I have a use case where i have to re-queue the message with updated properties , Messages are getting re queued but message properties are not getting updated
public class TestListener implements MessageListener{
#Override
public void onMessage(Message arg0) {
MessageProperties properties = arg0.getMessageProperties();
int count = properties.getMessageCount();
System.out.println(count);
properties.setMessageCount(++count);
throw new AmqpException("test");
}
But the value of count always prints its always as 0
You can't do that - the amqp protocol does not support sending data back when rejecting a message.
You have to republish the message yourself, e.g with a RabbitTemplate.send() call.
You should also not use a "system" property for your own purposes; use messageGetProperties().set("myHeader", count++).
Related
I am using message listener for performing some actions on activeMQ queues
I want to check size of queue while performing.
I am using below logic but it works outside listener.
Any suggestion?
public class TestClass {
MessageConsumer consumerTransformation;
MessageListener listenerObjectTransformation;
public static void main(String []args) throws JMSException {
ActiveMQModel activeMQModelObject = new ActiveMQModel();
//String subject = "TRANSFORMATION_QUEUE";
String subject = "IMPORT_QUEUE";
//consumerTransformation = activeMQModelObject.getActiveMQConsumer(subject);
// Here we set the listener to listen to all the messages in the queue
//listenerObjectTransformation = new TransformationMessageListener();
//consumerTransformation.setMessageListener(listenerObjectTransformation);
boolean isQueueEmpty = activeMQModelObject.isMessageQueueEmpty(subject);
System.out.println("Size " + isQueueEmpty);
}
/*private class TransformationMessageListener implements MessageListener {
#Override
public void onMessage(Message messagearg) {
System.out.println("test....");
}
}*/
}
What is way to check activeMQ queue size from message listener
The JMS API does not define methods for checking Queue size or other metrics from a client, the API is meant to decouple the clients from any server administration and from each other. A sender has no awareness of the receivers that might or might not be there and the receiver is unaware of who might be producing or if there is anything to consume at that given moment. By using the asynchronous listener you are subscribing for content either currently available or content yet to be produced.
You can in some cases make us of the JMX metrics that are available from the server in your code but this is not good practice.
How do I get a timestamp for when a message was received by RabbitMQ? In our application, we would like to measure how long a message was in the queue:
time_in_queue=System.currentTimeMillis() - timestamp_from_msg
I updated the "rabbitmq-message-timestamp" plugin. My change was merged and it is possible to use the new header "timestamp_in_ms" which contains timestamp in milliseconds.
There's the rabbitmq_message_timestamp plugin that does that:
A plugin that adds a timestamp when a
message first enters RabbitMQ.
Author: Team RabbitMQ
Github: rabbitmq/rabbitmq-message-timestamp
At least as of RMQ 5.10.0, it appears that there is a getTimestamp() method on the properties object returned with each message.
public class ExchangeConsumer extends DefaultConsumer {
...
#Override
public void handleDelivery(String consumerTag,
Envelope envelope,
AMQP.BasicProperties properties,
byte[] body) throws IOException {
Date timestamp = properties.getTimestamp();
}
I am trying to use delayed exchange plugin, but somehow its not working for me and message are received without delay.
I tried following things :
a) enabled rabbitmq_delayed_message_exchange successfully and restarted rabbitmq server on ubuntu-16.04.
b) Declaring exchange
Map<String,Object> props = new HashMap<String,Object>();
props.put("x-delayed-type", "direct");
this.automationExchange = new DirectExchange(exchangeName,true,false, props);
c) Pushing message as
DefaultClassMapper typeMapper = QueueUtils.classMapper;
typeMapper.setDefaultType(type);
Jackson2JsonMessageConverter converter = QueueUtils.converter;
converter.setClassMapper(typeMapper);
RabbitTemplate template = AMQPRabbitMQTemplate.getAMQPTemplate();
template.setMessageConverter(converter);
template.convertAndSend(routingKey, message, new MessagePostProcessor() {
#Override
public Message postProcessMessage(Message m) throws AmqpException {
m.getMessageProperties().setDelay(delayMiliSeconds);
m.getMessageProperties().setDeliveryMode(MessageDeliveryMode.PERSISTENT);
return m;
}
});
Now when i am printing message
public void onMessage(Message message, Channel channel) throws Exception{
System.out.println(message.getMessageProperties().getDelay());
channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
}
It is printing null for getDelay, which ideally should be negative of set value as per https://www.rabbitmq.com/blog/2015/04/16/scheduling-messages-with-rabbitmq.
Please let me know if i am doing something wrong.
I am using 1.6.8.RELEASE version for spring-amqp and spring-rabbit.
In order to avoid unexpected propagation of headers from an inbound message to an outbound message, certain headers for inbound messages are provided by MessageProperties.getReceived... methods.
In this case, the header is in MessageProperties.getReceivedDelay().
You also need setDelayed(true) on automationExchange before declaring it with the admin.
I presume you have set the exchange as the default in the RabbitTemplate too.
I've read that each message handler is wrapped in an "ambient transaction", and that database access is automatically enlisted in that transaction when possible. Does NServiceBus do anything else with that transaction? Specifically, I'm wondering if it can somehow cancel any messages that a handler sends/publishes in the case of an exception.
In the code below, does the bus Send the ArchiveMessage as soon as the Send method is called, or does it queue it up and only send it if the handler executes successfully?
public class BadHandler
{
public IBus Bus { get; set; }
public void Handle(MyMessage msg)
{
Bus.Send(new ArchiveMessage(msg.MessageId)); //does this message send?
throw new Exception("Something terrible happened, maybe my database connection failed!");
}
}
I this case the message would not be sent. MyMessage will be retried the configured number of times and them moved to the designated error queue. You can have greater control over that process if you wish, you would need to create a custom FaultManager.
If I have a saga that consists of two message types, say started by message1 and completed by message2, can I return a callback if a message2 comes in without a message1 already existing? I know it will dump it in the error queue, but I want to be able to return a status to the sending client to say there is an error state due to the first message not being there.
So I figured it out, I just needed to implement IFindSagas for the message type:
public class MySagaFinder : IFindSagas<MySagaData>.Using<Message2>
{
public ISagaPersister Persister { get; set; }
public IBus Bus { get; set; }
public MySagaFinder FindBy(Message2 message)
{
var data = Persister.Get<MySagaData>("MessageIdProperty", message.MessageIdProperty);
if (data == null)
{
Bus.Return(0);
}
return data;
}
}
I don't know if this is the right way to do it, but it works!
If you have a saga that can receive two messages, but messages can be received in any order, make sure the saga can be started by both messages. Then verify if both message have arrived by setting some state in the saga itself. If both messages have arrived, mark it as complete.
Default NServicebBus behavior is to ignore any message that has no corresponding saga. This is because you can set a timeout, for example. If nothing happens within 24 hours, the saga can send a Timeout message to itself. But if something did happen and you marked your saga as being completed, what should happen to the Timeout message? Therefor NServiceBus ignores it.