Add Kafka output plugin topic_suffix option (#3196)

plugins/outputs/kafka/kafka_test.go

@@ -8,6 +8,11 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+type topicSuffixTestpair struct {
+	topicSuffix   TopicSuffix
+	expectedTopic string
+}
+
 func TestConnectAndWrite(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping integration test in short mode")
@@ -28,4 +33,66 @@ func TestConnectAndWrite(t *testing.T) {
 	// Verify that we can successfully write data to the kafka broker
 	err = k.Write(testutil.MockMetrics())
 	require.NoError(t, err)
+	k.Close()
+}
+
+func TestTopicSuffixes(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping integration test in short mode")
+	}
+
+	topic := "Test"
+
+	metric := testutil.TestMetric(1)
+	metricTagName := "tag1"
+	metricTagValue := metric.Tags()[metricTagName]
+	metricName := metric.Name()
+
+	var testcases = []topicSuffixTestpair{
+		// This ensures empty separator is okay
+		{TopicSuffix{Method: "measurement"},
+			topic + metricName},
+		{TopicSuffix{Method: "measurement", Separator: "sep"},
+			topic + "sep" + metricName},
+		{TopicSuffix{Method: "tags", Keys: []string{metricTagName}, Separator: "_"},
+			topic + "_" + metricTagValue},
+		{TopicSuffix{Method: "tags", Keys: []string{metricTagName, metricTagName, metricTagName}, Separator: "___"},
+			topic + "___" + metricTagValue + "___" + metricTagValue + "___" + metricTagValue},
+		{TopicSuffix{Method: "tags", Keys: []string{metricTagName, metricTagName, metricTagName}},
+			topic + metricTagValue + metricTagValue + metricTagValue},
+		// This ensures non-existing tags are ignored
+		{TopicSuffix{Method: "tags", Keys: []string{"non_existing_tag", "non_existing_tag"}, Separator: "___"},
+			topic},
+		{TopicSuffix{Method: "tags", Keys: []string{metricTagName, "non_existing_tag"}, Separator: "___"},
+			topic + "___" + metricTagValue},
+		// This ensures backward compatibility
+		{TopicSuffix{},
+			topic},
+	}
+
+	for _, testcase := range testcases {
+		topicSuffix := testcase.topicSuffix
+		expectedTopic := testcase.expectedTopic
+		k := &Kafka{
+			Topic:       topic,
+			TopicSuffix: topicSuffix,
+		}
+
+		topic := k.GetTopicName(metric)
+		require.Equal(t, expectedTopic, topic)
+	}
+}
+
+func TestValidateTopicSuffixMethod(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping integration test in short mode")
+	}
+
+	err := ValidateTopicSuffixMethod("invalid_topic_suffix_method")
+	require.Error(t, err, "Topic suffix method used should be invalid.")
+
+	for _, method := range ValidTopicSuffixMethods {
+		err := ValidateTopicSuffixMethod(method)
+		require.NoError(t, err, "Topic suffix method used should be valid.")
+	}
 }