telegraf/plugins/outputs/kafka/kafka.go

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package kafka
import (
"crypto/tls"
"crypto/x509"
"errors"
"fmt"
"github.com/Shopify/sarama"
"github.com/influxdb/influxdb/client/v2"
"github.com/influxdb/telegraf/plugins/outputs"
"io/ioutil"
)
type Kafka struct {
// Kafka brokers to send metrics to
Brokers []string
// Kafka topic
Topic string
// Routing Key Tag
RoutingTag string `toml:"routing_tag"`
// TLS client certificate
Certificate string
// TLS client key
Key string
// TLS certificate authority
CA string
// Verfiy SSL certificate chain
VerifySsl bool
tlsConfig tls.Config
producer sarama.SyncProducer
}
var sampleConfig = `
# URLs of kafka brokers
brokers = ["localhost:9092"]
# Kafka topic for producer messages
topic = "telegraf"
# Telegraf tag to use as a routing key
# ie, if this tag exists, it's value will be used as the routing key
routing_tag = "host"
# Optional TLS configuration:
# Client certificate
certificate = ""
# Client key
key = ""
# Certificate authority file
ca = ""
# Verify SSL certificate chain
verify_ssl = false
`
func createTlsConfiguration(k *Kafka) (t *tls.Config, err error) {
if k.Certificate != "" && k.Key != "" && k.CA != "" {
cert, err := tls.LoadX509KeyPair(k.Certificate, k.Key)
if err != nil {
return nil, errors.New(fmt.Sprintf("Cout not load Kafka TLS client key/certificate: %s",
err))
}
caCert, err := ioutil.ReadFile(k.CA)
if err != nil {
return nil, errors.New(fmt.Sprintf("Cout not load Kafka TLS CA: %s",
err))
}
caCertPool := x509.NewCertPool()
caCertPool.AppendCertsFromPEM(caCert)
t = &tls.Config{
Certificates: []tls.Certificate{cert},
RootCAs: caCertPool,
InsecureSkipVerify: k.VerifySsl,
}
}
// will be nil by default if nothing is provided
return t, nil
}
func (k *Kafka) Connect() error {
config := sarama.NewConfig()
config.Producer.RequiredAcks = sarama.WaitForAll // Wait for all in-sync replicas to ack the message
config.Producer.Retry.Max = 10 // Retry up to 10 times to produce the message
tlsConfig, err := createTlsConfiguration(k)
if err != nil {
return err
}
if tlsConfig != nil {
config.Net.TLS.Config = tlsConfig
config.Net.TLS.Enable = true
}
producer, err := sarama.NewSyncProducer(k.Brokers, config)
if err != nil {
return err
}
k.producer = producer
return nil
}
func (k *Kafka) Close() error {
return k.producer.Close()
}
func (k *Kafka) SampleConfig() string {
return sampleConfig
}
func (k *Kafka) Description() string {
return "Configuration for the Kafka server to send metrics to"
}
func (k *Kafka) Write(points []*client.Point) error {
if len(points) == 0 {
return nil
}
for _, p := range points {
// Combine tags from Point and BatchPoints and grab the resulting
// line-protocol output string to write to Kafka
value := p.String()
m := &sarama.ProducerMessage{
Topic: k.Topic,
Value: sarama.StringEncoder(value),
}
if h, ok := p.Tags()[k.RoutingTag]; ok {
m.Key = sarama.StringEncoder(h)
}
_, _, err := k.producer.SendMessage(m)
if err != nil {
return errors.New(fmt.Sprintf("FAILED to send kafka message: %s\n",
err))
}
}
return nil
}
func init() {
outputs.Add("kafka", func() outputs.Output {
return &Kafka{}
})
}