I use https://github.com/Shopify/sarama for interaction with Kafka. I have a topic with, for example, 100 partitions. I have application, which is deployed on 1 host. So, I want to consume from this topic in multiple goroutines.
I see this example - https://github.com/Shopify/sarama/blob/master/examples/consumergroup/main.go , in which we can see, how to create consumer in specific consumer group.
So, my question is, should I create multiply such consumers, or there is some setting in Sarama
, where I can set up needed number of consumer goroutines.
P.S. I see this question - https://github.com/Shopify/sarama/issues/140 - but there is no answer, how to create MultiConsumer
.
This example shows a fully working console application which can consume for all partitions in a topic creating one goroutine per partition:
https://github.com/Shopify/sarama/blob/master/tools/kafka-console-consumer/kafka-console-consumer.go
It is linked at the end of the thread you posted in your question.
It basically creates one consumer:
c, err := sarama.NewConsumer(strings.Split(*brokerList, ","), config)
Then gets all the partitions for the desired topic:
func getPartitions(c sarama.Consumer) ([]int32, error) {
if *partitions == "all" {
return c.Partitions(*topic)
}
...
Then for each partition it creates a PartitionConsumer and consumes from each partition in a different goroutine:
for _, partition := range partitionList {
pc, err := c.ConsumePartition(*topic, partition, initialOffset)
....
wg.Add(1)
go func(pc sarama.PartitionConsumer) {
defer wg.Done()
for message := range pc.Messages() {
messages <- message
}
}(pc)
}