[chore]: Bump github.com/prometheus/client_golang from 1.19.1 to 1.20.0 (#3210)

vendor/github.com/prometheus/client_golang/prometheus/go_collector.go

@@ -22,13 +22,13 @@ import (
 // goRuntimeMemStats provides the metrics initially provided by runtime.ReadMemStats.
 // From Go 1.17 those similar (and better) statistics are provided by runtime/metrics, so
 // while eval closure works on runtime.MemStats, the struct from Go 1.17+ is
-// populated using runtime/metrics.
+// populated using runtime/metrics. Those are the defaults we can't alter.
 func goRuntimeMemStats() memStatsMetrics {
 	return memStatsMetrics{
 		{
 			desc: NewDesc(
 				memstatNamespace("alloc_bytes"),
-				"Number of bytes allocated and still in use.",
+				"Number of bytes allocated in heap and currently in use. Equals to /memory/classes/heap/objects:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.Alloc) },
@@ -36,7 +36,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("alloc_bytes_total"),
-				"Total number of bytes allocated, even if freed.",
+				"Total number of bytes allocated in heap until now, even if released already. Equals to /gc/heap/allocs:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.TotalAlloc) },
@@ -44,23 +44,16 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("sys_bytes"),
-				"Number of bytes obtained from system.",
+				"Number of bytes obtained from system. Equals to /memory/classes/total:byte.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.Sys) },
 			valType: GaugeValue,
-		}, {
-			desc: NewDesc(
-				memstatNamespace("lookups_total"),
-				"Total number of pointer lookups.",
-				nil, nil,
-			),
-			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.Lookups) },
-			valType: CounterValue,
 		}, {
 			desc: NewDesc(
 				memstatNamespace("mallocs_total"),
-				"Total number of mallocs.",
+				// TODO(bwplotka): We could add go_memstats_heap_objects, probably useful for discovery. Let's gather more feedback, kind of a waste of bytes for everybody for compatibility reasons to keep both, and we can't really rename/remove useful metric.
+				"Total number of heap objects allocated, both live and gc-ed. Semantically a counter version for go_memstats_heap_objects gauge. Equals to /gc/heap/allocs:objects + /gc/heap/tiny/allocs:objects.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.Mallocs) },
@@ -68,7 +61,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("frees_total"),
-				"Total number of frees.",
+				"Total number of heap objects frees. Equals to /gc/heap/frees:objects + /gc/heap/tiny/allocs:objects.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.Frees) },
@@ -76,7 +69,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("heap_alloc_bytes"),
-				"Number of heap bytes allocated and still in use.",
+				"Number of heap bytes allocated and currently in use, same as go_memstats_alloc_bytes. Equals to /memory/classes/heap/objects:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.HeapAlloc) },
@@ -84,7 +77,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("heap_sys_bytes"),
-				"Number of heap bytes obtained from system.",
+				"Number of heap bytes obtained from system. Equals to /memory/classes/heap/objects:bytes + /memory/classes/heap/unused:bytes + /memory/classes/heap/released:bytes + /memory/classes/heap/free:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.HeapSys) },
@@ -92,7 +85,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("heap_idle_bytes"),
-				"Number of heap bytes waiting to be used.",
+				"Number of heap bytes waiting to be used. Equals to /memory/classes/heap/released:bytes + /memory/classes/heap/free:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.HeapIdle) },
@@ -100,7 +93,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("heap_inuse_bytes"),
-				"Number of heap bytes that are in use.",
+				"Number of heap bytes that are in use. Equals to /memory/classes/heap/objects:bytes + /memory/classes/heap/unused:bytes",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.HeapInuse) },
@@ -108,7 +101,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("heap_released_bytes"),
-				"Number of heap bytes released to OS.",
+				"Number of heap bytes released to OS. Equals to /memory/classes/heap/released:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.HeapReleased) },
@@ -116,7 +109,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("heap_objects"),
-				"Number of allocated objects.",
+				"Number of currently allocated objects. Equals to /gc/heap/objects:objects.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.HeapObjects) },
@@ -124,7 +117,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("stack_inuse_bytes"),
-				"Number of bytes in use by the stack allocator.",
+				"Number of bytes obtained from system for stack allocator in non-CGO environments. Equals to /memory/classes/heap/stacks:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.StackInuse) },
@@ -132,7 +125,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("stack_sys_bytes"),
-				"Number of bytes obtained from system for stack allocator.",
+				"Number of bytes obtained from system for stack allocator. Equals to /memory/classes/heap/stacks:bytes + /memory/classes/os-stacks:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.StackSys) },
@@ -140,7 +133,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("mspan_inuse_bytes"),
-				"Number of bytes in use by mspan structures.",
+				"Number of bytes in use by mspan structures. Equals to /memory/classes/metadata/mspan/inuse:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.MSpanInuse) },
@@ -148,7 +141,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("mspan_sys_bytes"),
-				"Number of bytes used for mspan structures obtained from system.",
+				"Number of bytes used for mspan structures obtained from system. Equals to /memory/classes/metadata/mspan/inuse:bytes + /memory/classes/metadata/mspan/free:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.MSpanSys) },
@@ -156,7 +149,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("mcache_inuse_bytes"),
-				"Number of bytes in use by mcache structures.",
+				"Number of bytes in use by mcache structures. Equals to /memory/classes/metadata/mcache/inuse:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.MCacheInuse) },
@@ -164,7 +157,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("mcache_sys_bytes"),
-				"Number of bytes used for mcache structures obtained from system.",
+				"Number of bytes used for mcache structures obtained from system. Equals to /memory/classes/metadata/mcache/inuse:bytes + /memory/classes/metadata/mcache/free:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.MCacheSys) },
@@ -172,7 +165,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("buck_hash_sys_bytes"),
-				"Number of bytes used by the profiling bucket hash table.",
+				"Number of bytes used by the profiling bucket hash table. Equals to /memory/classes/profiling/buckets:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.BuckHashSys) },
@@ -180,7 +173,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("gc_sys_bytes"),
-				"Number of bytes used for garbage collection system metadata.",
+				"Number of bytes used for garbage collection system metadata. Equals to /memory/classes/metadata/other:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.GCSys) },
@@ -188,7 +181,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("other_sys_bytes"),
-				"Number of bytes used for other system allocations.",
+				"Number of bytes used for other system allocations. Equals to /memory/classes/other:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.OtherSys) },
@@ -196,7 +189,7 @@ func goRuntimeMemStats() memStatsMetrics {
 		}, {
 			desc: NewDesc(
 				memstatNamespace("next_gc_bytes"),
-				"Number of heap bytes when next garbage collection will take place.",
+				"Number of heap bytes when next garbage collection will take place. Equals to /gc/heap/goal:bytes.",
 				nil, nil,
 			),
 			eval:    func(ms *runtime.MemStats) float64 { return float64(ms.NextGC) },
@@ -225,7 +218,7 @@ func newBaseGoCollector() baseGoCollector {
 			nil, nil),
 		gcDesc: NewDesc(
 			"go_gc_duration_seconds",
-			"A summary of the pause duration of garbage collection cycles.",
+			"A summary of the wall-time pause (stop-the-world) duration in garbage collection cycles.",
 			nil, nil),
 		gcLastTimeDesc: NewDesc(
 			"go_memstats_last_gc_time_seconds",

