python 53 lines · 8 steps

How a Django settings module is wired

A settings file assembles paths, secrets, apps, middleware, and the database from code and environment variables.

Explained by highlit
Django Intermediate configuration environment-variables middleware project-structure
1import os
2from pathlib import Path
3 
4BASE_DIR = Path(__file__).resolve().parent.parent.parent
5 
6SECRET_KEY = os.environ["DJANGO_SECRET_KEY"]
7 
8INSTALLED_APPS = [
9 "django.contrib.admin",
10 "django.contrib.auth",
11 "django.contrib.contenttypes",
12 "django.contrib.sessions",
13 "django.contrib.messages",
14 "django.contrib.staticfiles",
15 "rest_framework",
16 "accounts",
17 "billing",
18]
19 
20MIDDLEWARE = [
21 "django.middleware.security.SecurityMiddleware",
22 "django.contrib.sessions.middleware.SessionMiddleware",
23 "django.middleware.common.CommonMiddleware",
24 "django.middleware.csrf.CsrfViewMiddleware",
25 "django.contrib.auth.middleware.AuthenticationMiddleware",
26 "django.contrib.messages.middleware.MessageMiddleware",
27]
28 
29ROOT_URLCONF = "config.urls"
30WSGI_APPLICATION = "config.wsgi.application"
31 
32DATABASES = {
33 "default": {
34 "ENGINE": "django.db.backends.postgresql",
35 "NAME": os.environ["POSTGRES_DB"],
36 "USER": os.environ["POSTGRES_USER"],
37 "PASSWORD": os.environ["POSTGRES_PASSWORD"],
38 "HOST": os.environ.get("POSTGRES_HOST", "localhost"),
39 "PORT": os.environ.get("POSTGRES_PORT", "5432"),
40 }
41}
42 
43AUTH_USER_MODEL = "accounts.User"
44 
45LANGUAGE_CODE = "en-us"
46TIME_ZONE = "UTC"
47USE_I18N = True
48USE_TZ = True
49 
50STATIC_URL = "static/"
51STATIC_ROOT = BASE_DIR / "staticfiles"
52 
53DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"
01 / 01
STEP 01

Walkthrough

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Three takeaways
  1. 1Deriving BASE_DIR from __file__ makes every path relative to the project, not the working directory.
  2. 2Reading secrets and credentials from os.environ keeps them out of source control and lets deploys differ safely.
  3. 3Django assembles its behavior from ordered lists and dotted string paths that it imports lazily at startup.

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