[exporter/awsemfexporter] Fix regression in dimension roll up (#14532)

* [exporter/awsemfexporter]Fix regression in dimension roll up

* Add changelog

* Fix linting errors

* Improve readability

* Improve unit tests

exporter/awsemfexporter/metric_translator_test.go

@@ -16,8 +16,8 @@ package awsemfexporter
 
 import (
  "os"
+ "reflect"
  "sort"
- "strings"
  "testing"
  "time"
 
@@ -296,17 +296,46 @@ func stringSlicesEqual(expected, actual []string) bool {
  return true
 }
 
-// hashDimensions hashes dimensions for equality checking.
-func hashDimensions(dims [][]string) []string {
+func min(i, j int) int {
+ if i < j {
+ return i
+ }
+ return j
+}
+
+type dimensionality [][]string
+
+func (d dimensionality) Len() int {
+ return len(d)
+}
+
+func (d dimensionality) Swap(i, j int) {
+ d[i], d[j] = d[j], d[i]
+}
+
+func (d dimensionality) Less(i, j int) bool {
+ dim1 := d[i]
+ dim2 := d[j]
+
+ for k := 0; k < min(len(dim1), len(dim2)); k++ {
+ if dim1[k] != dim2[k] {
+ return dim1[k] < dim2[k]
+ }
+ }
+
+ return len(dim1) < len(dim2)
+}
+
+// normalizes a dimensionality lexicographically so that it can be compared
+func normalizeDimensionality(dims [][]string) [][]string {
  // Convert to string for easier sorting
- stringified := make([]string, len(dims))
+ sortedDimensions := make([][]string, len(dims))
  for i, v := range dims {
  sort.Strings(v)
- stringified[i] = strings.Join(v, ",")
+ sortedDimensions[i] = v
  }
- // Sort across dimension sets for equality checking
- sort.Strings(stringified)
- return stringified
+ sort.Sort(dimensionality(sortedDimensions))
+ return sortedDimensions
 }
 
 // hashMetricSlice hashes a metrics slice for equality checking.
@@ -325,9 +354,9 @@ func hashMetricSlice(metricSlice []map[string]string) []string {
 // (i.e. has same sets of dimensions), regardless of order.
 func assertDimsEqual(t *testing.T, expected, actual [][]string) {
  assert.Equal(t, len(expected), len(actual))
- expectedHashedDimensions := hashDimensions(expected)
- actualHashedDimensions := hashDimensions(actual)
- assert.Equal(t, expectedHashedDimensions, actualHashedDimensions)
+ expectedDimensions := normalizeDimensionality(expected)
+ actualDimensions := normalizeDimensionality(actual)
+ assert.True(t, reflect.DeepEqual(expectedDimensions, actualDimensions))
 }
 
 // cWMeasurementEqual returns true if CW Measurements are equal.
@@ -351,9 +380,9 @@ func cWMeasurementEqual(expected, actual cWMeasurement) bool {
  if len(expected.Dimensions) != len(actual.Dimensions) {
  return false
  }
- expectedHashedDimensions := hashDimensions(expected.Dimensions)
- actualHashedDimensions := hashDimensions(actual.Dimensions)
- return stringSlicesEqual(expectedHashedDimensions, actualHashedDimensions)
+ expectedDimensions := normalizeDimensionality(expected.Dimensions)
+ actualDimensions := normalizeDimensionality(actual.Dimensions)
+ return reflect.DeepEqual(expectedDimensions, actualDimensions)
 }
 
 // assertCWMeasurementEqual asserts whether CW Measurements are equal.

exporter/awsemfexporter/util.go

@@ -131,13 +131,15 @@ func dedupDimensions(dimensions [][]string) (deduped [][]string) {
 // The returned dimensions are sorted in alphabetical order within each dimension set
 func dimensionRollup(dimensionRollupOption string, labels map[string]string) [][]string {
  var rollupDimensionArray [][]string
- var dimensionZero []string
+
+ // Empty dimension must be always present in a roll up.
+ dimensionZero := []string{}
 
  instrLibName, hasOTelKey := labels[oTellibDimensionKey]
  if hasOTelKey {
  // If OTel key exists in labels, add it as a zero dimension but remove it
  // temporarily from labels as it is not an original label
- dimensionZero = []string{oTellibDimensionKey}
+ dimensionZero = append(dimensionZero, oTellibDimensionKey)
  delete(labels, oTellibDimensionKey)
  }
 

unreleased/awsemfexporter-fix-regression-null-dimension.yaml

@@ -0,0 +1,11 @@
+# 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: awsemfexporter
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fix regression that causes null dimensions to be appended during dimension roll up.
+
+# One or more tracking issues related to the change
+issues: [14532]