telegraf/plugins/outputs/kafka/kafka.go

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package kafka
import (
"crypto/tls"
"fmt"
"log"
"strings"
"github.com/Shopify/sarama"
"github.com/gofrs/uuid"
"github.com/influxdata/telegraf"
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tlsint "github.com/influxdata/telegraf/internal/tls"
"github.com/influxdata/telegraf/plugins/outputs"
"github.com/influxdata/telegraf/plugins/serializers"
)
var ValidTopicSuffixMethods = []string{
"",
"measurement",
"tags",
}
type (
Kafka struct {
Brokers []string
Topic string
ClientID string `toml:"client_id"`
TopicSuffix TopicSuffix `toml:"topic_suffix"`
RoutingTag string `toml:"routing_tag"`
RoutingKey string `toml:"routing_key"`
CompressionCodec int
RequiredAcks int
MaxRetry int
MaxMessageBytes int `toml:"max_message_bytes"`
Version string `toml:"version"`
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// Legacy TLS config options
// TLS client certificate
Certificate string
// TLS client key
Key string
// TLS certificate authority
CA string
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tlsint.ClientConfig
// SASL Username
SASLUsername string `toml:"sasl_username"`
// SASL Password
SASLPassword string `toml:"sasl_password"`
tlsConfig tls.Config
producer sarama.SyncProducer
serializer serializers.Serializer
}
TopicSuffix struct {
Method string `toml:"method"`
Keys []string `toml:"keys"`
Separator string `toml:"separator"`
}
)
// DebugLogger logs messages from sarama at the debug level.
type DebugLogger struct {
}
func (*DebugLogger) Print(v ...interface{}) {
args := make([]interface{}, 0, len(v)+1)
args = append(args, "D! [sarama] ")
log.Print(v...)
}
func (*DebugLogger) Printf(format string, v ...interface{}) {
log.Printf("D! [sarama] "+format, v...)
}
func (*DebugLogger) Println(v ...interface{}) {
args := make([]interface{}, 0, len(v)+1)
args = append(args, "D! [sarama] ")
log.Println(args...)
}
var sampleConfig = `
## URLs of kafka brokers
brokers = ["localhost:9092"]
## Kafka topic for producer messages
topic = "telegraf"
## Optional Client id
# client_id = "Telegraf"
## Set the minimal supported Kafka version. Setting this enables the use of new
## Kafka features and APIs. Of particular interest, lz4 compression
## requires at least version 0.10.0.0.
## ex: version = "1.1.0"
# version = ""
## Optional topic suffix configuration.
## If the section is omitted, no suffix is used.
## Following topic suffix methods are supported:
## measurement - suffix equals to separator + measurement's name
## tags - suffix equals to separator + specified tags' values
## interleaved with separator
## Suffix equals to "_" + measurement name
# [outputs.kafka.topic_suffix]
# method = "measurement"
# separator = "_"
## Suffix equals to "__" + measurement's "foo" tag value.
## If there's no such a tag, suffix equals to an empty string
# [outputs.kafka.topic_suffix]
# method = "tags"
# keys = ["foo"]
# separator = "__"
## Suffix equals to "_" + measurement's "foo" and "bar"
## tag values, separated by "_". If there is no such tags,
## their values treated as empty strings.
# [outputs.kafka.topic_suffix]
# method = "tags"
# keys = ["foo", "bar"]
# separator = "_"
## Telegraf tag to use as a routing key
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## ie, if this tag exists, its value will be used as the routing key
routing_tag = "host"
