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| Guest |
 Posted: Thu Nov 19, 2009 11:08 pm |
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Guest
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I'm not sure what the .NET api looks like, but you want to do a basic get, rather then a basic subscribe.
It will return a single message from the queue, and then when you call it again, you will get the next message(or null/something similar)
Scott
On 2009-11-16, at 5:41 PM, JD Conley wrote:
> I'm using the .NET client and can't figure out how to consume only one
> message at a time. Basically I would like to simply:
>
> 1. Consume one message from a queue
> 2. Cancel consumption so I don't lose any messages
>
> My confusion comes with the statement in the user guide that "Application
> callback handlers must not invoke blocking AMQP operations (such as
> IModel.QueueDeclare or IModel.BasicCancel). If they do, the channel will
> deadlock." But, a BasicCancel is precisely what I want to do in the
> callback.
>
> I want to use the EventingBasicConsumer. What would be the best way to
> accomplish this? Which options do I set?
>
> -JD
>
>
> _______________________________________________
> rabbitmq-discuss mailing list
> rabbitmq-discuss@lists.rabbitmq.com
> http://lists.rabbitmq.com/cgi-bin/mailman/listinfo/rabbitmq-discuss
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| Guest |
| Posted: Fri Nov 20, 2009 12:38 am |
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Guest
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On Mon, Nov 16, 2009 at 08:59:35PM -0600, Scott Brooks wrote:
> I'm not sure what the .NET api looks like, but you want to do a basic get, rather then a basic subscribe.
>
> It will return a single message from the queue, and then when you call it again, you will get the next message(or null/something similar)
Yup, that'll work. Or set QoS to 1 and use subscribe and then you'll
only get the next msg when you ack the previous one.
Matthew
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| Guest |
| Posted: Fri Nov 20, 2009 12:38 am |
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Guest
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Thanks Scott. But I do want to subscribe/consume (I think), as it is unknown whether there will be any data in the queue, and I want to be notified immediately when there is. I don't really want to poll rabbit using a basic.get and would rather be notified asynchronously when new items are in the queue. I have hundreds (thousands soon) of queues waiting for data across a cluster and the polling overhead would be higher than I want it to be.
-JD
----- Original Message -----
From: "Scott Brooks" <scott.brooks@epicadvertising.com>
To: "JD Conley" <jdc@hive7.com>
Cc: rabbitmq-discuss@lists.rabbitmq.com
Sent: Monday, November 16, 2009 6:59:35 PM GMT -08:00 US/Canada Pacific
Subject: Re: [rabbitmq-discuss] how to consume one message at a time
I'm not sure what the .NET api looks like, but you want to do a basic get, rather then a basic subscribe.
It will return a single message from the queue, and then when you call it again, you will get the next message(or null/something similar)
Scott
On 2009-11-16, at 5:41 PM, JD Conley wrote:
> I'm using the .NET client and can't figure out how to consume only one
> message at a time. Basically I would like to simply:
>
> 1. Consume one message from a queue
> 2. Cancel consumption so I don't lose any messages
>
> My confusion comes with the statement in the user guide that "Application
> callback handlers must not invoke blocking AMQP operations (such as
> IModel.QueueDeclare or IModel.BasicCancel). If they do, the channel will
> deadlock." But, a BasicCancel is precisely what I want to do in the
> callback.
>
> I want to use the EventingBasicConsumer. What would be the best way to
> accomplish this? Which options do I set?
>
> -JD
>
>
> _______________________________________________
> rabbitmq-discuss mailing list
> rabbitmq-discuss@lists.rabbitmq.com
> http://lists.rabbitmq.com/cgi-bin/mailman/listinfo/rabbitmq-discuss
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| Guest |
| Posted: Fri Nov 20, 2009 12:38 am |
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Guest
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| Then adjusting the prefetch(part of basic.qos) is probably what you want. |
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| Guest |
| Posted: Fri Nov 20, 2009 1:38 am |
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Guest
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I'm using the .NET client and can't figure out how to consume only one
message at a time. Basically I would like to simply:
1. Consume one message from a queue
2. Cancel consumption so I don't lose any messages
My confusion comes with the statement in the user guide that "Application
callback handlers must not invoke blocking AMQP operations (such as
IModel.QueueDeclare or IModel.BasicCancel). If they do, the channel will
deadlock." But, a BasicCancel is precisely what I want to do in the
callback.
I want to use the EventingBasicConsumer. What would be the best way to
accomplish this? Which options do I set?
-JD
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rabbitmq-discuss@lists.rabbitmq.com
http://lists.rabbitmq.com/cgi-bin/mailman/listinfo/rabbitmq-discuss
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