Extend Counters, Summaries and Histograms with creation timestamp

Signed-off-by: Arthur Silva Sens <arthur.sens@coralogix.com>

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/cespare/xxhash/v2 v2.2.0
 	github.com/davecgh/go-spew v1.1.1
 	github.com/json-iterator/go v1.1.12
-	github.com/prometheus/client_model v0.4.0
+	github.com/prometheus/client_model v0.4.1-0.20230718164431-9a2bf3000d16
 	github.com/prometheus/common v0.44.0
 	github.com/prometheus/procfs v0.11.1
 	golang.org/x/sys v0.11.0

go.sum

@@ -34,8 +34,8 @@ github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRW
 github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/prometheus/client_model v0.4.0 h1:5lQXD3cAg1OXBf4Wq03gTrXHeaV0TQvGfUooCfx1yqY=
+github.com/prometheus/client_model v0.4.1-0.20230718164431-9a2bf3000d16 h1:v7DLqVdK4VrYkVD5diGdl4sxJurKJEMnODWRJlxV9oM=
-github.com/prometheus/client_model v0.4.0/go.mod h1:oMQmHW1/JoDwqLtg57MGgP/Fb1CJEYF2imWWhWtMkYU=
+github.com/prometheus/client_model v0.4.1-0.20230718164431-9a2bf3000d16/go.mod h1:oMQmHW1/JoDwqLtg57MGgP/Fb1CJEYF2imWWhWtMkYU=
 github.com/prometheus/common v0.44.0 h1:+5BrQJwiBB9xsMygAB3TNvpQKOwlkc25LbISbrdOOfY=
 github.com/prometheus/common v0.44.0/go.mod h1:ofAIvZbQ1e/nugmZGz4/qCb9Ap1VoSTIO7x0VV9VvuY=
 github.com/prometheus/procfs v0.11.1 h1:xRC8Iq1yyca5ypa9n1EZnWZkt7dwcoRPQwX/5gwaUuI=

prometheus/counter.go

@@ -20,6 +20,7 @@ import (
 	"time"
 
 	dto "github.com/prometheus/client_model/go"
+	"google.golang.org/protobuf/types/known/timestamppb"
 )
 
 // Counter is a Metric that represents a single numerical value that only ever
@@ -90,8 +91,12 @@ func NewCounter(opts CounterOpts) Counter {
 		nil,
 		opts.ConstLabels,
 	)
-	result := &counter{desc: desc, labelPairs: desc.constLabelPairs, now: time.Now}
+	if opts.now == nil {
+		opts.now = time.Now
+	}
+	result := &counter{desc: desc, labelPairs: desc.constLabelPairs, now: opts.now}
 	result.init(result) // Init self-collection.
+	result.createdTs = timestamppb.New(opts.now())
 	return result
 }
 
@@ -106,10 +111,11 @@ type counter struct {
 	selfCollector
 	desc *Desc
 
+	createdTs  *timestamppb.Timestamp
 	labelPairs []*dto.LabelPair
 	exemplar   atomic.Value // Containing nil or a *dto.Exemplar.
 
-	now func() time.Time // To mock out time.Now() for testing.
+	now func() time.Time // For testing, all constructors put time.Now() here.
 }
 
 func (c *counter) Desc() *Desc {
@@ -160,7 +166,8 @@ func (c *counter) Write(out *dto.Metric) error {
 	}
 	val := c.get()
 
-	return populateMetric(CounterValue, val, c.labelPairs, exemplar, out)
+	ct := c.createdTs.AsTime()
+	return populateMetric(CounterValue, val, c.labelPairs, exemplar, out, &ct)
 }
 
 func (c *counter) updateExemplar(v float64, l Labels) {
@@ -200,6 +207,9 @@ func (v2) NewCounterVec(opts CounterVecOpts) *CounterVec {
 		opts.VariableLabels,
 		opts.ConstLabels,
 	)
+	if opts.now == nil {
+		opts.now = time.Now
+	}
 	return &CounterVec{
 		MetricVec: NewMetricVec(desc, func(lvs ...string) Metric {
 			if len(lvs) != len(desc.variableLabels.names) {
@@ -207,6 +217,7 @@ func (v2) NewCounterVec(opts CounterVecOpts) *CounterVec {
 			}
 			result := &counter{desc: desc, labelPairs: MakeLabelPairs(desc, lvs), now: time.Now}
 			result.init(result) // Init self-collection.
+			result.createdTs = timestamppb.New(opts.now())
 			return result
 		}),
 	}

