In ActiveMQ (and Hawtio) there is Admin UI functionality to move a messages from one queue to another. This process keeps the body and all the headers all the same as the original message.
Is there a way to do this in Camel? A simple from(queue1).to(queue2) always seems to change headers.
thanks
edit: tried
from(
"cMQConnectionFactory1:queue:queue1"
+ "?forceSendOriginalMessage=" + true
+ "&mapJmsMessage=" + false)
.routeId("testMove_cJMS_1")
.to("cMQConnectionFactory1:queue:queue2"
+ "?forceSendOriginalMessage=" + true
+ "&mapJmsMessage=" + false).id("testMove_cJMS_2");
}`
The Camel documentation for the JMS component describes the forceSendOriginalMessage option saying:
When using mapJmsMessage=false Camel will create a new JMS message to send to a new JMS destination if you touch the headers (get or set) during the route. Set this option to true to force Camel to send the original JMS message that was received.
forceSendOriginalMessage defaults to false.
The docs say this about mapJmsMessage:
Specifies whether Camel should auto map the received JMS message to a suited payload type, such as javax.jms.TextMessage to a String etc.
mapJmsMessage defaults to true.
Therefore it seems like you need to set mapJmsMessage=false & forceSendOriginalMessage=true.
Keep in mind that Camel will be using the JMS API to consume the message and then resend it. Even though the new message will have the same body and headers as the old message it will be slightly different because the JMS specification dictates that when a message is sent the broker must assign it a message ID and timestamp. Therefore the JMSMessageID and JMSTimestamp on the new message will be different from the old message, and there's really no way around that. If you need to identify the message uniquely you should set the correlation ID on the original message and use that to identify the message rather than the JMSMessageID. Also, if you need to preserve the original time the message was sent then set that in a custom property.
The reason the JMSMessageID and JMSTimestamp are not changed when moving the messages via the management console is because the broker moves the messages internally with a completely different mechanism than JMS.
Related
I have a really simple route that GETs an URL and prints the content using Camel HTTP4 component:
from("timer://foo?fixedRate=true&delay=0&period=10000")
.to("http4://www.google.com")
.process(e -> System.out.println("Out body: " + e.getOut().getBody()));
Note that I'm using out.body because, as stated in Camel documentation:
Camel will store the HTTP response from the external server on the OUT
body. All headers from the IN message will be copied to the OUT
message, so headers are preserved during routing.
But I get null values from OUT (both body and headers). Everything is being filled only in the IN message.
Am I missing anything or is it a bug?
In Camel a route consists of nodes. Each node takes the Exchange. Exchange has an IN and OUT message. So in your case, node with http4 component took the Exchange, called google.com and wrote body and headers to OUT message. Next, node with your proccesor took the Exchange. Now IN message has the response from the previous node(http4), but you are printing OUT which is empty! So IN and OUT message are per node not per route!
You are getting the Out body from the processor without setting it up first. That’s why you get null. To make this work you first need explicitly copy the incoming message, headers and attachments to Out Body and then print it. Or more easily take the In message as you mentioned.
Next part is from “Camel in Action” book which is a great book and I think it is very helpful.
in practice there’s a common pitfall when using getOut: the incoming
message headers and attachments will be lost. This is often not what
you want, so you must copy the headers and attachments from the
incoming message to the outgoing message, which can be tedious.
I am attempting to construct a route which will do the following:
Consume a message from jms:sender-in. I am using a INOUTrequest reply pattern. The JMSReplyTo = sender-out
The above message will be routed to multiple recipients like jms:consumer1-in, jms:consumer2-in and jms:consumer3-in. All are using a request reply pattern. The JMSReplyTo is specified per consumer ( in this case, the JMSReplyTo are in this order jms:consumer1-out, jms:consumer2-out, jms:consumer3-out
I need to aggregate all the replies together and send the result back to jms:sender-out.
