Remove Event field as it is causing issues with pre-trained source ty…

…pes (influxdata#8039)

Co-authored-by: Oleksii Samorukov <oleksii_samorukov@mckinsey.com>

plugins/serializers/splunkmetric/splunkmetric.go

@@ -23,7 +23,6 @@ type CommonTags struct {
 
 type HECTimeSeries struct {
 	Time   float64                `json:"time"`
-	Event  string                 `json:"event"`
 	Host   string                 `json:"host,omitempty"`
 	Index  string                 `json:"index,omitempty"`
 	Source string                 `json:"source,omitempty"`
@@ -76,7 +75,6 @@ func (s *serializer) createMulti(metric telegraf.Metric, dataGroup HECTimeSeries
 	var metricJSON []byte
 
 	// Set the event data from the commonTags above.
-	dataGroup.Event = "metric"
 	dataGroup.Time = commonTags.Time
 	dataGroup.Host = commonTags.Host
 	dataGroup.Index = commonTags.Index
@@ -131,8 +129,6 @@ func (s *serializer) createSingle(metric telegraf.Metric, dataGroup HECTimeSerie
 			continue
 		}
 
-		dataGroup.Event = "metric"
-
 		dataGroup.Time = commonTags.Time
 
 		// Apply the common tags from above to every record.

plugins/serializers/splunkmetric/splunkmetric_test.go

@@ -52,7 +52,7 @@ func TestSerializeMetricFloatHec(t *testing.T) {
 	var buf []byte
 	buf, err = s.Serialize(m)
 	assert.NoError(t, err)
-	expS := `{"time":1529875740.819,"event":"metric","fields":{"_value":91.5,"cpu":"cpu0","metric_name":"cpu.usage_idle"}}`
+	expS := `{"time":1529875740.819,"fields":{"_value":91.5,"cpu":"cpu0","metric_name":"cpu.usage_idle"}}`
 	assert.Equal(t, string(expS), string(buf))
 }
 
@@ -92,7 +92,7 @@ func TestSerializeMetricIntHec(t *testing.T) {
 	buf, err = s.Serialize(m)
 	assert.NoError(t, err)
 
-	expS := `{"time":0,"event":"metric","fields":{"_value":90,"cpu":"cpu0","metric_name":"cpu.usage_idle"}}`
+	expS := `{"time":0,"fields":{"_value":90,"cpu":"cpu0","metric_name":"cpu.usage_idle"}}`
 	assert.Equal(t, string(expS), string(buf))
 }
 
@@ -132,7 +132,7 @@ func TestSerializeMetricBoolHec(t *testing.T) {
 	buf, err = s.Serialize(m)
 	assert.NoError(t, err)
 
-	expS := `{"time":0,"event":"metric","fields":{"_value":0,"container-name":"telegraf-test","metric_name":"docker.oomkiller"}}`
+	expS := `{"time":0,"fields":{"_value":0,"container-name":"telegraf-test","metric_name":"docker.oomkiller"}}`
 	assert.Equal(t, string(expS), string(buf))
 }
 
@@ -238,7 +238,7 @@ func TestSerializeBatchHec(t *testing.T) {
 	buf, err := s.SerializeBatch(metrics)
 	assert.NoError(t, err)
 
-	expS := `{"time":0,"event":"metric","fields":{"_value":42,"metric_name":"cpu.value"}}{"time":0,"event":"metric","fields":{"_value":92,"metric_name":"cpu.value"}}`
+	expS := `{"time":0,"fields":{"_value":42,"metric_name":"cpu.value"}}{"time":0,"fields":{"_value":92,"metric_name":"cpu.value"}}`
 	assert.Equal(t, string(expS), string(buf))
 }
 
@@ -260,6 +260,6 @@ func TestSerializeMultiHec(t *testing.T) {
 	buf, err := s.SerializeBatch(metrics)
 	assert.NoError(t, err)
 
-	expS := `{"time":0,"event":"metric","fields":{"metric_name:cpu.system":8,"metric_name:cpu.usage":42}}`
+	expS := `{"time":0,"fields":{"metric_name:cpu.system":8,"metric_name:cpu.usage":42}}`
 	assert.Equal(t, string(expS), string(buf))
 }