prometheus/counter_test.go

@@ -298,3 +298,40 @@ func TestCounterExemplar(t *testing.T) {
 		t.Error("adding exemplar with oversized labels succeeded")
 	}
 }
+
+func TestCounterCreatedTimestamp(t *testing.T) {
+	now := time.Now()
+	counter := NewCounter(CounterOpts{
+		Name: "test",
+		Help: "test help",
+		now:  func() time.Time { return now },
+	})
+
+	var metric dto.Metric
+	if err := counter.Write(&metric); err != nil {
+		t.Fatal(err)
+	}
+
+	if metric.Counter.CreatedTimestamp.AsTime().Unix() != now.Unix() {
+		t.Errorf("expected created timestamp %d, got %d", now.Unix(), metric.Counter.CreatedTimestamp.AsTime().Unix())
+	}
+}
+
+func TestCounterVecCreatedTimestamp(t *testing.T) {
+	now := time.Now()
+	counterVec := NewCounterVec(CounterOpts{
+		Name: "test",
+		Help: "test help",
+		now:  func() time.Time { return now },
+	}, []string{"label"})
+	counter := counterVec.WithLabelValues("value")
+
+	var metric dto.Metric
+	if err := counter.Write(&metric); err != nil {
+		t.Fatal(err)
+	}
+
+	if metric.Counter.CreatedTimestamp.AsTime().Unix() != now.Unix() {
+		t.Errorf("expected created timestamp %d, got %d", now.Unix(), metric.Counter.CreatedTimestamp.AsTime().Unix())
+	}
+}

prometheus/gauge.go

@@ -135,7 +135,7 @@ func (g *gauge) Sub(val float64) {
 
 func (g *gauge) Write(out *dto.Metric) error {
 	val := math.Float64frombits(atomic.LoadUint64(&g.valBits))
-	return populateMetric(GaugeValue, val, g.labelPairs, nil, out)
+	return populateMetric(GaugeValue, val, g.labelPairs, nil, out, nil)
 }
 
 // GaugeVec is a Collector that bundles a set of Gauges that all share the same

prometheus/histogram.go

@@ -25,6 +25,7 @@ import (
 	dto "github.com/prometheus/client_model/go"
 
 	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/timestamppb"
 )
 
 // nativeHistogramBounds for the frac of observed values. Only relevant for
@@ -471,6 +472,8 @@ type HistogramOpts struct {
 	NativeHistogramMaxBucketNumber  uint32
 	NativeHistogramMinResetDuration time.Duration
 	NativeHistogramMaxZeroThreshold float64
+
+	now func() time.Time // For testing, all constructors put time.Now() here.
 }
 
 // HistogramVecOpts bundles the options to create a HistogramVec metric.
@@ -568,7 +571,11 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 	atomic.StoreInt32(&h.counts[1].nativeHistogramSchema, h.nativeHistogramSchema)
 	h.exemplars = make([]atomic.Value, len(h.upperBounds)+1)
 
+	if opts.now == nil {
+		opts.now = time.Now
+	}
 	h.init(h) // Init self-collection.
+	h.createdTs = timestamppb.New(opts.now())
 	return h
 }
 
@@ -707,8 +714,9 @@ type histogram struct {
 	nativeHistogramMaxBuckets       uint32
 	nativeHistogramMinResetDuration time.Duration
 	lastResetTime                   time.Time // Protected by mtx.
+	createdTs                       *timestamppb.Timestamp
 
-	now func() time.Time // To mock out time.Now() for testing.
+	now func() time.Time // For testing, all constructors put time.Now() here.
 }
 
 func (h *histogram) Desc() *Desc {
@@ -747,9 +755,10 @@ func (h *histogram) Write(out *dto.Metric) error {
 	waitForCooldown(count, coldCounts)
 
 	his := &dto.Histogram{
-		Bucket:      make([]*dto.Bucket, len(h.upperBounds)),
+		Bucket:           make([]*dto.Bucket, len(h.upperBounds)),
-		SampleCount: proto.Uint64(count),
+		SampleCount:      proto.Uint64(count),
-		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+		SampleSum:        proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+		CreatedTimestamp: h.createdTs,
 	}
 	out.Histogram = his
 	out.Label = h.labelPairs
@@ -1194,6 +1203,7 @@ type constHistogram struct {
 	sum        float64
 	buckets    map[float64]uint64
 	labelPairs []*dto.LabelPair
+	createdTs  *timestamppb.Timestamp
 }
 
