How to get signals.py executed in django? - python-3.x

Question

I run the following signals.py on (Ubuntu2204/WSL2 Windows 11) using Django 4.1.1 / Python 3.10
from .models import Sale
from django.db.models.signals import m2m_changed
from django.dispatch import receiver
#receiver(m2m_changed, sender=Sale.positions.through)
def calculate_total_price(sender, instance, action, **kwargs):
print('action', action)
total_price = 0
if action == 'post_add' or action == 'post_remove':
for item in instance.get_positions():
total_price += item.price
instance.total_price = total_price
instance.save()
apps.py already signals in VSCode that signals is not used, this is also confirmed in the Django Debug Toolbar
from django.apps import AppConfig
class SalesConfig(AppConfig):
#default_auto_field = 'django.db.models.BigAutoField'
name = 'sales'
def ready(self):
import sales.signals
and then the __init__.py file
default_app_config = 'sales.apps.SalesConfig'
settings.py looks like this:
"""
Django settings for reports_proj project.
Generated by 'django-admin startproject' using Django 4.1.1.
For more information on this file, see
https://docs.djangoproject.com/en/4.1/topics/settings/
For the full list of settings and their values, see
https://docs.djangoproject.com/en/4.1/ref/settings/
"""
from pathlib import Path
# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent
# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/4.1/howto/deployment/checklist/
# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = "django-insecure-dbl^hk-m6-dz01+1i*hi5#rz4t90(y5s-cls1&0js5hj^ojo70"
# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True
ALLOWED_HOSTS = []
# Application definition
INSTALLED_APPS = [
"django.contrib.admin",
"django.contrib.auth",
"django.contrib.contenttypes",
"django.contrib.sessions",
"django.contrib.messages",
"django.contrib.staticfiles",
"debug_toolbar",
# my apps
"customers",
"products",
"profiles",
"reports",
"sales.apps.SalesConfig",
# 3rd party
"crispy_forms",
]
CRISPY_TEMPLATE_PACK = "bootstrap4"
MIDDLEWARE = [
"django.middleware.security.SecurityMiddleware",
"django.contrib.sessions.middleware.SessionMiddleware",
"django.middleware.common.CommonMiddleware",
"django.middleware.csrf.CsrfViewMiddleware",
"debug_toolbar.middleware.DebugToolbarMiddleware",
"django.contrib.auth.middleware.AuthenticationMiddleware",
"django.contrib.messages.middleware.MessageMiddleware",
"django.middleware.clickjacking.XFrameOptionsMiddleware",
]
ROOT_URLCONF = "reports_proj.urls"
TEMPLATES = [
{
"BACKEND": "django.template.backends.django.DjangoTemplates",
"DIRS": [BASE_DIR / 'templates'],
"APP_DIRS": True,
"OPTIONS": {
"context_processors": [
"django.template.context_processors.debug",
"django.template.context_processors.request",
"django.contrib.auth.context_processors.auth",
"django.contrib.messages.context_processors.messages",
],
},
},
]
WSGI_APPLICATION = "reports_proj.wsgi.application"
# Database
# https://docs.djangoproject.com/en/4.1/ref/settings/#databases
DATABASES = {
"default": {
"ENGINE": "django.db.backends.sqlite3",
"NAME": BASE_DIR / "db.sqlite3",
}
}
# Password validation
# https://docs.djangoproject.com/en/4.1/ref/settings/#auth-password-validators
AUTH_PASSWORD_VALIDATORS = [
{
"NAME": "django.contrib.auth.password_validation.UserAttributeSimilarityValidator",
},
{
"NAME": "django.contrib.auth.password_validation.MinimumLengthValidator",
},
{
"NAME": "django.contrib.auth.password_validation.CommonPasswordValidator",
},
{
"NAME": "django.contrib.auth.password_validation.NumericPasswordValidator",
},
]
# Internationalization
# https://docs.djangoproject.com/en/4.1/topics/i18n/
LANGUAGE_CODE = "en-us"
TIME_ZONE = "UTC"
USE_I18N = True
USE_TZ = True
# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/4.1/howto/static-files/
STATIC_URL = '/static/'
STATICFILES_DIRS = [
BASE_DIR / 'static',
BASE_DIR / 'sales' / 'static',
]
MEDIA_URL = '/media/'
MEDIA_ROOT = BASE_DIR / 'media'
# Default primary key field type
# https://docs.djangoproject.com/en/4.1/ref/settings/#default-auto-field
DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"
INTERNAL_IPS = [
"127.0.0.1",
]
Any hint would be highly appreciated, the code looks ok to me it must be some dependency issue but I have no idea where to start looking really

Answer 1

I just noticed that your ready identation is not correct, causing the problem...
You should change this:
from django.apps import AppConfig
class SalesConfig(AppConfig):
#default_auto_field = 'django.db.models.BigAutoField'
name = 'sales'
def ready(self):
import sales.signals
To this:
from django.apps import AppConfig
class SalesConfig(AppConfig):
#default_auto_field = 'django.db.models.BigAutoField'
name = 'sales'
def ready(self):
from . import signals
Generally because no indentation the method became global function and it was not called as it should.