[jira] [Commented] (CAMEL-8604) [RabbitMQ] Allow Remote procedure call (RPC) in camel-rabbitmq

["souciance eqdam rashti (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CAMEL-8604?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14943452#comment-14943452 ] 

souciance eqdam rashti commented on CAMEL-8604:
-----------------------------------------------

I actually ran into this scenario a few days at my employee where they want RPC support. The main reason is that the client is connecting via socket to Camel and is waiting for a response else it times out. Camel is sending the request via RPC to the backend and waiting as well. Right now we have to write the RPC code manually as written in the RabbitMQ documentation. The main argument for RPC here was that one did want to run into a scenario where the backend takes long time and returns messages after the client has closed the socket. Although it is always more suited to go with event-driven, sometimes its not possible for various reasons so it would be nice to have better functionality to support it.

> [RabbitMQ] Allow Remote procedure call (RPC) in camel-rabbitmq
> --------------------------------------------------------------
>
>                 Key: CAMEL-8604
>                 URL: https://issues.apache.org/jira/browse/CAMEL-8604
>             Project: Camel
>          Issue Type: Wish
>          Components: camel-rabbitmq
>    Affects Versions: 2.15.1
>            Reporter: Ramon Rosa da Silva
>            Priority: Minor
>   Original Estimate: 12h
>  Remaining Estimate: 12h
>
> I would like RabbitMQ component knew how to handle messages in RPC format more easily.
> RabbitMQ RPC Sample: https://www.rabbitmq.com/tutorials/tutorial-six-java.html
> Currently, to receive and reply in RPC is required (as server):
> {code:title=RouteSample.java|borderStyle=solid}
> from("rabbitmq://rabbit-server:5672/myExc?routingKey=myQueue&queue=myQueue&vhost=myVhost&autoAck=false&prefetchEnabled=true&prefetchCount=10&concurrentConsumers=10&declare=true")
> .transacted ()
> .setProperty (RabbitMQConstants.REPLY_TO) .header (RabbitMQConstants.REPLY_TO)
> .to ("sql: ......")
> .setHeader (RabbitMQConstants.ROUTING_KEY) .property (RabbitMQConstants.REPLY_TO)
> .setHeader (RabbitMQConstants.EXCHANGE_NAME) .simple ("")
> .to("rabbitmq://rabbit-server:5672/_required_fake_field?routingKey=_required_fake_field&vhost=myVhost&threadPoolSize=1");
> {code}
> So you must save "reply_to" from header to properties, set fake exchange and routing key, and overwrite with setHeader.
> Would be simpler:
> - The consumer save the reply_to in properties.
> - Enable exchange and routing key blank.
> - Use reply_to property as routhing key when exchange and key is blank.
> Test unit for improvement:
> {code:title=ProducerTest.java|borderStyle=solid}
>     private RabbitMQEndpoint endpoint = Mockito.mock(RabbitMQEndpoint.class);
>     private Exchange exchange = Mockito.mock(Exchange.class);
>     private Message message = new DefaultMessage();
>     private Connection conn = Mockito.mock(Connection.class);
>     private Channel channel = Mockito.mock(Channel.class);;
>     @Before
>     public void before() throws IOException {
>         Mockito.when(exchange.getIn()).thenReturn(message);
>         Mockito.when(endpoint.connect(Matchers.any(ExecutorService.class))).thenReturn(conn);
>         Mockito.when(conn.createChannel()).thenReturn(null);
>     }
>        @Test
>        public void testRpcReplyTo() throws Exception {             
>              message = Mockito.mock(Message.class);
>              Mockito.when(exchange.getIn()).thenReturn(message);         
>              Mockito.when(message.getHeader(RabbitMQConstants.EXCHANGE_NAME, String.class)).thenReturn("");
>              
>              Mockito.when(conn.createChannel()).thenReturn(channel);
>              RabbitMQProducer producer = new RabbitMQProducer(endpoint);
>              exchange.setFromEndpoint(endpoint);
>              exchange.setProperty(RabbitMQConstants.REPLY_TO, "queue_to_reply");
>              
>              producer.process(exchange);
>              
>              Mockito.verify(channel).basicPublish(Mockito.eq(""), Mockito.eq("queue_to_reply"), Mockito.any(BasicProperties.class), Mockito.any(byte[].class));
>        }
>        {code}



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