2018-06-02

How to publish your web apps which is used by Djano(2.0) and mod_wsgi on CentOS server.

Introduction
My develop environment
To build develop environment on your server
Setting of apache
If you want your multi services run on your one server
Deal with error
Refference

Introduction

This is a note for developing a web app which is used by Django(2.0) and mod_wsgi on a server(CentOS7) because I used to be stuck when I tried to publish my app using mod_wsgi. This was because I used the code python manage.py runserver to build my app in the local. I hope this article will help you.

In short, you can create virtual environment and set python path on your server.

My develop environment

・ CentOS 7.2
・ Apache 2.4.6
・ Python 3.6.5
・ Django 2.0

To build develop environment on your server

The version from Django2 is subject to only Python3. So, if your server doesn't install Python3 yet, you should.

$ sudo yum install -y https://centos7.iuscommunity.org/ius-release.rpm  
$ sudo yum install -y python36u python36u-devel python36u-libs

Symbolic link for Python should be changed to work for typing python3

$ which python3.6  
/usr/bin/python3.6  
$ sudo ln -s /usr/bin/python3.6 /usr/bin/python3  
$ python3 -V  
Python 3.6.5

To install pip.

$ sudo yum install epel-release  
$ sudo yum install python-pip

To build the virtual environment.

$ pip install virtualenv  
$ cd [project dir]  
$ python3 -m venv [newenvname]  
$ source [newenvname]/bin/activate  
([newenvname])$ python -V  
Python 3.6.5

When you want to escape from your virtual environment, you can just type deactivate.

You can install some library you need through pip.

([newenvname])$ pip install django mod-wsgi

If you cannnot install "mod-wsgi", you should install the following library before you install mod-wsgi.

yum install httpd httpd-devel

Setting of apache

I recommend you to copy your default httpd.conf as a backup.

$ cp /etc/httpd/conf/httpd.conf /  
$ vim /etc/httpd/conf/httpd.conf

Write the following code at the last line in httpd.conf.

IncludeOptional conf.d/*.conf

Make sure the path of wsgi_module.

$ mod_wsgi-express module-config  
LoadModule wsgi_module "{mod_wsgi-py-path}"
WSGIPythonHome "{home-path}"

Create new .conf file.

$ vim /etc/httpd/conf.d/django.conf

Add this code.

NameVirtualHost *:80  
    LoadModule wsgi_module "{mod_wsgi-py-path}"
    WSGISocketPrefix /var/run/wsgi

<VirtualHost *:80>  
    ServerName example.com  
    DocumentRoot /var/www/html/xxx

    WSGIDaemonProcess xxx python-home=/usr/{newenvname} python-path=/usr/xxx  
    WSGIProcessGroup xxx  
    WSGIScriptAlias / /usr/xxx/xxx/wsgi.py

    Alias /static/ /var/www/html/xxx/static/  
    <Directory /var/www/html/xxx/static>  
    Require all granted  
    </Directory>

    <Directory /usr/xxx/xxx>  
        <Files wsgi.py>  
            Require all granted  
        </Files>  
    </Directory>  
</VirtualHost>

※{newenvname} and "xxx" shoud be changed by depending on your environment.

Restart the apache on your server.

# make sure the condition of your server  
systemctl status httpd.service  
# restart the apache
systemctl restart httpd.service

# confirm log
tail -f /var/log/httpd/error_log

If you want your multi services run on your one server

You can copy and paste the following code to django.conf.

NameVirtualHost *:80  
    LoadModule wsgi_module "{mod_wsgi-py-path}"
    WSGISocketPrefix /var/run/wsgi

<VirtualHost *:80>  
    ServerName example.com  
    DocumentRoot /var/www/html/xxx

    WSGIDaemonProcess xxx python-home=/usr/{newenvname} python-path=/usr/xxx  
    WSGIProcessGroup xxx  
    WSGIScriptAlias / /usr/xxx/xxx/wsgi.py

    Alias /static/ /var/www/html/xxx/static/  
    <Directory /var/www/html/xxx/static>  
        Require all granted  
    </Directory>

    <Directory /usr/xxx/xxx>  
        <Files wsgi.py>  
            Require all granted  
        </Files>  
    </Directory>  
</VirtualHost>

<VirtualHost *:80>  
    ServerName sample.com  
    DocumentRoot /var/www/html/yyy

    WSGIDaemonProcess yyy python-home=/usr/{newenvname} python-path=/usr/yyy  
    WSGIProcessGroup yyy  
    WSGIScriptAlias / /usr/yyy/yyy/wsgi.py

    Alias /static/ /var/www/html/yyy/static/  
    <Directory /var/www/html/yyy/static>  
        Require all granted  
    </Directory>

    <Directory /usr/yyy/yyy>  
        <Files wsgi.py>  
            Require all granted  
        </Files>  
    </Directory>  
</VirtualHost>

The point is to separate WSGIDaemonProcess and WSGIProcessGroup.

Deal with error

When you encounter the following error, make sure if python-path or python-home is correct. Otherwise, you can check your file access permissions.

    Error ImportError: No module named 'encodings'  
    or  
    ModuleNotFoundError: No module named 'myProject'