Hi
Finally got around to playing with this.
I am clearly doing somethign wrong, as no matter how I configure
things, each instance of the consumer get the same message so I just
end up doing the same work multiple times.
I have a console app "Distributor", this starts a bus and a
loadbalancer with the following config:
<facilities>
<facility id="rhino.esb" >
<bus threadCount="1"
numberOfRetries="5"
loadBalancerEndpoint="msmq://localhost/ESBTests.balancer"
endpoint="msmq://localhost/ESBTests.queue"
/>
<messages>
</messages>
</facility>
<facility id="rhino.esb.loadbalancer" >
<loadBalancer threadCount="1"
endpoint="msmq://localhost/ESBTests.balancer"
/>
</facility>
</facilities>
</castle>
The distributor will send a message to the bus every time you press a
key like so:
var container = new WindsorContainer(new
XmlInterpreter());
container.Kernel.AddFacility("rhino.esb", new
RhinoServiceBusFacility());
var container2 = new WindsorContainer(new
XmlInterpreter());
container2.Kernel.AddFacility("rhino.esb.loadbalancer",
new LoadBalancerFacility());
using (var loadBalancer =
container2.Resolve<MsmqLoadBalancer>())
using (var bus =
container.Resolve<IStartableServiceBus>())
{
MsmqUtil.GetQueuePath(loadBalancer.Endpoint).Create();
loadBalancer.Start();
bus.Start();
while (true)
{
var message = new ActivityCreated() { ActivityID =
Guid.NewGuid() };
//bus.Send(message);
bus.Notify(message);
Console.WriteLine("Activity Created: {0}",
message.ActivityID);
Console.ReadLine();
}
}
Note: bus.Send is commented out as it errors complaining about no
message owners could be found (probably the key to the issue), so I am
using Notify instead.
I then have another console app "Consumer", this starts a bus with the
following config
<castle>
<facilities>
<facility id="rhino.esb" >
<bus threadCount="1"
numberOfRetries="5"
endpoint="msmq://localhost/ESBTests.consumer"
/>
<messages>
<add name="Common" endpoint="msmq://localhost/
ESBTests.balancer"/>
</messages>
</facility>
</facilities>
</castle>
And listens for messages
public class ActivityListener : ConsumerOf<ActivityCreated>
{
#region ConsumerOf<ActivityCreated> Members
public void Consume(ActivityCreated message)
{
Console.WriteLine("ActivityListener - Activity Created:
{0}", message.ActivityID);
}
#endregion
}
If you start up both apps whenever you hit return in the distributor
you see a Activity Created message in the consumer.
Now if I start up a second instance of the consumer app having
modified the endpoint in the bus config to be
msmq://localhost/ESBTests.consumer2,
because a load balancer is in place I would expect one instance of the
consumer app to take on the work i.e. only see a Activity Created
message in one consumer console window. What I am actually seeing is
no different to pub/sub, i.e both instances of the consumer app are
recieving the message and displaying the Activty Created message.
Any ideas?
On Apr 1, 6:57 pm, Ayende Rahien <[email protected]> wrote:
> Crowley,
> RSB comes with Load Balancer, which is how you would handle this scenario,
> take a look at the tests to see how this works.
>
> On Tue, Mar 30, 2010 at 12:08 AM, crowley_mark <[email protected]>wrote:
>
> > I have a consumer that processes a file. The activity of the consumer
> > process is resource intensive; therefore I have set the bus thread
> > count to 1 (effectively creating a queue).
>
> > In times of load I would like to start 1 or more new instances of the
> > consumer on new machines. We are using Amazons EC2 infrastructure so
> > creating new machine instances involves minimum effort.
>
> > My question is how to utilise ESB to the best advantage in such a
> > scenario.
>
> > My thoughts are...
>
> > I don’t think I can utilise the Publish/Subscribe functionality, as
> > each subscriber will just get the same message, so I will just end up
> > processing the same file multiple times on different machines.
>
> > As the process that sends the messages will not know of the location/
> > name/ip of the consumer machines, it could just send the messages to
> > a predefined local queue. Having this local queue will ensure that
> > messages are persisted, even if no consumers are in existence (unlike
> > pub/sub model).
>
> > Consumers on remote machines are configured to recieve messages from
> > the predefined queue, and use the reply semantics to send any response
> > message back to the sender. Any errors are persisted back to the
> > queues error subqueue.
>
> > New machines that come up will just pick off the next message,
> > process, and reply.
>
> > When a consumer machine is dropped (load reduced), because there are
> > no subscribers etc. it simply disappears.
>
> > Does this make sense. I believe this is possible, is there a better
> > way? Any obvious disadvantages, other thoughts?
>
> > Thanks.
>
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