Migrate to latest faas-provider version

Adds CRUD for namespaces and moves namespace for delete/
scale to the body from the query string.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alex@openfaas.com>

gateway/vendor/github.com/prometheus/client_golang/prometheus/counter.go

@@ -59,6 +59,18 @@ type ExemplarAdder interface {
 // CounterOpts is an alias for Opts. See there for doc comments.
 type CounterOpts Opts
 
+// CounterVecOpts bundles the options to create a CounterVec metric.
+// It is mandatory to set CounterOpts, see there for mandatory fields. VariableLabels
+// is optional and can safely be left to its default value.
+type CounterVecOpts struct {
+	CounterOpts
+
+	// VariableLabels are used to partition the metric vector by the given set
+	// of labels. Each label value will be constrained with the optional Contraint
+	// function, if provided.
+	VariableLabels ConstrainableLabels
+}
+
 // NewCounter creates a new Counter based on the provided CounterOpts.
 //
 // The returned implementation also implements ExemplarAdder. It is safe to
@@ -140,12 +152,13 @@ func (c *counter) get() float64 {
 }
 
 func (c *counter) Write(out *dto.Metric) error {
-	val := c.get()
-
+	// Read the Exemplar first and the value second. This is to avoid a race condition
+	// where users see an exemplar for a not-yet-existing observation.
 	var exemplar *dto.Exemplar
 	if e := c.exemplar.Load(); e != nil {
 		exemplar = e.(*dto.Exemplar)
 	}
+	val := c.get()
 
 	return populateMetric(CounterValue, val, c.labelPairs, exemplar, out)
 }
@@ -173,16 +186,24 @@ type CounterVec struct {
 // NewCounterVec creates a new CounterVec based on the provided CounterOpts and
 // partitioned by the given label names.
 func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
-	desc := NewDesc(
+	return V2.NewCounterVec(CounterVecOpts{
+		CounterOpts:    opts,
+		VariableLabels: UnconstrainedLabels(labelNames),
+	})
+}
+
+// NewCounterVec creates a new CounterVec based on the provided CounterVecOpts.
+func (v2) NewCounterVec(opts CounterVecOpts) *CounterVec {
+	desc := V2.NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
-		labelNames,
+		opts.VariableLabels,
 		opts.ConstLabels,
 	)
 	return &CounterVec{
 		MetricVec: NewMetricVec(desc, func(lvs ...string) Metric {
 			if len(lvs) != len(desc.variableLabels) {
-				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels.labelNames(), lvs))
 			}
 			result := &counter{desc: desc, labelPairs: MakeLabelPairs(desc, lvs), now: time.Now}
 			result.init(result) // Init self-collection.
@@ -245,7 +266,8 @@ func (v *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
 // GetMetricWithLabelValues would have returned an error. Not returning an
 // error allows shortcuts like
-//     myVec.WithLabelValues("404", "GET").Add(42)
+//
+//	myVec.WithLabelValues("404", "GET").Add(42)
 func (v *CounterVec) WithLabelValues(lvs ...string) Counter {
 	c, err := v.GetMetricWithLabelValues(lvs...)
 	if err != nil {
@@ -256,7 +278,8 @@ func (v *CounterVec) WithLabelValues(lvs ...string) Counter {
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
 // returned an error. Not returning an error allows shortcuts like
-//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
+//
+//	myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
 func (v *CounterVec) With(labels Labels) Counter {
 	c, err := v.GetMetricWith(labels)
 	if err != nil {

gateway/vendor/github.com/prometheus/client_golang/prometheus/desc.go

@@ -14,20 +14,16 @@
 package prometheus
 
 import (
-	"errors"
 	"fmt"
 	"sort"
 	"strings"
 
 	"github.com/cespare/xxhash/v2"
+	dto "github.com/prometheus/client_model/go"
+	"github.com/prometheus/common/model"
+	"google.golang.org/protobuf/proto"
 
 	"github.com/prometheus/client_golang/prometheus/internal"
-
-	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
-	"github.com/golang/protobuf/proto"
-	"github.com/prometheus/common/model"
-
-	dto "github.com/prometheus/client_model/go"
 )
 
 // Desc is the descriptor used by every Prometheus Metric. It is essentially
@@ -54,9 +50,9 @@ type Desc struct {
 	// constLabelPairs contains precalculated DTO label pairs based on
 	// the constant labels.
 	constLabelPairs []*dto.LabelPair
-	// variableLabels contains names of labels for which the metric
-	// maintains variable values.
-	variableLabels []string
+	// variableLabels contains names of labels and normalization function for
+	// which the metric maintains variable values.
+	variableLabels ConstrainedLabels
 	// id is a hash of the values of the ConstLabels and fqName. This
 	// must be unique among all registered descriptors and can therefore be
 	// used as an identifier of the descriptor.
@@ -80,10 +76,24 @@ type Desc struct {
 // For constLabels, the label values are constant. Therefore, they are fully
 // specified in the Desc. See the Collector example for a usage pattern.
 func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *Desc {
+	return V2.NewDesc(fqName, help, UnconstrainedLabels(variableLabels), constLabels)
+}
+
+// NewDesc allocates and initializes a new Desc. Errors are recorded in the Desc
+// and will be reported on registration time. variableLabels and constLabels can
+// be nil if no such labels should be set. fqName must not be empty.
+//
+// variableLabels only contain the label names and normalization functions. Their
+// label values are variable and therefore not part of the Desc. (They are managed
+// within the Metric.)
+//
+// For constLabels, the label values are constant. Therefore, they are fully
+// specified in the Desc. See the Collector example for a usage pattern.
+func (v2) NewDesc(fqName, help string, variableLabels ConstrainableLabels, constLabels Labels) *Desc {
 	d := &Desc{
 		fqName:         fqName,
 		help:           help,
-		variableLabels: variableLabels,
+		variableLabels: variableLabels.constrainedLabels(),
 	}
 	if !model.IsValidMetricName(model.LabelValue(fqName)) {
 		d.err = fmt.Errorf("%q is not a valid metric name", fqName)
@@ -93,7 +103,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	// their sorted label names) plus the fqName (at position 0).
 	labelValues := make([]string, 1, len(constLabels)+1)
 	labelValues[0] = fqName
-	labelNames := make([]string, 0, len(constLabels)+len(variableLabels))
+	labelNames := make([]string, 0, len(constLabels)+len(d.variableLabels))
 	labelNameSet := map[string]struct{}{}
 	// First add only the const label names and sort them...
 	for labelName := range constLabels {
@@ -118,16 +128,16 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	// 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.
-	for _, labelName := range variableLabels {
-		if !checkLabelName(labelName) {
-			d.err = fmt.Errorf("%q is not a valid label name for metric %q", labelName, fqName)
+	for _, label := range d.variableLabels {
+		if !checkLabelName(label.Name) {
+			d.err = fmt.Errorf("%q is not a valid label name for metric %q", label.Name, fqName)
 			return d
 		}
-		labelNames = append(labelNames, "$"+labelName)
-		labelNameSet[labelName] = struct{}{}
+		labelNames = append(labelNames, "$"+label.Name)
+		labelNameSet[label.Name] = struct{}{}
 	}
 	if len(labelNames) != len(labelNameSet) {
-		d.err = errors.New("duplicate label names")
+		d.err = fmt.Errorf("duplicate label names in constant and variable labels for metric %q", fqName)
 		return d
 	}
 

