Sm0ke

Posted on Nov 10, 2019 • Edited on Oct 5, 2023 • Originally published at docs.appseed.us

Flask Deploy with Apache on CentOS - Minimal Setup

#python #apache #centos

Hello Coders,

This article explains how to deploy a Flask application sandboxed with a virtualenv and served by Apache HTTP server using the mod_wsgi module.

For newcomers, Flask is a lightweight web application framework written in Python. Sometimes classified as a microframework, Flask provides a lightweight codebase that can be easily extended to become an API, a simple web app, or a complex eCommerce platform.

Dependencies

Apache / httpd (on CentOS) server
mod_wsgi
Flask web framework
Python3
Virtualenv

Prepare the environment

Install Apache server

$ sudo yum install httpd
$ 
$ # by default the server is down.
$ sudo systemctl start httpd

Install mod_wsgi

$ sudo yum install mod_wsgi
$
$ # restart apache
$ sudo systemctl restart httpd

Test if the `mod_wsgi` module is loaded

$ sudo httpd -M | grep wsgi
wsgi_module (shared) # <-- the OK response

Install Virtualenv

Virtual environments will sandbox the app to run isolated from the global server environment

$ sudo pip install virtualenv

Code the Flask App

We will use a simple Flask application that serves a simple Hello World message for all routes.
As mentioned before, this setup is executed on CentOs. The steps are:

Go to /var/www - the www_root of Apache server, and create the project directory.

$ cd /var/www
$ mkdir hitme

To have a runnable Flask app, we need to create two files: run.py and app.py inside the app folder. The files are structured as below:

/var/www/hitme
          | - run.py
          | - app/__init__.py

Where run.py is responsible to bootstrap the Flask app defined in the app directory.

app/init.py file contents


from flask import Flask
app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello world!"

run.py file contents


import os
from app import app

#----------------------------------------
# launch
#----------------------------------------

if __name__ == "__main__":
    port = int(os.environ.get("PORT", 5000))
    app.run(host='0.0.0.0', port=port, debug=True)

Test the Flask App

We have the test application, now let's start it to see something on the screen. First, we need to create and activate the virtual environment.

$ cd /var/www
$ virtualenv --python=python3 hitme # the venv is created inside the app folder
$ cd /var/www/hitme
$ source bin/activate

At this point, we will run the next commands inside the VENV. Let's install Flask

$ pip install flask

To run, a Flask application require FLASK_APP environment variable.

$ export FLASK_APP=run.py # please notice the name
$ flask run # start the app
$ # our app is running on port 5000

Apache Configuration

To execute a Flask application under the Apache HTTP server we need to bridge our application to the Apache engine using the mod_wsgi module. For this we need to create a new file wsgi.py inside our project folder:

/var/www/hitme
          | - wsgi.py
          | - run.py
          | - app/__init__.py

wsgi.py file contents

#!/usr/bin/env python

import sys
import site

site.addsitedir('/var/www/hitme/lib/python3.6/site-packages')

sys.path.insert(0, '/var/www/hitme')

from app import app as application

The next step is to configure Apache to serve the app and use this wsgi loader. The following settings should be added to the httpd.conf. On CentOS the file location is /etc/httpd/conf/httpd.conf

<VirtualHost *:80>

     ServerName localhost

     WSGIDaemonProcess hitme user=apache group=apache threads=2

     WSGIScriptAlias / /var/www/hitme/wsgi.py

     <Directory /var/www/hitme>
         Require all granted
     </Directory>

</VirtualHost>

Close and save the file and restart Apache to load the new settings.

$ # restart apache
$ sudo systemctl restart httpd

Our Flask app should be served by the Apache HTTP server. We can test the deploy by using lynx command:

$ lynx localhost # lynx

Thanks for reading! For more resources, feel free to access:

👉 More Flask Dashboards crafted in Django, Flask, and React
✨ More Flask Apps - free & PAID

Top comments (34)

Abdul Rahman Sabbagh • Aug 5 '20

Hi.. Thanks for this tutorial.. I tried it line by line and it worked. However, I've been trying to deploy a more complicated flask app that I have been working on for a while, and it's not working. I hope you can help me out. I'll be very grateful.

