Add support for created timestamp on const summaries

Signed-off-by: Steven Swartz <[email protected]>

Author: Steven Swartz

prometheus/examples_test.go

@@ -405,6 +405,35 @@ func ExampleNewConstSummary() {
 	// {"label":[{"name":"code","value":"200"},{"name":"method","value":"get"},{"name":"owner","value":"example"}],"summary":{"sampleCount":"4711","sampleSum":403.34,"quantile":[{"quantile":0.5,"value":42.3},{"quantile":0.9,"value":323.3}]}}
 }
 
+func ExampleNewConstSummaryWithCreatedTimestamp() {
+	desc := prometheus.NewDesc(
+		"http_request_duration_seconds",
+		"A summary of the HTTP request durations.",
+		[]string{"code", "method"},
+		prometheus.Labels{"owner": "example"},
+	)
+
+	// Create a constant summary with created timestamp set
+	createdTs := time.Unix(1719670764, 123)
+	s := prometheus.MustNewConstSummaryWithCreatedTimestamp(
+		desc,
+		4711, 403.34,
+		map[float64]float64{0.5: 42.3, 0.9: 323.3},
+		createdTs,
+		"200", "get",
+	)
+
+	// Just for demonstration, let's check the state of the summary by
+	// (ab)using its Write method (which is usually only used by Prometheus
+	// internally).
+	metric := &dto.Metric{}
+	s.Write(metric)
+	fmt.Println(toNormalizedJSON(metric))
+
+	// Output:
+	// {"label":[{"name":"code","value":"200"},{"name":"method","value":"get"},{"name":"owner","value":"example"}],"summary":{"sampleCount":"4711","sampleSum":403.34,"quantile":[{"quantile":0.5,"value":42.3},{"quantile":0.9,"value":323.3}],"createdTimestamp":"2024-06-29T14:19:24.000000123Z"}}
+}
+
 func ExampleHistogram() {
 	temps := prometheus.NewHistogram(prometheus.HistogramOpts{
 		Name:    "pond_temperature_celsius",
@@ -464,12 +493,12 @@ func ExampleNewConstHistogramWithCreatedTimestamp() {
 		prometheus.Labels{"owner": "example"},
 	)
 
-	ct := time.Unix(0, 0).UTC()
+	createdTs := time.Unix(1719670764, 123)
 	h := prometheus.MustNewConstHistogramWithCreatedTimestamp(
 		desc,
 		4711, 403.34,
 		map[float64]uint64{25: 121, 50: 2403, 100: 3221, 200: 4233},
-		ct,
+		createdTs,
 		"200", "get",
 	)
 
@@ -481,7 +510,7 @@ func ExampleNewConstHistogramWithCreatedTimestamp() {
 	fmt.Println(toNormalizedJSON(metric))
 
 	// Output:
-	// {"label":[{"name":"code","value":"200"},{"name":"method","value":"get"},{"name":"owner","value":"example"}],"histogram":{"sampleCount":"4711","sampleSum":403.34,"bucket":[{"cumulativeCount":"121","upperBound":25},{"cumulativeCount":"2403","upperBound":50},{"cumulativeCount":"3221","upperBound":100},{"cumulativeCount":"4233","upperBound":200}],"createdTimestamp":"1970-01-01T00:00:00Z"}}
+	// {"label":[{"name":"code","value":"200"},{"name":"method","value":"get"},{"name":"owner","value":"example"}],"histogram":{"sampleCount":"4711","sampleSum":403.34,"bucket":[{"cumulativeCount":"121","upperBound":25},{"cumulativeCount":"2403","upperBound":50},{"cumulativeCount":"3221","upperBound":100},{"cumulativeCount":"4233","upperBound":200}],"createdTimestamp":"2024-06-29T14:19:24.000000123Z"}}
 }
 
 func ExampleNewConstHistogram_WithExemplar() {

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
+}

prometheus/summary_test.go

@@ -474,3 +474,28 @@ func TestSummaryVecCreatedTimestampWithDeletes(t *testing.T) {
 		})
 	}
 }
+
+func TestNewConstSummaryWithCreatedTimestamp(t *testing.T) {
+	metricDesc := NewDesc(
+		"sample_value",
+		"sample value",
+		nil,
+		nil,
+	)
+	quantiles := map[float64]float64{50: 200.12, 99: 500.342}
+	createdTs := time.Unix(1719670764, 123)
+
+	s, err := NewConstSummaryWithCreatedTimestamp(metricDesc, 100, 200, quantiles, createdTs)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var metric dto.Metric
+	if err := s.Write(&metric); err != nil {
+		t.Fatal(err)
+	}
+
+	if metric.Summary.CreatedTimestamp.AsTime().UnixMicro() != createdTs.UnixMicro() {
+		t.Errorf("Expected created timestamp %v, got %v", createdTs, &metric.Summary.CreatedTimestamp)
+	}
+}