How to deploy my flask website to heroku without errors?

Question

I created a website using flask back-end, every thing works fine locally, but when i tried to deploy it on heroku I got those errors >> this is my Procfile

web: gunicorn wsgi:app

this is my wsgi file

from . import create_app
app = create_app()

this is my create app code >>

def create_app():

    app = Flask(__name__)

    if not os.getenv("DATABASE_URL"):
        raise RuntimeError("DATABASE_URL is not set")


    app.config['SQLALCHEMY_DATABASE_URI'] = os.getenv("DATABASE_URL")
    app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False

    db = SQLAlchemy()
    db.init_app(app)

    app.config['SECRET_KEY'] = os.getenv("SECRET_KEY")

    login_manager = LoginManager()
    login_manager.init_app(app)


    @login_manager.user_loader
    def load_user(user_id):
        return User.query.get(int(user_id))

    return app

and this what I get from heroku logs

2020-03-25T07:37:09.102934+00:00 heroku[web.1]: State changed from starting to crashed
2020-03-25T07:37:08.996125+00:00 app[web.1]: Traceback (most recent call last):
2020-03-25T07:37:08.996155+00:00 app[web.1]:   File "/app/.heroku/python/bin/gunicorn", line 7, in <module>
2020-03-25T07:37:08.996318+00:00 app[web.1]:     from gunicorn.app.wsgiapp import run
2020-03-25T07:37:08.996337+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/site-packages/gunicorn/app/wsgiapp.py", line 9, in <module>
2020-03-25T07:37:08.996465+00:00 app[web.1]:     from gunicorn.app.base import Application
2020-03-25T07:37:08.996496+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/site-packages/gunicorn/app/base.py", line 11, in <module>
2020-03-25T07:37:08.996623+00:00 app[web.1]:     from gunicorn import util
2020-03-25T07:37:08.996654+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/site-packages/gunicorn/util.py", line 6, in <module>
2020-03-25T07:37:08.996775+00:00 app[web.1]:     import ctypes.util
2020-03-25T07:37:08.996798+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/ctypes/util.py", line 3, in <module>
2020-03-25T07:37:08.996912+00:00 app[web.1]:     import subprocess
2020-03-25T07:37:08.996934+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/subprocess.py", line 153, in <module>
2020-03-25T07:37:08.997239+00:00 app[web.1]:     import select
2020-03-25T07:37:08.997265+00:00 app[web.1]:   File "/app/select.py", line 3, in <module>
2020-03-25T07:37:08.997509+00:00 app[web.1]:     from flask import Flask,jsonify
2020-03-25T07:37:08.997541+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/site-packages/flask/__init__.py", line 16, in <module>
2020-03-25T07:37:08.997670+00:00 app[web.1]:     from werkzeug.exceptions import abort
2020-03-25T07:37:08.997694+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/site-packages/werkzeug/__init__.py", line 218, in <module>
2020-03-25T07:37:08.997974+00:00 app[web.1]:     from .serving import run_simple
2020-03-25T07:37:08.997999+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/site-packages/werkzeug/serving.py", line 41, in <module>
2020-03-25T07:37:08.998139+00:00 app[web.1]:     import socket
2020-03-25T07:37:08.998163+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/socket.py", line 52, in <module>
2020-03-25T07:37:08.998310+00:00 app[web.1]:     import os, sys, io, selectors
2020-03-25T07:37:08.998334+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/selectors.py", line 290, in <module>
2020-03-25T07:37:08.998523+00:00 app[web.1]:     class SelectSelector(_BaseSelectorImpl):
2020-03-25T07:37:08.998547+00:00 app[web.1]:   File "/app/.heroku/python/lib/python3.7/selectors.py", line 317, in SelectSelector
2020-03-25T07:37:08.998734+00:00 app[web.1]:     _select = select.select
2020-03-25T07:37:08.998772+00:00 app[web.1]: AttributeError: module 'select' has no attribute 'select'
2020-03-25T07:37:09.084647+00:00 heroku[web.1]: Process exited with status 1



2020-03-25T07:39:11.077962+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=bookreviews101.herokuapp.com request_id=a08f3517-e1e7-439a-bd77-f676d217cc8b fwd="197.165.201.207" dyno= connect= service= status=503 bytes= protocol=https
2020-03-25T07:39:11.531655+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=bookreviews101.herokuapp.com request_id=27ee6d2f-2e85-4cb3-87dd-9856f84285e6 fwd="197.165.201.207" dyno= connect= service= status=503 bytes= protocol=https

I want to know what is the cause of this error and how to fix it

If you locked at the error you would find no route to my files all the routes are inside /lib>>> it's not the same error ?? your would find the /lib and selectors.py is missing that attribute !!! or tell me how to fix it in my case genius — AhmedElsayed, Mar 25 '20 at 16:34

score 0 · Answer 1 · answered Mar 25 '20 at 09:16

this is my wsgi file
from . import create_app
app = create_app()
this is my create app code
def create_app():
...

What's the file called in which you app code resides in. Your from . import create_app looks wrong. It is probably not importing the method.

Normally you are supposed to write something like this in an app.py:

app = Flask(__name__)
@app.route("/")
def exampleroot():
     return {'message': 'just an example'}

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=os.environ.get('PORT', 80))

You can execute this with python3 app.py.
You can run app.py via gunicorn via gunicorn app:app. (__name__ == "__main__" will return False.)

it's imported and running cause I imported like this inside the application file >> and it's working >> every thing runs fine locally ? I have many routes .. and every thing works fine — AhmedElsayed, Mar 25 '20 at 16:13

How to deploy my flask website to heroku without errors?

1 Answers1