split metrics based on UDPPayload size (#2795)

plugins/outputs/influxdb/client/udp.go

@@ -25,6 +25,7 @@ type UDPConfig struct {
 	PayloadSize int
 }
 
+// NewUDP will return an instance of the telegraf UDP output plugin for influxdb
 func NewUDP(config UDPConfig) (Client, error) {
 	p, err := url.Parse(config.URL)
 	if err != nil {
@@ -55,20 +56,22 @@ type udpClient struct {
 	buffer []byte
 }
 
+// Query will send the provided query command to the client, returning an error if any issues arise
 func (c *udpClient) Query(command string) error {
 	return nil
 }
 
+// Write will send the byte stream to the given UDP client endpoint
 func (c *udpClient) Write(b []byte) (int, error) {
 	return c.WriteStream(bytes.NewReader(b), -1)
 }
 
-// write params are ignored by the UDP client
+// WriteWithParams are ignored by the UDP client, will forward to WriteStream
 func (c *udpClient) WriteWithParams(b []byte, wp WriteParams) (int, error) {
 	return c.WriteStream(bytes.NewReader(b), -1)
 }
 
-// contentLength is ignored by the UDP client.
+// WriteStream will send the provided data through to the client, contentLength is ignored by the UDP client
 func (c *udpClient) WriteStream(r io.Reader, contentLength int) (int, error) {
 	var totaln int
 	for {
@@ -88,12 +91,13 @@ func (c *udpClient) WriteStream(r io.Reader, contentLength int) (int, error) {
 	return totaln, nil
 }
 
-// contentLength is ignored by the UDP client.
+// WriteStreamWithParams will forward the stream to the client backend, contentLength is ignored by the UDP client
 // write params are ignored by the UDP client
 func (c *udpClient) WriteStreamWithParams(r io.Reader, contentLength int, wp WriteParams) (int, error) {
 	return c.WriteStream(r, -1)
 }
 
+// Close will terminate the provided client connection
 func (c *udpClient) Close() error {
 	return c.conn.Close()
 }

plugins/outputs/influxdb/influxdb.go

@@ -15,6 +15,7 @@ import (
 	"github.com/influxdata/telegraf/plugins/outputs/influxdb/client"
 )
 
+// InfluxDB struct is the primary data structure for the plugin
 type InfluxDB struct {
 	// URL is only for backwards compatability
 	URL              string
@@ -79,11 +80,10 @@ var sampleConfig = `
   # insecure_skip_verify = false
 `
 
+// Connect initiates the primary connection to the range of provided URLs
 func (i *InfluxDB) Connect() error {
 	var urls []string
-	for _, u := range i.URLs {
+	urls = append(urls, i.URLs...)
-		urls = append(urls, u)
-	}
 
 	// Backward-compatability with single Influx URL config files
 	// This could eventually be removed in favor of specifying the urls as a list
@@ -144,26 +144,32 @@ func (i *InfluxDB) Connect() error {
 	return nil
 }
 
+// Close will terminate the session to the backend, returning error if an issue arises
 func (i *InfluxDB) Close() error {
 	return nil
 }
 
+// SampleConfig returns the formatted sample configuration for the plugin
 func (i *InfluxDB) SampleConfig() string {
 	return sampleConfig
 }
 
+// Description returns the human-readable function definition of the plugin
 func (i *InfluxDB) Description() string {
 	return "Configuration for influxdb server to send metrics to"
 }
 
-// Choose a random server in the cluster to write to until a successful write
+// Write will choose a random server in the cluster to write to until a successful write
 // occurs, logging each unsuccessful. If all servers fail, return error.
 func (i *InfluxDB) Write(metrics []telegraf.Metric) error {
 	bufsize := 0
+	splitData := make([]telegraf.Metric, 0)
+
 	for _, m := range metrics {
 		bufsize += m.Len()
+		splitData = append(splitData, m.Split(i.UDPPayload)...)
 	}
-	r := metric.NewReader(metrics)
+	r := metric.NewReader(splitData)
 
 	// This will get set to nil if a successful write occurs
 	err := fmt.Errorf("Could not write to any InfluxDB server in cluster")