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

@@ -17,6 +17,7 @@
 package prometheus
 
 import (
+	"fmt"
 	"math"
 	"runtime"
 	"runtime/metrics"
@@ -153,7 +154,8 @@ func defaultGoCollectorOptions() internal.GoCollectorOptions {
 			"/gc/heap/frees-by-size:bytes":  goGCHeapFreesBytes,
 		},
 		RuntimeMetricRules: []internal.GoCollectorRule{
-			//{Matcher: regexp.MustCompile("")},
+			// Recommended metrics we want by default from runtime/metrics.
+			{Matcher: internal.GoCollectorDefaultRuntimeMetrics},
 		},
 	}
 }
@@ -203,6 +205,7 @@ func NewGoCollector(opts ...func(o *internal.GoCollectorOptions)) Collector {
 			// to fail here. This condition is tested in TestExpectedRuntimeMetrics.
 			continue
 		}
+		help := attachOriginalName(d.Description.Description, d.Name)
 
 		sampleBuf = append(sampleBuf, metrics.Sample{Name: d.Name})
 		sampleMap[d.Name] = &sampleBuf[len(sampleBuf)-1]
@@ -214,7 +217,7 @@ func NewGoCollector(opts ...func(o *internal.GoCollectorOptions)) Collector {
 			m = newBatchHistogram(
 				NewDesc(
 					BuildFQName(namespace, subsystem, name),
-					d.Description.Description,
+					help,
 					nil,
 					nil,
 				),
@@ -226,7 +229,7 @@ func NewGoCollector(opts ...func(o *internal.GoCollectorOptions)) Collector {
 				Namespace: namespace,
 				Subsystem: subsystem,
 				Name:      name,
-				Help:      d.Description.Description,
+				Help:      help,
 			},
 			)
 		} else {
@@ -234,7 +237,7 @@ func NewGoCollector(opts ...func(o *internal.GoCollectorOptions)) Collector {
 				Namespace: namespace,
 				Subsystem: subsystem,
 				Name:      name,
-				Help:      d.Description.Description,
+				Help:      help,
 			})
 		}
 		metricSet = append(metricSet, m)
@@ -284,6 +287,10 @@ func NewGoCollector(opts ...func(o *internal.GoCollectorOptions)) Collector {
 	}
 }
 
