Deploy Airflow to Heroku HowTo

1. Install Airflow locally in Python3 venv

python3 -m venv .venv
source .venv/bin/activate
pip install "apache-airflow[postgres, password]"
pip install "cryptography"

2. Fix pydantic v2.x.x bug with Airflow v2.6.2

pip uninstall pydantic
pip install pydantic==1.10.10
pip freeze > requirements.txt

3. Create files for Heroku deployment

# Define Python buildpack's version
echo "python-3.9.16" > runtime.txt
# Define Procfile to launch Airflow server
echo "web: airflow webserver --port \$PORT" > Procfile

4. Create airflow-heroku Airflow repository on Github

git init .
git add --all
git commit -m "First commit"

5. Setup Heroku app

Login to Heroku Dashboard, create a new app with PostgreSQL db add-on, link app to airflow-heroku Github repository.

6. Define environnment variables on Heroku

# Generate Fernet key to enable passwords encryption
heroku config:set AIRFLOW__CORE__FERNET_KEY=`dd if=/dev/urandom bs=32 count=1 2>/dev/null | openssl base64`
heroku config:set AIRFLOW_HOME=/app

7. Init Airflow db

heroku run \bin\bash
airflow initdb

Airflow db should init successfully on Heroku logs, and Airflow server should start when application relaunches.