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

## Stop the docker

Before we start changing the code of the application, we have to tear down the system that’s running by executing the command below:

```
$ python3 manage.py compose down
/*
Stopping production_web_1   ... done
Stopping production_nginx_1 ... done
Stopping production_db_1    ... done
Removing production_web_1   ... done
Removing production_nginx_1 ... done
Removing production_db_1    ... done
Removing network production_default
*/
```


## Changes in the application
Thanks to the common interface between repositories, moving from the memory-based `MemRepo` to `PostgresRepo` is very simple. Because the external database won’t contain any data initially, the response of the use case will be empty.

First of all, let’s move the application to the PostgreSQL repository. The new version of the endpoint is as follows:


# Stop the docker

Before we start changing the code of the application, we have to tear down the system that’s running by executing the command below:

```
$ python3 manage.py compose down
/*
Stopping production_web_1   ... done
Stopping production_nginx_1 ... done
Stopping production_db_1    ... done
Removing production_web_1   ... done
Removing production_nginx_1 ... done
Removing production_db_1    ... done
Removing network production_default
*/
```


# Changes in the application
Thanks to the common interface between repositories, moving from the memory-based `MemRepo` to `PostgresRepo` is very simple. Because the external database won’t contain any data initially, the response of the use case will be empty.

First of all, let’s move the application to the PostgreSQL repository. The new version of the endpoint is as follows:


# Stop the docker

Before we start changing the code of the application, we have to tear down the system that’s running by executing the command below:

```
＄ python3 manage.py compose down
/*
Stopping production_web_1   ... done
Stopping production_nginx_1 ... done
Stopping production_db_1    ... done
Removing production_web_1   ... done
Removing production_nginx_1 ... done
Removing production_db_1    ... done
Removing network production_default
*/
```


# Changes in the application
Thanks to the common interface between repositories, moving from the memory-based `MemRepo` to `PostgresRepo` is very simple. Because the external database won’t contain any data initially, the response of the use case will be empty.

First of all, let’s move the application to the PostgreSQL repository. The new version of the endpoint is as follows:


Let’s learn how to connect to the database of a production-ready system.

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

Connect to a Production-ready Database

Stop the docker

Changes in the application