install_django.py

#!/usr/bin/env python

########################
##
## Robert Russell
## NTI-300 2/24/18
##
## Python Django install
## Centos 7
##
########################


#Import the os module to allow the python script to issue commands, fileinput to modify the settings file, and urllib2 to get public ip.
import os
import fileinput
import urllib2

#Install updates, python3, and pip. Use pip to install virtualenv.
def setup_install():

    os.system('yum install -y epel-release')
    os.system('yum update -y')
    os.system('yum install -y python34 python-pip')
    os.system('pip install --upgrade pip')
    os.system('pip install virtualenv')


#Make the directory structure for the django server using the virtualenv and install django using pip.
def install_django():

    os.chdir('/opt')
    os.system('virtualenv -p python3 django')
    os.chdir('/opt/django')
    os.system('source bin/activate ' + \
             '&& pip install django')
    os.system('source bin/activate ' + \
              '&& django-admin startproject project1')
    os.system('chown -R centos /opt/django')


#Get public IP and insert it into the settings.py file.
def allow_host():

    ip = urllib2.urlopen('http://169.254.169.254/latest/meta-data/public-ipv4').read()

    for line in fileinput.input('/opt/django/project1/project1/settings.py', inplace=1):

        if "ALLOWED_HOSTS" in line:
            line = "ALLOWED_HOSTS = ['" + ip + "']"
        print line

        
#Start the server using the non root user.
def start_django():

    os.system('sudo -u centos /bin/bash -c "' + \
             'source /opt/django/bin/activate &&' + \
             '/opt/django/project1/manage.py runserver 0:8000 &"')

#Call all the functions in order if the python script is being run directly and not loaded as a module.

if __name__ == "__main__":
    
    setup_install()
    install_django()
    allow_host()
    start_django()