Heroku 应用程序错误：OSError：[Errno 98] 地址已在使用中

Question

This is my project directory:

├── Procfile
├── app.py
└── requirements.txt

Procfile :

web: gunicorn app:app

app.py :

from flask import Flask

app = Flask(__name__)

@app.route("/")
def index():
    return "Hello, World!"

app.run()

requirements.txt :

certifi==2020.6.20
chardet==3.0.4
click==7.1.2
Flask==1.1.2
gunicorn==20.0.4
idna==2.10
itsdangerous==1.1.0
Jinja2==2.11.2
MarkupSafe==1.1.1
requests==2.24.0
urllib3==1.25.10
Werkzeug==1.0.1

This is what I ran in the terminal:

$ git init
$ heroku create
$ git add .
$ git commit -m "test"
$ git push heroku master
$ heroku open

When I open the website, I get an Application error and when I check the logs I see:

OSError: [Errno 98] Address already in use

I checked and don't seem to have anything else running, what could be causing this error?

Answer 1

Encapsulate the run:

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

it should work.