vendor: update buildkit to master@ae9d0f5

Signed-off-by: Justin Chadwell <me@jedevc.com>

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

@@ -76,16 +76,19 @@ func (r *responseWriterDelegator) Write(b []byte) (int, error) {
 	return n, err
 }
 
-type closeNotifierDelegator struct{ *responseWriterDelegator }
-type flusherDelegator struct{ *responseWriterDelegator }
-type hijackerDelegator struct{ *responseWriterDelegator }
-type readerFromDelegator struct{ *responseWriterDelegator }
-type pusherDelegator struct{ *responseWriterDelegator }
+type (
+	closeNotifierDelegator struct{ *responseWriterDelegator }
+	flusherDelegator       struct{ *responseWriterDelegator }
+	hijackerDelegator      struct{ *responseWriterDelegator }
+	readerFromDelegator    struct{ *responseWriterDelegator }
+	pusherDelegator        struct{ *responseWriterDelegator }
+)
 
 func (d closeNotifierDelegator) CloseNotify() <-chan bool {
 	//nolint:staticcheck // Ignore SA1019. http.CloseNotifier is deprecated but we keep it here to not break existing users.
 	return d.ResponseWriter.(http.CloseNotifier).CloseNotify()
 }
+
 func (d flusherDelegator) Flush() {
 	// If applicable, call WriteHeader here so that observeWriteHeader is
 	// handled appropriately.
@@ -94,9 +97,11 @@ 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 applicable, call WriteHeader here so that observeWriteHeader is
 	// handled appropriately.
@@ -107,6 +112,7 @@ func (d readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
 	d.written += n
 	return n, err
 }
+
 func (d pusherDelegator) Push(target string, opts *http.PushOptions) error {
 	return d.ResponseWriter.(http.Pusher).Push(target, opts)
 }
@@ -261,7 +267,7 @@ func init() {
 			http.Flusher
 		}{d, pusherDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
 	}
-	pickDelegator[pusher+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { //23
+	pickDelegator[pusher+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 23
 		return struct {
 			*responseWriterDelegator
 			http.Pusher

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

@@ -33,6 +33,7 @@ package promhttp
 
 import (
 	"compress/gzip"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -84,6 +85,13 @@ func Handler() http.Handler {
 // instrumentation. Use the InstrumentMetricHandler function to apply the same
 // kind of instrumentation as it is used by the Handler function.
 func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
+	return HandlerForTransactional(prometheus.ToTransactionalGatherer(reg), opts)
+}
+
+// HandlerForTransactional is like HandlerFor, but it uses transactional gather, which
+// can safely change in-place returned *dto.MetricFamily before call to `Gather` and after
+// call to `done` of that `Gather`.
+func HandlerForTransactional(reg prometheus.TransactionalGatherer, opts HandlerOpts) http.Handler {
 	var (
 		inFlightSem chan struct{}
 		errCnt      = prometheus.NewCounterVec(
@@ -103,7 +111,8 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
 		errCnt.WithLabelValues("gathering")
 		errCnt.WithLabelValues("encoding")
 		if err := opts.Registry.Register(errCnt); err != nil {
-			if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+			are := &prometheus.AlreadyRegisteredError{}
+			if errors.As(err, are) {
 				errCnt = are.ExistingCollector.(*prometheus.CounterVec)
 			} else {
 				panic(err)
@@ -123,7 +132,8 @@ func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
 				return
 			}
 		}
-		mfs, err := reg.Gather()
+		mfs, done, err := reg.Gather()
+		defer done()
 		if err != nil {
 			if opts.ErrorLog != nil {
 				opts.ErrorLog.Println("error gathering metrics:", err)
@@ -242,7 +252,8 @@ func InstrumentMetricHandler(reg prometheus.Registerer, handler http.Handler) ht
 	cnt.WithLabelValues("500")
 	cnt.WithLabelValues("503")
 	if err := reg.Register(cnt); err != nil {
-		if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+		are := &prometheus.AlreadyRegisteredError{}
+		if errors.As(err, are) {
 			cnt = are.ExistingCollector.(*prometheus.CounterVec)
 		} else {
 			panic(err)
@@ -254,7 +265,8 @@ func InstrumentMetricHandler(reg prometheus.Registerer, handler http.Handler) ht
 		Help: "Current number of scrapes being served.",
 	})
 	if err := reg.Register(gge); err != nil {
-		if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+		are := &prometheus.AlreadyRegisteredError{}
+		if errors.As(err, are) {
 			gge = are.ExistingCollector.(prometheus.Gauge)
 		} else {
 			panic(err)

