Am using the #MessageMapping(queue_name) annotation along with the spring-aws-cloud library to consume messages from two SQS queues.
I see that the SimpleMessageListenerContainer is used as the listener container for both message queues. There is a start() and a stop() method on the container, but I believe that will start/stop consumption from both queues.
I wanted to know if there is a way to programatically start/stop queue consumption for the queues separately. How can that be achieved?
Use start(queueName) and stop(queueName) function of SimpleMessageListenerContainer to start and stop individual queues programmatically.
You need separate containers for each queue to start/stop listening independently.
From a quick look at the code, it appears to me that there is only one listener container when using the annotation to create listeners.
I suggestion you open an issue/feature suggestion in GitHub; I suggest you post the issue number back here so interested parties can follow the discussion.
Related
I have a set of microservices using springboot rest. These microservices will be deployed in a autoscaled and load balanced environment. One of these services is responsible for managing the system's configuration. When other microservices startup, they obtain the configuration from this service. If and when the configuration is updated, I need to inform all currently running microservices instances to update their cached configuration.
I am considering using RabbitMQ with a fanout exchange. In this solution, each instance at startup will create its queue and bind that queue to the exchange. When there is a configuration change, the configuration service will publish an update to all queues currently bound to that exchange.
However, as service instances are deleted, I cannot figure out how would I delete the queue specific to that instance. I googled but could not find a complete working example of a solution.
Any help or advise?
The idea and solution is correct. What you just miss that those queues, created by your consumer services could be declared as auto-delete=true: https://www.rabbitmq.com/queues.html. As long as your service is UP, the queue is there as well. You stop your service, its consumers are stopped and unsubscribed. At the moment the last consumer is unsubscribed the queue is deleted from the broker.
On the other hand I would suggest to look into Spring Cloud Bus project which really is aimed for tasks like this: https://spring.io/projects/spring-cloud-bus.
I want to stop/pause the queue so that (https://issues.apache.org/jira/browse/AMQ-5229)
NO messages sent to the associate consumers
messages still to be enqueued on the queue
ability to be able to browse the queue
all the JMX counters for the queue to be available and correct.
Added: Apache ActiveMQ (Version 5.16.2)
But I don't know where to create the bean of JmsListenerEndpointRegistry and call start and stop method.
Sample code will be appreciated. Thanks.
The JmsListenerEndpointRegistry is automatically configured by Spring Boot.
Simply #Autowired it into the controlling class, give the JmsListener an id and stop/start it using the id.
Note: this does not use the AMQ feature you referenced; it simply tells the listener container to stop/start receiving messages.
I'm using a Spring project where I have an implementation of JMS Event listener to process messages from a queue.
To be precise, I'm using a SQS (AWS) queue.
All works fine.
My point is this:
I not configured anything about the concurrency but I would like to have more threads as listener to increase the performances (speed) about the messages processing from the queue.
I'm thinking about the possibility to configure a ThreadPool (TaskExecutor) and adding the annotation #Async on my methods about the message processing.
So, I will have a onMessage method into my listener where, after message validation I will call this async methods.
Is this a good practice? Will I have some issues using this approach?
I'm looking on the web for this and I see that I's possible to configure directly the concurrency value on the listener.
I'm very confusing there are a lot of possible ways to have this and I'm not able to understand the best approach.
Are these equivalent solutions?
Do not use #Async - simply increase the concurrency of the listener container and it will be handled for you automatically by spring-jms.
Using Spring boot #RabbitListener, we are able to process the AMQP messages.
Whenever a message sent to queue its immediately publish to destination exchange.
Using #RabbitListener we are able to process the message immediately.
But we need to process the message only between specific timings example 1AM to 6AM.
How to achieve that ?
First of all you can take a look into Delayed Exchange feature of RabbitMQ: https://docs.spring.io/spring-amqp/docs/current/reference/html/#delayed-message-exchange
So, this way on the producer side you should determine how long the message should be delayed before it is routed to the main exchange for the actual consuming afterwards.
Another way is to take a look into Spring Integration and its Delayer component: https://docs.spring.io/spring-integration/docs/5.2.0.BUILD-SNAPSHOT/reference/html/messaging-endpoints.html#delayer
This way you will consume messages from the RabbitMQ, but will delay them in the target application logic.
And another way I see like start()/stop() the listener container for consumption and after according your timing requirements. This way the message is going to stay in the RabbitMQ until you start the listener container: https://docs.spring.io/spring-amqp/docs/current/reference/html/#containerAttributes
In my POC, I am using Spring Cloud Config and Spring Stream Rabbit. I want to dynamically change number of listeners (concurrency). Is it possible to do that? I want to do following:
1) If there are too many messages in queue, i want to increase concurrency level.
2) In scenario where my downstream system is not available, I want to stop processing messages from queue (in short concurrency level 0).
How i can achieve this?
Thanks for help.
The listener container running in the binder supports such changes (although you can't go down to 0, but the container can be stop() ped).
However, spring-cloud-stream provides no mechanism for you to get a reference to the listener container.
You might want to consider using a #RabbitListener from Spring AMQP instead - it will give you complete control over the listener container.