PatCat

27 Jun 2022 in Blog on Django, Blockchain Last modified at: 2024-08-18

PatCat (Pattern Catalog) is a web catalog of business patterns applied in real cases of e-government.

Check the Live project and Github code

Architecture

The system is a Django web application that is deployed in AWS lambdas using Zappa. The application contains an SQLite in-memory database that obtains its data from a JSON file. The file is stored in an S3 bucket, and through the use of signals, it updates the file when a change in the database state occurs.

This architecture was chosen in the context of an application that will be used mostly for queries and will have a single administrator at any one time. This application requires a small database with public data.

Advantages of the architecture:

• Cost: Based on the expected usage, the application can run indefinitely on AWS’s free layer.
• Modularity: The data persistence mechanism can be modified at any time by removing the memoryDB application and configuring the new database from the settings file.
• Scalability: Because the application is deployed in AWS lambdas, it can scale automatically to provide services to an unlimited number of users.

Disadvantages of the architecture:

• Performance: Loading data into the memory database adds processing overhead that can decrease application response time.
• Data scalability: The persistence mechanism is not suitable for large amounts of data.

Sections

Admin section

This section that allows an administrator to register all the data of the pattern catalog

Researcher section

This section allows a researcher to search for business patterns that fit the problem they are dealing with.

Modules

Pattern

Manages the application models and their modification by an administrator.

Data models

MemoryDB

Data models

This module allows the application to manage a database in memory, making a single query to the real database, which is a file stored in an AWS S3

Installation

Install python 3.9 (for linux)

    sudo apt update
    sudo add-apt-repository ppa:deadsnakes/ppa
    sudo apt install python3.9
    sudo apt install python3.9-venv

Create virtual environment

    python3.9 -m venv venv

Install libraries:

    pip install -r requirements.txt

Generating the docs

    python manage.py graph_models -o docs/patterns_models.png

Development

To test the application run the init.sh script

    source init.sh

Deploy Django App as AWS Lambda

Collect the static files and place them in the S3.

    python manage.py collectstatic

Deploy lambda with Zappa

    zappa init
    zappa deploy
    zappa update