Deploy Python Flask to Heroku

2 min readFeb 12, 2021

Install the Heroku CLI

Download and install the Heroku CLI.

If you haven’t already, log in to your Heroku account and follow the prompts to create a new SSH public key.

$ heroku login

Pre-requisites:

Add the following files to the application’s root folder:

Procfile

Heroku apps include a Procfile that specifies the commands that are executed by the app on startup.

Add the following line:

web: python run.py

Note: Change the run.py to your startup file.

Pipfile

Pipfile is used to specify the preferred python version and all the dependencies of the application.

Add the following lines:

[[source]]
url = "https://pypi.org/simple"
verify_ssl = true
name = "pypi"[packages]
flask = "*"
adaboost-model = "0.1.0"[dev-packages][requires]
python_version = "3.7"

Note: Make sure to specify the correct python version and include all the required packages of you applicaiton.

Change the host of the flask application to this:

if __name__ == "__main__":
    port = int(os.environ.get("PORT", 5000))
    application.run(host='0.0.0.0', port=port)

Generate the Pipfile.lock file using the following command:

$ pipenv lock

Note: Every time you have a changes in the Pipfile, you must run this command.

Create Heroku Application

Login to Heroku site
Go to Heroku dashboard
Click New -> Create new app
Enter the App name
Click Create app button
Go to Settings tab of you app
Click the Add buildpack button
Select buildpack (in this article, choose python)
Click Save changes button

Deployment

Create a new Git repository

Initialize a git repository in a new or existing directory

$ cd my-project/
$ git init
$ heroku git:remote -a app-name

Note: Change the app-name to your application name from Heroku.

Deploy your application

Commit your code to the repository and deploy it to Heroku using Git.

$ git add .
$ git commit -am "make it better"
$ git push heroku master

Heroku will generate a new link for your application’s public access.