HowTo-Install-Rollout-on-RaspberryPi.txt

##################################################
#                                                #
#   HowTo install Django on a Raspberry Pi       #
#    after first installation 31.12.2013         #
#         	by Oerb                          #
#                                                #
##################################################

Helpfull Links:
===============
- Raspberry Pi:
[1] http://www.raspberrypi.org/downloads

- HowTo's Django / Nginx:
[2] https://code.djangoproject.com/wiki/DjangoAndNginx
[3] http://michal.karzynski.pl/blog/2013/06/09/django-nginx-gunicorn-virtualenv-supervisor/
[4] http://eshlox.net/en/2012/09/11/nginx-uwsgi-virtualenv-and-django-ubuntu-1204/

- HowTo's Django:
[5] https://docs.djangoproject.com/en/dev/howto/static-files/

Pre decisions:
==============

I'll use nginx because of it's Performance and it's a raspberry pi
8and dictum gives me the hind)

after bad Experiences in Installationprocess:
=============================================

1. I experimented with Fastcgi but I got in Problems (mostly Permissionproblems)
2. so I begin to use uwsgi where I got compareable Problems

>> conclusion after hard fails and Headdemage: 
  - nginx in raspberian user is www-data  ( OK )
  - uwsgi in raspberian user is pi        ( Fail ) - Hate #&%-*~
  > fastcgi may be user pi Problem too - not tested yet -

How I get this conclusion:
ps aux | grep nginx
ps aux | grep uwsgi


First install required applications:
====================================
sudo apt-get install git nginx uwsgi uwsgi-plugin-all python-virtualenv

Webserver Directory:
====================
mkdir /var/www/
sudo chown www-data:www-data -R /var/www
sudo chmod 755 -R /var/www

(Do not forget this Permissions in following Installationprocess)
(you could give www-data a Password by passwd www-data and change user by)
( su www-data )


get simplehome:
===============
cd /var/www/
git clone https://github.com/oerb/simplehome.git

set write permission for sqlite3.db:
====================================
sudo chmod 766 /var/www/simplehome/simplehome.db

generate vertualenv in env dir and install nessesary Packages:
==============================================================
cd ~/projects/simplehome/
virtualenv env
source env/bin/activate
pip install django Pillow django-tinymce django-endless-pagination

Nginx configuration:
====================
IMHO, by default, nginx is configured for basic tasks. I won't change this configuration in this entry. Configuration files are stored in /etc/nginx/sites-available. Go to this directory and create a new file.

vim /etc/nginx/sites-available/oerb.de

Example configuration:
-----------------------------------------------
server {
    listen  80;
    server_name oerb.de www.oerb.de;
    access_log /var/log/nginx/oerb.de_access.log;
    error_log /var/log/nginx/oerb.de_error.log;

    location / {
        uwsgi_pass  unix:///tmp/oerb.de.sock;
        include     uwsgi_params;
    }

    location /media/  {
        alias /var/www/simplehome/media/;
    }

    location  /static/ {
        alias  /var/www/simplehome/static/;
    }
}
------------------------------------------------

We must create symlink to enable this.

ln -s /etc/nginx/sites-enabled/sites-available/oerb.de .


Django Static collection:
=========================

as you can see in the Nginx configuration the Project staticfiles are 
centralised in the folder /var/www/simplehome/static/
for django development the static files are separated to their aps
and must be collected. This is done by [5]:

# Set the STATIC_ROOT setting to the directory from which you’d like to serve these files, for example:

STATIC_ROOT = "/var/www/example.com/static/"

# Run the collectstatic management command:

$ python manage.py collectstatic

(there are some more directory Infos in /var/www/simplehome/simplehome/settings.py
that have to be edit to the /var/www/simplehome/...... look example 
rolleout-setting.py.txt
)

Uwsgi configuration:
====================
Like with Nginx.. configuration files are stored in /etc/uwsgi/apps-available. Go to this directory and create a new file.

vim /etc/uwsgi/apps-available/oerb.de.ini

--------------------------------------
[uwsgi]
master = true
vhost = true
uid = www-data
gid = www-data
plugins = python
socket = /tmp/oerb.de.sock
master = true
enable-threads = false
processes = 1
module = simplehome.wsgi
chmod-socket = 666
wsgi-file = /var/www/simplehome/simplehome/wsgi.py
virtualenv = /var/www/simplehome/env
chdir = /var/www/simplehome/
vacuum = true
---------------------------------------

Enable this by setting a symlink:

ln -s /etc/uwsgi/enabled/oerb.de.ini /etc/uwsgi/apps-available/oerb.de.ini .

That's all. Now, run this services:
===================================

sudo service nginx start
sudo service uwsgi start

known Problems:
===============
first at all look into logs:
cat /var/log/nginx/simplehome.access.log | less
cat /var/log/uwsgi/app/oerb.de.log | less

The central Problem I run into was permission foo. Nginx was using
www-data user/group and uwsgi was using pi as user. That does not work.
In uwsgi the user/group is set into the configfile

/etc/uwsgi/apps-available/oerb.de.ini

by the Parameter
uid = www-data
gid = www-data

and in nginx the user/group is set into the central nginx configfile

/etc/nginx/nginx.conf

by the parameter
user www-data;

(for testing and understanding you could set to user pi if www-data 
runs into permissionfoo but for securityissues do not do this on 
productive System)