Add tags formatting util

exporter/datadogexporter/internal/instrumentationlibrary/metadata.go

@@ -15,9 +15,9 @@
 package instrumentationlibrary
 
 import (
-	"fmt"
-
 	"go.opentelemetry.io/collector/model/pdata"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter/internal/utils"
 )
 
 const (
@@ -29,7 +29,7 @@ const (
 // the instrumentation library and converts them to Datadog tags.
 func TagsFromInstrumentationLibraryMetadata(il pdata.InstrumentationLibrary) []string {
 	return []string{
-		fmt.Sprintf("%s:%s", instrumentationLibraryTag, il.Name()),
-		fmt.Sprintf("%s:%s", instrumentationLibraryVersionTag, il.Version()),
+		utils.FormatKeyValueTag(instrumentationLibraryTag, il.Name()),
+		utils.FormatKeyValueTag(instrumentationLibraryVersionTag, il.Version()),
 	}
 }

exporter/datadogexporter/internal/instrumentationlibrary/metadata_test.go

@@ -29,12 +29,12 @@ func TestTagsFromInstrumentationLibraryMetadata(t *testing.T) {
 		expectedTags []string
 	}{
 		{"test-il", "1.0.0", []string{fmt.Sprintf("%s:%s", instrumentationLibraryTag, "test-il"), fmt.Sprintf("%s:%s", instrumentationLibraryVersionTag, "1.0.0")}},
-		{"test-il", "", []string{fmt.Sprintf("%s:%s", instrumentationLibraryTag, "test-il"), fmt.Sprintf("%s:%s", instrumentationLibraryVersionTag, "")}},
-		{"", "1.0.0", []string{fmt.Sprintf("%s:%s", instrumentationLibraryTag, ""), fmt.Sprintf("%s:%s", instrumentationLibraryVersionTag, "1.0.0")}},
+		{"test-il", "", []string{fmt.Sprintf("%s:%s", instrumentationLibraryTag, "test-il"), fmt.Sprintf("%s:%s", instrumentationLibraryVersionTag, "n/a")}},
+		{"", "1.0.0", []string{fmt.Sprintf("%s:%s", instrumentationLibraryTag, "n/a"), fmt.Sprintf("%s:%s", instrumentationLibraryVersionTag, "1.0.0")}},
+		{"", "", []string{fmt.Sprintf("%s:%s", instrumentationLibraryTag, "n/a"), fmt.Sprintf("%s:%s", instrumentationLibraryVersionTag, "n/a")}},
 	}
 
 	for _, testInstance := range tests {
-		fmt.Println(testInstance)
 		il := pdata.NewInstrumentationLibrary()
 		il.SetName(testInstance.name)
 		il.SetVersion(testInstance.version)

exporter/datadogexporter/internal/translator/metrics_translator.go

@@ -32,6 +32,7 @@ import (
 	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter/internal/instrumentationlibrary"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter/internal/metrics"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter/internal/sketches"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter/internal/utils"
 )
 
 const metricName string = "metric name"
@@ -65,11 +66,7 @@ func getTags(labels pdata.AttributeMap) []string {
 	tags := make([]string, 0, labels.Len())
 	labels.Range(func(key string, value pdata.AttributeValue) bool {
 		v := value.AsString()
-		if v == "" {
-			// Tags can't end with ":" so we replace empty values with "n/a"
-			v = "n/a"
-		}
-		tags = append(tags, fmt.Sprintf("%s:%s", key, v))
+		tags = append(tags, utils.FormatKeyValueTag(key, v))
 		return true
 	})
 	return tags

exporter/datadogexporter/internal/utils/tags.go

@@ -0,0 +1,29 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package utils
+
+import (
+	"fmt"
+)
+
+// FormatKeyValueTag takes a key-value pair, and creates a tag string out of it
+// Tags can't end with ":" so we replace empty values with "n/a"
+func FormatKeyValueTag(key, value string) string {
+	// Should this check for empty keys, and return an error in that case?
+	if value == "" {
+		value = "n/a"
+	}
+	return fmt.Sprintf("%s:%s", key, value)
+}

exporter/datadogexporter/internal/utils/tags_test.go

@@ -0,0 +1,37 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package utils
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFormatKeyValueTag(t *testing.T) {
+	tests := []struct {
+		key         string
+		value       string
+		expectedTag string
+	}{
+		{"a.test.tag", "a.test.value", fmt.Sprintf("%s:%s", "a.test.tag", "a.test.value")},
+		{"a.test.tag", "", fmt.Sprintf("%s:%s", "a.test.tag", "n/a")},
+	}
+
+	for _, testInstance := range tests {
+		assert.Equal(t, testInstance.expectedTag, FormatKeyValueTag(testInstance.key, testInstance.value))
+	}
+}