PJ - Python Junior

Project to store the questions and answers for interview.

Table of Contents

• Global Development Requirements
• Running and working with the app locally
• Testing
• Project structure
• Initial setup
  • Setup Database
  • Add pre-commit hooks
  • Run pre-commit hooks
• Docker
• Other

Global Development Requirements

• Python 3.11
• Django >= 4.0
• Postgresql >= 14.5
• Docker and docker-compose (optional)

Running and working with the app locally

Instead of the standard runserver manage command (./manage.py runserver) you can use

(venv) $ ./manage.py runserver_plus

to run the app. This will enhance the server with the Werkzeug interactive debugger that will allow you to interact with your code (debug it) in the browser, when it throws an exception instead of returning a valid response.

Similarly, instead of ./manage shell you can use

(venv) $ ./manage.py shell_plus

and have your models (and a few frequently needed classes and modules) will be automatically imported.

Testing

pytest used for tests. Check https://djangostars.com/blog/django-pytest-testing/ article if not familiar.

Use following command to run tests before commit (With this call, pytest will spawn a number of workers processes equal to the number of available CPUs, and distribute the tests randomly across them):

pytest -n auto

Or during development:

pytest -s -vv --no-migrations --reuse-db --tb=short

Explanation (some flags used in pytest.ini):

• -s - don't capture output. By default pytest captures standard output while running tests.
• -vv - increases the verbosity level. Or use -v It’s only if a test fails that it shows the captured output.
• --no-migrations: This flag is specific to Django projects. It disables the execution of database migrations during testing.
• --reuse-db - after the test run, the test database will not be removed.
• --tb=short - sets the level of detail for the displayed traceback output when a test fails. In this case, short is the value specified. It provides a shorter traceback with only the most relevant information about the failure.

Optional:

• --disable-warnings - to disable warnings during the tests.
• --sw - run tests in stepwise move. The test suite will run until the first failure and then stop. At the next invocation, tests will continue from the last failing test and then run until the next failing test.

Caveat: If there were updates in the database, with you need to specify --create-db flag to update database with the last changes.

Project structure

.
├── .github/ - github actions
├── requirements/
│   ├── base.txt
│   ├── dev.txt
│   └── prod.txt
├── src/ - source directory
│   ├── apps/ - applications with business logic
│   ├── settings/ - project settings
│   ├── api_urls.py
│   └── urls.py
├── tests/
│   ├── apps/ - tests for apps
│   └── conftest.py - file with fixtures
├── .env.example - file with environment varialbes
├── Dockerfile
├── README.md
├── docker-compose.yml
├── manage.py
├── pyproject.toml
└── pytest.ini

Initial setup

• Clone the project
• Create an env dir and activate

python3.11 -m venv venv
source venv/bin/activate

• Install requirements.txt

(venv) $ pip install -r requirements/dev.txt

• Setup .env file. Copy and rename .env.example -> .env and fill with proper values. Check django-environ for details.

Setup Database

Override database configs in your .env file if necessary. postgres command to setup the DB

psql
#: CREATE DATABASE pythonjunior WITH OWNER postgres;

Before being able to run the project, you'll at least have to set up the database. (Remember, local settings go into the local.py file.) PostgreSQL is the db used for production, and multiple PostgreSQL-specific extensions are used.

After setting up the db, you should run

(venv) $ ./manage.py migrate

Add pre-commit hooks

pre-commit install

This will enable black, flake8 and default pre-commit hooks such as end-of-file-fixer.

Run pre-commit hooks

This command will format all changed files properly and also highlight problematic places

pre-commit

Then add any changed files to commit and try committing the changes.

Docker

Docker and docker-compose also available

docker-compose build
docker-compose up

or

docker-compose up --build

Other

• Update TOC in the README.md file (details)

markdown-toc -h 3 -t github README.md