[exporter/sumologicexporter] Change Prometheus le label for infinity bounds (#39904)

#### Description

For histograms, whenever a bound is (positive) infinity, give the
Prometheus `le` label a string value of "+Inf".
In all other cases, that label is set as a `double` value.

#### Testing

Unit tests.

---------

Co-authored-by: Pablo Baeyens <[email protected]>

Author: ccressent

.chloggen/otlp-inf-string.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: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: sumologicexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Change how infinity bounds are represented in histogram buckets so that the Sumologic backend can properly handle them.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [39904]
+
+# (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: [user]

exporter/sumologicexporter/otlp.go

@@ -87,7 +87,13 @@ func getHistogramBucketsMetric(metric pmetric.Metric) pmetric.Metric {
 			bucketDataPoint := bucketsDatapoints.AppendEmpty()
 			bound := histogramBounds.At(j)
 			histogramDataPoint.Attributes().CopyTo(bucketDataPoint.Attributes())
-			bucketDataPoint.Attributes().PutDouble(prometheusLeTag, bound)
+
+			if math.IsInf(bound, 1) {
+				bucketDataPoint.Attributes().PutStr(prometheusLeTag, prometheusInfValue)
+			} else {
+				bucketDataPoint.Attributes().PutDouble(prometheusLeTag, bound)
+			}
+
 			bucketDataPoint.SetStartTimestamp(histogramDataPoint.StartTimestamp())
 			bucketDataPoint.SetTimestamp(histogramDataPoint.Timestamp())
 			cumulative += histogramDataPoint.BucketCounts().At(j)
@@ -97,7 +103,7 @@ func getHistogramBucketsMetric(metric pmetric.Metric) pmetric.Metric {
 		// need to add one more bucket at +Inf
 		bucketDataPoint := bucketsDatapoints.AppendEmpty()
 		histogramDataPoint.Attributes().CopyTo(bucketDataPoint.Attributes())
-		bucketDataPoint.Attributes().PutDouble(prometheusLeTag, math.Inf(1))
+		bucketDataPoint.Attributes().PutStr(prometheusLeTag, prometheusInfValue)
 		bucketDataPoint.SetStartTimestamp(histogramDataPoint.StartTimestamp())
 		bucketDataPoint.SetTimestamp(histogramDataPoint.Timestamp())
 		cumulative += histogramDataPoint.BucketCounts().At(histogramDataPoint.ExplicitBounds().Len())

exporter/sumologicexporter/otlp_test.go

@@ -142,7 +142,13 @@ func addExpectedHistogramBuckets(metrics pmetric.MetricSlice) {
 		bound, bucketCount := pair.float64, pair.int64
 		dataPoint := metric.Gauge().DataPoints().AppendEmpty()
 		dataPoint.Attributes().PutStr("container", "dolor")
-		dataPoint.Attributes().PutDouble(prometheusLeTag, bound)
+
+		if math.IsInf(bound, 1) {
+			dataPoint.Attributes().PutStr(prometheusLeTag, prometheusInfValue)
+		} else {
+			dataPoint.Attributes().PutDouble(prometheusLeTag, bound)
+		}
+
 		dataPoint.SetTimestamp(timestamp1)
 		dataPoint.SetIntValue(bucketCount)
 	}
@@ -162,7 +168,13 @@ func addExpectedHistogramBuckets(metrics pmetric.MetricSlice) {
 		bound, bucketCount := pair.float64, pair.int64
 		dataPoint := metric.Gauge().DataPoints().AppendEmpty()
 		dataPoint.Attributes().PutStr("container", "sit")
-		dataPoint.Attributes().PutDouble(prometheusLeTag, bound)
+
+		if math.IsInf(bound, 1) {
+			dataPoint.Attributes().PutStr(prometheusLeTag, prometheusInfValue)
+		} else {
+			dataPoint.Attributes().PutDouble(prometheusLeTag, bound)
+		}
+
 		dataPoint.SetTimestamp(timestamp2)
 		dataPoint.SetIntValue(bucketCount)
 	}