Sm0ke • Aug 6 '20

Hello Abdul, Thanks for reading.
I'll be glad to help. Tell me more about your app.

Abdul Rahman Sabbagh • Aug 6 '20

Hi,
It's an app about running warehouses and simple accounting and invoices. It has a lot of local imports. I originally placed the "run.py" inside the project folder and it worked perfectly on the development server, but that does not match the structure described in your tutorial and it would not deploy.

When I place the "run.py" outside the project folder, it would not recognize the local packages I'm importing from within the project.

If you like to take a better look... here's the link on github

github.com/abbddos/Enterprise_1

This is my first web project ever, so I know there's a small twist somewhere that I'm missing.

Thank you very very much

Sm0ke • Aug 6 '20

Hello,
let's chat in private.

Veeresh Babu • Feb 22 '22

I tried the steps above, but stuck during "flask run" with below error, Can anyone please help / point out where I'm going wrong ?

Serving Flask app 'run.py' (lazy loading)
Environment: production WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
Debug mode: off Usage: flask run [OPTIONS] Try 'flask run --help' for help.

Error: While importing 'run', an ImportError was raised:

Traceback (most recent call last):
File "/var/www/hitme/lib/python3.6/site-packages/flask/cli.py", line 260, in locate_app
import(module_name)
File "/var/www/hitme/run.py", line 2, in
from app import app
ImportError: cannot import name 'app'

Veeresh Babu • Feb 28 '22

I was able to work through this and resolve this by using

import web_tool
app = web_tool.app

Xavier Alexander • Apr 26 '20

@sm0ke Thanks for this tutorial! Very helpful!

For anybody referencing a a virtual environment in their wsgi file, and getting Permission Denied in the httpd error logs:

Make sure proper permissions are applied to the virtual environment's parent directories, so that the apache user, or whatever user you have set for the WSGIDaemonProcess, can actually get to it.

Sm0ke • Apr 26 '20

Hello Xavier. If you have the time, please drop here a config sample that uses WSGIDaemonProcess.
10x mate

Xavier Alexander • Apr 26 '20

I used the same config as your tutorial where the WSGIDaemonProcess will be ran as the apache user.

 ServerName localhost

 WSGIDaemonProcess hitme user=apache group=apache threads=2

 WSGIScriptAlias / /var/www/hitme/wsgi.py

 <Directory /var/www/hitme>
     Require all granted
 </Directory>

Sm0ke • Apr 26 '20

Super cool. Thank you! :)

Sirisha-Muddana • Mar 25 '20

Hi,
I Followed your steps from the above tutorial without using lynx, directly used browser and given localhost:8080 but browser not giving Hello world and showing that site cant be reached. restarted Apache server, port 8080 is listening and open,even wsgi file is also same like yours. below are the logs. pls check it out
[Wed Mar 25 16:26:18.575220 2020] [core:notice] [pid 7322:tid 139847942441216] AH00094: Command line: '/usr/sbin/httpd -D FOREGROUND'
[Wed Mar 25 17:59:57.166193 2020] [wsgi:error] [pid 7326:tid 139847205377792] [client 162.243.129.144:49818] Target WSGI script not found or unable to stat: /var/www/flask/wsgi.py

Sm0ke • Mar 25 '20 • Edited

Hello Sirisha,
Thanks for noticing the article. Try to apply this short checklist:

check if /var/www/flask/wsgi.py exists on disk
see the permissions of the file

Please notice that Apache runs under certain privileges. Make sure that Apache can access the file.
Let me know if my suggestions helped.

Sirisha-Muddana • Mar 25 '20 • Edited

yes, exists on disk and given permission using this command: chmod 755 /var/www/flask/wsgi.py.. but no change

