telegraf/plugins/outputs/mqtt/mqtt.go

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package mqtt
import (
"crypto/rand"
"crypto/tls"
"crypto/x509"
"fmt"
"io/ioutil"
"strings"
"sync"
paho "git.eclipse.org/gitroot/paho/org.eclipse.paho.mqtt.golang.git"
"github.com/influxdb/influxdb/client/v2"
"github.com/influxdb/telegraf/internal"
"github.com/influxdb/telegraf/plugins/outputs"
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)
const MaxClientIdLen = 8
const MaxRetryCount = 3
const ClientIdPrefix = "telegraf"
type MQTT struct {
Servers []string `toml:"servers"`
Username string
Password string
Database string
Timeout internal.Duration
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TopicPrefix string
Client *paho.Client
Opts *paho.ClientOptions
sync.Mutex
}
var sampleConfig = `
servers = ["localhost:1883"] # required.
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# MQTT outputs send metrics to this topic format
# "<topic_prefix>/host/<hostname>/<pluginname>/"
# ex: prefix/host/web01.example.com/mem/available
# topic_prefix = "prefix"
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# username and password to connect MQTT server.
# username = "telegraf"
# password = "metricsmetricsmetricsmetrics"
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`
func (m *MQTT) Connect() error {
var err error
m.Lock()
defer m.Unlock()
m.Opts, err = m.CreateOpts()
if err != nil {
return err
}
m.Client = paho.NewClient(m.Opts)
if token := m.Client.Connect(); token.Wait() && token.Error() != nil {
return token.Error()
}
return nil
}
func (m *MQTT) Close() error {
if m.Client.IsConnected() {
m.Client.Disconnect(20)
}
return nil
}
func (m *MQTT) SampleConfig() string {
return sampleConfig
}
func (m *MQTT) Description() string {
return "Configuration for MQTT server to send metrics to"
}
func (m *MQTT) Write(points []*client.Point) error {
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m.Lock()
defer m.Unlock()
if len(points) == 0 {
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return nil
}
hostname, ok := points[0].Tags()["host"]
if !ok {
hostname = ""
}
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for _, p := range points {
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var t []string
if m.TopicPrefix != "" {
t = append(t, m.TopicPrefix)
}
tm := strings.Split(p.Name(), "_")
if len(tm) < 2 {
tm = []string{p.Name(), "stat"}
}
t = append(t, "host", hostname, tm[0], tm[1])
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topic := strings.Join(t, "/")
value := p.String()
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err := m.publish(topic, value)
if err != nil {
return fmt.Errorf("Could not write to MQTT server, %s", err)
}
}
return nil
}
func (m *MQTT) publish(topic, body string) error {
token := m.Client.Publish(topic, 0, false, body)
token.Wait()
if token.Error() != nil {
return token.Error()
}
return nil
}
func (m *MQTT) CreateOpts() (*paho.ClientOptions, error) {
opts := paho.NewClientOptions()
clientId := getRandomClientId()
opts.SetClientID(clientId)
TLSConfig := &tls.Config{InsecureSkipVerify: false}
ca := "" // TODO
scheme := "tcp"
if ca != "" {
scheme = "ssl"
certPool, err := getCertPool(ca)
if err != nil {
return nil, err
}
TLSConfig.RootCAs = certPool
}
TLSConfig.InsecureSkipVerify = true // TODO
opts.SetTLSConfig(TLSConfig)
user := m.Username
if user == "" {
opts.SetUsername(user)
}
password := m.Password
if password != "" {
opts.SetPassword(password)
}
if len(m.Servers) == 0 {
return opts, fmt.Errorf("could not get host infomations")
}
for _, host := range m.Servers {
server := fmt.Sprintf("%s://%s", scheme, host)
opts.AddBroker(server)
}
opts.SetAutoReconnect(true)
return opts, nil
}
func getRandomClientId() string {
const alphanum = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
var bytes = make([]byte, MaxClientIdLen)
rand.Read(bytes)
for i, b := range bytes {
bytes[i] = alphanum[b%byte(len(alphanum))]
}
return ClientIdPrefix + "-" + string(bytes)
}
func getCertPool(pemPath string) (*x509.CertPool, error) {
certs := x509.NewCertPool()
pemData, err := ioutil.ReadFile(pemPath)
if err != nil {
return nil, err
}
certs.AppendCertsFromPEM(pemData)
return certs, nil
}
func init() {
outputs.Add("mqtt", func() outputs.Output {
return &MQTT{}
})
}