Settings, files, and a checklist to deploy a Django app to Heroku with nginx + gunicorn + postgres + redis and using `poetry` for dependencies.

_heroku-checklist.md

• GitHub for code
• Heroku pipeline with one production app
  • Heroku Postgres
  • Heroku Redis
  • Linked to GitHub repo
  • Add environment variables for ENVIRONMENT=live, DISABLE_COLLECTSTATIC=1, and SECRET_KEY
  • Add pgbouncer and nginx buildpacks
• Cloudflare for SSL and CNAME pointing to Heroku app domain
  • Force SSL with a Cloudflare rule
• Namecheap for the domain
  • Point nameservers to Cloudflare
• Sentry for error logging
• Panelbear and Plausible for privacy-focused analytics
• UptimeRobot to get alerts for when the site goes down

gunicorn.conf.py

def when_ready(server):
    # touch app-initialized when ready
    open("/tmp/app-initialized", "w").close()


bind = "unix:///tmp/nginx.socket"
workers = 3

post_compile

rem this lives in the `bin` directory (i.e. bin/post_compile)

#!/usr/bin/env bash

set -eo pipefail

indent() {
  sed "s/^/       /"
}

puts-step() {
  echo "-----> $@"
}

/app/.heroku/python/bin/python -m pip install --upgrade pip

puts-step "Installing dependencies with poetry..."
poetry config virtualenvs.create false 2>&1 | indent
poetry install --no-dev 2>&1 | indent

puts-step "Collect static files (part 1)..."
python manage.py collectstatic --noinput 2>&1 | indent

puts-step "Compress files..."
python manage.py compress --force 2>&1 | indent

puts-step "Collect static files (part 2)..."
python manage.py collectstatic --noinput 2>&1 | indent

Procfile

web: python manage.py collectstatic --noinput && bin/start-pgbouncer bin/start-nginx gunicorn -c gunicorn.conf.py project.wsgi

requirements.txt

poetry==1.1.6

runtime.txt

python-3.7.12

settings.py

import os
from pathlib import Path

ENVIRONMENT = os.getenv("ENVIRONMENT", "dev")

# Regular dev settings go here

if ENVIRONMENT == "live":
    import dj_database_url
    import sentry_sdk
    from sentry_sdk.integrations.django import DjangoIntegration

    sentry_sdk.init(
        dsn=os.environ.get("SENTRY_DSN"),
        integrations=[DjangoIntegration()],
        traces_sample_rate=1.0,
        send_default_pii=True,
    )

    DEBUG = False
    COMPRESS_OFFLINE = True

    ALLOWED_HOSTS += [
        "ADD-DOMAINS-HERE"
    ]

    CACHES = {
        "default": {
            "BACKEND": "django_redis.cache.RedisCache",
            "LOCATION": os.environ.get("REDIS_URL"),
            "OPTIONS": {"CLIENT_CLASS": "django_redis.client.DefaultClient"},
        }
    }

    DATABASES["default"] = dj_database_url.config(conn_max_age=600)

    LOGGING = {
        "version": 1,
        "disable_existing_loggers": False,
        "formatters": {
            "console": {
                "format": "[%(asctime)s][%(levelname)s] %(name)s "
                "%(filename)s:%(funcName)s:%(lineno)d | %(message)s",
                "datefmt": "%H:%M:%S",
            },
            "verbose": {
                "format": (
                    "%(asctime)s [%(process)d] [%(levelname)s] "
                    + "pathname=%(pathname)s lineno=%(lineno)s "
                    + "funcname=%(funcName)s %(message)s"
                ),
                "datefmt": "%Y-%m-%d %H:%M:%S",
            },
            "simple": {"format": "%(levelname)s %(message)s"},
        },
        "handlers": {
            "null": {"level": "DEBUG", "class": "logging.NullHandler"},
            "console": {
                "level": "DEBUG",
                "class": "logging.StreamHandler",
                "formatter": "verbose",
            },
        },
        "loggers": {
            "": {"handlers": ["console"], "level": "INFO", "propagate": False},
            "testlogger": {"handlers": ["console"], "level": "INFO"},
            "deploylogs": {"level": "WARNING", "propagate": True},
        },
    }