Lando and Flask

Requirements

You'll need Lando installed, and that's it.

Setting up Lando

Get into your project directory, and get things started with a Lando file.

cd my-project
touch .lando.yml

Name your Lando project and define a python service.

name: flask-example
services:
  python:
    type: python:3.5

Expose python and pip command line tools.

tooling:
  pip:
    service: python
  python:
    service: python

Install Flask

Fire up the container, and let's get the requirements going. From the command line, run:

lando start
lando pip install Flask
lando pip freeze > requirements.txt

Note: It may be the case that this will add carriage return characters to your requirements.txt file. In that case, you may have to run lando ssh -s python -c 'pip freeze > requirements.txt' instead.

Now tell lando that we want it to install requirements during build.

services:
  python:
    type: python:3.5
    build:
      - 'pip install -r /app/requirements.txt'

Build an app

Build your app.py file, specifying the host as 0.0.0.0, with no port.

from flask import Flask
app = Flask(__name__)


@app.route('/')
def hello():
    return "Hello World!"


if __name__ == '__main__':
    app.run(host = '0.0.0.0')

Flask defaults to port 5000, so let's set up our Lando proxy with that port exposed internally.

proxy:
  python:
    - flask-example.lndo.site:5000

Tell lando to run the python app at startup.

services:
  python:
    type: python:3.5
    build:
      - 'pip install -r /app/requirements.txt'
    run:
      - python /app/app.py

Conclusion

Your Lando file will finally look like the following.

name: flask-example
proxy:
  python:
    - flask-example.lndo.site:5000
services:
  python:
    type: python:3.7
    build:
      - 'pip install -r /app/requirements.txt'
    run:
      - python /app/app.py
tooling:
  pip:
    service: python
  python:
    service: python

Enjoy!