Enhance the unit conversion in emf exporter

exporter/awsemfexporter/grouped_metric.go

@@ -5,6 +5,8 @@ package awsemfexporter // import "github.com/open-telemetry/opentelemetry-collec
 
 import (
 	"encoding/json"
+	"errors"
+	"reflect"
 	"strings"
 
 	"go.opentelemetry.io/collector/pdata/pmetric"
@@ -77,9 +79,13 @@ func addToGroupedMetric(
 				}
 			}
 
+			unit, val, err := translateUnit(pmd, descriptor, dp.value)
+			if err != nil {
+				config.logger.Warn("failed to translate unit", zap.Error(err))
+			}
 			metric := &metricInfo{
-				value: dp.value,
-				unit:  translateUnit(pmd, descriptor),
+				value: val,
+				unit:  unit,
 			}
 
 			if dp.timestampMs > 0 {
@@ -186,14 +192,28 @@ func mapGetHelper(labels map[string]string, key string) string {
 	return ""
 }
 
-func translateUnit(metric pmetric.Metric, descriptor map[string]MetricDescriptor) string {
+func translateUnit(metric pmetric.Metric, descriptor map[string]MetricDescriptor, value any) (string, any, error) {
 	unit := metric.Unit()
 	if descriptor, exists := descriptor[metric.Name()]; exists {
 		if unit == "" || descriptor.Overwrite {
-			return descriptor.Unit
+			return descriptor.Unit, value, nil
 		}
 	}
 	switch unit {
+	case "1":
+		unit = "Count"
+	case "ns":
+		// CloudWatch doesn't support Nanoseconds
+		switch v := value.(type) {
+		case int:
+			return "Microseconds", v / 1000, nil
+		case int64:
+			return "Microseconds", v / 1000, nil
+		case float64:
+			return "Microseconds", v / 1000, nil
+		default:
+			return unit, value, errors.New("Failed to convert ns to us with type " + reflect.TypeOf(value).String())
+		}
 	case "ms":
 		unit = "Milliseconds"
 	case "s":
@@ -202,8 +222,8 @@ func translateUnit(metric pmetric.Metric, descriptor map[string]MetricDescriptor
 		unit = "Microseconds"
 	case "By":
 		unit = "Bytes"
-	case "Bi":
+	case "bit":
 		unit = "Bits"
 	}
-	return unit
+	return unit, value, nil
 }

exporter/awsemfexporter/grouped_metric_test.go

@@ -487,25 +487,41 @@ func TestTranslateUnit(t *testing.T) {
 	}
 
 	translateUnitCases := map[string]string{
-		"Count": "Count",
-		"ms":    "Milliseconds",
-		"s":     "Seconds",
-		"us":    "Microseconds",
-		"By":    "Bytes",
-		"Bi":    "Bits",
+		"raw": "raw",
+		"1":   "Count",
+		"ms":  "Milliseconds",
+		"ns":  "Microseconds",
+		"s":   "Seconds",
+		"us":  "Microseconds",
+		"By":  "Bytes",
+		"bit": "Bits",
 	}
 	for input, output := range translateUnitCases {
 		t.Run(input, func(_ *testing.T) {
 			metric.SetUnit(input)
 
-			v := translateUnit(metric, translator.metricDescriptor)
-			assert.Equal(t, output, v)
+			convertedUnit, data, err := translateUnit(metric, translator.metricDescriptor, 1000)
+			if err != nil {
+				assert.Error(t, err)
+			} else {
+				assert.Equal(t, output, convertedUnit)
+				if input == "ns" {
+					assert.Equal(t, 1, data)
+				}
+			}
 		})
 	}
 
 	metric.SetName("forceOverwrite")
-	v := translateUnit(metric, translator.metricDescriptor)
-	assert.Equal(t, "Count", v)
+	convertedUnit, _, _ := translateUnit(metric, translator.metricDescriptor, 1)
+	assert.Equal(t, "Count", convertedUnit)
+
+	metric.SetName("failedConversion")
+	metric.SetUnit("ns")
+	convertedUnit, data, err := translateUnit(metric, translator.metricDescriptor, "any")
+	assert.NotNil(t, err)
+	assert.Equal(t, "ns", convertedUnit)
+	assert.Equal(t, "any", data)
 }
 
 func generateTestMetricMetadata(namespace string, timestamp int64, logGroup, logStreamName, instrumentationScopeName string, metricType pmetric.MetricType) cWMetricMetadata {