Documentation
¶
Overview ¶
Package kafka provides functions to trace the confluentinc/confluent-kafka-go package (https://github.com/confluentinc/confluent-kafka-go).
Example ¶
This example shows how a span context can be passed from a producer to a consumer.
// Unless explicitly stated otherwise all files in this repository are licensed
// under the Apache License Version 2.0.
// This product includes software developed at Datadog (https://www.datadoghq.com/).
// Copyright 2016 Datadog, Inc.
package main
import (
"fmt"
kafkatrace "gopkg.in/DataDog/dd-trace-go.v1/contrib/confluentinc/confluent-kafka-go/kafka.v2"
"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
"github.com/confluentinc/confluent-kafka-go/v2/kafka"
)
var (
testGroupID = "gotest"
testTopic = "gotest"
)
// This example shows how a span context can be passed from a producer to a consumer.
func main() {
tracer.Start()
defer tracer.Stop()
c, err := kafkatrace.NewConsumer(&kafka.ConfigMap{
"go.events.channel.enable": true, // required for the events channel to be turned on
"group.id": testGroupID,
"socket.timeout.ms": 10,
"session.timeout.ms": 10,
"enable.auto.offset.store": false,
})
err = c.Subscribe(testTopic, nil)
if err != nil {
panic(err)
}
// Create the span to be passed
parentSpan := tracer.StartSpan("test_parent_span")
// Produce a message with a span
go func() {
msg := &kafka.Message{
TopicPartition: kafka.TopicPartition{
Topic: &testTopic,
Partition: 1,
Offset: 1,
},
Key: []byte("key1"),
Value: []byte("value1"),
}
// Inject the span context in the message to be produced
carrier := kafkatrace.NewMessageCarrier(msg)
tracer.Inject(parentSpan.Context(), carrier)
c.Consumer.Events() <- msg
}()
msg := (<-c.Events()).(*kafka.Message)
// Extract the context from the message
carrier := kafkatrace.NewMessageCarrier(msg)
spanContext, err := tracer.Extract(carrier)
if err != nil {
panic(err)
}
parentContext := parentSpan.Context()
// Validate that the context passed is the context sent via the message
if spanContext.TraceID() == parentContext.TraceID() {
fmt.Println("Span context passed sucessfully from producer to consumer")
} else {
fmt.Println("Span context not passed")
}
c.Close()
// wait for the events channel to be closed
<-c.Events()
}
Output: Span context passed sucessfully from producer to consumer
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Consumer ¶
A Consumer wraps a kafka.Consumer.
func NewConsumer ¶
NewConsumer calls kafka.NewConsumer and wraps the resulting Consumer.
func WrapConsumer ¶
WrapConsumer wraps a kafka.Consumer so that any consumed events are traced.
func (*Consumer) Close ¶
Close calls the underlying Consumer.Close and if polling is enabled, finishes any remaining span.
func (*Consumer) Events ¶
Events returns the kafka Events channel (if enabled). Message events will be traced.
type MessageCarrier ¶
type MessageCarrier struct {
// contains filtered or unexported fields
}
A MessageCarrier injects and extracts traces from a sarama.ProducerMessage.
func NewMessageCarrier ¶
func NewMessageCarrier(msg *kafka.Message) MessageCarrier
NewMessageCarrier creates a new MessageCarrier.
func (MessageCarrier) ForeachKey ¶
func (c MessageCarrier) ForeachKey(handler func(key, val string) error) error
ForeachKey iterates over every header.
type Option ¶
type Option func(cfg *config)
An Option customizes the config.
func WithAnalytics ¶
WithAnalytics enables Trace Analytics for all started spans.
func WithAnalyticsRate ¶
WithAnalyticsRate sets the sampling rate for Trace Analytics events correlated to started spans.
func WithConfig ¶
WithConfig extracts the config information for the client to be tagged
func WithContext ¶
WithContext sets the config context to ctx. Deprecated: This is deprecated in favor of passing the context via the message headers
func WithCustomTag ¶
WithCustomTag will cause the given tagFn to be evaluated after executing a query and attach the result to the span tagged by the key.
func WithServiceName ¶
WithServiceName sets the config service name to serviceName.
type Producer ¶
A Producer wraps a kafka.Producer.
func NewProducer ¶
NewProducer calls kafka.NewProducer and wraps the resulting Producer.
func WrapProducer ¶
WrapProducer wraps a kafka.Producer so requests are traced.
func (*Producer) Close ¶
func (p *Producer) Close()
Close calls the underlying Producer.Close and also closes the internal wrapping producer channel.
func (*Producer) ProduceChannel ¶
ProduceChannel returns a channel which can receive kafka Messages and will send them to the underlying producer channel.
Source Files