Need Artemis Notification when the number of messages in the Queue are > 100

Question

We already have Apache ActiveMQ Artemis setup in place. A new requirement demands that we need a Artemis Notification ONLY when the number of messages in the queue are above 100. I have seen Notification Messages, but they all are on operations (like Queue creation, deletion, security violation, etc..) but not on a condition. How can I achieve this?

Answer 1

There's nothing within ActiveMQ Artemis itself that could directly send notifications when a queue's message count exceeds a configured size.

Typically in this kind of situation you'd have an external tool to monitor the broker and send notifications based on whatever metrics and thresholds you cared about.

For example, you could configure the Prometheus metrics plugin to expose metrics from the broker and then use Prometheus alerting or you could go a step further and integrate with Grafana and use its alerting.

If you wanted a simpler solution you could just write a Java application or a script that polled the broker via JMX or HTTP and then sent alerts as needed. You can find an example Java application that uses JMX for management operations in the broker's examples/features/standard/jmx directory. If you want to use HTTP you can use a command like curl to invoke management methods on the broker's MBeans. You just need to feed it the MBean's "object name." The "object name" for a queue on the broker follows this pattern:

org.apache.activemq.artemis:broker="<brokerName>",component=addresses,address="<addressName>",subcomponent=queues,routing-type="<routingType>",queue="<queueName>"

Of course, you'll need to replace <brokerName>, <addressName>, <routingType>, and <queueName> with the proper values for your configuration.

Here's a simple example that reads the MessageCount attribute for the queue foo:

curl -k --user admin:admin -H "Origin: http://localhost:8161" "http://localhost:8161/console/jolokia/read/org.apache.activemq.artemis:broker=%220.0.0.0%22,component=addresses,address=%22foo%22,subcomponent=queues,routing-type=%22anycast%22,queue=%22foo%22/MessageCount"

Note that the " characters have been escaped with %22 to allow for proper execution in a shell.