[rabbitmq-discuss] Persistent message in perl

[underattack7]

ok thanks for your help, that makes sense.

On 20 December 2010 16:42, Emile Joubert <emile at rabbitmq.com> wrote:

>
> Hi Fab,
>
> If you ran publish.pl before consume.pl then the messages will be
> discarded, because there is no queue for messages to be delivered to and no
> binding for messages to get there.
>
> As Alexandru explained, the binding and queue have to exist first. You
> could either launch the consumer in the background before starting the
> publisher, or declare the queue and binding in the publisher as well.
>
> Regards
>
> Emile
>
>
>
> Op 20/12/2010 16:11, het Alexandru Scvorţov geskryf:
>
>  Hi,
>>
>> Queues and exchanges don't work like that.
>>
>> An exchange is just a router, it doesn't store messages.  That's the
>> queues' job.
>>
>> What you want to do is this:
>>   - publisher declares a durable queue with a known name and binds it to
>> an
>>     exchange (by default it's bound the default exchange with its name
>>     as routing key; the default exchange is "amq.default" or "")
>>   - publisher publishes a persistent message to the exchange, which
>>     routes it to the queue (the routing key should be the queue's name,
>>     or whatever you bound the queue with)
>>
>>   - consumer declares a durable queue with the same name (this is just
>>     to make sure that it exists; it's effectively a no-op)
>>   - consumer consumes or gets from the queue.
>>
>> Hope this helps.
>>
>> Cheers,
>> Alex
>>
>> On Mon, Dec 20, 2010 at 03:38:11PM +0000, underattack7 wrote:
>>
>>> Hi,
>>>
>>> I am struggling with persistent message in perl.
>>>
>>> What I am trying to achieve is :
>>> - publish message to a direct exchange
>>> - the exchange stores the message
>>> - a consumer creates a queue, binds it to the exchange, and get all the
>>> stored messages
>>>
>>> I have a durable exchange, and apparently I would need to publish message
>>> using "delivery_mode = 2" for the exchange to store the message until a
>>> queue is bound to it....is that right ?
>>>
>>> The problem I have is that when my consumer creates a queue and bind it
>>> to
>>> the exchange, it does not get all the message sent.
>>>
>>>
>>> My publisher code :
>>>
>>> #!/usr/bin/perl
>>> use Net::RabbitMQ;
>>>
>>> my $myexchange=$ARGV[0];
>>> my $rkey=$ARGV[1];
>>> my $text=$ARGV[2];
>>>
>>> my $mq = Net::RabbitMQ->new();
>>> $mq->connect("rabbitmqserver", { vhost=>"chat", user =>  "guest",
>>> password =>
>>> "guest" });
>>> $mq->channel_open(1);
>>> $mq->publish(1, $rkey, $text, {exchange =>  $myexchange}, { content_type
>>> =>
>>> 'text/plain', delivery_mode =>  2});
>>> mqdisconnect;
>>> exit 0;
>>>
>>>
>>> I execute it with for example :
>>> ./publish.pl "exchangechat" "toto" "hi toto1"
>>> ./publish.pl "exchangechat" "toto" "hi toto2"
>>> ./publish.pl "exchangechat" "toto" "hi toto3"
>>>
>>>
>>>
>>> The consumer code is :
>>> #!/usr/bin/perl
>>> use Net::RabbitMQ;
>>>
>>> my $exchange=$ARGV[0];
>>> my $rkey=$ARGV[1];
>>>
>>> my $mq = Net::RabbitMQ->new();
>>> $mq->connect("rabbitmqserver", { vhost =>  "chat", user =>  "guest",
>>> password
>>> =>  "guest" });
>>> $mq->channel_open(1);
>>> my $queuename = $mq->queue_declare(1, '', {exclusive =>  1, durable =>
>>>  0,
>>> auto_delete =>  1});
>>> $mq->queue_bind(1, "$queue", "$exchange", "$rkey");
>>>
>>> while(1) {
>>>     my $message = $mq->get(1, $queuename);
>>>     if ( defined($message) ) {
>>>         print $message->{'routing_key'} . "\n";
>>>         print $message->{'body'} . "\n";
>>>         print "\n\n";
>>>     }
>>>     sleep(1);
>>> }
>>> exit 0;
>>>
>>> And I run it with :
>>> ./consume.pl exchangechat "toto"
>>>
>>> but I do not get the message "hi toto1"
>>>
>>>
>>> Any idea what's wrong here ?
>>>
>>> Thanks,
>>>
>>> Fab
>>>
>>
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