william • Apr 9 '20

I have followed your steps from the above tutorial and one of the problem is that i cannot specifying my python interpreter to be the vitual one, and apache just uses the default python2.7.5 initially installed in centos.how can i solve this
[Thu Apr 09 13:42:29.349530 2020] [lbmethod_heartbeat:notice] [pid 16236] AH02282: No slotmem from mod_heartmonitor
[Thu Apr 09 13:42:29.353249 2020] [mpm_prefork:notice] [pid 16236] AH00163: Apache/2.4.6 (CentOS) mod_wsgi/3.4 Python/2.7.5 configured -- resuming normal operations
[Thu Apr 09 13:42:29.353276 2020] [core:notice] [pid 16236] AH00094: Command line: '/usr/sbin/httpd -D FOREGROUND'
[Thu Apr 09 13:42:32.225160 2020] [:error] [pid 16242] [client 120.230.96.144:49562] mod_wsgi (pid=16242): Target WSGI script '/var/www/hitme/wsgi.py' cannot be loaded as Python module.
[Thu Apr 09 13:42:32.225201 2020] [:error] [pid 16242] [client 120.230.96.144:49562] mod_wsgi (pid=16242): Exception occurred processing WSGI script '/var/www/hitme/wsgi.py'.
[Thu Apr 09 13:42:32.225224 2020] [:error] [pid 16242] [client 120.230.96.144:49562] Traceback (most recent call last):
[Thu Apr 09 13:42:32.225243 2020] [:error] [pid 16242] [client 120.230.96.144:49562] File "/var/www/hitme/wsgi.py", line 13, in
[Thu Apr 09 13:42:32.225307 2020] [:error] [pid 16242] [client 120.230.96.144:49562] from app import app as application
[Thu Apr 09 13:42:32.225318 2020] [:error] [pid 16242] [client 120.230.96.144:49562] File "/var/www/hitme/app/init.py", line 2, in
[Thu Apr 09 13:42:32.225455 2020] [:error] [pid 16242] [client 120.230.96.144:49562] from flask import Flask
[Thu Apr 09 13:42:32.225469 2020] [:error] [pid 16242] [client 120.230.96.144:49562] File "/var/www/hitme/hitme/lib/python3.7/site-packages/flask/init.py", line 14, in
[Thu Apr 09 13:42:32.225511 2020] [:error] [pid 16242] [client 120.230.96.144:49562] from jinja2 import escape
[Thu Apr 09 13:42:32.225519 2020] [:error] [pid 16242] [client 120.230.96.144:49562] File "/var/www/hitme/hitme/lib/python3.7/site-packages/jinja2/init.py", line 9, in
[Thu Apr 09 13:42:32.225561 2020] [:error] [pid 16242] [client 120.230.96.144:49562] from .bccache import BytecodeCache
[Thu Apr 09 13:42:32.225570 2020] [:error] [pid 16242] [client 120.230.96.144:49562] File "/var/www/hitme/hitme/lib/python3.7/site-packages/jinja2/bccache.py", line 19, in
[Thu Apr 09 13:42:32.225649 2020] [:error] [pid 16242] [client 120.230.96.144:49562] from .compat import BytesIO
[Thu Apr 09 13:42:32.225658 2020] [:error] [pid 16242] [client 120.230.96.144:49562] File "/var/www/hitme/hitme/lib/python3.7/site-packages/jinja2/_compat.py", line 120, in
[Thu Apr 09 13:42:32.225701 2020] [:error] [pid 16242] [client 120.230.96.144:49562] from pathlib import PurePath
[Thu Apr 09 13:42:32.225709 2020] [:error] [pid 16242] [client 120.230.96.144:49562] File "/usr/local/Python-3.7.7/Lib/pathlib.py", line 9, in
[Thu Apr 09 13:42:32.226042 2020] [:error] [pid 16242] [client 120.230.96.144:49562] from _collections_abc import Sequence
[Thu Apr 09 13:42:32.226086 2020] [:error] [pid 16242] [client 120.230.96.144:49562] File "/usr/local/Python-3.7.7/Lib/_collections_abc.py", line 58