+func attachOriginalName(desc, origName string) string {
+	return fmt.Sprintf("%s Sourced from %s", desc, origName)
+}
+
 // Describe returns all descriptions of the collector.
 func (c *goCollector) Describe(ch chan<- *Desc) {
 	c.base.Describe(ch)
@@ -376,13 +383,13 @@ func unwrapScalarRMValue(v metrics.Value) float64 {
 		//
 		// This should never happen because we always populate our metric
 		// set from the runtime/metrics package.
-		panic("unexpected unsupported metric")
+		panic("unexpected bad kind metric")
 	default:
 		// Unsupported metric kind.
 		//
 		// This should never happen because we check for this during initialization
 		// and flag and filter metrics whose kinds we don't understand.
-		panic("unexpected unsupported metric kind")
+		panic(fmt.Sprintf("unexpected unsupported metric: %v", v.Kind()))
 	}
 }
 

vendor/github.com/prometheus/client_golang/prometheus/histogram.go

@@ -440,7 +440,7 @@ type HistogramOpts struct {
 	// constant (or any negative float value).
 	NativeHistogramZeroThreshold float64
 
-	// The remaining fields define a strategy to limit the number of
+	// The next three fields define a strategy to limit the number of
 	// populated sparse buckets. If NativeHistogramMaxBucketNumber is left
 	// at zero, the number of buckets is not limited. (Note that this might
 	// lead to unbounded memory consumption if the values observed by the
@@ -473,6 +473,22 @@ type HistogramOpts struct {
 	NativeHistogramMinResetDuration time.Duration
 	NativeHistogramMaxZeroThreshold float64
 
+	// NativeHistogramMaxExemplars limits the number of exemplars
+	// that are kept in memory for each native histogram. If you leave it at
+	// zero, a default value of 10 is used. If no exemplars should be kept specifically
+	// for native histograms, set it to a negative value. (Scrapers can
+	// still use the exemplars exposed for classic buckets, which are managed
+	// independently.)
+	NativeHistogramMaxExemplars int
+	// NativeHistogramExemplarTTL is only checked once
+	// NativeHistogramMaxExemplars is exceeded. In that case, the
+	// oldest exemplar is removed if it is older than NativeHistogramExemplarTTL.
+	// Otherwise, the older exemplar in the pair of exemplars that are closest
+	// together (on an exponential scale) is removed.
+	// If NativeHistogramExemplarTTL is left at its zero value, a default value of
+	// 5m is used. To always delete the oldest exemplar, set it to a negative value.
+	NativeHistogramExemplarTTL time.Duration
+
 	// now is for testing purposes, by default it's time.Now.
 	now func() time.Time
 
@@ -532,6 +548,7 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 	if opts.afterFunc == nil {
 		opts.afterFunc = time.AfterFunc
 	}
+
 	h := &histogram{
 		desc:                            desc,
 		upperBounds:                     opts.Buckets,
@@ -556,6 +573,7 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 			h.nativeHistogramZeroThreshold = DefNativeHistogramZeroThreshold
 		} // Leave h.nativeHistogramZeroThreshold at 0 otherwise.
 		h.nativeHistogramSchema = pickSchema(opts.NativeHistogramBucketFactor)
+		h.nativeExemplars = makeNativeExemplars(opts.NativeHistogramExemplarTTL, opts.NativeHistogramMaxExemplars)
 	}
 	for i, upperBound := range h.upperBounds {
 		if i < len(h.upperBounds)-1 {
@@ -725,7 +743,8 @@ type histogram struct {
 	// resetScheduled is protected by mtx. It is true if a reset is
 	// scheduled for a later time (when nativeHistogramMinResetDuration has
 	// passed).
-	resetScheduled bool
+	resetScheduled  bool
+	nativeExemplars nativeExemplars
 
 	// now is for testing purposes, by default it's time.Now.
 	now func() time.Time
@@ -742,6 +761,9 @@ func (h *histogram) Observe(v float64) {
 	h.observe(v, h.findBucket(v))
 }
 