gateway/vendor/github.com/prometheus/client_golang/prometheus/doc.go

@@ -21,55 +21,66 @@
 // All exported functions and methods are safe to be used concurrently unless
 // specified otherwise.
 //
-// A Basic Example
+// # A Basic Example
 //
 // As a starting point, a very basic usage example:
 //
-//    package main
+//	package main
 //
-//    import (
-//    	"log"
-//    	"net/http"
+//	import (
+//		"log"
+//		"net/http"
 //
-//    	"github.com/prometheus/client_golang/prometheus"
-//    	"github.com/prometheus/client_golang/prometheus/promhttp"
-//    )
+//		"github.com/prometheus/client_golang/prometheus"
+//		"github.com/prometheus/client_golang/prometheus/promhttp"
+//	)
 //
-//    var (
-//    	cpuTemp = prometheus.NewGauge(prometheus.GaugeOpts{
-//    		Name: "cpu_temperature_celsius",
-//    		Help: "Current temperature of the CPU.",
-//    	})
-//    	hdFailures = prometheus.NewCounterVec(
-//    		prometheus.CounterOpts{
-//    			Name: "hd_errors_total",
-//    			Help: "Number of hard-disk errors.",
-//    		},
-//    		[]string{"device"},
-//    	)
-//    )
+//	type metrics struct {
+//		cpuTemp  prometheus.Gauge
+//		hdFailures *prometheus.CounterVec
+//	}
 //
-//    func init() {
-//    	// Metrics have to be registered to be exposed:
-//    	prometheus.MustRegister(cpuTemp)
-//    	prometheus.MustRegister(hdFailures)
-//    }
+//	func NewMetrics(reg prometheus.Registerer) *metrics {
+//		m := &metrics{
+//			cpuTemp: prometheus.NewGauge(prometheus.GaugeOpts{
+//				Name: "cpu_temperature_celsius",
+//				Help: "Current temperature of the CPU.",
+//			}),
+//			hdFailures: prometheus.NewCounterVec(
+//				prometheus.CounterOpts{
+//					Name: "hd_errors_total",
+//					Help: "Number of hard-disk errors.",
+//				},
+//				[]string{"device"},
+//			),
+//		}
+//		reg.MustRegister(m.cpuTemp)
+//		reg.MustRegister(m.hdFailures)
+//		return m
+//	}
 //
-//    func main() {
-//    	cpuTemp.Set(65.3)
-//    	hdFailures.With(prometheus.Labels{"device":"/dev/sda"}).Inc()
+//	func main() {
+//		// Create a non-global registry.
+//		reg := prometheus.NewRegistry()
 //
-//    	// 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))
-//    }
+//		// Create new metrics and register them using the custom registry.
+//		m := NewMetrics(reg)
+//		// Set values for the new created metrics.
+//		m.cpuTemp.Set(65.3)
+//		m.hdFailures.With(prometheus.Labels{"device":"/dev/sda"}).Inc()
 //
+//		// Expose metrics and custom registry via an HTTP server
+//		// using the HandleFor function. "/metrics" is the usual endpoint for that.
+//		http.Handle("/metrics", promhttp.HandlerFor(reg, promhttp.HandlerOpts{Registry: reg}))
+//		log.Fatal(http.ListenAndServe(":8080", nil))
+//	}
 //
 // This is a complete program that exports two metrics, a Gauge and a Counter,
 // the latter with a label attached to turn it into a (one-dimensional) vector.
+// It register the metrics using a custom registry and exposes them via an HTTP server
+// on the /metrics endpoint.
 //
-// Metrics
+// # Metrics
 //
 // The number of exported identifiers in this package might appear a bit
 // overwhelming. However, in addition to the basic plumbing shown in the example
@@ -100,7 +111,7 @@
 // To create instances of Metrics and their vector versions, you need a suitable
 // …Opts struct, i.e. GaugeOpts, CounterOpts, SummaryOpts, or HistogramOpts.
 //
-// Custom Collectors and constant Metrics
+// # Custom Collectors and constant Metrics
 //
 // While you could create your own implementations of Metric, most likely you
 // will only ever implement the Collector interface on your own. At a first
@@ -141,7 +152,7 @@
 // a metric, GaugeFunc, CounterFunc, or UntypedFunc might be interesting
 // shortcuts.
 //
-// Advanced Uses of the Registry
+// # Advanced Uses of the Registry
 //
 // While MustRegister is the by far most common way of registering a Collector,
 // sometimes you might want to handle the errors the registration might cause.
@@ -176,23 +187,23 @@
 // NewProcessCollector). With a custom registry, you are in control and decide
 // yourself about the Collectors to register.
 //
-// HTTP Exposition
+// # HTTP Exposition
 //
 // The Registry implements the Gatherer interface. The caller of the Gather
 // method can then expose the gathered metrics in some way. Usually, the metrics
 // are served via HTTP on the /metrics endpoint. That's happening in the example
 // above. The tools to expose metrics via HTTP are in the promhttp sub-package.
 //
-// Pushing to the Pushgateway
+// # Pushing to the Pushgateway
 //
 // Function for pushing to the Pushgateway can be found in the push sub-package.
 //
-// Graphite Bridge
+// # Graphite Bridge
 //
 // Functions and examples to push metrics from a Gatherer to Graphite can be
 // found in the graphite sub-package.
 //
-// Other Means of Exposition
+// # Other Means of Exposition
 //
 // More ways of exposing metrics can easily be added by following the approaches
 // of the existing implementations.

gateway/vendor/github.com/prometheus/client_golang/prometheus/gauge.go

@@ -55,6 +55,18 @@ type Gauge interface {
 // GaugeOpts is an alias for Opts. See there for doc comments.
 type GaugeOpts Opts
 
