chore: fix prometheus remote write exporter not setting timestamp on …

…created metric (open-telemetry#29503)

As disucssed on cncf
[slack](https://cloud-native.slack.com/archives/C01LSCJBXDZ/p1700938910822949)
fixing the issue with _created metrics where prometheus backend refuses
it due to "too old" due to not setting a timestamp for the sample
created. The timestamp used is the timestamp for the original sample the
correspondent _created metrics is generated for.

**Link to tracking Issue:** open-telemetry#24915

Tested locally with prometheus compatible backend.

---------

Co-authored-by: Anthony Mirabella <a9@aneurysm9.com>
Co-authored-by: David Ashpole <dashpole@google.com>

.chloggen/-prometheus-remote-write-set-timestamp-on-created-metric.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: exporter/prometheusremotewrite
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: prometheusremotewrite exporter fix created metrics missing timestamp
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [ 24915 ]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

pkg/translator/prometheusremotewrite/helper.go

@@ -347,7 +347,7 @@ func addSingleHistogramDataPoint(pt pmetric.HistogramDataPoint, resource pcommon
 	startTimestamp := pt.StartTimestamp()
 	if settings.ExportCreatedMetric && startTimestamp != 0 {
 		labels := createLabels(createdSuffix)
-		addCreatedTimeSeriesIfNeeded(tsMap, labels, startTimestamp, metric.Type().String())
+		addCreatedTimeSeriesIfNeeded(tsMap, labels, startTimestamp, pt.Timestamp(), metric.Type().String())
 	}
 }
 
@@ -516,7 +516,7 @@ func addSingleSummaryDataPoint(pt pmetric.SummaryDataPoint, resource pcommon.Res
 	startTimestamp := pt.StartTimestamp()
 	if settings.ExportCreatedMetric && startTimestamp != 0 {
 		createdLabels := createLabels(baseName + createdSuffix)
-		addCreatedTimeSeriesIfNeeded(tsMap, createdLabels, startTimestamp, metric.Type().String())
+		addCreatedTimeSeriesIfNeeded(tsMap, createdLabels, startTimestamp, pt.Timestamp(), metric.Type().String())
 	}
 }
 
@@ -526,6 +526,7 @@ func addCreatedTimeSeriesIfNeeded(
 	series map[string]*prompb.TimeSeries,
 	labels []prompb.Label,
 	startTimestamp pcommon.Timestamp,
+	timestamp pcommon.Timestamp,
 	metricType string,
 ) {
 	sig := timeSeriesSignature(metricType, &labels)
@@ -534,7 +535,8 @@ func addCreatedTimeSeriesIfNeeded(
 			Labels: labels,
 			Samples: []prompb.Sample{
 				{ // convert ns to ms
-					Value: float64(convertTimeStamp(startTimestamp)),
+					Value:     float64(convertTimeStamp(startTimestamp)),
+					Timestamp: convertTimeStamp(timestamp),
 				},
 			},
 		}

pkg/translator/prometheusremotewrite/helper_test.go

@@ -706,7 +706,7 @@ func TestAddSingleSummaryDataPoint(t *testing.T) {
 					timeSeriesSignature(pmetric.MetricTypeSummary.String(), &createdLabels): {
 						Labels: createdLabels,
 						Samples: []prompb.Sample{
-							{Value: float64(convertTimeStamp(ts))},
+							{Value: float64(convertTimeStamp(ts)), Timestamp: convertTimeStamp(ts)},
 						},
 					},
 				}
@@ -816,7 +816,7 @@ func TestAddSingleHistogramDataPoint(t *testing.T) {
 					timeSeriesSignature(pmetric.MetricTypeHistogram.String(), &createdLabels): {
 						Labels: createdLabels,
 						Samples: []prompb.Sample{
-							{Value: float64(convertTimeStamp(ts))},
+							{Value: float64(convertTimeStamp(ts)), Timestamp: convertTimeStamp(ts)},
 						},
 					},
 				}

pkg/translator/prometheusremotewrite/number_data_points.go

@@ -96,7 +96,7 @@ func addSingleSumNumberDataPoint(
 				nameStr,
 				name+createdSuffix,
 			)
-			addCreatedTimeSeriesIfNeeded(series, createdLabels, startTimestamp, metric.Type().String())
+			addCreatedTimeSeriesIfNeeded(series, createdLabels, startTimestamp, pt.Timestamp(), metric.Type().String())
 		}
 	}
 }

pkg/translator/prometheusremotewrite/number_data_points_test.go

@@ -162,7 +162,7 @@ func TestAddSingleSumNumberDataPoint(t *testing.T) {
 					timeSeriesSignature(pmetric.MetricTypeSum.String(), &createdLabels): {
 						Labels: createdLabels,
 						Samples: []prompb.Sample{
-							{Value: float64(convertTimeStamp(ts))},
+							{Value: float64(convertTimeStamp(ts)), Timestamp: convertTimeStamp(ts)},
 						},
 					},
 				}