if [ $size -gt 0 ]; then
+            size=$(( size - 1 ))
+            continue
+        fi
+        if [[ $line =~ ^Path:\ (.*)$ ]]; then
+            path=${BASH_REMATCH[1]}
+        elif [[ $line =~ ^Lines:\ (.*)$ ]]; then
+            size=${BASH_REMATCH[1]}
+            echo "$path"
+        elif [[ $line =~ ^Directory:\ (.*)$ ]]; then
+            path=${BASH_REMATCH[1]}
+            echo "$path/"
+        elif [[ $line =~ ^SymlinkTo:\ (.*)$ ]]; then
+            echo  "$path -> ${BASH_REMATCH[1]}"
+        fi
+    done < "$ttar_file"
+}
+
+function extract {
+    local path=""
+    local size=0
+    local line_no=0
+    local ttar_file=$1
+    if [ -n "${2:-}" ]; then
+        echo >&2 "ERROR: too many arguments."
+        echo
+        usage 1
+    fi
+    if [ ! -e "$ttar_file" ]; then
+        echo >&2 "ERROR: file not found ($ttar_file)"
+        echo
+        usage 1
+    fi
+    while IFS= read -r line; do
+        line_no=$(( line_no + 1 ))
+        if [ "$size" -gt 0 ]; then
+            echo "$line" >> "$path"
+            size=$(( size - 1 ))
+            continue
+        fi
+        if [[ $line =~ ^Path:\ (.*)$ ]]; then
+            path=${BASH_REMATCH[1]}
+            if [ -e "$path" ] || [ -L "$path" ]; then
+                rm "$path"
+            fi
+        elif [[ $line =~ ^Lines:\ (.*)$ ]]; then
+            size=${BASH_REMATCH[1]}
+            # Create file even if it is zero-length.
+            touch "$path"
+            vecho "    $path"
+        elif [[ $line =~ ^Mode:\ (.*)$ ]]; then
+            mode=${BASH_REMATCH[1]}
+            chmod "$mode" "$path"
+            vecho "$mode"
+        elif [[ $line =~ ^Directory:\ (.*)$ ]]; then
+            path=${BASH_REMATCH[1]}
+            mkdir -p "$path"
+            vecho "    $path/"
+        elif [[ $line =~ ^SymlinkTo:\ (.*)$ ]]; then
+            ln -s "${BASH_REMATCH[1]}" "$path"
+            vecho "    $path -> ${BASH_REMATCH[1]}"
+        elif [[ $line =~ ^# ]]; then
+            # Ignore comments between files
+            continue
+        else
+            echo >&2 "ERROR: Unknown keyword on line $line_no: $line"
+            exit 1
+        fi
+    done < "$ttar_file"
+}
+
+function div {
+    echo "# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -" \
+         "- - - - - -"
+}
+
+function get_mode {
+    local mfile=$1
+    if [ -z "${STAT_OPTION:-}" ]; then
+        if stat -c '%a' "$mfile" >/dev/null 2>&1; then
+            STAT_OPTION='-c'
+            STAT_FORMAT='%a'
+        else
+            STAT_OPTION='-f'
+            STAT_FORMAT='%A'
+        fi
+    fi
+    stat "${STAT_OPTION}" "${STAT_FORMAT}" "$mfile"
+}
+
+function _create {
+    shopt -s nullglob
+    local mode
+    while (( "$#" )); do
+        file=$1
+        if [ -L "$file" ]; then
+            echo "Path: $file"
+            symlinkTo=$(readlink "$file")
+            echo "SymlinkTo: $symlinkTo"
+            vecho "    $file -> $symlinkTo"
+            div
+        elif [ -d "$file" ]; then
+            # Strip trailing slash (if there is one)
+            file=${file%/}
+            echo "Directory: $file"
+            mode=$(get_mode "$file")
+            echo "Mode: $mode"
+            vecho "$mode $file/"
+            div
+            # Find all files and dirs, including hidden/dot files
+            for x in "$file/"{*,.[^.]*}; do
+                _create "$x"
+            done
+        elif [ -f "$file" ]; then
+            echo "Path: $file"
+            lines=$(wc -l "$file"|awk '{print $1}')
+            echo "Lines: $lines"
+            cat "$file"
+            mode=$(get_mode "$file")
+            echo "Mode: $mode"
+            vecho "$mode $file"
+            div
+        else
+            echo >&2 "ERROR: file not found ($file in $(pwd))"
+            exit 2
+        fi
+        shift
+    done
+}
+
+function create {
+    ttar_file=$1
+    shift
+    if [ -z "${1:-}" ]; then
+        echo >&2 "ERROR: missing arguments."