+// GaugeVecOpts bundles the options to create a GaugeVec metric.
+// It is mandatory to set GaugeOpts, see there for mandatory fields. VariableLabels
+// is optional and can safely be left to its default value.
+type GaugeVecOpts struct {
+	GaugeOpts
+
+	// VariableLabels are used to partition the metric vector by the given set
+	// of labels. Each label value will be constrained with the optional Contraint
+	// function, if provided.
+	VariableLabels ConstrainableLabels
+}
+
 // NewGauge creates a new Gauge based on the provided GaugeOpts.
 //
 // The returned implementation is optimized for a fast Set method. If you have a
@@ -138,16 +150,24 @@ type GaugeVec struct {
 // NewGaugeVec creates a new GaugeVec based on the provided GaugeOpts and
 // partitioned by the given label names.
 func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
-	desc := NewDesc(
+	return V2.NewGaugeVec(GaugeVecOpts{
+		GaugeOpts:      opts,
+		VariableLabels: UnconstrainedLabels(labelNames),
+	})
+}
+
+// NewGaugeVec creates a new GaugeVec based on the provided GaugeVecOpts.
+func (v2) NewGaugeVec(opts GaugeVecOpts) *GaugeVec {
+	desc := V2.NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
-		labelNames,
+		opts.VariableLabels,
 		opts.ConstLabels,
 	)
 	return &GaugeVec{
 		MetricVec: NewMetricVec(desc, func(lvs ...string) Metric {
 			if len(lvs) != len(desc.variableLabels) {
-				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels.labelNames(), lvs))
 			}
 			result := &gauge{desc: desc, labelPairs: MakeLabelPairs(desc, lvs)}
 			result.init(result) // Init self-collection.
@@ -210,7 +230,8 @@ func (v *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
 // GetMetricWithLabelValues would have returned an error. Not returning an
 // error allows shortcuts like
-//     myVec.WithLabelValues("404", "GET").Add(42)
+//
+//	myVec.WithLabelValues("404", "GET").Add(42)
 func (v *GaugeVec) WithLabelValues(lvs ...string) Gauge {
 	g, err := v.GetMetricWithLabelValues(lvs...)
 	if err != nil {
@@ -221,7 +242,8 @@ func (v *GaugeVec) WithLabelValues(lvs ...string) Gauge {
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
 // returned an error. Not returning an error allows shortcuts like
-//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
+//
+//	myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
 func (v *GaugeVec) With(labels Labels) Gauge {
 	g, err := v.GetMetricWith(labels)
 	if err != nil {

gateway/vendor/github.com/prometheus/client_golang/prometheus/go_collector_latest.go

@@ -23,11 +23,10 @@ import (
 	"strings"
 	"sync"
 
-	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
-	"github.com/golang/protobuf/proto"
-	dto "github.com/prometheus/client_model/go"
-
 	"github.com/prometheus/client_golang/prometheus/internal"
+
+	dto "github.com/prometheus/client_model/go"
+	"google.golang.org/protobuf/proto"
 )
 
 const (

gateway/vendor/github.com/prometheus/client_golang/prometheus/internal/almost_equal.go

@@ -0,0 +1,60 @@
+// Copyright (c) 2015 Björn Rabenstein
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// The code in this package is copy/paste to avoid a dependency. Hence this file
+// carries the copyright of the original repo.
+// https://github.com/beorn7/floats
+package internal
+
+import (
+	"math"
+)
+
+// minNormalFloat64 is the smallest positive normal value of type float64.
+var minNormalFloat64 = math.Float64frombits(0x0010000000000000)
+
+// AlmostEqualFloat64 returns true if a and b are equal within a relative error
+// of epsilon. See http://floating-point-gui.de/errors/comparison/ for the
+// details of the applied method.
+func AlmostEqualFloat64(a, b, epsilon float64) bool {
+	if a == b {
+		return true
+	}
+	absA := math.Abs(a)
+	absB := math.Abs(b)
+	diff := math.Abs(a - b)
+	if a == 0 || b == 0 || absA+absB < minNormalFloat64 {
+		return diff < epsilon*minNormalFloat64
+	}
+	return diff/math.Min(absA+absB, math.MaxFloat64) < epsilon
+}
+
+// AlmostEqualFloat64s is the slice form of AlmostEqualFloat64.
+func AlmostEqualFloat64s(a, b []float64, epsilon float64) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if !AlmostEqualFloat64(a[i], b[i], epsilon) {
+			return false
+		}
+	}
+	return true
+}

gateway/vendor/github.com/prometheus/client_golang/prometheus/internal/difflib.go

@@ -201,12 +201,15 @@ func (m *SequenceMatcher) isBJunk(s string) bool {
 // If IsJunk is not defined:
 //
 // Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where
-//     alo <= i <= i+k <= ahi
-//     blo <= j <= j+k <= bhi
+//
+//	alo <= i <= i+k <= ahi
+//	blo <= j <= j+k <= bhi
+//
 // and for all (i',j',k') meeting those conditions,
-//     k >= k'
-//     i <= i'
-//     and if i == i', j <= j'
+//
+//	k >= k'
+//	i <= i'
+//	and if i == i', j <= j'
 //
 // In other words, of all maximal matching blocks, return one that
 // starts earliest in a, and of all those maximal matching blocks that

gateway/vendor/github.com/prometheus/client_golang/prometheus/labels.go

@@ -25,12 +25,85 @@ import (
 // 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)
+//
+//	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
 
+// ConstrainedLabels represents a label name and its constrain function
+// to normalize label values. This type is commonly used when constructing
+// metric vector Collectors.
+type ConstrainedLabel struct {
+	Name       string
+	Constraint func(string) string
+}
+
+func (cl ConstrainedLabel) Constrain(v string) string {
+	if cl.Constraint == nil {
+		return v
+	}
+	return cl.Constraint(v)
+}
+
+// ConstrainableLabels is an interface that allows creating of labels that can
+// be optionally constrained.
+//
+//	prometheus.V2().NewCounterVec(CounterVecOpts{
+//	  CounterOpts: {...}, // Usual CounterOpts fields
+//	  VariableLabels: []ConstrainedLabels{
+//	    {Name: "A"},
+//	    {Name: "B", Constraint: func(v string) string { ... }},
+//	  },
+//	})
+type ConstrainableLabels interface {
+	constrainedLabels() ConstrainedLabels
+	labelNames() []string
+}
+
+// ConstrainedLabels represents a collection of label name -> constrain function
+// to normalize label values. This type is commonly used when constructing
+// metric vector Collectors.
+type ConstrainedLabels []ConstrainedLabel
+
+func (cls ConstrainedLabels) constrainedLabels() ConstrainedLabels {
+	return cls
+}
+
+func (cls ConstrainedLabels) labelNames() []string {
+	names := make([]string, len(cls))
+	for i, label := range cls {
+		names[i] = label.Name
+	}
+	return names
+}
+
+// UnconstrainedLabels represents collection of label without any constraint on
+// their value. Thus, it is simply a collection of label names.
+//
+//	UnconstrainedLabels([]string{ "A", "B" })
+//
+// is equivalent to
+//
+//	ConstrainedLabels {
+//	  { Name: "A" },
+//	  { Name: "B" },
+//	}
+type UnconstrainedLabels []string
+
+func (uls UnconstrainedLabels) constrainedLabels() ConstrainedLabels {
+	constrainedLabels := make([]ConstrainedLabel, len(uls))
+	for i, l := range uls {
+		constrainedLabels[i] = ConstrainedLabel{Name: l}
+	}
+	return constrainedLabels
+}
+
+func (uls UnconstrainedLabels) labelNames() []string {
+	return uls
+}
+
 // reservedLabelPrefix is a prefix which is not legal in user-supplied
 // label names.
 const reservedLabelPrefix = "__"

gateway/vendor/github.com/prometheus/client_golang/prometheus/metric.go

@@ -20,11 +20,9 @@ import (
 	"strings"
 	"time"
 
