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.
Related
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 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.
I've got a webservice that accepts messages that can be sent to a RabbitMQ cluster using whatever queue they define. This is so front-end devs can send messages via javascript.
I want to make the webservice more robust so that when we have network trouble, the webservice can still accept messages and then handle them when the network is back up. After some initial reading, it seems that the Shovel plugin should handle this nicely.
What I was thinking was to install a local instance of RabbitMQ on the webservice box with shovel turned on. I can then send all messages through the local RabbitMQ instance and have it push all messages to the cluster and deal with the network problems.
My problem is after looking at the documentation it seems that I have to configure every queue I want to forward to in the shovel config file. If that's the case I'm not sure this will work since we allow clients to define a queue through the webservice on the fly.
I would like to have the webservice take the messages, hand them off to the local rmq instance and have it pass the messages off to the cluster using the same queues/exachanges/etc.
Has anyone tried this or can explain how the shovel plugin works?
Have you considered sending messages to an exchange instead of a queue. Send all messages to one exchange possibly a topic exchange if you need that kind of flexibility. Then have the consumer handle the different messages or different queues from the exchange. Sending to one exchange would make configuring the shovel considerably easier.
Can I access SEDA or VM queue from another machine or JVM?
I actually want to implement load balancing with the help of Camel but do not want introduce another messaging framework for this. I just want to distribute load to different consumers from a producers using some in built queue.
Is it possible? If no then what are my options?
Another Approach:(Pull Approach)
Not sure how optimum new approach is or what are the advantages and disadvantages of new approach, So please help me to analyze this approach.
Messages will be put into a Master queue and all the worker systems will be listening to Master queue.Let's say 100,000 messages are being put into Master queue and 5 worker systems are listening to it. Worker systems will process the messages one by one from the master queue. There are two big benefits with this approach:
I don't need to worry about registering my worker systems with the producer. Sixth system just boot up and start listening to Master queue.
I don't need to worry about sending message to a consumer system which is free. When worker system will be done processing a message, it pick up another one from the Master queue.
Let me know your thoughts on it.
SEDA and VM:// work only on the same JVM.
Load balancing in Java messaging is usually achieved using the JMS and Competing Consumers pattern. You send messages to the queue and multiple consumers compete to process them.
If broker with its queue becomes a bottleneck - consider using fan-out pattern and the network of brokers.
SEDA and VM endpoints are valid for the host Context and JVM respectively. To facilitate JVM-to-JVM messaging you will need to use an over-the-wire protocol component such as, but not limited to, Mina, HTTP or JMS.
The easiest way is to use jms. If you have n routes listening on the same jms queue then they will automatically load balance. If one goes away the load will be balanced over the remaining ones. I recommend starting with ActiveMQ as it is very easy to setup and well integrated with Camel.To make the broker highly available you can either setup two standalone brokers or setup one embedded broker per camel instance.
I'm currently in the middle of developing a webapplication which needs a websocket connection to receive notifications of events from the server.
The clients are separated in groups and all the clients in a group must receive the same event notifications.
I thought that ActiveMQ could probably support this model, using different queues for each group of clients. It would also be relatively easy to push events to ActiveMQ using stomp, and then use stomp-over-websockets for the clients.
The problem I see is that messages should not be consumed by only one client, but distributed to all the clients connected to the queue.
Also the queue should not be stored. If a client is not connected when the event is generated, then it will never receive it.
I don't know ActiveMQ that much, so I'm not sure if this is possible or if there is another easy solution that could be used instead of writing my own message server.
Thanks
ActiveMQ 5.4.1 supports WebSockets natively (just like Stomp, JMS, etc.).
There is the concept of queues (you mentioned these), but also of topics.
In a queue, a single message will be received by exactly one consumer, in a topic
it goes to all the subscribers. See: http://activemq.apache.org/how-does-a-queue-compare-to-a-topic.html
There are some Stomp-WebSocket JS libraries floating around. Kaazing has a bundle that includes ActiveMQ and supports JMS API/Stomp protocol over WebSockets with support for older browsers, different client technologies, and Cross-Site security.
Look at Pusher, otherwise you'll need something that supports topic based pub/sub. You could look at Redis or RabbitMQ