 func (h *constHistogram) Desc() *Desc {
@@ -1201,7 +1211,9 @@ func (h *constHistogram) Desc() *Desc {
 }
 
 func (h *constHistogram) Write(out *dto.Metric) error {
-	his := &dto.Histogram{}
+	his := &dto.Histogram{
+		CreatedTimestamp: h.createdTs,
+	}
 
 	buckets := make([]*dto.Bucket, 0, len(h.buckets))
 

prometheus/histogram_test.go

@@ -1152,3 +1152,44 @@ func TestGetLe(t *testing.T) {
 		}
 	}
 }
+
+func TestHistogramCreatedTimestamp(t *testing.T) {
+	now := time.Now()
+
+	histogram := NewHistogram(HistogramOpts{
+		Name:    "test",
+		Help:    "test help",
+		Buckets: []float64{1, 2, 3, 4},
+		now:     func() time.Time { return now },
+	})
+
+	var metric dto.Metric
+	if err := histogram.Write(&metric); err != nil {
+		t.Fatal(err)
+	}
+
+	if metric.Histogram.CreatedTimestamp.AsTime().Unix() != now.Unix() {
+		t.Errorf("expected created timestamp %d, got %d", now.Unix(), metric.Histogram.CreatedTimestamp.AsTime().Unix())
+	}
+}
+
+func TestHistogramVecCreatedTimestamp(t *testing.T) {
+	now := time.Now()
+
+	histogramVec := NewHistogramVec(HistogramOpts{
+		Name:    "test",
+		Help:    "test help",
+		Buckets: []float64{1, 2, 3, 4},
+		now:     func() time.Time { return now },
+	}, []string{"label"})
+	histogram := histogramVec.WithLabelValues("value").(Histogram)
+
+	var metric dto.Metric
+	if err := histogram.Write(&metric); err != nil {
+		t.Fatal(err)
+	}
+
+	if metric.Histogram.CreatedTimestamp.AsTime().Unix() != now.Unix() {
+		t.Errorf("expected created timestamp %d, got %d", now.Unix(), metric.Histogram.CreatedTimestamp.AsTime().Unix())
+	}
+}

prometheus/metric.go

@@ -92,6 +92,8 @@ type Opts struct {
 	// machine_role metric). See also
 	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
 	ConstLabels Labels
+
+	now func() time.Time // For testing, all constructors put time.Now() here.
 }
 
 // BuildFQName joins the given three name components by "_". Empty name

prometheus/summary.go

@@ -26,6 +26,7 @@ import (
 
 	"github.com/beorn7/perks/quantile"
 	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/timestamppb"
 )
 
 // quantileLabel is used for the label that defines the quantile in a
@@ -145,6 +146,8 @@ type SummaryOpts struct {
 	// is the internal buffer size of the underlying package
 	// "github.com/bmizerany/perks/quantile").
 	BufCap uint32
+
+	now func() time.Time // For testing, all constructors put time.Now() here.
 }
 
 // SummaryVecOpts bundles the options to create a SummaryVec metric.
@@ -222,6 +225,9 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 		opts.BufCap = DefBufCap
 	}
 
+	if opts.now == nil {
+		opts.now = time.Now
+	}
 	if len(opts.Objectives) == 0 {
 		// Use the lock-free implementation of a Summary without objectives.
 		s := &noObjectivesSummary{
@@ -230,6 +236,7 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 			counts:     [2]*summaryCounts{{}, {}},
 		}
 		s.init(s) // Init self-collection.
+		s.createdTs = timestamppb.New(opts.now())
 		return s
 	}
 
@@ -259,6 +266,7 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	sort.Float64s(s.sortedObjectives)
 
 	s.init(s) // Init self-collection.
+	s.createdTs = timestamppb.New(opts.now())
 	return s
 }
 
@@ -286,6 +294,8 @@ type summary struct {
 	headStream                       *quantile.Stream
 	headStreamIdx                    int
 	headStreamExpTime, hotBufExpTime time.Time
+
+	createdTs *timestamppb.Timestamp
 }
 
 func (s *summary) Desc() *Desc {
@@ -307,7 +317,9 @@ func (s *summary) Observe(v float64) {
 }
 
 func (s *summary) Write(out *dto.Metric) error {
-	sum := &dto.Summary{}
+	sum := &dto.Summary{
+		CreatedTimestamp: s.createdTs,
+	}
 	qs := make([]*dto.Quantile, 0, len(s.objectives))
 