-	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
-	"github.com/golang/protobuf/proto"
-	"github.com/prometheus/common/model"
-
 	dto "github.com/prometheus/client_model/go"
+	"github.com/prometheus/common/model"
+	"google.golang.org/protobuf/proto"
 )
 
 var separatorByteSlice = []byte{model.SeparatorByte} // For convenient use with xxhash.
@@ -187,7 +185,7 @@ func (m *withExemplarsMetric) Write(pb *dto.Metric) error {
 			} else {
 				// The +Inf bucket should be explicitly added if there is an exemplar for it, similar to non-const histogram logic in https://github.com/prometheus/client_golang/blob/main/prometheus/histogram.go#L357-L365.
 				b := &dto.Bucket{
-					CumulativeCount: proto.Uint64(pb.Histogram.Bucket[len(pb.Histogram.GetBucket())-1].GetCumulativeCount()),
+					CumulativeCount: proto.Uint64(pb.Histogram.GetSampleCount()),
 					UpperBound:      proto.Float64(math.Inf(1)),
 					Exemplar:        e,
 				}

gateway/vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go

@@ -37,6 +37,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -47,9 +48,10 @@ import (
 )
 
 const (
-	contentTypeHeader     = "Content-Type"
-	contentEncodingHeader = "Content-Encoding"
-	acceptEncodingHeader  = "Accept-Encoding"
+	contentTypeHeader      = "Content-Type"
+	contentEncodingHeader  = "Content-Encoding"
+	acceptEncodingHeader   = "Accept-Encoding"
+	processStartTimeHeader = "Process-Start-Time-Unix"
 )
 
 var gzipPool = sync.Pool{
@@ -121,6 +123,9 @@ func HandlerForTransactional(reg prometheus.TransactionalGatherer, opts HandlerO
 	}
 
 	h := http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
+		if !opts.ProcessStartTime.IsZero() {
+			rsp.Header().Set(processStartTimeHeader, strconv.FormatInt(opts.ProcessStartTime.Unix(), 10))
+		}
 		if inFlightSem != nil {
 			select {
 			case inFlightSem <- struct{}{}: // All good, carry on.
@@ -366,6 +371,14 @@ type HandlerOpts struct {
 	// (which changes the identity of the resulting series on the Prometheus
 	// server).
 	EnableOpenMetrics bool
+	// ProcessStartTime allows setting process start timevalue that will be exposed
+	// with "Process-Start-Time-Unix" response header along with the metrics
+	// payload. This allow callers to have efficient transformations to cumulative
+	// counters (e.g. OpenTelemetry) or generally _created timestamp estimation per
+	// scrape target.
+	// NOTE: This feature is experimental and not covered by OpenMetrics or Prometheus
+	// exposition format.
+	ProcessStartTime time.Time
 }
 
 // gzipAccepted returns whether the client will accept gzip-encoded content.

gateway/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client.go

@@ -68,17 +68,17 @@ func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.Rou
 		o.apply(rtOpts)
 	}
 
-	code, method := checkLabels(counter)
+	// Curry the counter with dynamic labels before checking the remaining labels.
+	code, method := checkLabels(counter.MustCurryWith(rtOpts.emptyDynamicLabels()))
 
 	return func(r *http.Request) (*http.Response, error) {
 		resp, err := next.RoundTrip(r)
 		if err == nil {
-			exemplarAdd(
-				counter.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)),
-				1,
-				rtOpts.getExemplarFn(r.Context()),
-			)
-			counter.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)).Inc()
+			l := labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)
+			for label, resolve := range rtOpts.extraLabelsFromCtx {
+				l[label] = resolve(resp.Request.Context())
+			}
+			addWithExemplar(counter.With(l), 1, rtOpts.getExemplarFn(r.Context()))
 		}
 		return resp, err
 	}
@@ -111,17 +111,18 @@ func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundT
 		o.apply(rtOpts)
 	}
 
-	code, method := checkLabels(obs)
+	// Curry the observer with dynamic labels before checking the remaining labels.
+	code, method := checkLabels(obs.MustCurryWith(rtOpts.emptyDynamicLabels()))
 
 	return func(r *http.Request) (*http.Response, error) {
 		start := time.Now()
 		resp, err := next.RoundTrip(r)
 		if err == nil {
-			exemplarObserve(
-				obs.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)),
-				time.Since(start).Seconds(),
-				rtOpts.getExemplarFn(r.Context()),
-			)
+			l := labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)
+			for label, resolve := range rtOpts.extraLabelsFromCtx {
+				l[label] = resolve(resp.Request.Context())
+			}
+			observeWithExemplar(obs.With(l), time.Since(start).Seconds(), rtOpts.getExemplarFn(r.Context()))
 		}
 		return resp, err
 	}

gateway/vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go

@@ -28,7 +28,9 @@ import (
 // magicString is used for the hacky label test in checkLabels. Remove once fixed.
 const magicString = "zZgWfBxLqvG8kc8IMv3POi2Bb0tZI3vAnBx+gBaFi9FyPzB/CzKUer1yufDa"
 
-func exemplarObserve(obs prometheus.Observer, val float64, labels map[string]string) {
+// observeWithExemplar is a wrapper for [prometheus.ExemplarAdder.ExemplarObserver],
+// which falls back to [prometheus.Observer.Observe] if no labels are provided.
+func observeWithExemplar(obs prometheus.Observer, val float64, labels map[string]string) {
 	if labels == nil {
 		obs.Observe(val)
 		return
@@ -36,7 +38,9 @@ func exemplarObserve(obs prometheus.Observer, val float64, labels map[string]str
 	obs.(prometheus.ExemplarObserver).ObserveWithExemplar(val, labels)
 }
 
-func exemplarAdd(obs prometheus.Counter, val float64, labels map[string]string) {
+// addWithExemplar is a wrapper for [prometheus.ExemplarAdder.AddWithExemplar],
+// which falls back to [prometheus.Counter.Add] if no labels are provided.
+func addWithExemplar(obs prometheus.Counter, val float64, labels map[string]string) {
 	if labels == nil {
 		obs.Add(val)
 		return
@@ -83,7 +87,8 @@ func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler, op
 		o.apply(hOpts)
 	}
 
-	code, method := checkLabels(obs)
+	// Curry the observer with dynamic labels before checking the remaining labels.
+	code, method := checkLabels(obs.MustCurryWith(hOpts.emptyDynamicLabels()))
 
 	if code {
 		return func(w http.ResponseWriter, r *http.Request) {
@@ -91,23 +96,22 @@ func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler, op
 			d := newDelegator(w, nil)
 			next.ServeHTTP(d, r)
 
