Python

The Wodby Python catalog stack runs a Python web application with Gunicorn. PostgreSQL, Valkey, Mailpit, OpenSMTPD, Gotenberg and Cloud PostgreSQL are available as optional services, all disabled by default. The current services and defaults are documented in wodby/stack-python.

Build and deployment

Start from the Python boilerplate or connect your own repository. The code is copied to /usr/src/app. The service's Dockerfile runs pip install -r requirements.txt when that file exists and does nothing else. If your pipeline passes a Dockerfile from the repository, that file installs the dependencies instead. See Application Builds.

The container runs Gunicorn on port 8080 with a configuration that Wodby writes on every start:

• Set GUNICORN_APP on the app service to your WSGI callable as module:callable. The default is myapp.wsgi:application.
• Gunicorn must be one of your application's dependencies. The image does not include it.
• Do not add a Gunicorn configuration file to the repository. The container does not load it. Set GUNICORN_WORKERS, GUNICORN_WORKER_CLASS, GUNICORN_TIMEOUT or the other GUNICORN_* variables on the app service instead. Changes apply with the next deployment.

The app service has no volume. Files written inside the container are lost when it is replaced.

Database, Valkey and mail

Nothing in the image reads link variables. Your application reads them. A variable is present only while its link exists and the linked service is enabled. With the defaults, no link variables are set.

Link	Variables
DBMS (PostgreSQL)	DB_HOST, DB_PORT, DB_NAME (also DB_DATABASE), DB_USERNAME, DB_PASSWORD, DB_DRIVER (also DB_CONNECTION)
Mail Transfer Agent	SMTP_HOST, SMTP_PORT
Redis (Valkey)	REDIS_HOST, REDIS_PORT, REDIS_PASSWORD

The mail link carries no credentials. Mailpit captures every message and delivers none of them, and an application that requires SMTP authentication or TLS fails against it. For real delivery, enable OpenSMTPD and attach an SMTP provider. See the OpenSMTPD guide.

Valkey is a cache by default. It evicts keys when its memory limit is reached and starts empty after a restart unless you add its data volume. For a job queue or other data you must keep, set VALKEY_MAXMEMORY_POLICY to noeviction and size VALKEY_MAXMEMORY on the Valkey app service.

Environment

WODBY_HOSTS is a JSON array of the environment's hosts, not a comma-separated string. Use WODBY_PRIMARY_URL for links generated outside a request. Other services reach the application at WODBY_APP_SERVICE_NAME on port 8080. See Environment variables.

Data and backups

PostgreSQL keeps data on a 20 GB data volume. A backup is a gzipped SQL dump of the environment's database. It carries no role names and no grants, so you can import it into a database with another name and other users. A database import replaces the whole data volume. See Application Backups and Application Imports.

Development workspace

In a development workspace, setup installs dependencies into .wodby-workspace/venv with uv sync --locked when uv.lock exists, otherwise with pip install -r requirements.txt. One of the two files must exist. Run setup again after you change dependencies.

The server starts with python -m gunicorn --reload on $HOST:$PORT (0.0.0.0:8080 by default). The generated Gunicorn configuration and the GUNICORN_* tuning variables are not used. Set WORKSPACE_PYTHON_COMMAND on the app service to replace the start command. A custom command must reload by itself. A change to variables or linked services still needs a deployment.