Convert UpDownCounters to Prometheus gauges (#3358)

* updown counters are now converted to prometheus gauges * Update CHANGELOG.md Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com> Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
open-telemetry · Oct 19, 2022 · 430f558 · 430f558
1 parent 6c0a7c4
commit 430f558
Show file tree

Hide file tree

Showing 4 changed files with 9 additions and 4 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -26,6 +26,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Slice attributes of `attribute` package are now comparable based on their value, not instance. (#3108 #3252)
 - Prometheus exporter will now cumulatively sum histogram buckets. (#3281)
 - Export the sum of each histogram datapoint uniquely with the `go.opentelemetry.io/otel/exporters/otlpmetric` exporters. (#3284, #3293)
+- UpDownCounters are now correctly output as prometheus gauges in the `go.opentelemetry.io/otel/exporters/prometheus` exporter. (#3358)
 
 ## [1.11.0/0.32.3] 2022-10-12
 

diff --git a/exporters/prometheus/exporter.go b/exporters/prometheus/exporter.go
@@ -168,6 +168,10 @@ func getHistogramMetricData(histogram metricdata.Histogram, m metricdata.Metrics
 }
 
 func getSumMetricData[N int64 | float64](sum metricdata.Sum[N], m metricdata.Metrics) []*metricData {
+	valueType := prometheus.CounterValue
+	if !sum.IsMonotonic {
+		valueType = prometheus.GaugeValue
+	}
 	dataPoints := make([]*metricData, 0, len(sum.DataPoints))
 	for _, dp := range sum.DataPoints {
 		keys, values := getAttrs(dp.Attributes)
@@ -176,7 +180,7 @@ func getSumMetricData[N int64 | float64](sum metricdata.Sum[N], m metricdata.Met
 			name:            m.Name,
 			description:     desc,
 			attributeValues: values,
-			valueType:       prometheus.CounterValue,
+			valueType:       valueType,
 			value:           float64(dp.Value),
 		}
 		dataPoints = append(dataPoints, md)

diff --git a/exporters/prometheus/testdata/gauge.txt b/exporters/prometheus/testdata/gauge.txt
@@ -1,3 +1,3 @@
 # HELP bar a fun little gauge
-# TYPE bar counter
+# TYPE bar gauge
 bar{A="B",C="D"} 75
diff --git a/exporters/prometheus/testdata/sanitized_names.txt b/exporters/prometheus/testdata/sanitized_names.txt
@@ -1,11 +1,11 @@
 # HELP bar a fun little gauge
-# TYPE bar counter
+# TYPE bar gauge
 bar{A="B",C="D"} 75
 # HELP _0invalid_counter_name a counter with an invalid name
 # TYPE _0invalid_counter_name counter
 _0invalid_counter_name{A="B",C="D"} 100
 # HELP invalid_gauge_name a gauge with an invalid name
-# TYPE invalid_gauge_name counter
+# TYPE invalid_gauge_name gauge
 invalid_gauge_name{A="B",C="D"} 100
 # HELP invalid_hist_name a histogram with an invalid name
 # TYPE invalid_hist_name histogram