-			exemplarObserve(
-				obs.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
-				time.Since(now).Seconds(),
-				hOpts.getExemplarFn(r.Context()),
-			)
+			l := labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)
+			for label, resolve := range hOpts.extraLabelsFromCtx {
+				l[label] = resolve(r.Context())
+			}
+			observeWithExemplar(obs.With(l), time.Since(now).Seconds(), hOpts.getExemplarFn(r.Context()))
 		}
 	}
 
 	return func(w http.ResponseWriter, r *http.Request) {
 		now := time.Now()
 		next.ServeHTTP(w, r)
-
-		exemplarObserve(
-			obs.With(labels(code, method, r.Method, 0, hOpts.extraMethods...)),
-			time.Since(now).Seconds(),
-			hOpts.getExemplarFn(r.Context()),
-		)
+		l := labels(code, method, r.Method, 0, hOpts.extraMethods...)
+		for label, resolve := range hOpts.extraLabelsFromCtx {
+			l[label] = resolve(r.Context())
+		}
+		observeWithExemplar(obs.With(l), time.Since(now).Seconds(), hOpts.getExemplarFn(r.Context()))
 	}
 }
 
@@ -134,28 +138,30 @@ func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler,
 		o.apply(hOpts)
 	}
 
-	code, method := checkLabels(counter)
+	// Curry the counter with dynamic labels before checking the remaining labels.
+	code, method := checkLabels(counter.MustCurryWith(hOpts.emptyDynamicLabels()))
 
 	if code {
 		return func(w http.ResponseWriter, r *http.Request) {
 			d := newDelegator(w, nil)
 			next.ServeHTTP(d, r)
 
-			exemplarAdd(
-				counter.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
-				1,
-				hOpts.getExemplarFn(r.Context()),
-			)
+			l := labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)
+			for label, resolve := range hOpts.extraLabelsFromCtx {
+				l[label] = resolve(r.Context())
+			}
+			addWithExemplar(counter.With(l), 1, hOpts.getExemplarFn(r.Context()))
 		}
 	}
 
 	return func(w http.ResponseWriter, r *http.Request) {
 		next.ServeHTTP(w, r)
-		exemplarAdd(
-			counter.With(labels(code, method, r.Method, 0, hOpts.extraMethods...)),
-			1,
-			hOpts.getExemplarFn(r.Context()),
-		)
+
+		l := labels(code, method, r.Method, 0, hOpts.extraMethods...)
+		for label, resolve := range hOpts.extraLabelsFromCtx {
+			l[label] = resolve(r.Context())
+		}
+		addWithExemplar(counter.With(l), 1, hOpts.getExemplarFn(r.Context()))
 	}
 }
 
@@ -187,16 +193,17 @@ func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Ha
 		o.apply(hOpts)
 	}
 
-	code, method := checkLabels(obs)
+	// Curry the observer with dynamic labels before checking the remaining labels.
+	code, method := checkLabels(obs.MustCurryWith(hOpts.emptyDynamicLabels()))
 
 	return func(w http.ResponseWriter, r *http.Request) {
 		now := time.Now()
 		d := newDelegator(w, func(status int) {
-			exemplarObserve(
-				obs.With(labels(code, method, r.Method, status, hOpts.extraMethods...)),
-				time.Since(now).Seconds(),
-				hOpts.getExemplarFn(r.Context()),
-			)
+			l := labels(code, method, r.Method, status, hOpts.extraMethods...)
+			for label, resolve := range hOpts.extraLabelsFromCtx {
+				l[label] = resolve(r.Context())
+			}
+			observeWithExemplar(obs.With(l), time.Since(now).Seconds(), hOpts.getExemplarFn(r.Context()))
 		})
 		next.ServeHTTP(d, r)
 	}
@@ -227,28 +234,32 @@ func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler,
 		o.apply(hOpts)
 	}
 
-	code, method := checkLabels(obs)
+	// Curry the observer with dynamic labels before checking the remaining labels.
+	code, method := checkLabels(obs.MustCurryWith(hOpts.emptyDynamicLabels()))
+
 	if code {
 		return func(w http.ResponseWriter, r *http.Request) {
 			d := newDelegator(w, nil)
 			next.ServeHTTP(d, r)
 			size := computeApproximateRequestSize(r)
-			exemplarObserve(
-				obs.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
-				float64(size),
-				hOpts.getExemplarFn(r.Context()),
-			)
+
+			l := labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)
+			for label, resolve := range hOpts.extraLabelsFromCtx {
+				l[label] = resolve(r.Context())
+			}
+			observeWithExemplar(obs.With(l), float64(size), hOpts.getExemplarFn(r.Context()))
 		}
 	}
 
 	return func(w http.ResponseWriter, r *http.Request) {
 		next.ServeHTTP(w, r)
 		size := computeApproximateRequestSize(r)
-		exemplarObserve(
-			obs.With(labels(code, method, r.Method, 0, hOpts.extraMethods...)),
-			float64(size),
-			hOpts.getExemplarFn(r.Context()),
-		)
+
+		l := labels(code, method, r.Method, 0, hOpts.extraMethods...)
+		for label, resolve := range hOpts.extraLabelsFromCtx {
+			l[label] = resolve(r.Context())
+		}
+		observeWithExemplar(obs.With(l), float64(size), hOpts.getExemplarFn(r.Context()))
 	}
 }
 
@@ -277,16 +288,18 @@ func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler
 		o.apply(hOpts)
 	}
 
-	code, method := checkLabels(obs)
+	// Curry the observer with dynamic labels before checking the remaining labels.
+	code, method := checkLabels(obs.MustCurryWith(hOpts.emptyDynamicLabels()))
 
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		d := newDelegator(w, nil)
 		next.ServeHTTP(d, r)
-		exemplarObserve(
-			obs.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
-			float64(d.Written()),
-			hOpts.getExemplarFn(r.Context()),
-		)
+
+		l := labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)
+		for label, resolve := range hOpts.extraLabelsFromCtx {
+			l[label] = resolve(r.Context())
+		}
+		observeWithExemplar(obs.With(l), float64(d.Written()), hOpts.getExemplarFn(r.Context()))
 	})
 }
 

gateway/vendor/github.com/prometheus/client_golang/prometheus/promhttp/option.go

@@ -24,14 +24,32 @@ type Option interface {
 	apply(*options)
 }
 
+// LabelValueFromCtx are used to compute the label value from request context.
+// Context can be filled with values from request through middleware.
+type LabelValueFromCtx func(ctx context.Context) string
+
 // options store options for both a handler or round tripper.
 type options struct {
-	extraMethods  []string
-	getExemplarFn func(requestCtx context.Context) prometheus.Labels
+	extraMethods       []string
+	getExemplarFn      func(requestCtx context.Context) prometheus.Labels
+	extraLabelsFromCtx map[string]LabelValueFromCtx
 }
 
 func defaultOptions() *options {
-	return &options{getExemplarFn: func(ctx context.Context) prometheus.Labels { return nil }}
+	return &options{
+		getExemplarFn:      func(ctx context.Context) prometheus.Labels { return nil },
+		extraLabelsFromCtx: map[string]LabelValueFromCtx{},
+	}
+}
+
+func (o *options) emptyDynamicLabels() prometheus.Labels {
+	labels := prometheus.Labels{}
+
+	for label := range o.extraLabelsFromCtx {
+		labels[label] = ""
+	}
+
+	return labels
 }
 
 type optionApplyFunc func(*options)
@@ -48,11 +66,19 @@ func WithExtraMethods(methods ...string) Option {
 	})
 }
 
