Depends on what you mean by “blocked”. If you mean “are existing connections closed when rebalance is triggered” then the answer is yes. The current Kafka’s rebalancing algorithm is unfortunately imperfect. Here is what is happening during consumer rebalance. Assume we have a topic with 10 partitions (0-9), and one consumer (lets name it consumer1) … Read more
That’s a great question since they are similar in that they provide an application access to a messaging system. It is how they acheive it I think that differentiates them. The Channel Adapter pattern deals how to get data from an existing system without modifying that system. Typically the Channel Adapdter is implemented out-of-process. Examples … Read more
In your specific case, where it’s just an email queue, I wold take the easy way out and use django-mailer. As a nice side bonues there are other pluggable projects that are smart enough to take advantage of django-mailer when they see it in the stack. As for more general queue solutions, I haven’t been … Read more
Try to install Redis as in your virtual environment as well: pip install Redis
@MSalters Re ‘message queue’: RabbitMQ’s default operation is exactly what you describe: transient pubsub. But with TCP instead of UDP. If you want guaranteed eventual delivery and other persistence and recovery features, then you CAN have that too – it’s an option. That’s the whole point of RabbitMQ and AMQP — you can have lots … Read more
A message queue is a data structure, or a container – a way to hold messages for eventual consumption. A message broker is a separate component that manages queues.
The two are incomparable, as they represent different layers. It’s like comparing a relational database to a file on a disk or comparing a house to a brick (i.e. certainly you need files to build databases and bricks to build houses, and sometimes all you need is a file or a brick, but that does … Read more
Pubsub doesn’t work that way – the message goes to all connected subscribed clients. However, you could set it up so that the channel is a notification of an update to a list. That way all clients will get the message, but only one can take the item from the list with LPOP.
I’m confused by your choice of three terms to compare. Within RabbitMQ, Fanout and Direct are exchange types. Pub-Sub is a generic messaging pattern but not an exchange type. And you didn’t even mention the 3rd and most important Exchange type, namely Topic. In fact, you can implement Fanout behavior on a Topic exchange just … Read more
There is a difference between the publish/subscribe and producer/consumer models. Publish/Subscriber: Subscribers subscribe to the publisher. Each message the Publisher publishes is sent to all the subscribers. That is, all subscribers receive the same message. (Think of a newspaper or magazine subscription. All subscribers receive the same magazine or newspaper) Producer/Consumer: Each message the producer … Read more