telegraf/plugins/outputs/graphite/graphite.go

150 lines
3.9 KiB
Go

package graphite
import (
"errors"
"io"
"log"
"math/rand"
"net"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/outputs"
"github.com/influxdata/telegraf/plugins/serializers"
)
type Graphite struct {
// URL is only for backwards compatability
Servers []string
Prefix string
Template string
Timeout int
conns []net.Conn
}
var sampleConfig = `
## TCP endpoint for your graphite instance.
## If multiple endpoints are configured, output will be load balanced.
## Only one of the endpoints will be written to with each iteration.
servers = ["localhost:2003"]
## Prefix metrics name
prefix = ""
## Graphite output template
## see https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_OUTPUT.md
template = "host.tags.measurement.field"
## timeout in seconds for the write connection to graphite
timeout = 2
`
func (g *Graphite) Connect() error {
// Set default values
if g.Timeout <= 0 {
g.Timeout = 2
}
if len(g.Servers) == 0 {
g.Servers = append(g.Servers, "localhost:2003")
}
// Get Connections
var conns []net.Conn
for _, server := range g.Servers {
conn, err := net.DialTimeout("tcp", server, time.Duration(g.Timeout)*time.Second)
if err == nil {
conns = append(conns, conn)
}
}
g.conns = conns
return nil
}
func (g *Graphite) Close() error {
// Closing all connections
for _, conn := range g.conns {
conn.Close()
}
return nil
}
func (g *Graphite) SampleConfig() string {
return sampleConfig
}
func (g *Graphite) Description() string {
return "Configuration for Graphite server to send metrics to"
}
// We need check eof as we can write to nothing without noticing anything is wrong
// the connection stays in a close_wait
// We can detect that by finding an eof
// if not for this, we can happily write and flush without getting errors (in Go) but getting RST tcp packets back (!)
// props to Tv via the authors of carbon-relay-ng` for this trick.
func checkEOF(conn net.Conn) {
b := make([]byte, 1024)
conn.SetReadDeadline(time.Now().Add(10 * time.Millisecond))
num, err := conn.Read(b)
if err == io.EOF {
log.Printf("E! Conn %s is closed. closing conn explicitly", conn)
conn.Close()
return
}
// just in case i misunderstand something or the remote behaves badly
if num != 0 {
log.Printf("I! conn %s .conn.Read data? did not expect that. data: %s\n", conn, b[:num])
}
// Log non-timeout errors or close.
if e, ok := err.(net.Error); !(ok && e.Timeout()) {
log.Printf("E! conn %s checkEOF .conn.Read returned err != EOF, which is unexpected. closing conn. error: %s\n", conn, err)
conn.Close()
}
}
// 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 (g *Graphite) Write(metrics []telegraf.Metric) error {
// Prepare data
var batch []byte
s, err := serializers.NewGraphiteSerializer(g.Prefix, g.Template)
if err != nil {
return err
}
for _, metric := range metrics {
buf, err := s.Serialize(metric)
if err != nil {
log.Printf("E! Error serializing some metrics to graphite: %s", err.Error())
}
batch = append(batch, buf...)
}
// This will get set to nil if a successful write occurs
err = errors.New("Could not write to any Graphite server in cluster\n")
// Send data to a random server
p := rand.Perm(len(g.conns))
for _, n := range p {
if g.Timeout > 0 {
g.conns[n].SetWriteDeadline(time.Now().Add(time.Duration(g.Timeout) * time.Second))
}
checkEOF(g.conns[n])
if _, e := g.conns[n].Write(batch); e != nil {
// Error
log.Println("E! Graphite Error: " + e.Error())
// Let's try the next one
} else {
// Success
err = nil
break
}
}
// try to reconnect
if err != nil {
log.Println("E! Reconnecting: ")
g.Connect()
}
return err
}
func init() {
outputs.Add("graphite", func() telegraf.Output {
return &Graphite{}
})
}