[Thu Apr 09 13:42:32.226092 2020] [:error] [pid 16242] [client 120.230.96.144:49562] async def _coro(): pass
[Thu Apr 09 13:42:32.226095 2020] [:error] [pid 16242] [client 120.230.96.144:49562] ^
[Thu Apr 09 13:42:32.226098 2020] [:error] [pid 16242] [client 120.230.96.144:49562] SyntaxError: invalid syntax
[Thu Apr 09 13:42:35.936716 2020] [:error] [pid 16243] [client 120.230.96.144:49564] mod_wsgi (pid=16243): Target WSGI script '/var/www/hitme/wsgi.py' cannot be loaded as Python module.
[Thu Apr 09 13:42:35.936795 2020] [:error] [pid 16243] [client 120.230.96.144:49564] mod_wsgi (pid=16243): Exception occurred processing WSGI script '/var/www/hitme/wsgi.py'.
[Thu Apr 09 13:42:35.936830 2020] [:error] [pid 16243] [client 120.230.96.144:49564] Traceback (most recent call last):
[Thu Apr 09 13:42:35.936861 2020] [:error] [pid 16243] [client 120.230.96.144:49564] File "/var/www/hitme/wsgi.py", line 13, in
[Thu Apr 09 13:42:35.936955 2020] [:error] [pid 16243] [client 120.230.96.144:49564] from app import app as application
[Thu Apr 09 13:42:35.936972 2020] [:error] [pid 16243] [client 120.230.96.144:49564] File "/var/www/hitme/app/init.py", line 2, in
[Thu Apr 09 13:42:35.937159 2020] [:error] [pid 16243] [client 120.230.96.144:49564] from flask import Flask
[Thu Apr 09 13:42:35.937179 2020] [:error] [pid 16243] [client 120.230.96.144:49564] File "/var/www/hitme/hitme/lib/python3.7/site-packages/flask/init.py", line 14, in
[Thu Apr 09 13:42:35.937246 2020] [:error] [pid 16243] [client 120.230.96.144:49564] from jinja2 import escape
[Thu Apr 09 13:42:35.937261 2020] [:error] [pid 16243] [client 120.230.96.144:49564] File "/var/www/hitme/hitme/lib/python3.7/site-packages/jinja2/init_.py", line 9, in
[Thu Apr 09 13:42:35.937313 2020] [:error] [pid 16243] [client 120.230.96.144:49564] from .bccache import BytecodeCache
[Thu Apr 09 13:42:35.937361 2020] [:error] [pid 16243] [client 120.230.96.144:49564] File "/var/www/hitme/hitme/lib/python3.7/site-packages/jinja2/bccache.py", line 19, in
[Thu Apr 09 13:42:35.937490 2020] [:error] [pid 16243] [client 120.230.96.144:49564] from ._compat import BytesIO
[Thu Apr 09 13:42:35.937505 2020] [:error] [pid 16243] [client 120.230.96.144:49564] File "/var/www/hitme/hitme/lib/python3.7/site-packages/jinja2/_compat.py", line 120, in
[Thu Apr 09 13:42:35.937589 2020] [:error] [pid 16243] [client 120.230.96.144:49564] from pathlib import PurePath
[Thu Apr 09 13:42:35.937606 2020] [:error] [pid 16243] [client 120.230.96.144:49564] File "/usr/local/Python-3.7.7/Lib/pathlib.py", line 9, in
[Thu Apr 09 13:42:35.938027 2020] [:error] [pid 16243] [client 120.230.96.144:49564] from _collections_abc import Sequence
[Thu Apr 09 13:42:35.938093 2020] [:error] [pid 16243] [client 120.230.96.144:49564] File "/usr/local/Python-3.7.7/Lib/_collections_abc.py", line 58
[Thu Apr 09 13:42:35.938104 2020] [:error] [pid 16243] [client 120.230.96.144:49564] async def _coro(): pass
[Thu Apr 09 13:42:35.938109 2020] [:error] [pid 16243] [client 120.230.96.144:49564] ^
[Thu Apr 09 13:42:35.938114 2020] [:error] [pid 16243] [client 120.230.96.144:49564] SyntaxError: invalid syntax
this is the error caused by python2.x in my app