+        echo
+        usage 1
+    fi
+    if [ -e "$ttar_file" ]; then
+        rm "$ttar_file"
+    fi
+    exec > "$ttar_file"
+    _create "$@"
+}
+
+if [ -n "${CDIR:-}" ]; then
+    if [[ "$ARCHIVE" != /* ]]; then
+        # Relative path: preserve the archive's location before changing
+        # directory
+        ARCHIVE="$(pwd)/$ARCHIVE"
+    fi
+    cd "$CDIR"
+fi
+
+"$CMD" "$ARCHIVE" "$@"
diff --git a/vendor/github.com/prometheus/procfs/xfrm.go b/vendor/github.com/prometheus/procfs/xfrm.go
new file mode 100644
index 0000000..ffe9df5
--- /dev/null
+++ b/vendor/github.com/prometheus/procfs/xfrm.go
@@ -0,0 +1,187 @@
+// Copyright 2017 Prometheus Team
+// 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 procfs
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// XfrmStat models the contents of /proc/net/xfrm_stat.
+type XfrmStat struct {
+	// All errors which are not matched by other
+	XfrmInError int
+	// No buffer is left
+	XfrmInBufferError int
+	// Header Error
+	XfrmInHdrError int
+	// No state found
+	// i.e. either inbound SPI, address, or IPSEC protocol at SA is wrong
+	XfrmInNoStates int
+	// Transformation protocol specific error
+	// e.g. SA Key is wrong
+	XfrmInStateProtoError int
+	// Transformation mode specific error
+	XfrmInStateModeError int
+	// Sequence error
+	// e.g. sequence number is out of window
+	XfrmInStateSeqError int
+	// State is expired
+	XfrmInStateExpired int
+	// State has mismatch option
+	// e.g. UDP encapsulation type is mismatched
+	XfrmInStateMismatch int
+	// State is invalid
+	XfrmInStateInvalid int
+	// No matching template for states
+	// e.g. Inbound SAs are correct but SP rule is wrong
+	XfrmInTmplMismatch int
+	// No policy is found for states
+	// e.g. Inbound SAs are correct but no SP is found
+	XfrmInNoPols int
+	// Policy discards
+	XfrmInPolBlock int
+	// Policy error
+	XfrmInPolError int
+	// All errors which are not matched by others
+	XfrmOutError int
+	// Bundle generation error
+	XfrmOutBundleGenError int
+	// Bundle check error
+	XfrmOutBundleCheckError int
+	// No state was found
+	XfrmOutNoStates int
+	// Transformation protocol specific error
+	XfrmOutStateProtoError int
+	// Transportation mode specific error
+	XfrmOutStateModeError int
+	// Sequence error
+	// i.e sequence number overflow
+	XfrmOutStateSeqError int
+	// State is expired
+	XfrmOutStateExpired int
+	// Policy discads
+	XfrmOutPolBlock int
+	// Policy is dead
+	XfrmOutPolDead int
+	// Policy Error
+	XfrmOutPolError     int
+	XfrmFwdHdrError     int
+	XfrmOutStateInvalid int
+	XfrmAcquireError    int
+}
+
+// NewXfrmStat reads the xfrm_stat statistics.
+func NewXfrmStat() (XfrmStat, error) {
+	fs, err := NewFS(DefaultMountPoint)
+	if err != nil {
+		return XfrmStat{}, err
+	}
+
+	return fs.NewXfrmStat()
+}
+
+// NewXfrmStat reads the xfrm_stat statistics from the 'proc' filesystem.