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

@@ -38,11 +38,11 @@ func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) {
 //
 // 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) {
+	return func(r *http.Request) (*http.Response, error) {
 		gauge.Inc()
 		defer gauge.Dec()
 		return next.RoundTrip(r)
-	})
+	}
 }
 
 // InstrumentRoundTripperCounter is a middleware that wraps the provided
@@ -59,22 +59,28 @@ func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripp
 // If the wrapped RoundTripper panics or returns a non-nil error, the Counter
 // is not incremented.
 //
+// Use with WithExemplarFromContext to instrument the exemplars on the counter of requests.
+//
 // See the example for ExampleInstrumentRoundTripperDuration for example usage.
 func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper, opts ...Option) RoundTripperFunc {
-	rtOpts := &option{}
+	rtOpts := defaultOptions()
 	for _, o := range opts {
-		o(rtOpts)
+		o.apply(rtOpts)
 	}
 
 	code, method := checkLabels(counter)
 
-	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+	return func(r *http.Request) (*http.Response, error) {
 		resp, err := next.RoundTrip(r)
 		if err == nil {
-			counter.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)).Inc()
+			addWithExemplar(
+				counter.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)),
+				1,
+				rtOpts.getExemplarFn(r.Context()),
+			)
 		}
 		return resp, err
-	})
+	}
 }
 
 // InstrumentRoundTripperDuration is a middleware that wraps the provided
@@ -94,24 +100,30 @@ func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.Rou
 // If the wrapped RoundTripper panics or returns a non-nil error, no values are
 // reported.
 //
+// Use with WithExemplarFromContext to instrument the exemplars on the duration histograms.
+//
 // 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, opts ...Option) RoundTripperFunc {
-	rtOpts := &option{}
+	rtOpts := defaultOptions()
 	for _, o := range opts {
-		o(rtOpts)
+		o.apply(rtOpts)
 	}
 
 	code, method := checkLabels(obs)
 
-	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+	return 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, rtOpts.extraMethods...)).Observe(time.Since(start).Seconds())
+			observeWithExemplar(
+				obs.With(labels(code, method, r.Method, resp.StatusCode, rtOpts.extraMethods...)),
+				time.Since(start).Seconds(),
+				rtOpts.getExemplarFn(r.Context()),
+			)
 		}
 		return resp, err
-	})
+	}
 }
 
 // InstrumentTrace is used to offer flexibility in instrumenting the available
@@ -149,7 +161,7 @@ type InstrumentTrace struct {
 //
 // 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) {
+	return func(r *http.Request) (*http.Response, error) {
 		start := time.Now()
 
 		trace := &httptrace.ClientTrace{
@@ -231,5 +243,5 @@ func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) Ro
 		r = r.WithContext(httptrace.WithClientTrace(r.Context(), trace))
 
 		return next.RoundTrip(r)
-	})
+	}
 }

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

@@ -28,6 +28,26 @@ import (
 // magicString is used for the hacky label test in checkLabels. Remove once fixed.
 const magicString = "zZgWfBxLqvG8kc8IMv3POi2Bb0tZI3vAnBx+gBaFi9FyPzB/CzKUer1yufDa"
 
