Gain insights into clean architecture using Python. Delve into layered systems, design efficient applications, and integrate web components, error handling, and databases with test-driven development practices.

tarball.tar.gz

POSTGRES_USER

POSTGRES_PASSWORD

POSTGRES_HOSTNAME

APPLICATION_DB

POSTGRES_PORT

POSTGRES_DB

Python Execution

Flask

Flask + Postgres

Python Test

Clean architecture is a software design methodology that separates the processes of an application into discrete steps instead of presenting them as “spaghetti code.” With the versatility of Python, software engineers can build performant, modular applications quickly using the Flask framework.

This course will help you build better applications using the principles of clean architecture. You’ll start with an introduction to data flow in clean systems and learn about the advantages of layered architectures. Next, you’ll learn system components and the connections between application layers. You’ll then design and build a clean system using Python by layering components in guided coding exercises. Finally, you’ll learn how to add functional components for the web, handle errors, and work with external databases using both Postgres and MongoDB. At each step, you’ll use test-driven development practices to ensure robust functionality.

Clean Architecture in Python

When we define the database configuration in a JSON file, we need a fixture that loads that same configuration. This is so we can connect to the database during our tests. Since we already have the function `read_json_configuration` in our management script, all we need to do is wrap it.

# Update the conftest file

## Update the common conftest file

This is a fixture that isn’t specific to the PostgreSQL repository, so we’ll introduce it in the following code.

from manage import read_json_configuration

...

@pytest.fixture(scope="session")
def app_configuration():
    return read_json_configuration("testing")


As we can see in the code above, we hardcode the name of the configuration file for the sake of simplicity. Alternately, we can also create an environment variable with the application configuration in the management script and read it from there.

## Update the conftest for our repository

The rest of the fixtures contain code that’s specific to PostgreSQL. Therefore, it’s better to keep the code separated in another file that’s more specific, such as the `conftest.py` file. An example of this is found in the code below:

Let’s learn how to implement and execute test suites with integration.

Get Started

A Day in the Life of a Clean System

Components of Clean Architecture

A Simple Coding Example

Add a Web Application

Error Management

Integration with a Real External System Postgres

Integration with a Real External System MongoDB

Run a Production-ready System

Appendix

Database Fixtures

Update the conftest file

Update the common conftest file