[rabbitmq-discuss] ewbie question - need modified fanaout/publish/subscribe behavior

scott taggart taggart at taggarts.org
Thu Nov 8 15:57:29 GMT 2012


As I research and better understand AMQP better, I learn that messages are 
never queued in an exchange - they are always routed to existing queues or 
tossed.  Given my basic requirement that messages be queued for as-yet 
non-existent queues, this seems not possible directly with amqp/rabbitmq.

On Wednesday, November 7, 2012 8:40:47 PM UTC-8, scott taggart wrote:
>
> the rabbitmq tutorial 3 for python talks about the publish/subscribe 
> (fanout) model. 
>
> I have this working for multiple subscribers but I need something slightly 
> different. 
>
> The current model says that any subscriber sees only the messages AFTER it 
> subscribes (i.e., creates the subscriber Q) and this is the behavior I 
> see.  I need to be able to see all messages ever sent to the exchange.  To 
> be very clear, the current behavior is that if a publisher produces 
> messages 1, 2, 3 and C1 starts consuming after 2 but before 3, the consumer 
> only sees 3.  Similarly, if C2 starts after message 3, it never sees 1, 2 
> or 3.  I need C1 & C2 to see 1, 2, & 3 regardless of where they start in 
> the publishing sequence. 
>
> How can I create the Q after a fanout exchange is created so that that Q 
> sees all messages sent to an exchange to that point, not just post-Q 
> creation?  If it takes a different exchange or Q model, please let me know. 
>
> Your help is greatly appreciated. 
>
>
> ---- please ecuse me if this message shows up twice - I wan't sure if the 
> email request I sent earlier would end up here -----
>
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