Flask - Deploy on Heroku with Gunicorn

Heroku works with Git. You create your projects on a local computer, and manage the version control with Git. Then, push the project to heroku master and deploy by few setting.

Prepare a flask project.

# app.py
from flask import Flask
app = Flask(__name__)
def hello_world():
return ‘Hello, World!’
if __name__ == ‘__main__’:

Create requirements.txt. Remember to add gunicorn package.

# requirements.txt

Create a Procfile without a file extension.

# Procfile
web gunicorn app:app

The first app in app:app is the filename of app.py where flask application initiated.

Use Git to manage version control.

For example, in terminal,

cd project_location/
git add .
git commit -m <message>

If your python project run on virtual environment, adding .gitignore to exclude the directory venv/. There is no need to use virtual environment in heroku. It was not working when I included it.

# .gitignore

In terminal, login heroku account.

heroku login

The terminal will open browser for login page.

After login, back to terminal.

cd project_location/heroku create <project-name> 
heroku git:remote -a <project-name>
git push heroku master # Push the project to heroku and Deploy


At this moment, the flask web server should be deployed successfully on heroku. You can open the web by using the command in terminal.

heroku open

If there is something wrong, using the command in terminal to see logs.

heroku logs — tail

As a beginner, I am trying to use the easiest way to build up a website. Thanks for reading .



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Liwei Cheng

Liwei Cheng

Find all fascinating things on the world. 不愛說話,但想當說故事的人。