+// 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
+	}
+	obs.(prometheus.ExemplarObserver).ObserveWithExemplar(val, labels)
+}
+
+// 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
+	}
+	obs.(prometheus.ExemplarAdder).AddWithExemplar(val, labels)
+}
+
 // 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.
@@ -48,7 +68,7 @@ func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handl
 // names are "code" and "method". The function panics otherwise. For the "method"
 // label a predefined default label value set is used to filter given values.
 // Values besides predefined values will count as `unknown` method.
-//`WithExtraMethods` can be used to add more methods to the set. The Observe
+// `WithExtraMethods` can be used to add more methods to the set. 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
@@ -62,28 +82,37 @@ func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handl
 // 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, opts ...Option) http.HandlerFunc {
-	mwOpts := &option{}
+	hOpts := defaultOptions()
 	for _, o := range opts {
-		o(mwOpts)
+		o.apply(hOpts)
 	}
 
 	code, method := checkLabels(obs)
 
 	if code {
-		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		return 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(), mwOpts.extraMethods...)).Observe(time.Since(now).Seconds())
-		})
+			observeWithExemplar(
+				obs.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
+				time.Since(now).Seconds(),
+				hOpts.getExemplarFn(r.Context()),
+			)
+		}
 	}
 
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
 		now := time.Now()
 		next.ServeHTTP(w, r)
-		obs.With(labels(code, method, r.Method, 0, mwOpts.extraMethods...)).Observe(time.Since(now).Seconds())
-	})
+
+		observeWithExemplar(
+			obs.With(labels(code, method, r.Method, 0, hOpts.extraMethods...)),
+			time.Since(now).Seconds(),
+			hOpts.getExemplarFn(r.Context()),
+		)
+	}
 }
 
 // InstrumentHandlerCounter is a middleware that wraps the provided http.Handler
@@ -104,25 +133,34 @@ func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler, op
 //
 // See the example for InstrumentHandlerDuration for example usage.
 func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler, opts ...Option) http.HandlerFunc {
-	mwOpts := &option{}
+	hOpts := defaultOptions()
 	for _, o := range opts {
-		o(mwOpts)
+		o.apply(hOpts)
 	}
 
 	code, method := checkLabels(counter)
 
 	if code {
-		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		return func(w http.ResponseWriter, r *http.Request) {
 			d := newDelegator(w, nil)
 			next.ServeHTTP(d, r)
-			counter.With(labels(code, method, r.Method, d.Status(), mwOpts.extraMethods...)).Inc()
-		})
+
+			addWithExemplar(
+				counter.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
+				1,
+				hOpts.getExemplarFn(r.Context()),
+			)
+		}
 	}
 
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
 		next.ServeHTTP(w, r)
-		counter.With(labels(code, method, r.Method, 0, mwOpts.extraMethods...)).Inc()
-	})
+		addWithExemplar(
+			counter.With(labels(code, method, r.Method, 0, hOpts.extraMethods...)),
+			1,
+			hOpts.getExemplarFn(r.Context()),
+		)
+	}
 }
 
 // InstrumentHandlerTimeToWriteHeader is a middleware that wraps the provided
@@ -148,20 +186,24 @@ func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler,
 //
 // See the example for InstrumentHandlerDuration for example usage.
 func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Handler, opts ...Option) http.HandlerFunc {
-	mwOpts := &option{}
+	hOpts := defaultOptions()
 	for _, o := range opts {
-		o(mwOpts)
+		o.apply(hOpts)
 	}
 
 	code, method := checkLabels(obs)
 
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
 		now := time.Now()
 		d := newDelegator(w, func(status int) {
-			obs.With(labels(code, method, r.Method, status, mwOpts.extraMethods...)).Observe(time.Since(now).Seconds())
+			observeWithExemplar(
+				obs.With(labels(code, method, r.Method, status, hOpts.extraMethods...)),
+				time.Since(now).Seconds(),
+				hOpts.getExemplarFn(r.Context()),
+			)
 		})
 		next.ServeHTTP(d, r)
-	})
+	}
 }
 
