update latest prometheus client dependency and its dependencies

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.

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

@@ -68,16 +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 {
-			addWithExemplar(
-				counter.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)),
-				1,
-				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())
+			}
+			addWithExemplar(counter.With(l), 1, rtOpts.getExemplarFn(r.Context()))
 		}
 		return resp, err
 	}
@@ -110,17 +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 {
-			observeWithExemplar(
-				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
 	}

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

@@ -87,7 +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) {
@@ -95,23 +96,22 @@ func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler, op
 			d := newDelegator(w, nil)
 			next.ServeHTTP(d, r)
 
-			observeWithExemplar(
-				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)
-
-		observeWithExemplar(
-			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()))
 	}
 }
 
@@ -138,28 +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)
 
-			addWithExemplar(
-				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)
-		addWithExemplar(
-			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()))
 	}
 }
 
@@ -191,16 +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) {
-			observeWithExemplar(
-				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)
 	}
@@ -231,28 +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)
-			observeWithExemplar(
-				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)
-		observeWithExemplar(
-			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()))
 	}
 }
 
@@ -281,16 +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)
-		observeWithExemplar(
-			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()))
 	})
 }
 
@@ -380,16 +389,13 @@ func isLabelCurried(c prometheus.Collector, label string) bool {
 	return true
 }
 
-// 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, extraMethods ...string) prometheus.Labels {
-	if !(code || method) {
-		return emptyLabels
-	}
 	labels := prometheus.Labels{}
 
+	if !(code || method) {
+		return labels
+	}
+
 	if code {
 		labels["code"] = sanitizeCode(status)
 	}

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
+	})
+}