I constructed a route which will resemble this:
from("jms:sender-in")
.to("jms:consumer1-in?exchangePattern=InOut&replyTo=queue:consumer1-out&preserveMessageQos=true")
.to("jms:consumer2-in?exchangePattern=InOut&replyTo=queue:consumer2-out&preserveMessageQos=true")
.to("jms:consumer3-in?exchangePattern=InOut&replyTo=queue:consumer3-out&preserveMessageQos=true");
I then send the replies back to some queue to gather and aggreagte:
from("jms:consumer1-out?preserveMessageQos=true").to("jms:gather");
from("jms:consumer1-out?preserveMessageQos=true").to("jms:gather");
from("jms:consumer1-out?preserveMessageQos=true").to("jms:gather");
from("jms:gather").aggregate(header("TransactionID"), new GatherResponses()).completionSize(3).to("jms:sender-out");
To emulate the behavior of my consumers, I added the following route:
from("jms:consumer1-in").setBody(body());
from("jms:consumer2-in").setBody(body());
from("jms:consumer3-in").setBody(body());
I am getting a couple off issues:
I am getting a timeout error on the replies. If I comment out the gather part, then no issues. Why is there a timeout even though the replies are coming back to the queue and then forwarded to another queue.
How can I store the original JMSReplyTo value so Camel is able to send the aggregated result back to the sender's reply queue.
I have a feeling that I am struggling with some basic concepts. Any help is appreciated.
Thanks.
A good question!
There are two things you need to consider
Don't mix the exchange patterns, Request Reply (InOut) vs Event
message (InOnly). (Unless you have a good reason).
If you do a scatter-gather, you need to make the requests
multicast, otherwise they will be pipelined which is not
really scatter-gather.
I've made two examples which are similar to your case - one with Request Reply and one with (one way) Event messages.
Feel free to replace the activemq component with jms - it's the same thing in these examples.
Example one, using event messages - InOnly:
from("activemq:amq.in")
.multicast()
.to("activemq:amq.q1")
.to("activemq:amq.q2")
.to("activemq:amq.q3");
from("activemq:amq.q1").setBody(constant("q1")).to("activemq:amq.gather");
from("activemq:amq.q2").setBody(constant("q2")).to("activemq:amq.gather");
from("activemq:amq.q3").setBody(constant("q3")).to("activemq:amq.gather");
from("activemq:amq.gather")
.aggregate(new ConcatAggregationStrategy())
.header("breadcrumbId")
.completionSize(3)
.to("activemq:amq.out");
from("activemq:amq.out")
.log("${body}"); // logs "q1q2q3"
Example two, using Request reply - note that the scattering route has to gather the responses as they come in. The result is the same as the first example, but with less routes and less configuration.
from("activemq:amq.in2")
.multicast(new ConcatAggregationStrategy())
.inOut("activemq:amq.q4")
.inOut("activemq:amq.q5")
.inOut("activemq:amq.q6")
.end()
.log("Received replies: ${body}"); // logs "q4q5q6"
from("activemq:amq.q4").setBody(constant("q4"));
from("activemq:amq.q5").setBody(constant("q5"));
from("activemq:amq.q6").setBody(constant("q6"));
As for your question two - of course, it's possible to pass around JMSReplyTo headers and force exchange patterns along the road - but you will create hard to debug code. Keep your exchange patterns simple and clean - it keep bugs away.
Currently I'm receiving messages over tcp in a self written component that allows me to use Netty as a TCP server producer.
the messages i receive are formatted in XML style, for example:
<customheader>
<someattribute></someattribute>
</customheader>
<custombody>
</custombody>
The messages I receive are stored in a byte[] and to send it to another endpoint I create a new exchange via:
Exchange exchange = new DefaultExchange(endpoint);
exchange.getContext().createProducerTemplate().sendBody("someendpointuri", receivedbytes);
now my questions:
Is my approach with the new exchange correct?
If want to for example get rid of the header or use other camel components, do I need to convert the receivedbytes from byte[] to a different datatype or is byte[] okay?
If i want to remove the custom header can i use the remove header component from camel?
