[rabbitmq-discuss] pub-sub erlang problem

Tue Apr 8 13:00:56 BST 2008

Joe,

Sorry about the delay in answering your question.

It looks like you're trying to publish to an exchange that doesn't  
exist, although the server diagnostic could be a little clearer on  
this point.

To fix your test, precede the exchange declare command before the  
publish command, i.e. put this code before the publish call:

ExchangeDeclare = #'exchange.declare'{ticket = Ticket, exchange = X,  
type = <<"topic">>,
                                           passive = false, durable =  
false, auto_delete = false, internal = false,
                                           nowait = false, arguments =  
[]},
#'exchange.declare_ok'{} = amqp_channel:call(Channel, ExchangeDeclare)

We should probably take on board better server diagnostics as an  
improvement item.

HTH,

Ben

On 6 Apr 2008, at 22:53, Joe Lee wrote:

> I am trying to get pub-sub model to work in rabbitmq.  My  
> understanding is that you still have to perform  
> amqp_connection:start, amqp_connection:open_channel,  
> amqp_channel:call(Channel, Access), channel close and connection  
> close on each async call.
> I am not sure what payload_fragments_rev = [Payload] is for.  I have  
> searched through amqp xml specs and pdf.  Maybe I am not hitting the  
> right keywords.  For pub-sub model, how do you assign the message,  
> assign it to Payload variable?
>
> I am new to erlang.  This shouldn't be a show stopper.  I just need  
> to get this working.  I am getting following error:
>
> (rabbit at home)1> amqp_async:amqp_lifecycle().
> Connection: {<0.217.0>,direct}
>
> =ERROR REPORT==== 6-Apr-2008::16:33:51 ===
> Lax ticket check mode: ignoring cross-realm access for ticket 101
> ** exception exit: {{amqp,not_found,'basic.publish'},
>                     {gen_server,call,
>                         [<0.218.0>,
>                          {call,{'channel.close',200,<<"Goodbye">>, 
> 0,0}}]}}
>      in function  gen_server:call/2
>      in call from amqp_async:amqp_lifecycle/0
>
> my pub-sub code:
>
> -module(amqp_async).
>
> -include_lib("rabbitmq_server/include/rabbit_framing.hrl").
> -include_lib("rabbitmq_server/include/rabbit.hrl").
>
> -export([amqp_lifecycle/0]).
>
> amqp_lifecycle() ->
>     User = Password = "guest",
>     Realm = <<"/data">>,
>
>     %% Start a connection to the server
>
>     Connection = amqp_connection:start(User, Password),
>     io:format("Connection: ~p~n",[Connection]),
>     %% Once you have a connection to the server, you can start an  
> AMQP channel gain access to a realm
>
>     Channel = amqp_connection:open_channel(Connection),
>     Access = #'access.request'{realm = Realm,
>                                exclusive = false,
>                                passive = true,
>                                active = true,
>                                write = true,
>                                read = true},
>     #'access.request_ok'{ticket = Ticket} =  
> amqp_channel:call(Channel, Access),
>
>     X = <<"x">>,
>     RoutingKey = <<"a.b.c.*">>,
>     Payload = <<"foobar">>,
>     BasicPublish = #'basic.publish'{ticket = Ticket,
>                                     exchange = X,
>                                     routing_key = RoutingKey,
>                                     mandatory = false,
>                                     immediate = false},
>     Content = #content{class_id = 60,
>          properties = amqp_util:basic_properties(),
>          properties_bin = none,
>          payload_fragments_rev = [Payload]
>         },
>     amqp_channel:cast(Channel, BasicPublish, Content),
>
>     %% After you've finished with the channel and connection you  
> should close them down
>
>     ChannelClose = #'channel.close'{reply_code = 200, reply_text =  
> <<"Goodbye">>,
>                                     class_id = 0, method_id = 0},
>     #'channel.close_ok'{} = amqp_channel:call(Channel, ChannelClose),
>     ConnectionClose = #'connection.close'{reply_code = 200,  
> reply_text = <<"Goodbye">>,
>                                           class_id = 0, method_id =  
> 0},
>     #'connection.close_ok'{} = amqp_connection:close(Connection,  
> ConnectionClose),
>     ok.
>
> Thank you,
> Joe
>
>
>
>
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