/
consumer.go
159 lines (140 loc) · 3.68 KB
/
consumer.go
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package main
import "C"
import (
"encoding/json"
"fmt"
"github.com/confluentinc/confluent-kafka-go/kafka"
log "github.com/sirupsen/logrus"
"math"
"sync"
"time"
)
type Consumer struct {
consumer *kafka.Consumer
exitWaitGroup *sync.WaitGroup
rebalanceWaitGroup *sync.WaitGroup
quit chan struct{}
watcher *StateWatcher
fetcher TokenFetcher
}
func NewConsumer(conf *kafka.ConfigMap, watcher *StateWatcher, fetcher TokenFetcher) (*Consumer, error) {
var exitWaitGroup sync.WaitGroup
var rebalanceWaitGroup sync.WaitGroup
kafkaConsumer, err := kafka.NewConsumer(conf)
if err != nil {
return nil, err
}
return &Consumer{
consumer: kafkaConsumer,
exitWaitGroup: &exitWaitGroup,
rebalanceWaitGroup: &rebalanceWaitGroup,
quit: make(chan struct{}),
watcher: watcher,
fetcher: fetcher,
}, nil
}
func (c *Consumer) callback(_ *kafka.Consumer, event kafka.Event) error {
log.Debugf("called callback: %v", event)
switch event.(type) {
case kafka.AssignedPartitions:
c.rebalanceWaitGroup.Done()
default:
log.Debugf("Got event from events consumer: %s", event)
}
return nil
}
// This method blocks until the consumer group has rebalanced
func (c *Consumer) subscribeAndConsume(topic string) error {
c.rebalanceWaitGroup.Add(1)
c.exitWaitGroup.Add(1)
log.Infof("Subscribing to topic '%s'", topic)
err := c.consumer.SubscribeTopics([]string{topic}, c.callback)
if err != nil {
return err
}
go c.consume()
c.rebalanceWaitGroup.Wait()
log.Infof("Successfully joined the consumer group")
return nil
}
func (c *Consumer) consume() {
// Process messages
for true {
select {
case <-c.quit:
c.exitWaitGroup.Done()
return
default:
ev, err := ReadMessage(time.Second, c.consumer, c.fetcher)
if err != nil {
if err.(kafka.Error).Code() != kafka.ErrTimedOut {
log.Debugf("Informal error, apparently: %v", err.(kafka.Error).Code())
}
// Errors are informational and automatically handled by the consumer
continue
}
var msg message
err = json.Unmarshal(ev.Value, &msg)
if err != nil {
log.Errorf("Failed to parse message from '%s': %v", string(ev.Value), err)
}
c.watcher.received(msg.Sequence)
}
}
}
// ReadMessage is a copy of the upstream version to experiment with
func ReadMessage(timeout time.Duration, c *kafka.Consumer, fetcher TokenFetcher) (*kafka.Message, error) {
var absTimeout time.Time
var timeoutMs int
if timeout > 0 {
absTimeout = time.Now().Add(timeout)
timeoutMs = (int)(timeout.Seconds() * 1000.0)
} else {
timeoutMs = (int)(timeout)
}
for {
ev := c.Poll(timeoutMs)
switch e := ev.(type) {
case *kafka.Message:
if e.TopicPartition.Error != nil {
return e, e.TopicPartition.Error
}
return e, nil
case kafka.Error:
return nil, e
case kafka.OAuthBearerTokenRefresh:
if fetcher == nil {
return nil, fmt.Errorf("got token request but token fetcher is missing")
}
log.Infof("Providing token")
token, err := fetcher.Fetch()
if err != nil {
log.Warnf("Failed to fetch token: %v", err)
err = c.SetOAuthBearerTokenFailure(err.Error())
if err != nil {
return nil, err
}
}
err = c.SetOAuthBearerToken(*token)
if err != nil {
return nil, err
}
default:
if e != nil {
log.Debugf("Got message: %v", e)
}
}
if timeout > 0 {
// Calculate remaining time
timeoutMs = int(math.Max(0.0, absTimeout.Sub(time.Now()).Seconds()*1000.0))
}
if timeoutMs == 0 && ev == nil {
return nil, kafka.NewError(kafka.ErrTimedOut, "", false)
}
}
}
func (c *Consumer) Stop() error {
close(c.quit)
c.exitWaitGroup.Wait()
return c.consumer.Close()
}