-// WithExemplarFromContext adds allows to put a hook to all counter and histogram metrics.
-// If the hook function returns non-nil labels, exemplars will be added for that request, otherwise metric
-// will get instrumented without exemplar.
+// WithExemplarFromContext allows to inject function that will get exemplar from context that will be put to counter and histogram metrics.
+// If the function returns nil labels or the metric does not support exemplars, no exemplar will be added (noop), but
+// metric will continue to observe/increment.
 func WithExemplarFromContext(getExemplarFn func(requestCtx context.Context) prometheus.Labels) Option {
 	return optionApplyFunc(func(o *options) {
 		o.getExemplarFn = getExemplarFn
 	})
 }
+
+// WithLabelFromCtx registers a label for dynamic resolution with access to context.
+// See the example for ExampleInstrumentHandlerWithLabelResolver for example usage
+func WithLabelFromCtx(name string, valueFn LabelValueFromCtx) Option {
+	return optionApplyFunc(func(o *options) {
+		o.extraLabelsFromCtx[name] = valueFn
+	})
+}

gateway/vendor/github.com/prometheus/client_golang/prometheus/registry.go

@@ -21,18 +21,17 @@ import (
 	"path/filepath"
 	"runtime"
 	"sort"
+	"strconv"
 	"strings"
 	"sync"
 	"unicode/utf8"
 
-	"github.com/cespare/xxhash/v2"
-	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
-	"github.com/golang/protobuf/proto"
-	"github.com/prometheus/common/expfmt"
-
-	dto "github.com/prometheus/client_model/go"
-
 	"github.com/prometheus/client_golang/prometheus/internal"
+
+	"github.com/cespare/xxhash/v2"
+	dto "github.com/prometheus/client_model/go"
+	"github.com/prometheus/common/expfmt"
+	"google.golang.org/protobuf/proto"
 )
 
 const (
@@ -252,9 +251,12 @@ func (errs MultiError) MaybeUnwrap() error {
 }
 
 // Registry registers Prometheus collectors, collects their metrics, and gathers
-// them into MetricFamilies for exposition. It implements both Registerer and
-// Gatherer. The zero value is not usable. Create instances with NewRegistry or
-// NewPedanticRegistry.
+// them into MetricFamilies for exposition. It implements Registerer, Gatherer,
+// and Collector. The zero value is not usable. Create instances with
+// NewRegistry or NewPedanticRegistry.
+//
+// Registry implements Collector to allow it to be used for creating groups of
+// metrics. See the Grouping example for how this can be done.
 type Registry struct {
 	mtx                   sync.RWMutex
 	collectorsByID        map[uint64]Collector // ID is a hash of the descIDs.
@@ -556,6 +558,31 @@ func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 	return internal.NormalizeMetricFamilies(metricFamiliesByName), errs.MaybeUnwrap()
 }
 
+// Describe implements Collector.
+func (r *Registry) Describe(ch chan<- *Desc) {
+	r.mtx.RLock()
+	defer r.mtx.RUnlock()
+
+	// Only report the checked Collectors; unchecked collectors don't report any
+	// Desc.
+	for _, c := range r.collectorsByID {
+		c.Describe(ch)
+	}
+}
+
+// Collect implements Collector.
+func (r *Registry) Collect(ch chan<- Metric) {
+	r.mtx.RLock()
+	defer r.mtx.RUnlock()
+
+	for _, c := range r.collectorsByID {
+		c.Collect(ch)
+	}
+	for _, c := range r.uncheckedCollectors {
+		c.Collect(ch)
+	}
+}
+
 // WriteToTextfile calls Gather on the provided Gatherer, encodes the result in the
 // Prometheus text format, and writes it to a temporary file. Upon success, the
 // temporary file is renamed to the provided filename.
@@ -905,6 +932,10 @@ func checkMetricConsistency(
 		h.WriteString(lp.GetValue())
 		h.Write(separatorByteSlice)
 	}
+	if dtoMetric.TimestampMs != nil {
+		h.WriteString(strconv.FormatInt(*(dtoMetric.TimestampMs), 10))
+		h.Write(separatorByteSlice)
+	}
 	hSum := h.Sum64()
 	if _, exists := metricHashes[hSum]; exists {
 		return fmt.Errorf(
@@ -934,7 +965,7 @@ func checkDescConsistency(
 	copy(lpsFromDesc, desc.constLabelPairs)
 	for _, l := range desc.variableLabels {
 		lpsFromDesc = append(lpsFromDesc, &dto.LabelPair{
-			Name: proto.String(l),
+			Name: proto.String(l.Name),
 		})
 	}
 	if len(lpsFromDesc) != len(dtoMetric.Label) {

gateway/vendor/github.com/prometheus/client_golang/prometheus/summary.go

@@ -22,11 +22,10 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/beorn7/perks/quantile"
-	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
-	"github.com/golang/protobuf/proto"
-
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/beorn7/perks/quantile"
+	"google.golang.org/protobuf/proto"
 )
 
 // quantileLabel is used for the label that defines the quantile in a
@@ -148,6 +147,18 @@ type SummaryOpts struct {
 	BufCap uint32
 }
 
+// SummaryVecOpts bundles the options to create a SummaryVec metric.
+// It is mandatory to set SummaryOpts, see there for mandatory fields. VariableLabels
+// is optional and can safely be left to its default value.
+type SummaryVecOpts struct {
+	SummaryOpts
+
+	// VariableLabels are used to partition the metric vector by the given set
+	// of labels. Each label value will be constrained with the optional Contraint
+	// function, if provided.
+	VariableLabels ConstrainableLabels
+}
+
 // Problem with the sliding-window decay algorithm... The Merge method of
 // perk/quantile is actually not working as advertised - and it might be
 // unfixable, as the underlying algorithm is apparently not capable of merging
@@ -178,11 +189,11 @@ func NewSummary(opts SummaryOpts) Summary {
 
 func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
+		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels.labelNames(), labelValues))
 	}
 