+// ObserveWithExemplar should not be called in a high-frequency setting
+// for a native histogram with configured exemplars. For this case,
+// the implementation isn't lock-free and might suffer from lock contention.
 func (h *histogram) ObserveWithExemplar(v float64, e Labels) {
 	i := h.findBucket(v)
 	h.observe(v, i)
@@ -821,6 +843,15 @@ func (h *histogram) Write(out *dto.Metric) error {
 				Length: proto.Uint32(0),
 			}}
 		}
+
+		// If exemplars are not configured, the cap will be 0.
+		// So append is not needed in this case.
+		if cap(h.nativeExemplars.exemplars) > 0 {
+			h.nativeExemplars.Lock()
+			his.Exemplars = append(his.Exemplars, h.nativeExemplars.exemplars...)
+			h.nativeExemplars.Unlock()
+		}
+
 	}
 	addAndResetCounts(hotCounts, coldCounts)
 	return nil
@@ -1091,8 +1122,10 @@ func (h *histogram) resetCounts(counts *histogramCounts) {
 	deleteSyncMap(&counts.nativeHistogramBucketsPositive)
 }
 
-// updateExemplar replaces the exemplar for the provided bucket. With empty
-// labels, it's a no-op. It panics if any of the labels is invalid.
+// updateExemplar replaces the exemplar for the provided classic bucket.
+// With empty labels, it's a no-op. It panics if any of the labels is invalid.
+// If histogram is native, the exemplar will be cached into nativeExemplars,
+// which has a limit, and will remove one exemplar when limit is reached.
 func (h *histogram) updateExemplar(v float64, bucket int, l Labels) {
 	if l == nil {
 		return
@@ -1102,6 +1135,10 @@ func (h *histogram) updateExemplar(v float64, bucket int, l Labels) {
 		panic(err)
 	}
 	h.exemplars[bucket].Store(e)
+	doSparse := h.nativeHistogramSchema > math.MinInt32 && !math.IsNaN(v)
+	if doSparse {
+		h.nativeExemplars.addExemplar(e)
+	}
 }
 
 // HistogramVec is a Collector that bundles a set of Histograms that all share the
@@ -1336,6 +1373,48 @@ func MustNewConstHistogram(
 	return m
 }
 
+// NewConstHistogramWithCreatedTimestamp does the same thing as NewConstHistogram but sets the created timestamp.
+func NewConstHistogramWithCreatedTimestamp(
+	desc *Desc,
+	count uint64,
+	sum float64,
+	buckets map[float64]uint64,
+	ct time.Time,
+	labelValues ...string,
+) (Metric, error) {
+	if desc.err != nil {
+		return nil, desc.err
+	}
+	if err := validateLabelValues(labelValues, len(desc.variableLabels.names)); err != nil {
+		return nil, err
+	}
+	return &constHistogram{
+		desc:       desc,
+		count:      count,
+		sum:        sum,
+		buckets:    buckets,
+		labelPairs: MakeLabelPairs(desc, labelValues),
+		createdTs:  timestamppb.New(ct),
+	}, nil
+}
+
+// MustNewConstHistogramWithCreatedTimestamp is a version of NewConstHistogramWithCreatedTimestamp that panics where
+// NewConstHistogramWithCreatedTimestamp would have returned an error.
+func MustNewConstHistogramWithCreatedTimestamp(
+	desc *Desc,
+	count uint64,
+	sum float64,
+	buckets map[float64]uint64,
+	ct time.Time,
+	labelValues ...string,
+) Metric {
+	m, err := NewConstHistogramWithCreatedTimestamp(desc, count, sum, buckets, ct, labelValues...)
+	if err != nil {
+		panic(err)
+	}
+	return m
+}
+
 type buckSort []*dto.Bucket
 
