Python: Getting Started

A barebones Flask app, which can easily be deployed to Heroku.

This application supports the Getting Started with Python on Heroku article - check it out.

Running Locally

Make sure you have Python 3.9 installed locally. To push to Heroku, you'll need to install the Heroku CLI.

$ git clone https://github.com/heroku/python-sample.git
$ cd python-sample

$ python3 -m venv venv
$ source ./venv/bin/activate
$ pip install -r requirements.txt

$ # createdb python_getting_started

$ # python manage.py migrate
$ # python manage.py collectstatic

$ heroku local

Your app should now be running on localhost:5000.

Deploying to Heroku

$ heroku create  # first time only
$ git add .
$ git commit -m "update repo"
$ git push heroku master

$ # heroku run python manage.py migrate
$ heroku logs --tail
$ heroku run bash
$ # heroku open

or

Documentation

For more information about using Python on Heroku, see these Dev Center articles:

• Python on Heroku

Deploying to Cloud Foundry

Create .cfignore to ignore files / directories as needed

$ cf push python-sample --random-route

• Python Buildpack

Deploying to Docker with CF Local plugin

Create local.yml with latest buildpack

$ sudo cf local stage python-sample
$ sudo cf local run python-sample -i 0.0.0.0 -p 8080

• CF Local Plugin

Building with Cloud Native Buildpacks

See Turn Your Code into Docker Images with Cloud Native Buildpacks and An App’s Brief Journey from Source to Image

Install Pack.

Create project.toml to exclude/include files for the image, specify buildpacks etc.

Adapt Procfile to bind gunicorn to 0.0.0.0 if you want to use heroku buildpacks:

$ cat Procfile
web: gunicorn app:app -b 0.0.0.0:8000

Build (and optionally publish) container image with appropriate builder:

$ pack build --builder heroku/buildpacks mikespub/heroku-python-sample
latest: Pulling from heroku/buildpacks
...
===> ANALYZING
[analyzer] Restoring data for SBOM from previous image
===> DETECTING
[detector] heroku/python 0.0.0
===> RESTORING
[restorer] Restoring metadata for "heroku/python:shim" from cache
[restorer] Restoring data for "heroku/python:shim" from cache
===> BUILDING
[builder] -----> Using Python version specified in runtime.txt
...
[builder] -----> Installing requirements with pip
===> EXPORTING
...
[exporter] Setting default process type 'web'
[exporter] Saving mikespub/heroku-python-sample...
[exporter] *** Images (8b8f78fac102):
[exporter]       mikespub/heroku-python-sample
[exporter] Adding cache layer 'heroku/python:shim'
Successfully built image mikespub/heroku-python-sample

Test the containerized app image with Docker:

$ docker run --rm -p 8080:8000 mikespub/heroku-python-sample
[2022-11-21 16:34:31 +0000] [1] [INFO] Starting gunicorn 20.1.0
[2022-11-21 16:34:31 +0000] [1] [INFO] Listening at: http://0.0.0.0:8000 (1)
...