Flask-Docker Template

🐳 Template for a simple Flask-Docker service with hot reloading.

Usage

1. Use/Pull/Fork this template
2. Navigate to the folder
3. Run docker-compose up

Hot Reloading

• removing volumes malfunctions hot reloading

• installing new packages will not trigger hot reloading. In that case, you should remove the running container and rebuild the Docker image (don't forget to update requirements.txt with the new package).

  Alternatively, you can execute installation in the container:

  • docker exec -it <CONTAINER_ID> bash
  • pip3 install -r requirements.txt

Production Deploy

container's content

The built container in production will only contain files/folders not ignored by the .dockerignore file (wanted behaviour).

docker-compose.yml

The docker-compose.yml file and docker-compose commands should not be used in production. This file's purpose is to ease the local development, including adding the hot reloading ability.

command

When deploying the service to production, set gunicorn -b 0.0.0.0:8080 -w 1 --threads 3 -t 0 app:app as the container's "command".

Examples:

• In AWS ECS: Container Definitions -> command
• In GCP Cloud Run: Container command

gunicorn 🦄 is a popular WSGI suitable for running the web server in production. Tweak the number of workers, threads, and other flags based on how powerful your machine is.

Errors

When you encounter an error (or unexpected behaviour) that you cannot solve:

1. Remove the Docker container and image

2. Then run docker-compose build --no-cache flask-docker

3. Lastly, run docker-compose up flask-docker

In case this does not fix the error, or you have any additional questions, feel free to open a GitHub issue.