[rabbitmq-discuss] Perl Net::RabbitMQ and failure conditions

[Alexis Richardson]

Ronald

Were you able to find an answer to this?

alexis



On Thu, May 19, 2011 at 9:44 PM, Ronald J Kimball
<rkimball at pangeamedia.com> wrote:
> I'm trying to understand how RabbitMQ behaves under failure conditions,
> specifically when using the Net::RabbitMQ Perl module.
>
> We have RabbitMQ set up with three nodes, one on the backend, which holds
> the actual queues, and two on the frontend, which receive publish requests.
>
> RabbitMQ 2.2.0
> Net::RabbitMQ 0.1.8
>
>
> Below is the chart of behaviors that I have observed.
>
> "+" means the behavior is as I expected: either the message is successfully
> queued, or an error is thrown.
> "-" means the behavior is not as I expected, but can be managed:
> specifically, the process receives a SIGPIPE, which I can trap and recover
> from.
> "!" means the behavior is not as I expected, and cannot be managed: the
> message is not queued but no error is thrown and/or the process hangs.
>
> "App down" means I ran `rabbitmqctl stop_app`.  "Daemon down" means I ran
> `rabbitmqctl stop`.
>
>   As publishing process starts up:
>
>     Remote daemon up, app up
>       + Everything okay
>
>     Remote daemon up, app down
>       ! Net::RabbitMQ hangs when declaring queue
>
>     Remote daemon down
>       + Net::RabbitMQ throws error when declaring queue
>         "Declaring queue: server channel error 404, message: NOT_FOUND - no
> queue 'test' in vhost '/'"
>
>     Local daemon up, app down
>       + Net::RabbitMQ throws error when connecting
>         "Opening socket: Connection refused"
>
>     Local daemon down
>       + Net::RabbitMQ throws error when connecting
>         "Opening socket: Connection refused"
>
>
>   After publishing process starts up:
>
>     Local app goes down
>       - Process receives SIGPIPE
>
>     Local daemon goes down
>       - Process receives SIGPIPE
>
>     Remote app goes down
>       ! Net::RabbitMQ falsely indicates success when publishing, then hangs
> (in DESTROY?)
>
>     Remote daemon goes down
>       ! Net::RabbitMQ falsely indicates success when publishing
>
>
>     Local app goes down, comes back up
>       - Process receives SIGPIPE
>
>     Local daemon goes down, comes back up
>       - Process receives SIGPIPE
>
>     Remote app goes down, comes back up
>       + Everything okay
>
>     Remote daemon goes down, comes back up
>       + Everything okay
>
>
> Have other people had these problems with Net::RabbitMQ?  Can we resolve
> these issues by changing something in our RabbitMQ configuration?
>
>
> thanks,
> Ronald
>
>
> P.S. Here's my script.
>
> #!/usr/local/bin/perl
>
> use strict;
> use warnings;
>
> use Net::RabbitMQ;
>
> $| = 1;
>
> $SIG{'PIPE'} = sub { die "SIGPIPE\n" };
>
> my $mq = Net::RabbitMQ->new();
>
> alarm(10);
>
> print "Connecting\n";
> $mq->connect('localhost', { user => 'engagement', password => '********' })
>   or die "Can't connect to RabbitMQ\n";
>
> print "Opening channel\n";
> $mq->channel_open(1);
>
> print "Declaring exchange\n";
> $mq->exchange_declare(1, 'ee_exchange', { durable => 1 });
>
> print "Declaring queue\n";
> $mq->queue_declare(1, 'test', { durable => 1 });
>
> print "Binding queue\n";
> $mq->queue_bind(1, 'test', 'ee_exchange', 'ee_test');
>
> alarm(0);
>
> print "> ";
> <>;
>
> alarm(10);
>
> print "Publishing message\n";
> my $rc =
>   $mq->publish(1, 'ee_test', 'hello world!',
>                { exchange => 'ee_exchange', mandatory => 1, immediate => 0
> },
>                { delivery_mode => 2 });
> print "Result: $rc\n";
>
> __END__
>
>
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