 	for _, n := range desc.variableLabels {
-		if n == quantileLabel {
+		if n.Name == quantileLabel {
 			panic(errQuantileLabelNotAllowed)
 		}
 	}
@@ -530,20 +541,28 @@ type SummaryVec struct {
 // it is handled by the Prometheus server internally, “quantile” is an illegal
 // label name. NewSummaryVec will panic if this label name is used.
 func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
-	for _, ln := range labelNames {
+	return V2.NewSummaryVec(SummaryVecOpts{
+		SummaryOpts:    opts,
+		VariableLabels: UnconstrainedLabels(labelNames),
+	})
+}
+
+// NewSummaryVec creates a new SummaryVec based on the provided SummaryVecOpts.
+func (v2) NewSummaryVec(opts SummaryVecOpts) *SummaryVec {
+	for _, ln := range opts.VariableLabels.labelNames() {
 		if ln == quantileLabel {
 			panic(errQuantileLabelNotAllowed)
 		}
 	}
-	desc := NewDesc(
+	desc := V2.NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
-		labelNames,
+		opts.VariableLabels,
 		opts.ConstLabels,
 	)
 	return &SummaryVec{
 		MetricVec: NewMetricVec(desc, func(lvs ...string) Metric {
-			return newSummary(desc, opts, lvs...)
+			return newSummary(desc, opts.SummaryOpts, lvs...)
 		}),
 	}
 }
@@ -603,7 +622,8 @@ func (v *SummaryVec) GetMetricWith(labels Labels) (Observer, error) {
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
 // GetMetricWithLabelValues would have returned an error. Not returning an
 // error allows shortcuts like
-//     myVec.WithLabelValues("404", "GET").Observe(42.21)
+//
+//	myVec.WithLabelValues("404", "GET").Observe(42.21)
 func (v *SummaryVec) WithLabelValues(lvs ...string) Observer {
 	s, err := v.GetMetricWithLabelValues(lvs...)
 	if err != nil {
@@ -614,7 +634,8 @@ func (v *SummaryVec) WithLabelValues(lvs ...string) Observer {
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
 // returned an error. Not returning an error allows shortcuts like
-//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)
+//
+//	myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)
 func (v *SummaryVec) With(labels Labels) Observer {
 	s, err := v.GetMetricWith(labels)
 	if err != nil {
@@ -701,7 +722,8 @@ func (s *constSummary) Write(out *dto.Metric) error {
 //
 // quantiles maps ranks to quantile values. For example, a median latency of
 // 0.23s and a 99th percentile latency of 0.56s would be expressed as:
-//     map[float64]float64{0.5: 0.23, 0.99: 0.56}
+//
+//	map[float64]float64{0.5: 0.23, 0.99: 0.56}
 //
 // NewConstSummary returns an error if the length of labelValues is not
 // consistent with the variable labels in Desc or if Desc is invalid.

gateway/vendor/github.com/prometheus/client_golang/prometheus/timer.go

@@ -23,13 +23,24 @@ type Timer struct {
 }
 
 // NewTimer creates a new Timer. The provided Observer is used to observe a
-// duration in seconds. Timer is usually used to time a function call in the
+// duration in seconds. If the Observer implements ExemplarObserver, passing exemplar
+// later on will be also supported.
+// Timer is usually used to time a function call in the
 // following way:
-//    func TimeMe() {
-//        timer := NewTimer(myHistogram)
-//        defer timer.ObserveDuration()
-//        // Do actual work.
-//    }
+//
+//	func TimeMe() {
+//	    timer := NewTimer(myHistogram)
+//	    defer timer.ObserveDuration()
+//	    // Do actual work.
+//	}
+//
+// or
+//
+//	func TimeMeWithExemplar() {
+//		    timer := NewTimer(myHistogram)
+//		    defer timer.ObserveDurationWithExemplar(exemplar)
+//		    // Do actual work.
+//		}
 func NewTimer(o Observer) *Timer {
 	return &Timer{
 		begin:    time.Now(),
@@ -52,3 +63,19 @@ func (t *Timer) ObserveDuration() time.Duration {
 	}
 	return d
 }
+
+// ObserveDurationWithExemplar is like ObserveDuration, but it will also
+// observe exemplar with the duration unless exemplar is nil or provided Observer can't
+// be casted to ExemplarObserver.
+func (t *Timer) ObserveDurationWithExemplar(exemplar Labels) time.Duration {
+	d := time.Since(t.begin)
+	eo, ok := t.observer.(ExemplarObserver)
+	if ok && exemplar != nil {
+		eo.ObserveWithExemplar(d.Seconds(), exemplar)
+		return d
+	}
+	if t.observer != nil {
+		t.observer.Observe(d.Seconds())
+	}
+	return d
+}

gateway/vendor/github.com/prometheus/client_golang/prometheus/value.go

@@ -19,13 +19,11 @@ import (
 	"time"
 	"unicode/utf8"
 
-	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
-	"github.com/golang/protobuf/proto"
-	"google.golang.org/protobuf/types/known/timestamppb"
-
 	"github.com/prometheus/client_golang/prometheus/internal"
 
 	dto "github.com/prometheus/client_model/go"
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/timestamppb"
 )
 
 // ValueType is an enumeration of metric types that represent a simple value.
@@ -188,9 +186,9 @@ func MakeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 		return desc.constLabelPairs
 	}
 	labelPairs := make([]*dto.LabelPair, 0, totalLen)
-	for i, n := range desc.variableLabels {
+	for i, l := range desc.variableLabels {
 		labelPairs = append(labelPairs, &dto.LabelPair{
-			Name:  proto.String(n),
+			Name:  proto.String(l.Name),
 			Value: proto.String(labelValues[i]),
 		})
 	}

gateway/vendor/github.com/prometheus/client_golang/prometheus/vec.go

@@ -20,6 +20,24 @@ import (
 	"github.com/prometheus/common/model"
 )
 
+var labelsPool = &sync.Pool{
+	New: func() interface{} {
+		return make(Labels)
+	},
+}
+
+func getLabelsFromPool() Labels {
+	return labelsPool.Get().(Labels)
+}
+
+func putLabelsToPool(labels Labels) {
+	for k := range labels {
+		delete(labels, k)
+	}
+
+	labelsPool.Put(labels)
+}
+
 // MetricVec is a Collector to bundle metrics of the same name that differ in
 // their label values. MetricVec is not used directly but as a building block
 // for implementations of vectors of a given metric type, like GaugeVec,
@@ -72,6 +90,7 @@ func NewMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *MetricVec {
 // with a performance overhead (for creating and processing the Labels map).
 // See also the CounterVec example.
 func (m *MetricVec) DeleteLabelValues(lvs ...string) bool {
+	lvs = constrainLabelValues(m.desc, lvs, m.curry)
 	h, err := m.hashLabelValues(lvs)
 	if err != nil {
 		return false
@@ -91,6 +110,9 @@ func (m *MetricVec) DeleteLabelValues(lvs ...string) bool {
 // 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 {
+	labels = constrainLabels(m.desc, labels)
+	defer putLabelsToPool(labels)
+
 	h, err := m.hashLabels(labels)
 	if err != nil {
 		return false
@@ -106,6 +128,9 @@ func (m *MetricVec) Delete(labels Labels) bool {
 // Note that curried labels will never be matched if deleting from the curried vector.
 // To match curried labels with DeletePartialMatch, it must be called on the base vector.
 func (m *MetricVec) DeletePartialMatch(labels Labels) int {
+	labels = constrainLabels(m.desc, labels)
+	defer putLabelsToPool(labels)
+
 	return m.metricMap.deleteByLabels(labels, m.curry)
 }
 