 func (s buckSort) Len() int {
@@ -1575,3 +1654,142 @@ func addAndResetCounts(hot, cold *histogramCounts) {
 	atomic.AddUint64(&hot.nativeHistogramZeroBucket, atomic.LoadUint64(&cold.nativeHistogramZeroBucket))
 	atomic.StoreUint64(&cold.nativeHistogramZeroBucket, 0)
 }
+
+type nativeExemplars struct {
+	sync.Mutex
+
+	ttl       time.Duration
+	exemplars []*dto.Exemplar
+}
+
+func makeNativeExemplars(ttl time.Duration, maxCount int) nativeExemplars {
+	if ttl == 0 {
+		ttl = 5 * time.Minute
+	}
+
+	if maxCount == 0 {
+		maxCount = 10
+	}
+
+	if maxCount < 0 {
+		maxCount = 0
+	}
+
+	return nativeExemplars{
+		ttl:       ttl,
+		exemplars: make([]*dto.Exemplar, 0, maxCount),
+	}
+}
+
+func (n *nativeExemplars) addExemplar(e *dto.Exemplar) {
+	if cap(n.exemplars) == 0 {
+		return
+	}
+
+	n.Lock()
+	defer n.Unlock()
+
+	// The index where to insert the new exemplar.
+	var nIdx int = -1
+
+	// When the number of exemplars has not yet exceeded or
+	// is equal to cap(n.exemplars), then
+	// insert the new exemplar directly.
+	if len(n.exemplars) < cap(n.exemplars) {
+		for nIdx = 0; nIdx < len(n.exemplars); nIdx++ {
+			if *e.Value < *n.exemplars[nIdx].Value {
+				break
+			}
+		}
+		n.exemplars = append(n.exemplars[:nIdx], append([]*dto.Exemplar{e}, n.exemplars[nIdx:]...)...)
+		return
+	}
+
+	// When the number of exemplars exceeds the limit, remove one exemplar.
+	var (
+		rIdx int // The index where to remove the old exemplar.
+
+		ot    = time.Now() // Oldest timestamp seen.
+		otIdx = -1         // Index of the exemplar with the oldest timestamp.
+
+		md    = -1.0  // Logarithm of the delta of the closest pair of exemplars.
+		mdIdx = -1    // Index of the older exemplar within the closest pair.
+		cLog  float64 // Logarithm of the current exemplar.
+		pLog  float64 // Logarithm of the previous exemplar.
+	)
+
+	for i, exemplar := range n.exemplars {
+		// Find the exemplar with the oldest timestamp.
+		if otIdx == -1 || exemplar.Timestamp.AsTime().Before(ot) {
+			ot = exemplar.Timestamp.AsTime()
+			otIdx = i
+		}
+
+		// Find the index at which to insert new the exemplar.
+		if *e.Value <= *exemplar.Value && nIdx == -1 {
+			nIdx = i
+		}
+
+		// Find the two closest exemplars and pick the one the with older timestamp.
+		pLog = cLog
+		cLog = math.Log(exemplar.GetValue())
+		if i == 0 {
+			continue
+		}
+		diff := math.Abs(cLog - pLog)
+		if md == -1 || diff < md {
+			md = diff
+			if n.exemplars[i].Timestamp.AsTime().Before(n.exemplars[i-1].Timestamp.AsTime()) {
+				mdIdx = i
+			} else {
+				mdIdx = i - 1
+			}
+		}
+
+	}
+
+	// If all existing exemplar are smaller than new exemplar,
+	// then the exemplar should be inserted at the end.
+	if nIdx == -1 {
+		nIdx = len(n.exemplars)
+	}
+
+	if otIdx != -1 && e.Timestamp.AsTime().Sub(ot) > n.ttl {
+		rIdx = otIdx
+	} else {
+		// In the previous for loop, when calculating the closest pair of exemplars,
+		// we did not take into account the newly inserted exemplar.
+		// So we need to calculate with the newly inserted exemplar again.
+		elog := math.Log(e.GetValue())
+		if nIdx > 0 {
+			diff := math.Abs(elog - math.Log(n.exemplars[nIdx-1].GetValue()))
+			if diff < md {
+				md = diff
+				mdIdx = nIdx
+				if n.exemplars[nIdx-1].Timestamp.AsTime().Before(e.Timestamp.AsTime()) {
+					mdIdx = nIdx - 1
+				}
+			}
+		}
+		if nIdx < len(n.exemplars) {
+			diff := math.Abs(math.Log(n.exemplars[nIdx].GetValue()) - elog)
+			if diff < md {
+				mdIdx = nIdx
+				if n.exemplars[nIdx].Timestamp.AsTime().Before(e.Timestamp.AsTime()) {
+					mdIdx = nIdx
+				}
+			}
+		}
+		rIdx = mdIdx
+	}
+
+	// Adjust the slice according to rIdx and nIdx.
+	switch {
+	case rIdx == nIdx:
+		n.exemplars[nIdx] = e
+	case rIdx < nIdx:
+		n.exemplars = append(n.exemplars[:rIdx], append(n.exemplars[rIdx+1:nIdx], append([]*dto.Exemplar{e}, n.exemplars[nIdx:]...)...)...)
+	case rIdx > nIdx:
+		n.exemplars = append(n.exemplars[:nIdx], append([]*dto.Exemplar{e}, append(n.exemplars[nIdx:rIdx], n.exemplars[rIdx+1:]...)...)...)
+	}
+}

vendor/github.com/prometheus/client_golang/prometheus/internal/go_collector_options.go

