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

Wed Jun 1 13:54:02 BST 2011

Ronald

Have you been able to speak to the author(s) of the client?

alexis

On Tue, May 31, 2011 at 6:34 PM, Ronald J Kimball
<rkimball at pangeamedia.com> wrote:
> Hi, thanks for the response.  Unfortunately, I haven't really found an
> answer.
>
> We upgraded RabbitMQ to 2.4.1, after which Net::RabbitMQ no longer hangs
> when the remote server is up but the remote app is down.
>
> However, Net::RabbitMQ still returns a false success when the remote server
> or app goes down after the publisher connects to the local node.  (The queue
> is located on the remote app.)
>
> For now, we've switched to having a single node.  This decreases our
> throughput slightly, but at least we don't risk dropping messages.
>
> I think we must be doing something wrong, but I don't know what...
>
> Ronald
>
>
> On Tue, May 31, 2011 at 7:41 AM, Alexis Richardson <alexis at rabbitmq.com>
> wrote:
>>
>> 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__
>> >
>> >
>> > _______________________________________________
>> > rabbitmq-discuss mailing list
>> > rabbitmq-discuss at lists.rabbitmq.com
>> > https://lists.rabbitmq.com/cgi-bin/mailman/listinfo/rabbitmq-discuss
>> >
>> >
>
>