In my knowledge, rabbitmq is a HA message queue. Is is possible use it as a task queue.
Some requirement:
load balanced should consider the worker node idle resource
should dynamic add/del worker thread
worker node hot-plugging
can dynamice set routing.
As rabbitmq consumer can fetch message and define callback function to handle the message.
it is much possible to do that. But I don't know how to use it flexible,dynamically.
Can you give some example or idea?
In RabbitMQ, if more than one consumers binds to a queue, then messages will be load-balanced in a round-robin fashion.
To better understand, you can read this article.
https://techietweak.wordpress.com/2015/08/14/rabbitmq-a-cloud-based-message-oriented-middleware/
Thanks,
Saravanan S.
Related
I am using Spring AMQP to listen RabbitMQ queue. While listening queue, depending on business logic, my service can throw RuntimeException and in this case message will retry several times. After max count retries, message will stay in DLQ. And I am wondering, what is the best approach to deal with these messages in DLQ? I read from blogs that I can use ParkingLot Queue. But also in this case, how to monitor the queue and notify people about dead-letter messages?
P.S. Sorry for my English. Hope that I was able to explain my problem :)
You can use the RabbitMQ REST api (Hop client) to get the status of the DLQ.
You can also use Spring's RabbitAdmin.getQueueProperties("my.dlq") to get the message count.
https://docs.spring.io/spring-amqp/docs/current/reference/html/#broker-configuration
Other options include adding another listener on the DLQ and run it periodically to either send it back to the original queue or send it to a parking lot queue if it fails too many times.
There's an example of that in the spring cloud stream documentation.
I'm doing some research if rabbitMQ is the way to go for me.
Can I mix publish/subscribe and worker queues?
The goal is to have have a few queues which holds items of for specific process.
Each process can have a lot of workers.
The setup shown in this diagram is possible. If the exchange X is a direct or topic exchange, the 'specific process' would be represented by one of the two queues and routing of messages would be based on the routing key or topic of a message.
Consumers ('workers') would consume messages from the queues using round-robin.
So I'm testing RabbitMQ in one node. Plain and simple,
One producer sends messages to the queue,
Multiple consumers take tasks from that queue.
Currently consumers execute thousands of messages per second, they are too fast so I need them to slow down. Managing consumer-side throttling is not possible due to network unreliable nature.
Collectively consumers must not take more than 10 messages per second altogether from that queue.
Is there a way to configure RabbitMQ so as the queue dispatches a maximum of 10 messages per second?
If I remember correctly, once Rabbit MQ has delivered a message to the queue, it's up to consumers to consume a message. There are various consumers in different languages, you haven't mentioned anything specific, so I'm giving a generic answer.
In my understanding, you shouldn't try to impose any restrictions on Rabbit MQ itself, instead, consider implementing connection pool of message consumers that will be able to handle not more than X messages simultaneously on the client side. Alternatively, you can provide some kind of semaphore at the handler itself, but not on the Rabbit MQ server itself.
Is it possible to implement the aggregator pattern in RabbitMQ?
I have A … N messages that I need to wait for/aggregate before sending off to another queue X.
So I'm thinking I will have some kind of unique ID that ensures that messages are routed exclusively to the same consumer and then wait for all the messages to arrive.
Is this possible in RabbitMQ?
Yes, it is possible.
But this is not RabbitMQ specific. Understanding what to aggregate and how to do it is beyond the responsibility of the message broker.
You need to write a service to subscribe to the relevant messages and then publish the result back. In the context of RabbitMQ, you could use routing keys to ensure the right consumer gets the messages, but that is not the only way.
I am starting with ActiveMQ and I have a usecase. i have n producers sending messages into a Queue Q1. I want to stop the delivery of messages (i.e. i do not want consumers to consume those messages). I want to store the messages for sometime without those being consumed.
I was looking at ways this can be achieved. These two things came into my mind based on what i browsed through.
Using Mirrored queues, so that I can wiretap the messages and save into a virtual queue.
Possibly stop consumers from doing a PULL on the queue.
Another dirty way of doing this is by making consumers not send ack messages once its consumed a message from the queue.
We are currently not happy with either of these.
Any other way you can suggest.
Thanks in advance.
If you always want message delivery to be delayed you can use the scheduler feature of ActiveMQ to delay delivery until a set time or a fixed delay etc.
Other strategies might also work but it really up to you to design something that fits your use case. You can try to use Apache Camel to define a route that implements the logic of your use case to either dispatch a message to a Queue or send it to the scheduler for delayed processing. It all really depends on your use case and requirements.