I am totally new to spring framework. I am trying to create a project where I can have the connectivity to the rabbitMq and I even before I publish the message, I want to check if the queues are alive or not. Is this possible to ping the queue to see if it is alive or not?
RabbitMQ have the management API. You can use it to check the status of queue,exchange,binding.
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This is a follow-up question of How to implement HTTP request/reply when the response comes from a rabbitMQ reply queue using Spring Integration DSL?.
We were able to build the Spring Integration application and the SCDF stream successfully locally. We could send a http request to the rabbitMQ request queue which was bound to the SCDF stream rabbit source. We could also receive the response back from the rabbitMQ response queue which was bound to the SCDF stream rabbit sink.
We have deployed the SCDF stream into PCF environment which had a binding of an internal rabbitMQ broker. Now we need to specify the spring rabbitMQ connection information in the Spring Integration application properties - currently it's using the default localhost#5762, which is no longer valid. Does anyone know how to get this rabbitMQ configuration properties? We already checked the SCDF stream rabbit source/sink log files but couldn't find the information. I know we probably need to check internally whoever set up the SCDF/rabbitMQ in PCF environment, but so far we haven't heard the answers from them.
Also, it appears we can have a different approach that binds both the SCDF stream and the integration application to a separate rabbitMQ instance (instead of using the existing one bundled with the SCDF configuration). Is it a recommended solution?
Thanks,
It is unclear whether you're using the SCDF tile or the SCDF OSS (via manfest.yml) on PCF.
Suppose you're using the OSS, AFA. In that case, you are providing the right RMQ service-instance configuration (that you pre-created) in the manifest.yml, then SCDF would automatically propagate that RMQ service instance and bind it to the apps it is deploying to your ORG/Space. You don't need to muck around with connection credentials manually.
On the other hand, if you are using the SCDF Tile, the SCDF service broker will auto-create the RMQ SI and automatically bind it to the apps it deploys.
In summary, there's no reason to manually pass the connection credentials or pack them as application properties inside your apps. You can automate all this provided you're configuring all this correctly.
I'm looking to use a message queue system for an ongoing project, which now is relying on a custom (and brittle) message subsystem to interconnect multiple applications. Both the pub/sub and queue patterns are heavily used in my system.
Apache Apollo is one of the message queue systems I'm taking into account, but I don't find information about how can I handle (for instance) an Apollo server failure.
Is there a way to provide failover support in Apollo?
No, as of now this has not been resolved. Apollo is a very good broker, indeed, but lacks some production critical features like fail over. Apollo was an attempt to make a core for the next generation of ActiveMQ. However, the development is no loger active.
Have you considered other brokers like Apache Artemis? It's basically a new attempt to remake ActiveMQ with code from HornetQ, ActiveMQ and Apollo. Development is very active at the moment and there is support for fail over etc.
I have a Java API on my server, and I want it to create tasks and add them to Celery via RabbitMQ. I followed the following tutorial, http://www.rabbitmq.com/tutorials/tutorial-two-python.html, where I used java for the client (send.java) and python to receive (receive.py). In receive.py, where the callback method is invoked, I call a method that I've annotated with #celery.task so that the task is added to celery.
I'm wondering how all of this is deployed on a server though, specifically, why there is a receive.py file. Is receive.py a process that must continually run on the server? Is there a way to configure RabbitMQ so that it automatically routes java client tasks to celery?
Thanks!
RabbitMQ is just a message queue. Producers put messages and consumers get them on demand. You can only restrict access for specific queues via RabbitMQ's auth options.
As for deployment: yes, receive.py needs to continuously run. It is Celery's job to do that. See the Workers Guide for info on running a worker.
What is the best way to combine a single instance WCF service that uses ActiveMQ and runs within IIS/AppFabric?
Our Services need to support both HTTP transports and ActiveMQ (listening and sending messages). We've elected not to use MSMQ, and will use Spring.Net.NMS. The fundamental issue I have now is that ActiveMQ needs to connect to the queue(s) at startup and remain connected, but WAS is getting in the way with it's message-activation feature. If the service is not activated until a message arrives (HTTP/MSMQ, etc) then there is no trigger to have the connection to AMQ occur.
I know I can disable the recycling behavior, and I know I can do self-hosting with a Windows Service. But I want to take advantage of the monitoring and other features in AppFabric. I've already been down the route with IServiceBehavior and will use that for other nice things. But that interface is not called until a (non-AMQ) message arrives. So it won't work for this. What I was hoping for was something along the line of how ServletContextListeners work in Java, where you get both the start up and shutdown events. But it seems no such thing exists in WAS... it is driven only by messages arriving.
I've scoured every inch of web info for 3 days and the only thing I came across was to use a static class construction (C#) trick as the trigger. That's a hack, but i can live with it. It still leaves the issue of cleanly shutting down, which I can figure out later.
Anyone have a solid solution to this?
The direct WCF support for ActiveMQ that Ladislav mentions is still being supported. There just hasn't been an official release for the module in a while. However, you can still get the latest version of it from the 1.5.x branch or trunk and compile it yourself.
1.5.x branch for use with Apache.NMS 1.5.0:
https://svn.apache.org/repos/asf/activemq/activemq-dotnet/Apache.NMS.WCF/branches/1.5.x/
Check out instructions:
http://activemq.apache.org/nms/source.html
There was direct WCF support for ActiveMQ but I guess it is not developed anymore. Your problem actually is the IIS / WAS (provides hosting for non-http protocols) hosting architecture. Services in WAS are always activated when message arrives - there is no global startup. The reason for this is that WAS hosting expects that there is separate process (windows service) running the listener all the time and this process has adapter which calls WAS and uses message level activation. I guess you don't have such process for ActiveMQ and because of that you will have trouble to use ActiveMQ endpoint hosted in WAS. Developing such listener can be challenging task (example for UDP).
Creating custom listener can be probably avoided by using IIS 7.5 / AppFabric auto start feature. There is also not very well documented way to run the code when the application starts.
Well i am intending to implement a paired connection between server and client , as of now i have sent chunk of data and code to the slave system using rabbitMq and the slave system executes it . But i am unable to again send back the code to server , since rabbitMq has the classic implementation of Publisher / subscriber model . Is there any way to go around this and ensure that the server also fetches result from the slave systems ? i am using python bindings for rabbitMQ .
You can easily simulate RPC semantics with RabbitMQ (or indeed, any messaging system). All you need is a form of correlation identifier so that the response message can be tracked and interpreted as the "answer" for the original request.
Luckily, the RabbitMQ online documentation has an entire page with examples on how to do this using Python.