Docker#

Docker is a containerization platform that allows you to package your application and all its dependencies together. It is useful for creating consistent environments for your application to run in, irrespective of the host system and its own configuration or dependencies - which is especially helpful in preventing dependency conflicts.

This guide uses the Docker official Python container as a base image.

Use When#

Docker is ideal for deploying Python web applications in scenarios where:

Isolation: You require a consistent, isolated environment for your application, independent of the host system.
Scalability: Your application needs to be easily scaled up or down based on demand.
Portability: The need to run your application consistently across different environments (development, testing, production) is crucial.
Microservices Architecture: You are adopting a microservices architecture, where each service can be containerized and managed independently.
Continuous Integration/Continuous Deployment (CI/CD): You are implementing CI/CD pipelines, and Docker facilitates the building, testing, and deployment of applications.
Dependency Management: Ensuring that your application has all its dependencies bundled together without conflicts with other applications.

Alternatives#

For different deployment scenarios, consider these alternatives:

systemd:
A system and service manager, integrated into many Linux distributions for managing system processes.

Note

Official documentation coming soon
Supervisor:
A process control system that can be used to automatically start, stop and restart processes; includes a web UI.
Manually with an ASGI server:
Direct control by running the application with an ASGI server like Uvicorn, Hypercorn, Daphne, etc.

This guide assumes that you have Docker installed and running on your system, and that you have the following files in your project directory:

requirements.txt#

litestar[standard]>=2.4.0,<3.0.0

Python 3.8+

app.py#

"""Minimal Litestar application."""

from asyncio import sleep
from typing import Any, Dict

from litestar import Litestar, get


@get("/")
async def async_hello_world() -> Dict[str, Any]:
    """Route Handler that outputs hello world."""
    await sleep(0.1)
    return {"hello": "world"}


@get("/sync", sync_to_thread=False)
def sync_hello_world() -> Dict[str, Any]:
    """Route Handler that outputs hello world."""
    return {"hello": "world"}


app = Litestar(route_handlers=[sync_hello_world, async_hello_world])

Python 3.10+

app.py#

"""Minimal Litestar application."""

from asyncio import sleep
from typing import Any

from litestar import Litestar, get


@get("/")
async def async_hello_world() -> dict[str, Any]:
    """Route Handler that outputs hello world."""
    await sleep(0.1)
    return {"hello": "world"}


@get("/sync", sync_to_thread=False)
def sync_hello_world() -> dict[str, Any]:
    """Route Handler that outputs hello world."""
    return {"hello": "world"}


app = Litestar(route_handlers=[sync_hello_world, async_hello_world])

Dockerfile#

Example Dockerfile#

# Set the base image using Python 3.12 and Debian Bookworm
FROM python:3.12-slim-bookworm

# Set the working directory to /app
WORKDIR /app

# Copy only the necessary files to the working directory
COPY . /app

# Install the requirements
RUN pip install --no-cache-dir --upgrade -r /app/requirements.txt

# Expose the port the app runs on
EXPOSE 80

# Run the app with the Litestar CLI
CMD ["litestar", "run", "--host", "0.0.0.0", "--port", "80"]

This copies your local project folder to the /app directory in the Docker container and runs your app via uvicorn utilizing the litestar run command. uvicorn is provided by the litestar[standard] extra, which is installed in the requirements.txt file.

You can also launch the application with an ASGI server directly, if you prefer.

Once you have your Dockerfile defined, you can build the image with docker build and run it with docker run.

Docker Compose#

Compose is a tool for defining and running multi-container Docker applications. Read more about Compose in the official Docker documentation.

If you want to run the container as part of a Docker Compose setup then you can simply use this compose file:

docker-compose.yml#

version: "3.9"

services:
  exampleapp:
    build:
      context: ./
      dockerfile: Dockerfile
    container_name: "exampleapp"
    depends_on:
      - database
    ports:
      - "80:80"
    environment:
      - DB_HOST=database
      - DB_PORT=5432
      - DB_USER=litestar
      - DB_PASS=r0cks
      - DB_NAME=exampleapp

  database:
    image: postgres:latest
    container_name: "exampledb"
    environment:
      POSTGRES_USER: exampleuser
      POSTGRES_PASSWORD: examplepass
      POSTGRES_DB: exampledb
    ports:
      - "5432:5432"
    volumes:
      - db_data:/var/lib/postgresql/data

volumes:
  db_data:

This compose file defines two services: exampleapp and database. The exampleapp service is built from the Dockerfile in the current directory, and exposes port 80. The database service uses the official PostgreSQL image, and exposes port 5432. The exampleapp service depends on the database service, so the database will be started before the app. The exampleapp service also has environment variables set for the database connection details, which are used by the app.

Once you have your docker-compose.yml defined, you can run docker compose up to start the containers. You can also run docker compose up -d to run the containers in the background, or “detached” mode.