+func (fs FS) NewXfrmStat() (XfrmStat, error) {
+	file, err := os.Open(fs.Path("net/xfrm_stat"))
+	if err != nil {
+		return XfrmStat{}, err
+	}
+	defer file.Close()
+
+	var (
+		x = XfrmStat{}
+		s = bufio.NewScanner(file)
+	)
+
+	for s.Scan() {
+		fields := strings.Fields(s.Text())
+
+		if len(fields) != 2 {
+			return XfrmStat{}, fmt.Errorf(
+				"couldnt parse %s line %s", file.Name(), s.Text())
+		}
+
+		name := fields[0]
+		value, err := strconv.Atoi(fields[1])
+		if err != nil {
+			return XfrmStat{}, err
+		}
+
+		switch name {
+		case "XfrmInError":
+			x.XfrmInError = value
+		case "XfrmInBufferError":
+			x.XfrmInBufferError = value
+		case "XfrmInHdrError":
+			x.XfrmInHdrError = value
+		case "XfrmInNoStates":
+			x.XfrmInNoStates = value
+		case "XfrmInStateProtoError":
+			x.XfrmInStateProtoError = value
+		case "XfrmInStateModeError":
+			x.XfrmInStateModeError = value
+		case "XfrmInStateSeqError":
+			x.XfrmInStateSeqError = value
+		case "XfrmInStateExpired":
+			x.XfrmInStateExpired = value
+		case "XfrmInStateInvalid":
+			x.XfrmInStateInvalid = value
+		case "XfrmInTmplMismatch":
+			x.XfrmInTmplMismatch = value
+		case "XfrmInNoPols":
+			x.XfrmInNoPols = value
+		case "XfrmInPolBlock":
+			x.XfrmInPolBlock = value
+		case "XfrmInPolError":
+			x.XfrmInPolError = value
+		case "XfrmOutError":
+			x.XfrmOutError = value
+		case "XfrmInStateMismatch":
+			x.XfrmInStateMismatch = value
+		case "XfrmOutBundleGenError":
+			x.XfrmOutBundleGenError = value
+		case "XfrmOutBundleCheckError":
+			x.XfrmOutBundleCheckError = value
+		case "XfrmOutNoStates":
+			x.XfrmOutNoStates = value
+		case "XfrmOutStateProtoError":
+			x.XfrmOutStateProtoError = value
+		case "XfrmOutStateModeError":
+			x.XfrmOutStateModeError = value
+		case "XfrmOutStateSeqError":
+			x.XfrmOutStateSeqError = value
+		case "XfrmOutStateExpired":
+			x.XfrmOutStateExpired = value
+		case "XfrmOutPolBlock":
+			x.XfrmOutPolBlock = value
+		case "XfrmOutPolDead":
+			x.XfrmOutPolDead = value
+		case "XfrmOutPolError":
+			x.XfrmOutPolError = value
+		case "XfrmFwdHdrError":
+			x.XfrmFwdHdrError = value
+		case "XfrmOutStateInvalid":
+			x.XfrmOutStateInvalid = value
+		case "XfrmAcquireError":
+			x.XfrmAcquireError = value
+		}
+
+	}
+
+	return x, s.Err()
+}
diff --git a/vendor/github.com/prometheus/procfs/xfs/parse.go b/vendor/github.com/prometheus/procfs/xfs/parse.go
index d1285fa..c8f6279 100644
--- a/vendor/github.com/prometheus/procfs/xfs/parse.go
+++ b/vendor/github.com/prometheus/procfs/xfs/parse.go
@@ -17,7 +17,6 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"log"
 	"strconv"
 	"strings"
 )
@@ -273,7 +272,6 @@ func vnodeStats(us []uint32) (VnodeStats, error) {
 	// stats versions.  Therefore, 7 or 8 elements may appear in
 	// this slice.
 	l := len(us)
-	log.Println(l)
 	if l != 7 && l != 8 {
 		return VnodeStats{}, fmt.Errorf("incorrect number of values for XFS vnode stats: %d", l)
 	}
diff --git a/vendor/github.com/prometheus/procfs/xfs/xfs.go b/vendor/github.com/prometheus/procfs/xfs/xfs.go
index ed77d90..d86794b 100644
--- a/vendor/github.com/prometheus/procfs/xfs/xfs.go
+++ b/vendor/github.com/prometheus/procfs/xfs/xfs.go
@@ -22,6 +22,11 @@ package xfs
 // kernel source. Most counters are uint32s (same data types used in
 // xfs_stats.h), but some of the "extended precision stats" are uint64s.
 type Stats struct {
+	// The name of the filesystem used to source these statistics.
+	// If empty, this indicates aggregated statistics for all XFS
+	// filesystems on the host.
+	Name string
+
 	ExtentAllocation   ExtentAllocationStats
 	AllocationBTree    BTreeStats
 	BlockMapping       BlockMappingStats