@@ -30,3 +30,5 @@ type GoCollectorOptions struct {
 	RuntimeMetricSumForHist    map[string]string
 	RuntimeMetricRules         []GoCollectorRule
 }
+
+var GoCollectorDefaultRuntimeMetrics = regexp.MustCompile(`/gc/gogc:percent|/gc/gomemlimit:bytes|/sched/gomaxprocs:threads`)

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

@@ -234,7 +234,7 @@ func NewMetricWithExemplars(m Metric, exemplars ...Exemplar) (Metric, error) {
 	)
 	for i, e := range exemplars {
 		ts := e.Timestamp
-		if ts == (time.Time{}) {
+		if ts.IsZero() {
 			ts = now
 		}
 		exs[i], err = newExemplar(e.Value, ts, e.Labels)

vendor/github.com/prometheus/client_golang/prometheus/process_collector.go

@@ -22,14 +22,15 @@ import (
 )
 
 type processCollector struct {
-	collectFn       func(chan<- Metric)
-	pidFn           func() (int, error)
-	reportErrors    bool
-	cpuTotal        *Desc
-	openFDs, maxFDs *Desc
-	vsize, maxVsize *Desc
-	rss             *Desc
-	startTime       *Desc
+	collectFn         func(chan<- Metric)
+	pidFn             func() (int, error)
+	reportErrors      bool
+	cpuTotal          *Desc
+	openFDs, maxFDs   *Desc
+	vsize, maxVsize   *Desc
+	rss               *Desc
+	startTime         *Desc
+	inBytes, outBytes *Desc
 }
 
 // ProcessCollectorOpts defines the behavior of a process metrics collector
@@ -100,6 +101,16 @@ func NewProcessCollector(opts ProcessCollectorOpts) Collector {
 			"Start time of the process since unix epoch in seconds.",
 			nil, nil,
 		),
+		inBytes: NewDesc(
+			ns+"process_network_receive_bytes_total",
+			"Number of bytes received by the process over the network.",
+			nil, nil,
+		),
+		outBytes: NewDesc(
+			ns+"process_network_transmit_bytes_total",
+			"Number of bytes sent by the process over the network.",
+			nil, nil,
+		),
 	}
 
 	if opts.PidFn == nil {

vendor/github.com/prometheus/client_golang/prometheus/process_collector_other.go

@@ -63,4 +63,18 @@ func (c *processCollector) processCollect(ch chan<- Metric) {
 	} else {
 		c.reportError(ch, nil, err)
 	}
+
+	if netstat, err := p.Netstat(); err == nil {
+		var inOctets, outOctets float64
+		if netstat.IpExt.InOctets != nil {
+			inOctets = *netstat.IpExt.InOctets
+		}
+		if netstat.IpExt.OutOctets != nil {
+			outOctets = *netstat.IpExt.OutOctets
+		}
+		ch <- MustNewConstMetric(c.inBytes, CounterValue, inOctets)
+		ch <- MustNewConstMetric(c.outBytes, CounterValue, outOctets)
+	} else {
+		c.reportError(ch, nil, err)
+	}
 }

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

@@ -76,6 +76,12 @@ func (r *responseWriterDelegator) Write(b []byte) (int, error) {
 	return n, err
 }
 
+// Unwrap lets http.ResponseController get the underlying http.ResponseWriter,
+// by implementing the [rwUnwrapper](https://cs.opensource.google/go/go/+/refs/tags/go1.21.4:src/net/http/responsecontroller.go;l=42-44) interface.
+func (r *responseWriterDelegator) Unwrap() http.ResponseWriter {
+	return r.ResponseWriter
+}
+
 type (
 	closeNotifierDelegator struct{ *responseWriterDelegator }
 	flusherDelegator       struct{ *responseWriterDelegator }

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

@@ -38,12 +38,13 @@ import (
 	"io"
 	"net/http"
 	"strconv"
-	"strings"
 	"sync"
 	"time"
 
+	"github.com/klauspost/compress/zstd"
 	"github.com/prometheus/common/expfmt"
 
+	"github.com/prometheus/client_golang/internal/github.com/golang/gddo/httputil"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -54,6 +55,18 @@ const (
 	processStartTimeHeader = "Process-Start-Time-Unix"
 )
 
