Fix influxdb output serialization on connection closed (#6621)

plugins/outputs/influxdb_v2/http.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
@@ -214,7 +215,12 @@ func (c *httpClient) writeBatch(ctx context.Context, bucket string, metrics []te
 		return err
 	}
 
-	reader := influx.NewReader(metrics, c.serializer)
+	reader, err := c.requestBodyReader(metrics)
+	if err != nil {
+		return err
+	}
+	defer reader.Close()
+
 	req, err := c.makeWriteRequest(url, reader)
 	if err != nil {
 		return err
@@ -282,12 +288,6 @@ func (c *httpClient) writeBatch(ctx context.Context, bucket string, metrics []te
 
 func (c *httpClient) makeWriteRequest(url string, body io.Reader) (*http.Request, error) {
 	var err error
-	if c.ContentEncoding == "gzip" {
-		body, err = internal.CompressWithGzip(body)
-		if err != nil {
-			return nil, err
-		}
-	}
 
 	req, err := http.NewRequest("POST", url, body)
 	if err != nil {
@@ -304,6 +304,23 @@ func (c *httpClient) makeWriteRequest(url string, body io.Reader) (*http.Request
 	return req, nil
 }
 
+// requestBodyReader warp io.Reader from influx.NewReader to io.ReadCloser, which is usefully to fast close the write
+// side of the connection in case of error
+func (c *httpClient) requestBodyReader(metrics []telegraf.Metric) (io.ReadCloser, error) {
+	reader := influx.NewReader(metrics, c.serializer)
+
+	if c.ContentEncoding == "gzip" {
+		rc, err := internal.CompressWithGzip(reader)
+		if err != nil {
+			return nil, err
+		}
+
+		return rc, nil
+	}
+
+	return ioutil.NopCloser(reader), nil
+}
+
 func (c *httpClient) addHeaders(req *http.Request) {
 	for header, value := range c.Headers {
 		req.Header.Set(header, value)

plugins/outputs/influxdb_v2/influxdb.go

@@ -96,8 +96,7 @@ type InfluxDB struct {
 	UintSupport      bool              `toml:"influx_uint_support"`
 	tls.ClientConfig
 
-	clients    []Client
-	serializer *influx.Serializer
+	clients []Client
 }
 
 func (i *InfluxDB) Connect() error {
@@ -107,11 +106,6 @@ func (i *InfluxDB) Connect() error {
 		i.URLs = append(i.URLs, defaultURL)
 	}
 
-	i.serializer = influx.NewSerializer()
-	if i.UintSupport {
-		i.serializer.SetFieldTypeSupport(influx.UintSupport)
-	}
-
 	for _, u := range i.URLs {
 		parts, err := url.Parse(u)
 		if err != nil {
@@ -196,7 +190,7 @@ func (i *InfluxDB) getHTTPClient(ctx context.Context, url *url.URL, proxy *url.U
 		UserAgent:        i.UserAgent,
 		ContentEncoding:  i.ContentEncoding,
 		TLSConfig:        tlsConfig,
-		Serializer:       i.serializer,
+		Serializer:       i.newSerializer(),
 	}
 
 	c, err := NewHTTPClient(config)
@@ -207,6 +201,15 @@ func (i *InfluxDB) getHTTPClient(ctx context.Context, url *url.URL, proxy *url.U
 	return c, nil
 }
 
+func (i *InfluxDB) newSerializer() *influx.Serializer {
+	serializer := influx.NewSerializer()
+	if i.UintSupport {
+		serializer.SetFieldTypeSupport(influx.UintSupport)
+	}
+
+	return serializer
+}
+
 func init() {
 	outputs.Add("influxdb_v2", func() telegraf.Output {
 		return &InfluxDB{