Sm0ke • Apr 9 '20 • Edited

Oh .. , sounds like super fun. I see two options here:

Recompile the mod_wsgi module using Python3
Update the deployment schema to use Apache as a reverse proxy and start the app using Gunicorn

Let me know if this helps.

william • Apr 11 '20 • Edited

I have gone with the first approach and encounters problems and would like to communicate with you on this a bit more.
so i uninstall mod_wsgi on python2, and tried install using zip pack from mod_wsgi website
./configure --with-python=/usr/local/bin/python3 this is the configure that i used to specify python interpreter
then make && make install
problem occurs(part of the error reports looks like the following)

/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(Python-ast.o): relocation R_X86_64_32S against `.rodata' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(ast.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(ast_opt.o): relocation R_X86_64_32S against `.rodata' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(ast_unparse.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(getcompiler.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(getcopyright.o): relocation R_X86_64_32 against `.rodata' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(getplatform.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(structmember.o): relocation R_X86_64_32S against `.rodata' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(getopt.o): relocation R_X86_64_32S against `.rodata.str4.4' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(parser.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(node.o): relocation R_X86_64_PC32 against symbol `PyObject_Free' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
apxs:Error: Command failed with rc=65536
.
make: *** [src/server/mod_wsgi.la] Error 1

my server is a centos 7 with gcc and python2 installed already. i install python3 using zip pack from its home webside and set --enable-shared to make sure that its library can be shared.
another way i tried is through pip3 install mod_wsgi
problems:

/usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(Python-ast.o): relocation R_X86_64_32S against `.rodata' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(ast.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(ast_opt.o): relocation R_X86_64_32S against `.rodata' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(ast_unparse.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(getcompiler.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(getcopyright.o): relocation R_X86_64_32 against `.rodata' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(getplatform.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(structmember.o): relocation R_X86_64_32S against `.rodata' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(getopt.o): relocation R_X86_64_32S against `.rodata.str4.4' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(parser.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: /usr/local/python3/lib/libpython3.7m.a(node.o): relocation R_X86_64_PC32 against symbol `PyObject_Free' can not be used when making a shared object; recompile with -fPIC
    /usr/bin/ld: final link failed: Bad value
    collect2: error: ld returned 1 exit status
    error: command 'gcc' failed with exit status 1
    ----------------------------------------
ERROR: Command errored out with exit status 1: /usr/local/python3/bin/python3.7 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-313gyz5m/mod-wsgi/setup.py'"'"'; __file__='"'"'/tmp/pip-install-313gyz5m/mod-wsgi/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-a4z7qsiz/install-record.txt --single-version-externally-managed --compile --install-headers /usr/local/python3/include/python3.7m/mod-wsgi Check the logs for full command output.

i have stuck with this for a few days and would really appreciated if you can help
thx sincerely.

Sm0ke • Apr 11 '20 • Edited

Hello,
That's a super heavy error. I've googled a little, nothing relevant found. Apache mod_wsgi is super buggy on CentOS. I had many issues in the past and skip over that setup.

I'm using on CentOS a simple setup that uses uWSGI to start the Flask/Django app and Apache as a reverse proxy.
uWSGI is fast but is not handle the SSL layer (that's why you need Apache in front). Feel free to use Gunicorn instead of uWSGI, in case you are familiar with it.

I'm not super free with my time, but we can chat LIVE on Discord. I'm Sm0ke on that server (the moderator).

David Link • Jun 22 '21

Hi Sm0ke, Thank you for this great article. It is very helpful and well written.

I noticed what I believe is one small typo. Where it says "app/init.py file contents" I believe it should say "app/init.py file contents", and that is probably a Markdown issue.

Were you able to resolve @williamium3000 's issues regarding setting the python interpreter? I'm trying to get this to work with pyenv (pyenv install 3.9.5), but can't get mod_wsgi to see my locally installed interpreter in my venv, even if I put it in the she-bang

#!/data/apps/hitme/.venv/bin/python

import os
import sys

def application(environ, start_response):
    status = '200 OK'
    output = bytes(getEnv(), 'utf-8')
    response_headers = [('Content-type', 'text/plain'),
                        ('Content-Length', str(len(output)))]
    start_response(status, response_headers)
    return [output]

def getEnv():
    keys = list(os.environ.keys())
    keys.sort()
    o = ''
    o += "OS Environment\n"
    o += 'Python Version: %s\n' % sys.version
    o += 'Python prefix: %s\n' % sys.prefix
    for k in keys:
        v = os.environ[k]
        o += ("  %s: %s\n" % (k, v))
    return o

Reports:

OS Environment
Python Version: 3.6.8 (default, Mar 18 2021, 08:58:41)
[GCC 8.4.1 20200928 (Red Hat 8.4.1-1)]
Python prefix: /apps/mod_wsgi/.venv
  INVOCATION_ID: 8c7e2ab82ab7415ca0e1e2c1fddde05a
  JOURNAL_STREAM: 9:1072847
  LANG: C
  NOTIFY_SOCKET: /run/systemd/notify
  PATH: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin

3.6.8 is the OS's python version. Thanks for your help

Sm0ke • Jun 23 '21 • Edited

Hello @dlink ,

Indeed the app/\_\_init\_\_.py cannot be formatted being styled automatically by the Markdown parser.

