How to terminate EventMachine after one iteration?

Question

I want to publish messages to a direct exchange, so I have the following function:

def publish_message_to_direct(server_params, exchange, payload)
    AMQP.start(server_params) do |connection|
        channel  = AMQP::Channel.new(connection)
        exchange = channel.direct(exchange,:durable=>true)
        exchange.publish(payload)
        puts payload
        connection.close do
            EM.stop { exit }
        end
    end
end

After I call the function, it prints the payload to the terminal, but does not publish the message to the exchange. However, if I add a SIGTRAP like this then it publishes the message:

.
.
.
            Signal.trap("INT") do 
                connection.close do
                    EM.stop { exit }
                end
            end

How do I get EM to stop without having to send it this signal? IOW, I just want it to publish the message and return.

Answer 1

Well, I just read the documentation and found the section on publishing one-off messages:

So the code as follows now works:

def publish_message_to_direct(server_params, exchange, payload)
    AMQP.start(server_params) do |connection|
        channel  = AMQP::Channel.new(connection)
        exchange = channel.direct(exchange,:durable=>true)
        exchange.publish(payload, :nowait => false) do              
            puts payload
            connection.close do
                EM.stop
            end
        end
    end
end

Apparently, the difference was adding the closing event inside a block passed to the publish function and using the option :nowait => false. Hope this helps someone else with the same question.