Retrying messages at some point in the future (ActiveMQ)

Question

I\'m working on a system in ActiveMQ where I would really prefer not to lose messages. My problem is that retrying messages is causing my consumers to block (instead of working

Answer 1

Camel can definitely help with this...

One way is to use a separate queue and periodically retry messages separately from the main flow (especially when performance is a concern). Also, this provides a separate queue to allow you to triage those error messages (view, clear, alter, manually retry, etc)...

something like this...see polling consumer for more details

//main route to process message from a queue (needs to be fast)
from("activemq:queue:mainQ").process(...);

//handle any errors by simply moving them to an error queue (for retry later)
onException(Exception.class)
    .handled(true).to("activemq:queue:mainErrorQ");

//retry the error queue
from("timer://retryTimer?fixedRate=true&period=60000")
    .bean(myBean, "retryErrors"); 

...

public void retryErrors() {
    // loop to empty queue
    while (true) {
        // receive the message from the queue, wait at most 3 sec
        Exchange msg = consumer.receive("activemq:queue.mainErrorQ", 3000);
        if (msg == null) {
            // no more messages in queue
            break;
        }

        // send it to the starting queue
        producer.send("activemq:queue.mainQ", msg);
    }
}   

If you land on a better solution, let me know...good luck

Answer 2

ActiveMQ trunk now has support for broker based redelivery https://issues.apache.org/jira/browse/AMQ-3894