How can I observe what's happening under the hood of ActiveMQ? - activemq

I'm experiencing an issue with ActiveMQ and would like to trace/view all ActiveMQ activity. The only log file I can find is one associated with persistent data (if this is turned on). Are there any other log files I view or generate to tell me what's happening under the hood of ActiveMQ and why my consumers aren't consuming messages? Any other suggestions?
Thanks in advance!

activemq has a jmx interface that you can connect to.
this gives us access to consumer counts messages queued dequeue and all sorts of data on memory usage etc.
http://activemq.apache.org/jmx.html
Has all the details to get you started.
I find it excellent in finding out whats going on with activemq.
A quick firing up of jconsole and you will be well on your way to finding out what is going on.
Paul

Agreed. Also you can add the logging interceptor which helps.
Finally for browsing messages, moving them, creating/deleting queues and sending message I highly recommend the new web console for ActiveMQ, Camel and many other plugins: hawtio

Try HawtIO. Assuming you are not using Active MQ 5.9 you can add this feature to your broker. It is a much better web console and a good JMX monitoring utility as well.
http://www.christianposta.com/blog/?p=315

Related

Rabbit MQ fault tolerance

I have a project where we are using Rabbit MQ has message broker, I have below concern, please help on the same.
If Rabbit MQ goes down, how we can retrieve the queued message.is there any configuration in rabbit MQ?
Can we implement same in java thread and collection combination, that can be used as alternative to rabbit MQ? if yes help with an example.
'You should listen to ShutdownListenercallback on both Connection and Channelclasses'. By this way, you know if the queue is down. After that, you need to re-transmit your queued messages. This is what official documentations says. https://www.rabbitmq.com/reliability.html
Of course you can implement your own library, but you have to think if this would be better for you. I suggest you not to do that. RabbitMQ is a well-known open source library that many people use and trust for years. I think there is no side-effect using that in any project.
Deploy RabbitMQ on Kubernetes with stateful sets. This will replicate state in multiple instances. One of them will be primary. Failover will be handled by Kubernetes.
See https://kublr.com/blog/reliable-fault-tolerant-messaging-rabbitmq-kublr/

Can any queuing system trigger external Applications

Right now we have a queuing system(activemq) which is storing the messages. And we have written a separate java application that will read the queue and then trigger a exe to do some processing. But we want to do away with this extra application that is linking our activemq and exe. So i want to know whether any queuing system houses a code which will help me run the exe without any extra code written by me.
Any inputs regarding which queuing system can get me this done will be greatly appreciated.
This isn't really how Message Brokers work. You could however embed a broker inside your own application or create a broker plugin to do something. In the end though the best way to do this is to create your own client that can implement your business logic and let the Message Broker do what it was designed to do, route message traffic.
If you want more of a 'push' solution rather than a producer-consumer solution (which sounds to me like you are) you could look into the use of WebSockets. That would be another way of dealing with messages.
As others have said it doesn't look like using a message broker is the solution you want if you don't want to have some additional middleware to provide asynchronous communication.
So you just need something to launch an EXE on message arrival?
Message Queuing Triggers
Just some additional information for you... Triggered applications are natively supported in IBM Websphere MQ via a Trigger Monitor application that runs as a service (in windows implementations) or a daemon (in UNixish implementations).
When a message arrives in a queue, the MQ software will generate another message ("Trigger" message and send it to the "Trigger" queue, which is being monitored by the Trigger Manager app. The app then starts the required application.
So your implementation of an "app to start an app" is not odd ball or strange at all.. IBM do it in their implementation. I see nothing wrong with your implementation and if you can integrate it tighter to activeMQ then you are on a winner.
What about IBM MQ's triggering feature ?
WebSphere MQ provides a feature that enables an application or channel to be started automatically when there are messages available to retrieve from a queue. A message is put to a queue defined as triggered. If a series of conditions are met, the queue manager sends a trigger message to an initiation queue.
https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_9.0.0/com.ibm.mq.dev.doc/q026940_.htm

message deleted from queue

I have used BlockingQueue implementation to process my events by services from a queue. However in case if the server goes down, all my events from that queue are getting deleted and hence I am missing events to process. (I am looking for some internal DB where server can store the event/messages from queue and if server goes down and up again, it can load all events/messages to process again, without manually intervention).
Any help on this. I am not sure if I should use Apache ActiveMQ. I am using apache servicemix.
Thanks in advance.
I can not answer about how to do this with BlockingQueue.
But ActiveMQ has two features that you will benefit from:
Persistent Queues and possibly you might also want to look at Durable Queues
It has a built in database that just does this under the hood and allows messages to be persisted in queue even if broker or consumer has to restart.

Using Camel to transparently log messages from queue

I have a legacy application running on Glassfish which I have just recently configured to use activemq rather than openMQ. My activemq broker is running in a separate process outside of glassfish. I was thinking it would be nice to configure a camel route that logs messages as they are sent to the queue. I want to do something like this
from("activemq:myqueue")
.to("activemq:myqueue")
.wireTap("direct:tap")
.to("log:myqueue");
I don't think that makes sense though. What I want to happen is for camel to log the message transparently to the consumer. I don't want to have to change code so that the producer sends to an "inbound" queue and the consumer receives from an "outbound" queue and camel hooks them up, since that would require changes to the legacy app. I don't think this is possible, but just wondering.
Yeah I was about to suggest looking for a broker solution as it would be the most optimized and performant. Obvious monitoring the message flow in the broker is a common requirement and thus ActiveMQ has features for that:
http://activemq.apache.org/mirrored-queues.html
I think I just found out how I can do what I want with mirrored Queues:
http://activemq.apache.org/mirrored-queues.html
This is a change to the broker, and not purely done in camel.

What is the best alternative way of monitoring apache Active MQ other than using JMX API

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