CODEWITHSUNDEEP
gorabbitmq
George
George

Reputation: 37

How can i consume a batches of messages from rabbitmq?

Before consuming i set

consumeChannel.Qos(5,0,false)

but still getting only one message, not a pack of five. what i'm doing wrong?

full code:

consumeChannel.Qos(5,0,false)
msgs, _ := consumeChannel.Consume("ticks", "", false, false, false, false, nil, )

for d := range msgs {
    println("Received a message: %s", d.Body)
    println("Done")
    //here will be some extra multiple message handling
    //d.Ack(false)
}

Upvotes: 1

Views: 1279

Answers (1)

Luke Bakken
Luke Bakken

Reputation: 9627

but still getting only one message, not a pack of five. what i'm doing wrong?

You don't understand how RabbitMQ and QoS / prefetch works (docs), or how it interacts with the range operator of the Go client.

QoS does not mean "send messages in batches", it sets a limit to the number of unacknowledged messages on a channel. If you were to remove the d.Ack call in your code and run the for loop indefinitely, it would only run for 5 iterations, then stop, because RabbitMQ would have stopped delivering messages by then to your consumer.

I haven't reviewed the code, but I assume the Go client you're using is written in such a way that, as soon as a message has been received and decoded, it is delivered to the msgs channel. When you ack the message in the loop, it indicates to RabbitMQ that one more message can be delivered to that channel.

I suggest re-writing your code to keep track of how many messages have been delivered via the msgs channel, do your work, and then use a multiple acknowledgement to ack them all at the same time.

Upvotes: 2

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