@@ -145,10 +170,10 @@ func (m *MetricVec) CurryWith(labels Labels) (*MetricVec, error) {
 		iCurry   int
 	)
 	for i, label := range m.desc.variableLabels {
-		val, ok := labels[label]
+		val, ok := labels[label.Name]
 		if iCurry < len(oldCurry) && oldCurry[iCurry].index == i {
 			if ok {
-				return nil, fmt.Errorf("label name %q is already curried", label)
+				return nil, fmt.Errorf("label name %q is already curried", label.Name)
 			}
 			newCurry = append(newCurry, oldCurry[iCurry])
 			iCurry++
@@ -156,7 +181,7 @@ func (m *MetricVec) CurryWith(labels Labels) (*MetricVec, error) {
 			if !ok {
 				continue // Label stays uncurried.
 			}
-			newCurry = append(newCurry, curriedLabelValue{i, val})
+			newCurry = append(newCurry, curriedLabelValue{i, label.Constrain(val)})
 		}
 	}
 	if l := len(oldCurry) + len(labels) - len(newCurry); l > 0 {
@@ -199,6 +224,7 @@ func (m *MetricVec) CurryWith(labels Labels) (*MetricVec, error) {
 // a wrapper around MetricVec, implementing a vector for a specific Metric
 // implementation, for example GaugeVec.
 func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
+	lvs = constrainLabelValues(m.desc, lvs, m.curry)
 	h, err := m.hashLabelValues(lvs)
 	if err != nil {
 		return nil, err
@@ -224,6 +250,9 @@ func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
 // around MetricVec, implementing a vector for a specific Metric implementation,
 // for example GaugeVec.
 func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) {
+	labels = constrainLabels(m.desc, labels)
+	defer putLabelsToPool(labels)
+
 	h, err := m.hashLabels(labels)
 	if err != nil {
 		return nil, err
@@ -266,16 +295,16 @@ func (m *MetricVec) hashLabels(labels Labels) (uint64, error) {
 		iCurry int
 	)
 	for i, label := range m.desc.variableLabels {
-		val, ok := labels[label]
+		val, ok := labels[label.Name]
 		if iCurry < len(curry) && curry[iCurry].index == i {
 			if ok {
-				return 0, fmt.Errorf("label name %q is already curried", label)
+				return 0, fmt.Errorf("label name %q is already curried", label.Name)
 			}
 			h = m.hashAdd(h, curry[iCurry].value)
 			iCurry++
 		} else {
 			if !ok {
-				return 0, fmt.Errorf("label name %q missing in label map", label)
+				return 0, fmt.Errorf("label name %q missing in label map", label.Name)
 			}
 			h = m.hashAdd(h, val)
 		}
@@ -453,7 +482,7 @@ func valueMatchesVariableOrCurriedValue(targetValue string, index int, values []
 func matchPartialLabels(desc *Desc, values []string, labels Labels, curry []curriedLabelValue) bool {
 	for l, v := range labels {
 		// Check if the target label exists in our metrics and get the index.
-		varLabelIndex, validLabel := indexOf(l, desc.variableLabels)
+		varLabelIndex, validLabel := indexOf(l, desc.variableLabels.labelNames())
 		if validLabel {
 			// Check the value of that label against the target value.
 			// We don't consider curried values in partial matches.
@@ -605,7 +634,7 @@ func matchLabels(desc *Desc, values []string, labels Labels, curry []curriedLabe
 			iCurry++
 			continue
 		}
-		if values[i] != labels[k] {
+		if values[i] != labels[k.Name] {
 			return false
 		}
 	}
@@ -621,7 +650,7 @@ func extractLabelValues(desc *Desc, labels Labels, curry []curriedLabelValue) []
 			iCurry++
 			continue
 		}
-		labelValues[i] = labels[k]
+		labelValues[i] = labels[k.Name]
 	}
 	return labelValues
 }
@@ -640,3 +669,35 @@ func inlineLabelValues(lvs []string, curry []curriedLabelValue) []string {
 	}
 	return labelValues
 }
+
+func constrainLabels(desc *Desc, labels Labels) Labels {
+	constrainedLabels := getLabelsFromPool()
+	for l, v := range labels {
+		if i, ok := indexOf(l, desc.variableLabels.labelNames()); ok {
+			v = desc.variableLabels[i].Constrain(v)
+		}
+
+		constrainedLabels[l] = v
+	}
+
+	return constrainedLabels
+}
+
+func constrainLabelValues(desc *Desc, lvs []string, curry []curriedLabelValue) []string {
+	constrainedValues := make([]string, len(lvs))
+	var iCurry, iLVs int
+	for i := 0; i < len(lvs)+len(curry); i++ {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			iCurry++
+			continue
+		}
+
+		if i < len(desc.variableLabels) {
+			constrainedValues[iLVs] = desc.variableLabels[i].Constrain(lvs[iLVs])
+		} else {
+			constrainedValues[iLVs] = lvs[iLVs]
+		}
+		iLVs++
+	}
+	return constrainedValues
+}

gateway/vendor/github.com/prometheus/client_golang/prometheus/vnext.go

@@ -0,0 +1,23 @@
+// Copyright 2022 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
+
+type v2 struct{}
+
+// V2 is a struct that can be referenced to access experimental API that might
+// be present in v2 of client golang someday. It offers extended functionality
+// of v1 with slightly changed API. It is acceptable to use some pieces from v1
+// and e.g `prometheus.NewGauge` and some from v2 e.g. `prometheus.V2.NewDesc`
+// in the same codebase.
+var V2 = v2{}

gateway/vendor/github.com/prometheus/client_golang/prometheus/wrap.go

@@ -17,12 +17,10 @@ import (
 	"fmt"
 	"sort"
 
-	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
-	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/client_golang/prometheus/internal"
 
 	dto "github.com/prometheus/client_model/go"
-
-	"github.com/prometheus/client_golang/prometheus/internal"
+	"google.golang.org/protobuf/proto"
 )
 
 // WrapRegistererWith returns a Registerer wrapping the provided
@@ -206,7 +204,7 @@ func wrapDesc(desc *Desc, prefix string, labels Labels) *Desc {
 		constLabels[ln] = lv
 	}
 	// NewDesc will do remaining validations.
-	newDesc := NewDesc(prefix+desc.fqName, desc.help, desc.variableLabels, constLabels)
+	newDesc := V2.NewDesc(prefix+desc.fqName, desc.help, desc.variableLabels, constLabels)
 	// Propagate errors if there was any. This will override any errer
 	// created by NewDesc above, i.e. earlier errors get precedence.
 	if desc.err != nil {