Building a message bus

For this section, we will be using the Celery and Redis packages to build and run our message bus. Once we have completed this section, our mechanism will take a form that is similar to the following:

Figure 9.6 – A message bus with Flask and Celery

As shown in the preceding diagram, we have two processes running. One is running our Flask application, while the other is running Celery, which handles queuing and processing tasks. To make this work, we are going to perform the following steps:

1. Build a Celery broker for Flask.
2. Build a Fibonacci calculation task for Celery.
3. Update our calculation view with Celery.
4. Define our Celery service in Docker.

Before we embark on these steps, we have to install the following packages using pip:

• Celery: This is the message bus broker that we are going to use.
• Redis: This is the storage system that Celery is going to use.

Now that we have installed...