host mod_wsgi in Apache2

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Apache2 Background

Apache2 virutal host

  • site-available

all virtual hosts are configured in individual files with /etc/apache2/sites-available

  • site-enabled

until the *.config in site-available are enabled, Apache2 won’t know know.

sudo sevice apache2 reload
  • IP based virtual host

use IP address of the connection to determine the correct virtual host to serve, so each host needs a separate IP

we had name-based vhost in LAN, a few web servers sharing the same IP in the same physical machine, but with different Ports, and even we don’t use DNS server to tell the domains.

apache mode cores

refer

  • VirtualHost

the title to define this virutal host, and tell which port to listen. by default is port80

  • ServerName

sets the request scheme, hostname, and port that the server uses to identify itself

  • ServerAlias

sets the alternate name for a host

  • WSGIDaemonProcess

for wsgi app, which usually define in a seperate Python virtual environment, rather than the default localhost user or root. so WSGIDaemonProcess point to the python virtual env.

  • WSGIScriptAlias

point to the wsgi_app.wsgi

  • DocumentRoot

set the directory from which httpd/apache2 will serve files /var/www/html

mod_wsgi

  • install apt-get install apache2 libapache2-mode-wsgi-py3

config in Apache2

config with configure file

  • create example.conf under /etc/apache2/conf-available/
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<VirtualHost *:8084>
        ServerName  10.20.181.119:8084
        ServerAlias example.com
        DocumentRoot "/var/www/html"
        ErrorLog "/var/www/example/logs/error.log"
 
</VirtualHost>

the served web content is stored at /var/www/html, which can simple include a index.html or a few js.

  • enable configure, which will create corresponding conf under conf-enable folder

    sudo a2enconf example

  • check configure

    sudo apachectl -S 
sudo apachectl configtest

config with virtual host

  • create example.conf under /etc/apache2/site-available/
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    <VirtualHost *:8085>
            ServerName  10.20.181.119:8085
            ServerAlias application.com
            DocumentRoot "/var/www/wsgy_example"
            ErrorLog "/var/www/wsgy_example/logs/error.log"
            WSGIScriptAlias /application /var/www/wsgy_app/application.wsgi
    </VirtualHost>

here used the additional WSGI script, link

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import os
import sys
sys.path.append('/var/www/wsgy_app/')
os.environ['PYTHON_EGG_CACHE'] = '/var/www/wsgy_app/.python-egg'
def application(environ, start_response):
        status = '200 OK'
        output = b'Helo World'
        response_headers = [('Content-type', 'text/plain'),
                            ('Content-length', str(len(output)))]
        start_response(status, response_headers)
        return [output]

  • enable configure, which will create corresponding conf under site-enable folder

    sudo a2ensite wsgy_example

  • check configure

    sudo apachectl -S 
sudo apachectl configtest

add multi ports:

in /etc/apache2/ports.conf:

Listen 8083
Listen 8084

since this Apache server host system_engineering web and pgadmin4 web, and share the same IP.

restart apache

sudo systemctl restart apache2

test apache

in browser:

10.20.181.119:8085/application

should view “hello world”

refer

name based virtual host

Apache2 virutal host

vhost with different ports