/
sflow.go
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/
sflow.go
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//go:generate ../../../tools/readme_config_includer/generator
package sflow
import (
"bytes"
_ "embed"
"fmt"
"io"
"net"
"net/url"
"strings"
"sync"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/config"
"github.com/influxdata/telegraf/plugins/inputs"
)
// DO NOT REMOVE THE NEXT TWO LINES! This is required to embed the sampleConfig data.
//go:embed sample.conf
var sampleConfig string
const (
maxPacketSize = 64 * 1024
)
type SFlow struct {
ServiceAddress string `toml:"service_address"`
ReadBufferSize config.Size `toml:"read_buffer_size"`
Log telegraf.Logger `toml:"-"`
addr net.Addr
decoder *PacketDecoder
closer io.Closer
wg sync.WaitGroup
}
func (*SFlow) SampleConfig() string {
return sampleConfig
}
func (s *SFlow) Init() error {
s.decoder = NewDecoder()
s.decoder.Log = s.Log
return nil
}
// Start starts this sFlow listener listening on the configured network for sFlow packets
func (s *SFlow) Start(acc telegraf.Accumulator) error {
s.decoder.OnPacket(func(p *V5Format) {
metrics, err := makeMetrics(p)
if err != nil {
s.Log.Errorf("Failed to make metric from packet: %s", err)
return
}
for _, m := range metrics {
acc.AddMetric(m)
}
})
u, err := url.Parse(s.ServiceAddress)
if err != nil {
return err
}
conn, err := listenUDP(u.Scheme, u.Host)
if err != nil {
return err
}
s.closer = conn
s.addr = conn.LocalAddr()
if s.ReadBufferSize > 0 {
if err := conn.SetReadBuffer(int(s.ReadBufferSize)); err != nil {
return err
}
}
s.Log.Infof("Listening on %s://%s", s.addr.Network(), s.addr.String())
s.wg.Add(1)
go func() {
defer s.wg.Done()
s.read(acc, conn)
}()
return nil
}
// Gather is a NOOP for sFlow as it receives, asynchronously, sFlow network packets
func (s *SFlow) Gather(_ telegraf.Accumulator) error {
return nil
}
func (s *SFlow) Stop() {
if s.closer != nil {
// Ignore the returned error as we cannot do anything about it anyway
//nolint:errcheck,revive
s.closer.Close()
}
s.wg.Wait()
}
func (s *SFlow) Address() net.Addr {
return s.addr
}
func (s *SFlow) read(acc telegraf.Accumulator, conn net.PacketConn) {
buf := make([]byte, maxPacketSize)
for {
n, _, err := conn.ReadFrom(buf)
if err != nil {
if !strings.HasSuffix(err.Error(), ": use of closed network connection") {
acc.AddError(err)
}
break
}
s.process(acc, buf[:n])
}
}
func (s *SFlow) process(acc telegraf.Accumulator, buf []byte) {
if err := s.decoder.Decode(bytes.NewBuffer(buf)); err != nil {
acc.AddError(fmt.Errorf("unable to parse incoming packet: %s", err))
}
}
func listenUDP(network string, address string) (*net.UDPConn, error) {
switch network {
case "udp", "udp4", "udp6":
addr, err := net.ResolveUDPAddr(network, address)
if err != nil {
return nil, err
}
return net.ListenUDP(network, addr)
default:
return nil, fmt.Errorf("unsupported network type: %s", network)
}
}
// init registers this SFlow input plug in with the Telegraf framework
func init() {
inputs.Add("sflow", func() telegraf.Input {
return &SFlow{}
})
}