+// Compression represents the content encodings handlers support for the HTTP
+// responses.
+type Compression string
+
+const (
+	Identity Compression = "identity"
+	Gzip     Compression = "gzip"
+	Zstd     Compression = "zstd"
+)
+
+var defaultCompressionFormats = []Compression{Identity, Gzip, Zstd}
+
 var gzipPool = sync.Pool{
 	New: func() interface{} {
 		return gzip.NewWriter(nil)
@@ -122,6 +135,18 @@ func HandlerForTransactional(reg prometheus.TransactionalGatherer, opts HandlerO
 		}
 	}
 
+	// Select compression formats to offer based on default or user choice.
+	var compressions []string
+	if !opts.DisableCompression {
+		offers := defaultCompressionFormats
+		if len(opts.OfferedCompressions) > 0 {
+			offers = opts.OfferedCompressions
+		}
+		for _, comp := range offers {
+			compressions = append(compressions, string(comp))
+		}
+	}
+
 	h := http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
 		if !opts.ProcessStartTime.IsZero() {
 			rsp.Header().Set(processStartTimeHeader, strconv.FormatInt(opts.ProcessStartTime.Unix(), 10))
@@ -165,21 +190,21 @@ func HandlerForTransactional(reg prometheus.TransactionalGatherer, opts HandlerO
 		} else {
 			contentType = expfmt.Negotiate(req.Header)
 		}
-		header := rsp.Header()
-		header.Set(contentTypeHeader, string(contentType))
+		rsp.Header().Set(contentTypeHeader, string(contentType))
 
-		w := io.Writer(rsp)
-		if !opts.DisableCompression && gzipAccepted(req.Header) {
-			header.Set(contentEncodingHeader, "gzip")
-			gz := gzipPool.Get().(*gzip.Writer)
-			defer gzipPool.Put(gz)
-
-			gz.Reset(w)
-			defer gz.Close()
-
-			w = gz
+		w, encodingHeader, closeWriter, err := negotiateEncodingWriter(req, rsp, compressions)
+		if err != nil {
+			if opts.ErrorLog != nil {
+				opts.ErrorLog.Println("error getting writer", err)
+			}
+			w = io.Writer(rsp)
+			encodingHeader = string(Identity)
 		}
 
+		defer closeWriter()
+
+		rsp.Header().Set(contentEncodingHeader, encodingHeader)
+
 		enc := expfmt.NewEncoder(w, contentType)
 
 		// handleError handles the error according to opts.ErrorHandling
@@ -343,9 +368,19 @@ type HandlerOpts struct {
 	// no effect on the HTTP status code because ErrorHandling is set to
 	// ContinueOnError.
 	Registry prometheus.Registerer
-	// If DisableCompression is true, the handler will never compress the
-	// response, even if requested by the client.
+	// DisableCompression disables the response encoding (compression) and
+	// encoding negotiation. If true, the handler will
+	// never compress the response, even if requested
+	// by the client and the OfferedCompressions field is set.
 	DisableCompression bool
+	// OfferedCompressions is a set of encodings (compressions) handler will
+	// try to offer when negotiating with the client. This defaults to identity, gzip
+	// and zstd.
+	// NOTE: If handler can't agree with the client on the encodings or
+	// unsupported or empty encodings are set in OfferedCompressions,
+	// handler always fallbacks to no compression (identity), for
+	// compatibility reasons. In such cases ErrorLog will be used if set.
+	OfferedCompressions []Compression
 	// The number of concurrent HTTP requests is limited to
 	// MaxRequestsInFlight. Additional requests are responded to with 503
 	// Service Unavailable and a suitable message in the body. If
@@ -381,19 +416,6 @@ type HandlerOpts struct {
 	ProcessStartTime time.Time
 }
 
