Create development server similar to Tommy

[heirloom]

I'm having trouble debugging the code from a github repository that works on my machine, but I can't make it work on the server. So I would like to make a virtual machine with the same os and applications to be able to debug the code. I'm doing a flask website. What are the applications that Tommy has installed to deal with flask? Which os? How to install wsgi?

Edited August 4, 2020 by heirloom

[Krydos]

CentOS 7, mod_wsgi-4.6.7. You install mod_wsgi by downloading the source, running ./configure, make, make install. Python 3.7.4. Flask 1.1.1. Let us know if you need more help.

[heirloom]

I've had some trouble configuring the 'flask' folder. I don't know why I've had to include the location of the python packages in the wsgi file. Or else it said:

Exception occurred processing WSGI script '/var/www/flask/myapp.wsgi'.
Traceback (most recent call last):
    File "/var/www/flask/myapp.wsgi", line 6, in <module>
        from myapp import app as application
    File "/var/www/flask/myapp/__init__.py", line 1, in <module>
        from flask import Flask
ImportError: No module named flask

Also although I've installed python 3.7.4 I had to end up using the default Python 3, which is 3.6.8, because I didn't know how to use pip without installing the default. And I couldn't install mod_wsgi from source because it gave me an error, that was something like: 'apxs command not found'. Probably I forgot some dependency.

 

Here I write all the commands I used to deploy flask apps with apache in centos in a similar way as how the Tommy server does it:

# VirtualBox guest additions

sudo yum install -y epel-release centos-release-scl

sudo yum update -y

sudo yum install -y make gcc kernel-headers kernel-devel perl dkms bzip2

# Devices -> Insert Guest Additions CD image and run it

sudo reboot

sudo yum install -y dconf-editor

bash <(curl -s https://raw.githubusercontent.com/ajr-dev/post-install-script/master/install/settings/gnome.sh)

 

# Install apache

sudo yum install -y httpd httpd-devel python3 python3-pip python3-devel

sudo systemctl start httpd

sudo systemctl enable httpd

 

# Install mod_wsgi 4.6.7

wget -q "https://github.com/GrahamDumpleton/mod_wsgi/archive/4.6.7.tar.gz"

tar -xzf '4.6.7.tar.gz'

rm '4.6.7.tar.gz'

cd 'mod_wsgi-4.6.7'

./configure --with-python=/usr/local/bin/python3

make

sudo make install

 

# Add this to `/etc/httpd/conf/httpd.conf`

# LoadModule wsgi_module modules/mod_wsgi.so

apachectl restart

sudo cat /var/log/httpd/error_log

# If all is okay, you should see a line of the form:

# Apache/2.4.6 (CentOS) mod_wsgi/4.6.7 Python/3.6 configured

 

cd ..

sudo rm -rf 'mod_wsgi-4.6.7'

apachectl restart

# Flask Deploy with Apache on CentOS

sudo pip3 install flask==1.1.1
cd /var/www

sudo mkdir flask

cd flask

sudo mkdir website

 

sudo vi __init__.py

from flask import Flask
app = Flask(__name__)

sudo vi main.py

import sys
import platform

from website import app

def linux_distribution():
    try:
        return platform.linux_distribution()
    except:
        return "N/A"

@app.route("/")
def hello():
    return """
        Hello World!<br><br>
        <a href="/flask/info/">System Information</a><br>
    """

@app.route("/info/")
def info():
    return f"""
        Python version: {sys.version}<br>
        dist: {platform.dist()}<br>
        linux_distribution: {linux_distribution()}<br>
        system: {platform.system()}<br>
        machine: {platform.machine()}<br>
        platform: {platform.platform()}<br>
        uname: {platform.uname()}<br>
    """"

if __name__ == "__main__":
    app.run(debug=True)

sudo vi website.wsgi

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

from website import main, app as application

cd /etc/httpd/conf/

sudo cp httpd.conf httpd.conf.bak

sudo vi httpd.conf

Insert:

<VirtualHost *:80>
    ServerName localhost
    WSGIScriptAlias /flask /var/www/flask/website.wsgi
    <Directory /var/www/flask>
        Require all granted
    </Directory>
</VirtualHost>

apachectl restart

 

# Get IP

hostname -I

 

# When visiting 'http://my_host_ip/flask' you should see 'Hello World!'

# If you are getting an error you can see it by doing

sudo cat /var/log/httpd/error_log

Edited August 13, 2020 by heirloom

[heirloom]

Actually the installed mod_wsgi was using Python 2.7. So I need a way to install the correct version of mod_wsgi.

 

After installing the correct version of mod_wsgi I no longer have to include the location of the packages. mod_wsgi is now using the default Python3 which is 3.6.8. I couldn't get it to run with 3.7.4, even when installing it with --enable-shared it gave 'Error while loading shared libraries' unless I specified the location of the packages in the code like:

import site

site.addsitedir('/usr/local/lib/python3.7/site-packages')
site.addsitedir('/usr/local/lib64/python3.7/site-packages')

Install mod_wsgi 4.6.7 with python 3.7.4 in CentOs 7

Edited August 14, 2020 by heirloom

[heirloom]

In the WSGIScriptAlias the alias should be '/' or else all links inside the application will have to include '/flask/path' and changing all the links in the application is not easy unless you've made them relative to a specific url that you can easily change. This has be done for heliohost anyway.

 

This problem has an answer in Path configuration problem with mod_wsgi - WSGIScriptAlias

 

The way in which the Tommy server is configured is probably using the technique explained there.

Edited August 14, 2020 by heirloom

[heirloom]

How do I set up the public_html/flask folder?

[Krydos]

How do I set up the public_html/flask folder?

It explains how to set up the flask directory in the wiki https://wiki.helionet.org/tutorials/flask

[heirloom]

With my current configuration apache won't read the .htaccess file in the folder /home/username/public_html/flask. First I have to setup apache to read from that folder. How do I do that?

[Krydos]

By default apache ignores .htaccess files. You have to edit the configuration, find the directory block, and change "AllowOverride None" to "AllowOverride All".