Flask on Heroku
This project is intended to help you tie together some important concepts and technologies from the 12-day course, including Git, Flask, JSON, Pandas, Requests, Heroku, and Bokeh for visualization.
The repository contains a basic template for a Flask configuration that will work on Heroku.
A finished example that demonstrates some basic functionality.
Step 1: Setup and deploy
Git clone the existing template repository.
runtime.txtcontain some default settings.
There is some boilerplate HTML in
Create Heroku application with
heroku create <app_name>or leave blank to auto-generate a name.
(Suggested) Use the conda buildpack. If you choose not to, put all requirements into
heroku config:add BUILDPACK_URL=https://github.com/thedataincubator/conda-buildpack.git#py3
The advantages of conda include easier virtual environment management and fast package installation from binaries (as compared to the compilation that pip-installed packages sometimes require). One disadvantage is that binaries take up a lot of memory, and the slug pushed to Heroku is limited to 300 MB. Another note is that the conda buildpack is being deprecated in favor of a Docker solution (see docker branch of this repo for an example).
Deploy to Heroku:
git push heroku master
You should be able to see your site at
A useful reference is the Heroku quickstart guide.
Step 2: Get data from API and put it in pandas
- Use the
requestslibrary to grab some data from a public API. This will often be in JSON format, in which case
simplejsonwill be useful.
- Build in some interactivity by having the user submit a form which determines which data is requested.
- Create a
pandasdataframe with the data.
Step 3: Use Bokeh to plot pandas data
- Create a Bokeh plot from the dataframe.
- Consult the Bokeh documentation and examples.
- Make the plot visible on your website through embedded HTML or other methods - this is where Flask comes in to manage the interactivity and display the desired content.
- Some good references for Flask: This article, especially the links in "Starting off", and this tutorial.