Regarding the Python version, try to force the PATH update in wsgi.py as below

site.addsitedir('/data/apps/hitme/.venv/..../site-packages')
sys.path.insert(0, '/data/apps/hitme/')

P.S. adapt the paths to be resolved properly.
Let me know the results.

Ivan López • Oct 27 '20

Hi, thanks for this tutorial dude, I'm following the tutorial and work fine but with personal project not work and send me error "Target WSGI script .... cannot be loaded as python module". Any idea what happend? thank you

Darya • Oct 5 '20

Hi!
I am on flask run part, in console it shows:
Serving Flask app "run.py" (lazy loading)

Environment: development
Debug mode: on
Running on 127.0.0.1:5000/ (Press CTRL+C to quit)
Restarting with stat
Debugger is active!
Debugger PIN: but in browser 127.0.0.1:5000 says site can't be reached

Cao Anh Tuan • Jun 29 '20 • Edited

Thanks for this tutorial.
I have a problem, WSGT cannot load Python module. I checked to error_log

Do you have any idea to resolve this problem?

Chase • Feb 5 '20

hi, I got a 403 forbidden error, any possible solutions? I created my app not in www folder, is this going to cause a trouble.

Sm0ke • Feb 6 '20

Hello Chase. Thank you for noticing the article.
Can you extract drop here some relevant information from the apache logs?
Also, using a Heroku deploy, might be a good choice.

Chase • Feb 6 '20

Hi, I have figured out the problem, all I have to do is to create every in var/www folder instead. But I started to have another problem is that, the system try to run the app using python2.7 which is absolutely causing errors.
Here is the error log gives me,

[Thu Feb 06 23:17:27.417817 2020] [:error] [pid 24709] [client ::1:39996] SyntaxError: invalid syntax
[Thu Feb 06 23:20:07.161239 2020] [:error] [pid 24708] [client ::1:39998] mod_wsgi (pid=24708): Target WSGI script '/var/www/nzn/wsgi.py' cannot be loaded as Python module.
[Thu Feb 06 23:20:07.161274 2020] [:error] [pid 24708] [client ::1:39998] mod_wsgi (pid=24708): Exception occurred processing WSGI script '/var/www/nzn/wsgi.py'.
[Thu Feb 06 23:20:07.161288 2020] [:error] [pid 24708] [client ::1:39998] Traceback (most recent call last):
[Thu Feb 06 23:20:07.161301 2020] [:error] [pid 24708] [client ::1:39998] File "/var/www/nzn/wsgi.py", line 10, in
[Thu Feb 06 23:20:07.161344 2020] [:error] [pid 24708] [client ::1:39998] from nzn import app as application
[Thu Feb 06 23:20:07.161372 2020] [:error] [pid 24708] [client ::1:39998] File "/var/www/nzn/nzn/init.py", line 64
[Thu Feb 06 23:20:07.161376 2020] [:error] [pid 24708] [client ::1:39998] marks = {range: f'{range:.2f}' for range in [0.02, 0.05, 0.1, 0.15, 0.2]},
[Thu Feb 06 23:20:07.161379 2020] [:error] [pid 24708] [client ::1:39998] ^
[Thu Feb 06 23:20:07.161381 2020] [:error] [pid 24708] [client ::1:39998] SyntaxError: invalid syntax

As my personal experience this error is caused by using the python2 instead of python3.

Thanks

Sm0ke • Feb 7 '20

Hello, yep might be the Python version.
Using Python3 is not an option? Python2 reach the EOL in Jan this year.

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Flask Deploy with Apache on CentOS - Minimal Setup

Prepare the environment

Install Apache server

Install mod_wsgi

Test if the `mod_wsgi` module is loaded

Install Virtualenv

Code the Flask App

Test the Flask App

Apache Configuration

Top comments (34)

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