Thanks for your help
You're creating an new Exchange, but you're not actually using it. Instead, you only use it to access CamelContext. The method sendBody is creating a new Exchange for you and it is this Exchange that is actually being sent to endpoint specified by someendpointuri. Note that you should not create a new producer template every time you want to send a message.
When you say that you store messages as byte[], I assume you're storing it inside Message body. In this case you store both customheaders and custombody as byte[] and Camel treats them both as Message body, not headers.
If you want to use Camel header-related components or language constructs, you need to parse your customheaders and then set them on the Message as headers by using Exchange.getIn().setHeaders() (see API with a note about this). If you do that, you would probably only want to set content of custombody in the Exchange.getIn().setBody().
If you do these changes in your custom component, your component will now be handling this specific XML format only. If you want to keep your component generic, you can instead implement a custom DataFormat and call marshal() and unmarshal() in your routes. I think SOAP DataFormat does something very similar.
I've set up a topic exchange such that the consumer queue is bound with "#.topic". I'd like to use different acknowledgement strategies based on the prefix. Is the full routing key sent to the consumer? If so, how do I access it? An answer in terms of AMQP concepts would probably be sufficient, but an answer involving rabbitmq-c would be ideal.
Even when you do a binding like you have given in your example the message received contains the full routing key. This means you can extract that in order to help you process the message. Unfortunately I only know how to do this in Java so try to extrapolate from there.
QueueingConsumer.Delivery delivery = consumer.nextDelivery();
String routingKey = delivery.getEnvelope().getRoutingKey();
The delivery object contains a body which is the payload and can be retrieve with delivery.getBody() and an Envelope object which contains other information like the full routing key.
I'm trying to implement a mina service where the response to the final message should be based on the previous messages. Each message (header (1), data (n), end (1)) should receive a response, but the response to the "end" message should be based on the "header", and any "data" messages received as well as the "end" message. Currently, I'm routing the messages to an aggregator which completes when it finds a "header" and "end" message for a particular correlation id. Unfortunately, the response is being sent before (or at the same time?) the message is sent to the aggregator, so I don't have access to the aggregated message (which contains all the data I need to build the correct response) when building the response.
Is there a way to do this without manually storing and accessing the accumulated data (that is, without re-implementing camel's aggregator)?
Edit:
Route is something like:
<camelContext>
<route>
<from uri="mina:..."/>
<process ref="messageProcessor"/>
<aggregate>
<process ref="completeMessageProcessor"/>
</aggregate>
</route>
</camelContext>
I left out some tags and attributes (correlationExpression, completionPredicate, strategyRef, etc.) for clarity.
The messages were being aggregated properly, and they were being processed properly when "completed" (that is, when aggregated). But the response sent back through the mina endpoint to the client was the one generated by the messageProcessor, never the one generated by the completeMessageProcessor.
For example (and yes, it's a rather contrived example, but bear with me), let's say the protocol involves the client sending a header message which includes the total number of data messages it expects to send. Then it sends a number of data messages, which might be different in number to what it expected to send. Finally, it sends a footer, or end, message. The server should then respond back with the difference between the expected number of messages and the actual number of messages. With the route as written, that is impossible, since the number of messages is not known by the messageProcessor, which only processes individual messages. The completeMessageProcessor, having the aggregated message (consisting of header, all the data, and the end) does know this number, but the response generated at that point is not propagated back to the mina endpoint.
Changing the parsing of the messages to generate a message only when entire composed message is received is not an option, since the server must respond to the individual messages.
off the top, my guess is that the messageProcessor is setting up the OUT message, but the completeMessageProcessor is setting up the IN message. The mina consumer response is expecting/using the OUT message instead.
you can add some logging to verify this. if this is the case, then you might change your messageProcessor to use the IN body instead (or use exchanges headers) and add a transform after your completeMessageProcessor to set the OUT body based on the IN body
<transform>
<simple>${in.body}</simple>
</transform>
see this for more information: http://camel.apache.org/using-getin-or-getout-methods-on-exchange.html
UPDATE: after some discussion, the real issue is that the aggregator currently only handles "InOnly" exchanges