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POMessage queue with random read\write access to queue elements before dequeing (rabbitmq or)
 

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    <p>I use rabbitmq in Python via amqplib. I try to use AMQP for something more than just a queue, if that's possible - searching messages by ID, modifying them before dequeing, deleting from queue before dequeing. Those things are used to store/update a real users queue for a balancer, and that queue could be updated asynchronously by changing real user' state (for example, user is dead - his AMQP message must be deleted, or user changed it's state - and every such a change must be reflected in users' AMQP queue, in appropriate user's AMQP message) , and before the real dequeuing of a message happens. My questions are the following :</p> <ol> <li><p>Is there a way through amqplib to modify AMQP message body in some queueN before it would be dequed , searching it by some ID in it's header? I mean - i want to modify message body before dispatching it by receiver. </p></li> <li><p>Is there a way for a worker to pop excactly 5 (any number) last messages from queueN via amqplib? </p></li> <li><p>Can i asynchronously delete message from a queueN before it would be dequed, and it's neighbors would take it's place in the queueN? </p></li> <li><p>Which is the way for a message ID1 from queueN - to get it's real current queue position, counted from the beginning of the queueN? Does AMQP stores/updates for any message it's real queue position?</p> <p>Thanks in advance.</p></li> </ol> <p>UPDATE: according to rabbitmq documentation, there are problem with such a random access to messages in AMQP queue. Please advise another proper decision of a queue in Python, which supports fast asynchronous access to it's elements- searching a message by it's body, updating/deleting queue messages and getting fast queue index for any queue message. We tried deque + additional dict with user_info, but in this case we need to lock this deque+dict on each update, to avoid race conditions. Main purpose - is to serve a load balancer's queue and get rid of blocking when counting changes in queue.</p>
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