How to deploy a Django application to Heroku

deploy_django_to_heroku.sh

# How to deploy a Django application to Heroku with PostgreSQL

#========== Pre-requirements ==========# 
### 1. make sure Heroku CLI is installed
###    read more here: https://devcenter.heroku.com/articles/heroku-cli
### 2. use virtualenv to control python packages
### 3. replace 'projectname' with your project's name throughout this script
### 4. this script is for MacOS and Bash, but is very similar for Linux and other shells

#========== if you're lazy like me, make an alias ==========#
alias django='python manage.py'

#========== start venv ==========#
### if we don't have virtualenv installed, let's install it
pip install virtualenv

### create new venv, if it doesn't exist already (ignore this step if it does)
virtualenv -p `which python3` venv
echo "venv/" >> .gitignore

### activate venv
source venv/bin/activate

#========== setup staticfile management ==========#
### first, turn off debug settings to simulate production environment
### put this in settings.py
"""
debug = False
allowed_hosts = ['*']
SECRET_KEY = os.environ.get('DJANGO_SECRET_KEY', 'local_insecure_key')
"""

### make sure you have your static files configured properly in settings.py
cat <<EOT >> settings.py
STATICFILES_DIRS = (
    os.path.join(BASE_DIR, '<YOUR STATIC DIRS HERE>'),
)
STATIC_ROOT = os.path.join(BASE_DIR, 'staticfiles')
EOT

### install whitenoise for production static file management
pip install whitenoise

### make sure local still works
django collectstatic
django runserver

#========== switch from SQLite to PostgreSQL ==========#
### install psycopg2 for django ORM
pip install psycopg2-binary

### for MacOS, you might need Homebrew
### install Homebrew from here: https://brew.sh/
### then, do:
brew install postgresql

### make local database
psql
> CREATE DATABASE projectname_db;
> CREATE USER projectname_admin WITH PASSWORD 'projectname_db_password';
> ALTER ROLE projectname_admin SET client_encoding TO 'utf8';
> ALTER ROLE projectname_admin SET default_transaction_isolation TO 'read committed';
> ALTER ROLE projectname_admin SET timezone TO 'UTC';
> GRANT ALL PRIVILEGES ON DATABASE projectname_db TO projectname_admin;
> ALTER DATABASE projectname_db OWNER TO projectname_admin;
> \q

### set up credentials
export DB_PASSWORD=projectname_db_password

### configure Django db management
pip install dj_database_url

### add the following to settings.py IN PLACE OF your previous `DATABASES = ...`
"""
DATABASES = {
    'default': dj_database_url.config()
}
try:
    from local_settings import *
except ImportError:
    pass
"""

### then, add this to a new local_settings.py file
"""
import os
DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql_psycopg2",
        'NAME': 'projectname_db',
        'USER': 'projectname_admin',
        'PASSWORD': os.environ.get('DB_PASSWORD'),
        'HOST': 'localhost',
        'PORT': '5432',
    }
}
"""

### make sure still works on local
django makemigrations
django migrate
django runserver

#========== save deployment ready app to dev git remote ==========#
echo "web: gunicorn projectname.wsgi" > Procfile
pip install gunicorn
pip freeze > requirements.txt
echo "staticfiles/" >> .gitignore

git add -A
git commit -m "Ready for deploy"
git push

#========== configure heroku ==========#
### create app(s), usually one for production and one for development
### make sure you repeat each of these steps for each app you create
### it's good to start with dev, then repeat with prod
heroku create projectname-dev
heroku create projectname-prod

### initial push to Heroku
git push https://git.heroku.com/projectname-dev.git master

### setup necessary environment variables
### go to https://djskgen.herokuapp.com/ to generate a secure Django secret ID
heroku config:set --app projectname-dev DJANGO_SECRET_KEY="YOUR SECRET KEY"
heroku config:set --app projectname-dev DB_PASSWORD=$DB_PASSWORD

### configure PostgreSQL addon
heroku addons:create --app projectname-dev heroku-postgresql:hobby-dev

### migrate the database
heroku run --app projectname-dev python manage.py makemigrations
heroku run --app projectname-dev python manage.py migrate

### if you have a script to initialize database values, run that too
heroku run --app projectname-dev python your_db_script.py

### check the Heroku deployment
open https://projectname-dev.herokuapp.com

### unwind
open https://www.ballastpoint.com/location/ballast-point-miramar/