-// gzipAccepted returns whether the client will accept gzip-encoded content.
-func gzipAccepted(header http.Header) bool {
-	a := header.Get(acceptEncodingHeader)
-	parts := strings.Split(a, ",")
-	for _, part := range parts {
-		part = strings.TrimSpace(part)
-		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
-			return true
-		}
-	}
-	return false
-}
-
 // httpError removes any content-encoding header and then calls http.Error with
 // the provided error and http.StatusInternalServerError. Error contents is
 // supposed to be uncompressed plain text. Same as with a plain http.Error, this
@@ -406,3 +428,38 @@ func httpError(rsp http.ResponseWriter, err error) {
 		http.StatusInternalServerError,
 	)
 }
+
+// negotiateEncodingWriter reads the Accept-Encoding header from a request and
+// selects the right compression based on an allow-list of supported
+// compressions. It returns a writer implementing the compression and an the
+// correct value that the caller can set in the response header.
+func negotiateEncodingWriter(r *http.Request, rw io.Writer, compressions []string) (_ io.Writer, encodingHeaderValue string, closeWriter func(), _ error) {
+	if len(compressions) == 0 {
+		return rw, string(Identity), func() {}, nil
+	}
+
+	// TODO(mrueg): Replace internal/github.com/gddo once https://github.com/golang/go/issues/19307 is implemented.
+	selected := httputil.NegotiateContentEncoding(r, compressions)
+
+	switch selected {
+	case "zstd":
+		// TODO(mrueg): Replace klauspost/compress with stdlib implementation once https://github.com/golang/go/issues/62513 is implemented.
+		z, err := zstd.NewWriter(rw, zstd.WithEncoderLevel(zstd.SpeedFastest))
+		if err != nil {
+			return nil, "", func() {}, err
+		}
+
+		z.Reset(rw)
+		return z, selected, func() { _ = z.Close() }, nil
+	case "gzip":
+		gz := gzipPool.Get().(*gzip.Writer)
+		gz.Reset(rw)
+		return gz, selected, func() { _ = gz.Close(); gzipPool.Put(gz) }, nil
+	case "identity":
+		// This means the content is not compressed.
+		return rw, selected, func() {}, nil
+	default:
+		// The content encoding was not implemented yet.
+		return nil, "", func() {}, fmt.Errorf("content compression format not recognized: %s. Valid formats are: %s", selected, defaultCompressionFormats)
+	}
+}

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

@@ -314,16 +314,17 @@ func (r *Registry) Register(c Collector) error {
 			if dimHash != desc.dimHash {
 				return fmt.Errorf("a previously registered descriptor with the same fully-qualified name as %s has different label names or a different help string", desc)
 			}
-		} else {
-			// ...then check the new descriptors already seen.
-			if dimHash, exists := newDimHashesByName[desc.fqName]; exists {
-				if dimHash != desc.dimHash {
-					return fmt.Errorf("descriptors reported by collector have inconsistent label names or help strings for the same fully-qualified name, offender is %s", desc)
-				}
-			} else {
-				newDimHashesByName[desc.fqName] = desc.dimHash
-			}
+			continue
 		}
+
+		// ...then check the new descriptors already seen.
+		if dimHash, exists := newDimHashesByName[desc.fqName]; exists {
+			if dimHash != desc.dimHash {
+				return fmt.Errorf("descriptors reported by collector have inconsistent label names or help strings for the same fully-qualified name, offender is %s", desc)
+			}
+			continue
+		}
+		newDimHashesByName[desc.fqName] = desc.dimHash
 	}
 	// A Collector yielding no Desc at all is considered unchecked.
 	if len(newDescIDs) == 0 {

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

@@ -783,3 +783,45 @@ func MustNewConstSummary(
 	}
 	return m
 }
+
+// NewConstSummaryWithCreatedTimestamp does the same thing as NewConstSummary but sets the created timestamp.
+func NewConstSummaryWithCreatedTimestamp(
+	desc *Desc,
+	count uint64,
+	sum float64,
+	quantiles map[float64]float64,
+	ct time.Time,
+	labelValues ...string,
+) (Metric, error) {
+	if desc.err != nil {
+		return nil, desc.err
+	}
+	if err := validateLabelValues(labelValues, len(desc.variableLabels.names)); err != nil {
+		return nil, err
+	}
+	return &constSummary{
+		desc:       desc,
+		count:      count,
+		sum:        sum,
+		quantiles:  quantiles,
+		labelPairs: MakeLabelPairs(desc, labelValues),
+		createdTs:  timestamppb.New(ct),
+	}, nil
+}
+
+// MustNewConstSummaryWithCreatedTimestamp is a version of NewConstSummaryWithCreatedTimestamp that panics where
+// NewConstSummaryWithCreatedTimestamp would have returned an error.
+func MustNewConstSummaryWithCreatedTimestamp(
+	desc *Desc,
+	count uint64,
+	sum float64,
+	quantiles map[float64]float64,
+	ct time.Time,
+	labelValues ...string,
+) Metric {
+	m, err := NewConstSummaryWithCreatedTimestamp(desc, count, sum, quantiles, ct, labelValues...)
+	if err != nil {
+		panic(err)
+	}
+	return m
+}

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

@@ -507,7 +507,7 @@ func (m *metricMap) getOrCreateMetricWithLabelValues(
 	return metric
 }
 
-// getOrCreateMetricWithLabelValues retrieves the metric by hash and label value
+// getOrCreateMetricWithLabels retrieves the metric by hash and label value
 // or creates it and returns the new one.
 //
 // This function holds the mutex.