From 24b78bef32e83ba0d882fb3ada3819e83d6b387d Mon Sep 17 00:00:00 2001 From: Arve Knudsen Date: Mon, 1 Jul 2024 11:02:09 +0200 Subject: [PATCH 1/2] otlp: Clean up exponential histogram code slightly Signed-off-by: Arve Knudsen --- .../prometheusremotewrite/helper.go | 7 ++++--- .../prometheusremotewrite/histograms.go | 17 +++++++++-------- 2 files changed, 13 insertions(+), 11 deletions(-) diff --git a/storage/remote/otlptranslator/prometheusremotewrite/helper.go b/storage/remote/otlptranslator/prometheusremotewrite/helper.go index 68be82e44..acd400320 100644 --- a/storage/remote/otlptranslator/prometheusremotewrite/helper.go +++ b/storage/remote/otlptranslator/prometheusremotewrite/helper.go @@ -182,12 +182,13 @@ func createAttributes(resource pcommon.Resource, attributes pcommon.Map, externa if i+1 >= len(extras) { break } - _, found := l[extras[i]] + + name := extras[i] + _, found := l[name] if found && logOnOverwrite { - log.Println("label " + extras[i] + " is overwritten. Check if Prometheus reserved labels are used.") + log.Println("label " + name + " is overwritten. Check if Prometheus reserved labels are used.") } // internal labels should be maintained - name := extras[i] if !(len(name) > 4 && name[:2] == "__" && name[len(name)-2:] == "__") { name = prometheustranslator.NormalizeLabel(name) } diff --git a/storage/remote/otlptranslator/prometheusremotewrite/histograms.go b/storage/remote/otlptranslator/prometheusremotewrite/histograms.go index 31d343fe4..e26ce6a57 100644 --- a/storage/remote/otlptranslator/prometheusremotewrite/histograms.go +++ b/storage/remote/otlptranslator/prometheusremotewrite/histograms.go @@ -31,9 +31,15 @@ import ( const defaultZeroThreshold = 1e-128 func (c *PrometheusConverter) addExponentialHistogramDataPoints(dataPoints pmetric.ExponentialHistogramDataPointSlice, - resource pcommon.Resource, settings Settings, baseName string) error { + resource pcommon.Resource, settings Settings, promName string) error { for x := 0; x < dataPoints.Len(); x++ { pt := dataPoints.At(x) + + histogram, err := exponentialToNativeHistogram(pt) + if err != nil { + return err + } + lbls := createAttributes( resource, pt.Attributes(), @@ -41,14 +47,9 @@ func (c *PrometheusConverter) addExponentialHistogramDataPoints(dataPoints pmetr nil, true, model.MetricNameLabel, - baseName, + promName, ) ts, _ := c.getOrCreateTimeSeries(lbls) - - histogram, err := exponentialToNativeHistogram(pt) - if err != nil { - return err - } ts.Histograms = append(ts.Histograms, histogram) exemplars := getPromExemplars[pmetric.ExponentialHistogramDataPoint](pt) @@ -58,7 +59,7 @@ func (c *PrometheusConverter) addExponentialHistogramDataPoints(dataPoints pmetr return nil } -// exponentialToNativeHistogram translates OTel Exponential Histogram data point +// exponentialToNativeHistogram translates OTel Exponential Histogram data point // to Prometheus Native Histogram. func exponentialToNativeHistogram(p pmetric.ExponentialHistogramDataPoint) (prompb.Histogram, error) { scale := p.Scale() From 9595b174e5eebb4e24fc95044abfd9a946fd1ed1 Mon Sep 17 00:00:00 2001 From: Arve Knudsen Date: Mon, 1 Jul 2024 13:35:40 +0200 Subject: [PATCH 2/2] otlp: Document regular and exponential histogram conversions Signed-off-by: Arve Knudsen --- .../remote/otlptranslator/prometheusremotewrite/helper.go | 7 +++++++ .../otlptranslator/prometheusremotewrite/histograms.go | 2 ++ 2 files changed, 9 insertions(+) diff --git a/storage/remote/otlptranslator/prometheusremotewrite/helper.go b/storage/remote/otlptranslator/prometheusremotewrite/helper.go index acd400320..257133853 100644 --- a/storage/remote/otlptranslator/prometheusremotewrite/helper.go +++ b/storage/remote/otlptranslator/prometheusremotewrite/helper.go @@ -220,6 +220,13 @@ func isValidAggregationTemporality(metric pmetric.Metric) bool { return false } +// addHistogramDataPoints adds OTel histogram data points to the corresponding Prometheus time series +// as classical histogram samples. +// +// Note that we can't convert to native histograms, since these have exponential buckets and don't line up +// with the user defined bucket boundaries of non-exponential OTel histograms. +// However, work is under way to resolve this shortcoming through a feature called native histograms custom buckets: +// https://github.com/prometheus/prometheus/issues/13485. func (c *PrometheusConverter) addHistogramDataPoints(dataPoints pmetric.HistogramDataPointSlice, resource pcommon.Resource, settings Settings, baseName string) { for x := 0; x < dataPoints.Len(); x++ { diff --git a/storage/remote/otlptranslator/prometheusremotewrite/histograms.go b/storage/remote/otlptranslator/prometheusremotewrite/histograms.go index e26ce6a57..21b3f5dd9 100644 --- a/storage/remote/otlptranslator/prometheusremotewrite/histograms.go +++ b/storage/remote/otlptranslator/prometheusremotewrite/histograms.go @@ -30,6 +30,8 @@ import ( const defaultZeroThreshold = 1e-128 +// addExponentialHistogramDataPoints adds OTel exponential histogram data points to the corresponding time series +// as native histogram samples. func (c *PrometheusConverter) addExponentialHistogramDataPoints(dataPoints pmetric.ExponentialHistogramDataPointSlice, resource pcommon.Resource, settings Settings, promName string) error { for x := 0; x < dataPoints.Len(); x++ {