Azure AppFabric Queues and Topics
June 9, 2011 2 Comments
The code used in this demo refers to a depricated version of the Topics API. Please refer to this post for an example that is compatible with the 1.6 or 1.7 Windows Azure SDK’s.
First some old business…. NEVER assume you know what a SequenceNumber property indicates. More on this later. Secondly, thanks to Clemens Vasters and his colleague Kartik. You are both gentlemen and scholars!
Ok… back to the topic at hand. A few weeks ago, I was making plans to be in Seattle and reached out to Wade Wegner (Azure Architect Evangelist) to see if he was going to be around so we could get together and talk shop. Well he lets me know that he’s taking some well deserved time off. Jokingly, I tell him I’d fill in for him on the cloud cover show. Two hours later I get an email in my inbox saying it was all set up and I need to pick a topic to demo and come up with news and the “tip of the week”.. that’ll teach me!
So here I was with just a couple weeks to prepare (and even less time as I had a vacation of my own already planned in the middle of all this). Wade and I both always had a soft spot for the oft maligned Azure AppFabric, so I figured I’d dive in and revisit an old topic, the re-introduction of AppFabric Queues and the new feature, Topics.
Service Bus? Azure Storage Queues? AppFabric Queues?
So the first question I ran into was trying to explain the differences between these three items. To try and be succinct about it… The Service Bus is good for low latency situations where you want dedicated connections or TCP/IP tunnels. Problem is that this doesn’t scale well, so we’ll need a disconnected messaging model and we have a simple, fairly lightweight model for this with Azure Storage Queues.
Now the new AppFabric Queues are more what I would classify as an enterprise level queue mechanism. Unlike Storage Queues, AppFabric Queues can be bound too with WCF as well as a RESTful API and .NET client library. There’s also a roadmap showing that we may get the old Routers back and some message transformation functionality. As if this wasn’t enough, AppFabric Queues are supposed to have real FIFO delivery (unlike Storage Queues “best attempt” FIFO) and full ACS integration.
Sounds like some strong differentiators to me.
So what about the cloud cover show?
So everything went ok, we recorded the show this morning. I was having some technical challenges with the demo I had wanted to do (look for my original goal in the next couple weeks). But I got a demo that worked (mostly), some good news items, and even a tip of the day. All in all things went well.
Anyways… It’s likely you’re here because you watched the show so here is a link to the code for the demo we showed on the show. Please take it and feel free to use it. Just keep in mind its only demo code and don’t just plug it onto a production solution.
Being on the show was a great experience and I’d love to be back again some day. The Channel 9 crew was great to work with and really made me feel at ease. Hopefully if you have seen the episode, you enjoyed it as well.
My tip of the day
So as I mentioned when kicking off this update, never assume you know what a SequenceNumber indicates. In preparing my demo, I burned A LOT of my time and bugged the heck out of Clemens and Kartrik. All this because I incorrectly assumed that the SequenceNumber property of the BrokeredMessages I was pulling from my subscriptions was based on the original topic. If I was dealing with a queue, this would have been the case. Instead, it is based on the subscription. This may not mean much at the moment, but I’m going to be put together a couple posts on Topics in the next couple weeks that will bring it into better context. So tune back in later when I build the demo I originally wanted to demo on Cloud Cover.
PS – If you are ever asked to appear on an episode of the Cloud Cover show, it is recommended you not wear white or stripes. FYI…