 	s.bufMtx.Lock()
@@ -440,6 +452,8 @@ type noObjectivesSummary struct {
 	counts [2]*summaryCounts
 
 	labelPairs []*dto.LabelPair
+
+	createdTs *timestamppb.Timestamp
 }
 
 func (s *noObjectivesSummary) Desc() *Desc {
@@ -490,8 +504,9 @@ func (s *noObjectivesSummary) Write(out *dto.Metric) error {
 	}
 
 	sum := &dto.Summary{
-		SampleCount: proto.Uint64(count),
+		SampleCount:      proto.Uint64(count),
-		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+		SampleSum:        proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+		CreatedTimestamp: s.createdTs,
 	}
 
 	out.Summary = sum
@@ -681,6 +696,7 @@ type constSummary struct {
 	sum        float64
 	quantiles  map[float64]float64
 	labelPairs []*dto.LabelPair
+	createdTs  *timestamppb.Timestamp
 }
 
 func (s *constSummary) Desc() *Desc {
@@ -688,7 +704,9 @@ func (s *constSummary) Desc() *Desc {
 }
 
 func (s *constSummary) Write(out *dto.Metric) error {
-	sum := &dto.Summary{}
+	sum := &dto.Summary{
+		CreatedTimestamp: s.createdTs,
+	}
 	qs := make([]*dto.Quantile, 0, len(s.quantiles))
 
 	sum.SampleCount = proto.Uint64(s.count)

prometheus/summary_test.go

@@ -420,3 +420,78 @@ func getBounds(vars []float64, q, ε float64) (min, max float64) {
 	}
 	return
 }
+
+func TestSummaryCreatedTimestamp(t *testing.T) {
+	testCases := []struct {
+		desc       string
+		objectives map[float64]float64
+	}{
+		{
+			desc: "summary with objectives",
+			objectives: map[float64]float64{
+				1.0: 1.0,
+			},
+		},
+		{
+			desc:       "no objectives summary",
+			objectives: nil,
+		},
+	}
+	now := time.Now()
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			summary := NewSummary(SummaryOpts{
+				Name:       "test",
+				Help:       "test help",
+				Objectives: test.objectives,
+				now:        func() time.Time { return now },
+			})
+
+			var metric dto.Metric
+			summary.Write(&metric)
+
+			if metric.Summary.CreatedTimestamp.AsTime().Unix() != now.Unix() {
+				t.Errorf("expected created timestamp %d, got %d", now.Unix(), metric.Summary.CreatedTimestamp.AsTime().Unix())
+			}
+		})
+	}
+}
+
+func TestSummaryVecCreatedTimestamp(t *testing.T) {
+	testCases := []struct {
+		desc       string
+		objectives map[float64]float64
+	}{
+		{
+			desc: "summary with objectives",
+			objectives: map[float64]float64{
+				1.0: 1.0,
+			},
+		},
+		{
+			desc:       "no objectives summary",
+			objectives: nil,
+		},
+	}
+	now := time.Now()
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			summaryVec := NewSummaryVec(SummaryOpts{
+				Name:       "test",
+				Help:       "test help",
+				Objectives: test.objectives,
+				now:        func() time.Time { return now },
+			},
+				[]string{"label"})
+			summary := summaryVec.WithLabelValues("value").(Summary)
+			var metric dto.Metric
+			summary.Write(&metric)
+
+			if metric.Summary.CreatedTimestamp.AsTime().Unix() != now.Unix() {
+				t.Errorf("expected created timestamp %d, got %d", now.Unix(), metric.Summary.CreatedTimestamp.AsTime().Unix())
+			}
+		})
+	}
+}

prometheus/value.go

@@ -14,6 +14,7 @@
 package prometheus
 
 import (
+	"errors"
 	"fmt"
 	"sort"
 	"time"
@@ -91,7 +92,7 @@ func (v *valueFunc) Desc() *Desc {
 }
 
 func (v *valueFunc) Write(out *dto.Metric) error {
-	return populateMetric(v.valType, v.function(), v.labelPairs, nil, out)
+	return populateMetric(v.valType, v.function(), v.labelPairs, nil, out, nil)
 }
 
 // NewConstMetric returns a metric with one fixed value that cannot be
@@ -110,7 +111,7 @@ func NewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues
 	}
 
 	metric := &dto.Metric{}
-	if err := populateMetric(valueType, value, MakeLabelPairs(desc, labelValues), nil, metric); err != nil {
+	if err := populateMetric(valueType, value, MakeLabelPairs(desc, labelValues), nil, metric, nil); err != nil {
 		return nil, err
 	}
 
