can I create queue dynamically using RabbitMQ?
In my application, I want the queues to scale up dynamically whenever the queue is full.can I do that with RabbitMQ?
Thanks in advance.
You can't create a dynamic queue but you can create a fixed size one, then monitorize it and scale up when it is getting full.
You can change the size at runtime via a policy in the RabbitMQ server through the management plugin's HTTP API.
Here it is a example of how to change the queue size parameter: https://www.rabbitmq.com/maxlength.html.
And here how you can change it at runtime via a policy: https://www.rabbitmq.com/parameters.html.
The monitoring task is also done via management plugin's HTTP API. Here some help: https://stackoverflow.com/a/24408669/8041414
I hope this helps you
Related
Is it possible to make a queue non durable in rabbitMq management portal or via the command line tool ?
If queue or exchange was once declared you can't change it parameters. Not via management plugin nor via CLI nor via API or else. If you want to have queue or exchange with the same name but different parameters, you have to delete existent one and then create new with desired parameters (don't forget to bind queue if you do that).
Note, that policies differs from parameters and they can be added, changed and deleted on existent queues and exchanges on-the-fly.
Also note, if you will delete and then create queue and/or exchanges, there are some chance to lost messages. For more details see RabbitMQ change queue parameters on a production system and Toggle routing in Rabbit MQ questions on SO.
We have a use case where we would like to get a certain messages in a queue distributed into other queues after we browse the queue and get the message properties. Can that be done with JMS API for hornetq or should we use a JMX client as that seems to be a possible operation in jvisualvm?
I don't know if I understand You correctly but if You would like to copy from one queue to another only filtered messages You can use bridge.
http://docs.jboss.org/hornetq/2.3.0.CR2/docs/user-manual/html/core-bridges.html
In bridge configuration You can define which messages should be copied from one queue to another
It seems that org.hornetq.api.jms.management.JMSQueueControl from the HornetQ Management API will do the trick. I was hoping for some generic JMS API that would allow that as well but this will work.
I am running a performance test using JMeter for our application and the there is some asynchronous processing in the form of events on an ActiveMQ queue. I want to wait for the ActiveMQ queue to be empty before recording the statistics for my test. Is there a good way to do that?
I have explored the JMS Producer/Consumers in JMeter 2.10 but they consume messages off the queue which is not what I want as it modifies the original flow of the application. Is there a way to monitor the draining of the queue without consuming the messages of ActiveMQ?
I am using ActiveMQ 5.8 and JMeter 2.10
I was able to monitor ActiveMQ using the HTTP Request to poll the ActiveMQ web console and get the state of all the queues in XML format. After that I used XPATH to extract the size of the queue I was interested in. The snapshots below show the configuration which I was finally able to use. The XPATH expression which I used was
/queues/queue[#name='${queueName}']/stats/#size
One additional thing which I has to do was to setup basic HTTP authentication to be able to connect to the ActiveMQ web console.
The MBean solution by Mahesh should also work if JMX is enabled on the server but it is not enabled by default.
I have documented it in detail here
You can get the pending messages in that queue using the MBean
"org.apache.activemq:BrokerName=host1,Type=Queue,Destination=dest1"
attribute: "QueueSize"
After checking once every few seconds and the value being not more than zero, you can start recording the statistics.
You can create a simple Java class that consumes all messages from the queue. JMeter can run it before tests.
I read in ActiveMQ page, using JMX we can monitor queues in activemq. How can we get notified if a queue has messages (depth high) or service interval is high in ActiveMQ. Without using any shell scripts in unix environment. Is it possible through Java program? If yes, give me some ideas to get this done.
For a JMX-free approach, you can also use the XML feed served by the activemq console page. The XML feed is hosted at http://ip:port/admin/xml/queues.jsp
This will have tags similar to this for each queue:
<queue name="your queue">
<stats size="0" consumerCount="1" enqueueCount="0" dequeueCount="0"/>
....
</queue>
Just parse this XML in your code and you are good to go.
you can use Java via JMX APIs to periodically poll for queue stats (see this guide)
for the notification approach, you'd need to use advisory messages to monitor messages delivered to a queue (see this guide)
Yes it is possible in Java.
Starting from version 5.8 of ActiveMQ jolokia agent comes embedded. So it is possible for you to get all stats that JMX can pull using HTTP request which will retuen you stats as JSON and then you can check current values and raise Email alert using SMTP if values go beyond threshold you have decided.
Lets say you want to pull Broker stats using Jolokia hit below URL in your browser enter AMQ console username and password which is admin by default
http://servername.com:8161/api/jolokia/read/org.apache.activemq:type=Broker,brokerName=localhost
Or if you dont want to go through all this trouble , You can use ready made Python script which I have created to Monitor AMQ Heap, Queue params and Broker availability.You can take a look , it may help you in developing your custiom script or program
AMQMonitor and Alerting script
I have tried and tested the JMX API and it is pretty simple to use and provides a vast number of statistics required for monitoring ActiveMQ.
But the problem is, i dont want to monitor my ActiveMQ remotely and also i dont want to use another API.To be more precise, i want to use the JMS API itself to get statistics related to various destinations and the broker itself.
Advisory messages seem to be an alternative but they provide limited Amount of Administrative Messages to monitor.
Any input is highly appreciated...
There is no built-in support for this. But you can implement a JMS topic which publishes the monitoring data every few seconds. Make the connection non-persistent so that it doesn't pile up when there are no listeners or when they loose connection.
Now you can write a client that connects to this topic and it will receive updates.
AMQ-2379 resulted in a broker plugin for grabbing statistics from destinations by sending a simple JMS message. Check out the docs that show how to use it here:
http://activemq.apache.org/statisticsplugin.html
The statistics plugin is available in the 5.3 release.
You can checkout this http://issues.apache.org/activemq/browse/AMQ-2379, it will be avaiable in upcoming 5.3.0 release
There's a blog post queued up to go on http://issues.apache.org/activemq/browse/AMQ-2379 - will post it in a couple of days or so