Message Queue vs Task Queue difference
I wonder what is the difference between them. Are they describing the same thing?
Is Google App Engine Service Task Queue is an implementation of Message Queue?
Answer
I asked a similar question on some Developer Community Groups on Facebook. It was not about GoogleAppEngine specifically - i asked in more of a general sense to determine use case between RabbitMQ and Celery. Here are the responses I got which I think is relevant to the topic and fairly clarifies the difference between a message queue and a task queue.
I asked:
Will it be appropriate to say that "Celery is a QueueWrapper/QueueFramework which takes away the complexity of having to manage the internal queueManagement/queueAdministration activities etc"?
I understand the book language which says "Celery is a task queue" and "RabbitMQ is a message broker". However, it seems a little confusing as a first-time celery user because we have always known RabbitMQ to be the 'queue'.
Please help in explaining how/what celery does in constrast with rabbitMQ
A response I got from Abu Ashraf Masnun
Task Queue and Message Queue. RabbitMQ is a "MQ". It receives messages and delivers messages.
Celery is a Task Queue. It receives tasks with their related data, runs them and delivers the results.
Let's forget Celery for a moment. Let's talk about RabbitMQ. What would we usually do? Our Django/Flask app would send a message to a queue. We will have some workers running which will be waiting for new messages in certain queues. When a new message arrives, it starts working and processes the tasks.
Celery manages this entire process beautifully. We no longer need to learn or worry about the details of AMQP or RabbitMQ. We can use Redis or even a database (MySQL for example) as a message broker. Celery allows us to define "Tasks" with our worker codes. When we need to do something in the background (or even foreground), we can just call this task (for instant execution) or schedule this task for delayed processing. Celery would handle the message passing and running the tasks. It would launch workers which would know how to run your defined tasks and store the results. So you can later query the task result or even task progress when needed.
You can use Celery as an alternative for cron job too (though I don't really like it)!
Another response I got from Juan Francisco Calderon Zumba
My understanding is that celery is just a very high level of abstraction to implement the producer / consumer of events. It takes out several painful things you need to do to work for example with rabbitmq. Celery itself is not the queue. The events queues are stored in the system of your choice, celery helps you to work with such events without having to write the producer / consumer from scratch.
Eventually, here is what I took home as my final learning:
Celery is a queue Wrapper/Framework which takes away the complexity of having to manage the underlying AMQP mechanisms/architecture that come with operating RabbitMQ directly