Refactor InfluxDB listener (#6974)

Use streaming parser in InfluxDB listener

metric/builder.go

@@ -1,55 +0,0 @@
-package metric
-
-import (
-	"time"
-
-	"github.com/influxdata/telegraf"
-)
-
-type TimeFunc func() time.Time
-
-type Builder struct {
-	TimeFunc
-	TimePrecision time.Duration
-
-	*metric
-}
-
-func NewBuilder() *Builder {
-	b := &Builder{
-		TimeFunc:      time.Now,
-		TimePrecision: 1 * time.Nanosecond,
-	}
-	b.Reset()
-	return b
-}
-
-func (b *Builder) SetName(name string) {
-	b.name = name
-}
-
-func (b *Builder) AddTag(key string, value string) {
-	b.metric.AddTag(key, value)
-}
-
-func (b *Builder) AddField(key string, value interface{}) {
-	b.metric.AddField(key, value)
-}
-
-func (b *Builder) SetTime(tm time.Time) {
-	b.tm = tm
-}
-
-func (b *Builder) Reset() {
-	b.metric = &metric{
-		tp: telegraf.Untyped,
-	}
-}
-
-func (b *Builder) Metric() (telegraf.Metric, error) {
-	if b.tm.IsZero() {
-		b.tm = b.TimeFunc().Truncate(b.TimePrecision)
-	}
-
-	return b.metric, nil
-}

metric/metric.go

@@ -50,13 +50,15 @@ func New(
 		sort.Slice(m.tags, func(i, j int) bool { return m.tags[i].Key < m.tags[j].Key })
 	}
 
-	m.fields = make([]*telegraf.Field, 0, len(fields))
-	for k, v := range fields {
-		v := convertField(v)
-		if v == nil {
-			continue
+	if len(fields) > 0 {
+		m.fields = make([]*telegraf.Field, 0, len(fields))
+		for k, v := range fields {
+			v := convertField(v)
+			if v == nil {
+				continue
+			}
+			m.AddField(k, v)
 		}
-		m.AddField(k, v)
 	}
 
 	return m, nil