[rabbitmq-discuss] Persistent message in perl

[Alexandru Scvorţov]

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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