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WGSI can't import modules

Hello,

I'm trying to add dash instance to a flask app, but struggle with WGSI import.

WGSI doesn't want to import the dash module while it's installed and works well when I run directly the file Flask_app.py.

The /var/www/pythonanywhere_com_wsgi.py

import sys

# add your project directory to the sys.path
project_home = '/home/mysite'
if project_home not in sys.path:
    sys.path = [project_home] + sys.path

# import flask app but need to call it "application" for WSGI to work
from flask_app import app as application  # noqa

The /home/mysite/flask_app.py

from flask import Flask, render_template
import dash

app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello from Flask!

# Set-up endpoint 1
app_1 = dash.Dash(name='app1', server=app, url_base_pathname='/app1/')
app_1.layout = html.H1('App 1')

The error: 

Error running WSGI application
2021-12-14 16:16:26,591: ModuleNotFoundError: No module named 'dash'
2021-12-14 16:16:26,591:   File "/var/www/pythonanywhere_com_wsgi.py", line 16, in <module>
2021-12-14 16:16:26,591:     from flask_app import app as application  # noqa
2021-12-14 16:16:26,591: 
2021-12-14 16:16:26,592:   File "/home/mysite/flask_app.py", line 5, in <module>
2021-12-14 16:16:26,592:     import dash
2021-12-14 16:16:26,592: ***************************************************
2021-12-14 16:16:26,592: If you're seeing an import error and don't know why,
2021-12-14 16:16:26,592: we have a dedicated help page to help you debug: 
2021-12-14 16:16:26,592: https://help.pythonanywhere.com/pages/DebuggingImportError/
2021-12-14 16:16:26,592: ***************************************************

I tried with an other module and it's the same behavior: 

2021-12-14 16:47:51,730: Error running WSGI application
2021-12-14 16:47:51,734: ModuleNotFoundError: No module named 'pandas'
2021-12-14 16:47:51,734:   File "/var/www/pythonanywhere_com_wsgi.py", line 17, in <module>
2021-12-14 16:47:51,734:     from flask_app import app as application  # noqa
2021-12-14 16:47:51,734: 
2021-12-14 16:47:51,735:   File "/home/mysite/flask_app.py", line 5, in <module>
2021-12-14 16:47:51,735:     import pandas
2021-12-14 16:47:51,735: ***************************************************
2021-12-14 16:47:51,735: If you're seeing an import error and don't know why,
2021-12-14 16:47:51,735: we have a dedicated help page to help you debug: 
2021-12-14 16:47:51,735: https://help.pythonanywhere.com/pages/DebuggingImportError/
2021-12-14 16:47:51,735: ***************************************************
Beloved premium user urbest | 3 posts | Dec. 14, 2021, 5:12 p.m. | permalink

Your web app is using a virtualenv. You need to install the modules you want to use in that virtualenv.

Staff glenn | 9498 posts | PythonAnywhere staff | Dec. 14, 2021, 5:45 p.m. | permalink

All the module seems installed (let me know if I'm wrong) and I still have the error

(venv) 18:41 ~/.virtualenvs/venv $ pip list --local
Package              Version
-------------------- ---------
Brotli               1.0.9
certifi              2021.10.8
charset-normalizer   2.0.9
click                8.0.3
dash                 2.0.0
dash-core-components 2.0.0
dash-html-components 2.0.0
dash-table           5.0.0
dataclasses          0.8
Flask                2.0.2
Flask-Compress       1.10.1
idna                 3.3
importlib-metadata   4.8.2
itsdangerous         2.0.1
Jinja2               3.0.3
MarkupSafe           2.0.1
numpy                1.19.5
pandas               1.1.5
pip                  21.1.2
plotly               5.4.0
python-dateutil      2.8.2
pytz                 2021.3
requests             2.26.0
setuptools           57.0.0
six                  1.16.0
tenacity             8.0.1
typing-extensions    4.0.1
urllib3              1.26.7
Werkzeug             2.0.2
wheel                0.36.2
zipp                 3.6.0
Beloved premium user urbest | 3 posts | Dec. 14, 2021, 6:43 p.m. | permalink

Make sure that the virtualenv that you're looking at is actually the one that is being used by your web app.

Staff glenn | 9498 posts | PythonAnywhere staff | Dec. 14, 2021, 7:12 p.m. | permalink

I was in the wrong environment, after installing all dependencies in the right on it works! Thanks

Beloved premium user urbest | 3 posts | Dec. 14, 2021, 7:18 p.m. | permalink

Glad to hear that you made it work!

Staff fjl | 4352 posts | PythonAnywhere staff | Dec. 15, 2021, 9:48 a.m. | permalink