I'm trying to run a simple Flask web app that displays a pygal graph. When I run it with the python development server, the application runs fine. However, when I try to run it in apache2, I get the following error:
[Thu Dec 10 19:55:22.745469 2020] [wsgi:error] [pid 17741] [client ::1:34366] mod_wsgi (pid=17741): Failed to exec Python script file '/var/www/FlaskApp/FlaskApp.wsgi'.
[Thu Dec 10 19:55:22.745521 2020] [wsgi:error] [pid 17741] [client ::1:34366] mod_wsgi (pid=17741): Exception occurred processing WSGI script '/var/www/FlaskApp/FlaskApp.wsgi'.
[Thu Dec 10 19:55:22.745553 2020] [wsgi:error] [pid 17741] [client ::1:34366] Traceback (most recent call last):
[Thu Dec 10 19:55:22.745586 2020] [wsgi:error] [pid 17741] [client ::1:34366] File "/var/www/FlaskApp/FlaskApp.wsgi", line 8, in <module>
[Thu Dec 10 19:55:22.745650 2020] [wsgi:error] [pid 17741] [client ::1:34366] from FlaskApp import app as application
[Thu Dec 10 19:55:22.745665 2020] [wsgi:error] [pid 17741] [client ::1:34366] File "/var/www/FlaskApp/FlaskApp/__init__.py", line 2, in <module>
[Thu Dec 10 19:55:22.745707 2020] [wsgi:error] [pid 17741] [client ::1:34366] import pygal
[Thu Dec 10 19:55:22.745723 2020] [wsgi:error] [pid 17741] [client ::1:34366] File "/var/www/FlaskApp/FlaskApp/venv/lib/python3.8/site-packages/pygal/__init__.py", line 28, in <module>
[Thu Dec 10 19:55:22.745786 2020] [wsgi:error] [pid 17741] [client ::1:34366] import pkg_resources
[Thu Dec 10 19:55:22.745838 2020] [wsgi:error] [pid 17741] [client ::1:34366] File "/var/www/FlaskApp/FlaskApp/venv/lib/python3.8/site-packages/pkg_resources/__init__.py", line 1365
[Thu Dec 10 19:55:22.745850 2020] [wsgi:error] [pid 17741] [client ::1:34366] raise SyntaxError(e) from e
[Thu Dec 10 19:55:22.745857 2020] [wsgi:error] [pid 17741] [client ::1:34366] ^
[Thu Dec 10 19:55:22.745864 2020] [wsgi:error] [pid 17741] [client ::1:34366] SyntaxError: invalid syntax
Here is the code that I'm running
# -*- coding: utf-8 -*-
import pygal
from flask import Flask, Response
app = Flask(__name__)
@app.route('/')
def index():
""" render svg on html """
return """
<html>
<body>
<h1>hello pygal</h1>
<figure>
<embed type="image/svg+xml" src="/graph/" />
</figure>
</body>
</html>'
"""
@app.route('/graph/')
def graph():
""" render svg graph """
bar_chart = pygal.Bar()
bar_chart.add('Fibonacci', [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55])
return Response(response=bar_chart.render(), content_type='image/svg+xml')
if __name__ == '__main__':
app.run()
(Note that this code is just a sample copied from github)
Here is my apache site configuration:
<VirtualHost *:443>
ServerName flaskapp.localhost
ServerAdmin [email protected]
WSGIScriptAlias / /var/www/FlaskApp/FlaskApp.wsgi
<Directory /var/www/FlaskApp/FlaskApp/>
Order allow,deny
Allow from all
</Directory>
Alias /static /var/www/FlaskApp/FlaskApp/static
<Directory /var/www/FlaskApp/FlaskApp/static/>
Order allow,deny
Allow from all
</Directory>
DocumentRoot /var/www/FlaskApp
SSLEngine on
SSLCertificateFile /etc/ssl/certs/apache-selfsigned.crt
SSLCertificateKeyFile /etc/ssl/private/apache-selfsigned.key
ErrorLog ${APACHE_LOG_DIR}/FlaskApp-error.log
LogLevel warn
CustomLog ${APACHE_LOG_DIR}/FlaskApp-access.log combined
AddDefaultCharset utf-8
</VirtualHost>
Here is my wsgi file:
python_home = '/var/www/FlaskApp/FlaskApp/venv'
activate_this = python_home + '/bin/activate_this.py'
execfile(activate_this, dict(__file__=activate_this))
import sys
import logging
logging.basicConfig(stream=sys.stderr)
sys.path.insert(0,"/var/www/FlaskApp/")
sys.path.insert(0,"/var/www/FlaskApp/FlaskApp/venv/lib/python3.8/site-packages/")
from FlaskApp import app as application
application.secret_key = 'secret key stuff'
Here are some details about my environment:
Ubuntu 20.04.1 LTS
Apache/2.4.41 (Ubuntu)
Python 3.8.5 (installed in a virtual environment)
Any thoughts would be greatly appreciated!
It appears that the python interpreter is compiled into the mod_wsgi.so file. An old version, that included python2, was being pointed to by Apache. To fix it I did the following:
sudo apt-get remove libapache2-mod-wsgiI suspect that modifying it here points all Apache virtual hosts to this python virtual environment, which isn't really ideal. It would be better if each Apache virtual host pointed to its own python environment.
__init__.pyfile to be preceeded by a dot(.)Following these changes the site is now working as expected.