## Static routing key. Used when no routing_tag is set or as a fallback
## when the tag specified in routing tag is not found. If set to "random",
## a random value will be generated for each message.
## ex: routing_key = "random"
## routing_key = "telegraf"
# routing_key = ""
## CompressionCodec represents the various compression codecs recognized by
## Kafka in messages.
## 0 : No compression
## 1 : Gzip compression
## 2 : Snappy compression
## 3 : LZ4 compression
# compression_codec = 0
## RequiredAcks is used in Produce Requests to tell the broker how many
## replica acknowledgements it must see before responding
## 0 : the producer never waits for an acknowledgement from the broker.
## This option provides the lowest latency but the weakest durability
## guarantees (some data will be lost when a server fails).
## 1 : the producer gets an acknowledgement after the leader replica has
## received the data. This option provides better durability as the
## client waits until the server acknowledges the request as successful
## (only messages that were written to the now-dead leader but not yet
## replicated will be lost).
## -1: the producer gets an acknowledgement after all in-sync replicas have
## received the data. This option provides the best durability, we
## guarantee that no messages will be lost as long as at least one in
## sync replica remains.
# required_acks = -1
## The maximum number of times to retry sending a metric before failing
## until the next flush.
# max_retry = 3
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## The maximum permitted size of a message. Should be set equal to or
## smaller than the broker's 'message.max.bytes'.
# max_message_bytes = 1000000
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## Optional TLS Config
# tls_ca = "/etc/telegraf/ca.pem"
# tls_cert = "/etc/telegraf/cert.pem"
# tls_key = "/etc/telegraf/key.pem"
## Use TLS but skip chain & host verification
# insecure_skip_verify = false
## Optional SASL Config
# sasl_username = "kafka"
# sasl_password = "secret"
## Data format to output.
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## Each data format has its own unique set of configuration options, read
## more about them here:
## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_OUTPUT.md
# data_format = "influx"
`
func ValidateTopicSuffixMethod(method string) error {
for _, validMethod := range ValidTopicSuffixMethods {
if method == validMethod {
return nil
}
}
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return fmt.Errorf("Unknown topic suffix method provided: %s", method)
}
func (k *Kafka) GetTopicName(metric telegraf.Metric) string {
var topicName string
switch k.TopicSuffix.Method {
case "measurement":
topicName = k.Topic + k.TopicSuffix.Separator + metric.Name()
case "tags":
var topicNameComponents []string
topicNameComponents = append(topicNameComponents, k.Topic)
for _, tag := range k.TopicSuffix.Keys {
tagValue := metric.Tags()[tag]
if tagValue != "" {
topicNameComponents = append(topicNameComponents, tagValue)
}
}
topicName = strings.Join(topicNameComponents, k.TopicSuffix.Separator)
default:
topicName = k.Topic
}
return topicName
}
func (k *Kafka) SetSerializer(serializer serializers.Serializer) {
k.serializer = serializer
}
func (k *Kafka) Connect() error {
err := ValidateTopicSuffixMethod(k.TopicSuffix.Method)
if err != nil {
return err
}
config := sarama.NewConfig()
if k.Version != "" {
version, err := sarama.ParseKafkaVersion(k.Version)
if err != nil {
return err
}
config.Version = version
}
if k.ClientID != "" {
config.ClientID = k.ClientID
} else {
config.ClientID = "Telegraf"
}
config.Producer.RequiredAcks = sarama.RequiredAcks(k.RequiredAcks)
config.Producer.Compression = sarama.CompressionCodec(k.CompressionCodec)
config.Producer.Retry.Max = k.MaxRetry
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config.Producer.Return.Successes = true
if k.MaxMessageBytes > 0 {
config.Producer.MaxMessageBytes = k.MaxMessageBytes
}
// Legacy support ssl config
if k.Certificate != "" {
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k.TLSCert = k.Certificate
k.TLSCA = k.CA
k.TLSKey = k.Key
}
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tlsConfig, err := k.ClientConfig.TLSConfig()
if err != nil {
return err
}
if tlsConfig != nil {
config.Net.TLS.Config = tlsConfig
config.Net.TLS.Enable = true
}
if k.SASLUsername != "" && k.SASLPassword != "" {
config.Net.SASL.User = k.SASLUsername
config.Net.SASL.Password = k.SASLPassword
config.Net.SASL.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) routingKey(metric telegraf.Metric) (string, error) {
if k.RoutingTag != "" {
key, ok := metric.GetTag(k.RoutingTag)
if ok {
return key, nil
}
}
if k.RoutingKey == "random" {
u, err := uuid.NewV4()
if err != nil {
return "", err
}
return u.String(), nil
}
return k.RoutingKey, nil
}
func (k *Kafka) Write(metrics []telegraf.Metric) error {
msgs := make([]*sarama.ProducerMessage, 0, len(metrics))
for _, metric := range metrics {
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buf, err := k.serializer.Serialize(metric)
if err != nil {
log.Printf("D! [outputs.kafka] Could not serialize metric: %v", err)
continue
}
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m := &sarama.ProducerMessage{
Topic: k.GetTopicName(metric),
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Value: sarama.ByteEncoder(buf),
}
key, err := k.routingKey(metric)
if err != nil {
return fmt.Errorf("could not generate routing key: %v", err)
}
if key != "" {
m.Key = sarama.StringEncoder(key)
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}
msgs = append(msgs, m)
}
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err := k.producer.SendMessages(msgs)
if err != nil {
// We could have many errors, return only the first encountered.
if errs, ok := err.(sarama.ProducerErrors); ok {
for _, prodErr := range errs {
if prodErr.Err == sarama.ErrMessageSizeTooLarge {
log.Printf("E! Error writing to output [kafka]: Message too large, consider increasing `max_message_bytes`; dropping batch")
return nil
}
return prodErr
}
}
return err
}
return nil
}
func init() {
sarama.Logger = &DebugLogger{}
outputs.Add("kafka", func() telegraf.Output {
return &Kafka{
MaxRetry: 3,
RequiredAcks: -1,
}
})
}