 // InstrumentHandlerRequestSize is a middleware that wraps the provided
@@ -184,27 +226,34 @@ func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Ha
 //
 // See the example for InstrumentHandlerDuration for example usage.
 func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler, opts ...Option) http.HandlerFunc {
-	mwOpts := &option{}
+	hOpts := defaultOptions()
 	for _, o := range opts {
-		o(mwOpts)
+		o.apply(hOpts)
 	}
 
 	code, method := checkLabels(obs)
-
 	if code {
-		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		return 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(), mwOpts.extraMethods...)).Observe(float64(size))
-		})
+			observeWithExemplar(
+				obs.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
+				float64(size),
+				hOpts.getExemplarFn(r.Context()),
+			)
+		}
 	}
 
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
 		next.ServeHTTP(w, r)
 		size := computeApproximateRequestSize(r)
-		obs.With(labels(code, method, r.Method, 0, mwOpts.extraMethods...)).Observe(float64(size))
-	})
+		observeWithExemplar(
+			obs.With(labels(code, method, r.Method, 0, hOpts.extraMethods...)),
+			float64(size),
+			hOpts.getExemplarFn(r.Context()),
+		)
+	}
 }
 
 // InstrumentHandlerResponseSize is a middleware that wraps the provided
@@ -227,9 +276,9 @@ func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler,
 //
 // See the example for InstrumentHandlerDuration for example usage.
 func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler, opts ...Option) http.Handler {
-	mwOpts := &option{}
+	hOpts := defaultOptions()
 	for _, o := range opts {
-		o(mwOpts)
+		o.apply(hOpts)
 	}
 
 	code, method := checkLabels(obs)
@@ -237,7 +286,11 @@ func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler
 	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(), mwOpts.extraMethods...)).Observe(float64(d.Written()))
+		observeWithExemplar(
+			obs.With(labels(code, method, r.Method, d.Status(), hOpts.extraMethods...)),
+			float64(d.Written()),
+			hOpts.getExemplarFn(r.Context()),
+		)
 	})
 }
 
@@ -246,7 +299,7 @@ func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler
 // Collector does not have a Desc or has more than one Desc or its Desc is
 // invalid. It also panics if the Collector has any non-const, non-curried
 // labels that are not named "code" or "method".
-func checkLabels(c prometheus.Collector) (code bool, method bool) {
+func checkLabels(c prometheus.Collector) (code, method bool) {
 	// TODO(beorn7): Remove this hacky way to check for instance labels
 	// once Descriptors can have their dimensionality queried.
 	var (

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

@@ -13,19 +13,46 @@
 
 package promhttp
 
-// Option are used to configure a middleware or round tripper..
-type Option func(*option)
+import (
+	"context"
 
-type option struct {
-	extraMethods []string
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Option are used to configure both handler (middleware) or round tripper.
+type Option interface {
+	apply(*options)
 }
 
+// options store options for both a handler or round tripper.
+type options struct {
+	extraMethods  []string
+	getExemplarFn func(requestCtx context.Context) prometheus.Labels
+}
+
+func defaultOptions() *options {
+	return &options{getExemplarFn: func(ctx context.Context) prometheus.Labels { return nil }}
+}
+
+type optionApplyFunc func(*options)
+
+func (o optionApplyFunc) apply(opt *options) { o(opt) }
+
 // WithExtraMethods adds additional HTTP methods to the list of allowed methods.
 // See https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods for the default list.
 //
 // See the example for ExampleInstrumentHandlerWithExtraMethods for example usage.
 func WithExtraMethods(methods ...string) Option {
-	return func(o *option) {
+	return optionApplyFunc(func(o *options) {
 		o.extraMethods = methods
-	}
+	})
+}
+
+// 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.
+func WithExemplarFromContext(getExemplarFn func(requestCtx context.Context) prometheus.Labels) Option {
+	return optionApplyFunc(func(o *options) {
+		o.getExemplarFn = getExemplarFn
+	})
 }