@@ -130,6 +131,43 @@ func MustNewConstMetric(desc *Desc, valueType ValueType, value float64, labelVal
 	return m
 }
 
+// NewConstMetricWithCreatedTimestamp does the same thing as NewConstMetric, but generates Counters
+// with created timestamp set and returns an error for other metric types.
+func NewConstMetricWithCreatedTimestamp(desc *Desc, valueType ValueType, value 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
+	}
+	switch valueType {
+	case CounterValue:
+		break
+	default:
+		return nil, errors.New("Created timestamps are only supported for counters")
+	}
+
+	metric := &dto.Metric{}
+	if err := populateMetric(valueType, value, MakeLabelPairs(desc, labelValues), nil, metric, &ct); err != nil {
+		return nil, err
+	}
+
+	return &constMetric{
+		desc:   desc,
+		metric: metric,
+	}, nil
+}
+
+// MustNewConstMetricWithCreatedTimestamp is a version of NewConstMetricWithCreatedTimestamp that panics where
+// NewConstMetricWithCreatedTimestamp would have returned an error.
+func MustNewConstMetricWithCreatedTimestamp(desc *Desc, valueType ValueType, value float64, ct time.Time, labelValues ...string) Metric {
+	m, err := NewConstMetricWithCreatedTimestamp(desc, valueType, value, ct, labelValues...)
+	if err != nil {
+		panic(err)
+	}
+	return m
+}
+
 type constMetric struct {
 	desc   *Desc
 	metric *dto.Metric
@@ -153,11 +191,16 @@ func populateMetric(
 	labelPairs []*dto.LabelPair,
 	e *dto.Exemplar,
 	m *dto.Metric,
+	createdTimestamp *time.Time,
 ) error {
 	m.Label = labelPairs
 	switch t {
 	case CounterValue:
-		m.Counter = &dto.Counter{Value: proto.Float64(v), Exemplar: e}
+		var ct *timestamppb.Timestamp
+		if createdTimestamp != nil {
+			ct = timestamppb.New(*createdTimestamp)
+		}
+		m.Counter = &dto.Counter{Value: proto.Float64(v), Exemplar: e, CreatedTimestamp: ct}
 	case GaugeValue:
 		m.Gauge = &dto.Gauge{Value: proto.Float64(v)}
 	case UntypedValue:

prometheus/value_test.go

@@ -16,6 +16,10 @@ package prometheus
 import (
 	"fmt"
 	"testing"
+	"time"
+
+	dto "github.com/prometheus/client_model/go"
+	"google.golang.org/protobuf/types/known/timestamppb"
 )
 
 func TestNewConstMetricInvalidLabelValues(t *testing.T) {
@@ -54,3 +58,56 @@ func TestNewConstMetricInvalidLabelValues(t *testing.T) {
 		}
 	}
 }
+
+func TestNewConstMetricWithCreatedTimestamp(t *testing.T) {
+	now := time.Now()
+	testCases := []struct {
+		desc             string
+		metricType       ValueType
+		createdTimestamp time.Time
+		expecErr         bool
+		expectedCt       *timestamppb.Timestamp
+	}{
+		{
+			desc:             "gauge with CT",
+			metricType:       GaugeValue,
+			createdTimestamp: now,
+			expecErr:         true,
+			expectedCt:       nil,
+		},
+		{
+			desc:             "counter with CT",
+			metricType:       CounterValue,
+			createdTimestamp: now,
+			expecErr:         false,
+			expectedCt:       timestamppb.New(now),
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			metricDesc := NewDesc(
+				"sample_value",
+				"sample value",
+				nil,
+				nil,
+			)
+			m, err := NewConstMetricWithCreatedTimestamp(metricDesc, test.metricType, float64(1), test.createdTimestamp)
+			if test.expecErr && err == nil {
+				t.Errorf("Expected error is test %s, got no err", test.desc)
+			}
+			if !test.expecErr && err != nil {
+				t.Errorf("Didn't expect error in test %s, got %s", test.desc, err.Error())
+			}
+
+			if test.expectedCt != nil {
+				var metric dto.Metric
+				m.Write(&metric)
+				if metric.Counter.CreatedTimestamp.AsTime() != test.expectedCt.AsTime() {
+					t.Errorf("Expected timestamp %v, got %v", test.expectedCt, &metric.Counter.CreatedTimestamp)
+				}
+			}
+		})
+	}
+}