Card store project #2: Installing Satchmo, Django, PostgreSQL, and Apache on Ubuntu at Slicehost

Date: 2008-12-11 | Modified: 2009-01-21 | Tags: cardstore, django, linux, sql, ubuntu | 6 Comments

As I mentioned in my previous post, I'm planning to set up an e-commerce site using the Satchmo shopping cart framework. Satchmo is built on the Django web framework which is written in the Python programming language. Satchmo has a lot of features built in which means it saves you a lot of work implementing them yourself. Check out this video introduction to Satchmo at this year's DjangoCon for more information.

After reading this discussion on the Satchmo mailing list, I decided to use Slicehost for hosting my site. Their cheapest plan provides 256MB of RAM for $20/month. Here are my notes on setting up Satchmo and Django with PostgreSQL, Apache, and mod_python on Ubuntu Intrepid at Slicehost. It seems lighttpd and nginx are popular lightweight alternatives to Apache on VPS setups. I do not know too much about this, but may explore these in the future.

Note, I don't describe how to setup a Satchmo project below. Maybe I will write another post about that later... For more information, see the Satchmo Installation documentation. Update 2008-12-12: I did write another blog post-- see Installing Satchmo, part 2.

Setup Slicehost

Sign up for an account at http://www.slicehost.com/ I chose Ubuntu Intrepid for my operating system and named my slice "toad".
I followed the following two excellent Slicehost tutorials: Ubuntu Setup Part 1 and Part 2.
An important step is setting the system locale. Since I'm in the United States, I used the following commands (run as root):
```
locale-gen en_US.UTF-8
update-locale LANG=en_US.UTF-8
```

Install apache, mod_python, postgresql, and postgres python bindings

Run as root (or use sudo):

apt-get update
apt-get upgrade
apt-get dist-upgrade
apt-get install apache2 apache2-mpm-prefork
apt-get install libapache2-mod-python
apt-get install postgresql
apt-get install python-psycopg2

Configure apache

I used the following Slicehost tutorials: Install Apache, Configure Apache Part 1, Configure Apache Part 2
Of particular note, when installing apache, I got this warning:
```
apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName
```
Fix it by setting the ServerName in /etc/apache2/apache2.conf:
```
ServerName yourdomain.com
ServerTokens Prod
```
See the Apache docs for more information on ServerName.

Install Django 1.0.2

Run the following as root:

cd /srv
wget http://www.djangoproject.com/download/1.0.2/tarball/

tar zxvf Django-1.0.2-final.tar.gz
mkdir python-packages
cd python-packages
ln -s ../Django-1.0.2-final/django

Test Django (optional)

Run the following as root:

export PYTHONPATH=/srv/python-packages
/srv/Django-1.0.2-final/django/bin/django-admin.py startproject testdjango

Edit /etc/apache2/httpd.conf:

<location "/">
    SetHandler python-program
    PythonHandler django.core.handlers.modpython
    SetEnv DJANGO_SETTINGS_MODULE testdjango.settings
    PythonPath "['/srv', '/srv/python-packages'] + sys.path"
    PythonDebug On
</location>

Restart apache:
```
/etc/init.d/apache2 restart
```
Navigate to your slice's IP address in your browser and you should see the Django "It worked!" page.

Install Satchmo

Satchmo requires a number of external Python packages besides Django. Unfortunately, there isn't one standard way of installing Python packages. I decided to install most of them using Ubuntu's APT package management and one of them using easy_install, and one of them from source. Alternatively, I could have installed most of the packages with easy_install, and one of them with APT (and one of them from source). Or, I could have done it another way... sigh.

Note, I use the directory /srv/python-packages to store symbolic links to my needed python packages. Then I add this directory to my Python Path in the PYTHONPATH environment variable or in the Apache httpd.conf file. See my post, Somewhere on your Python path for more information.

Install Satchmo prerequisites. Run the following commands as root:
Install APT packages:

apt-get update
apt-get upgrade
apt-get install python-crypto
apt-get install python-yaml
apt-get install python-imaging
apt-get install python-reportlab
apt-get install python-trml2pdf

Install django-registration using easy_install:

apt-get install python-setuptools python-dev build-essential
easy_install django-registration

Install comment_utils source:

apt-get install subversion
mkdir -p /srv/python-packages/dist
cd /srv/python-packages/dist
svn co http://django-comment-utils.googlecode.com/svn/trunk/comment_utils/ 
mv comment_utils comment_utils_rev92
cd /srv/python-packages
ln -s dist/comment_utils_rev92 comment_utils

Install Satchmo 0.8. Run the following as root: Update 2008-12-12: I changed this to use release 0.8 instead of the SVN trunk version.

cd /srv
wget http://www.satchmoproject.com/snapshots/satchmo-0.8.tgz
tar zxvf satchmo-0.8.tgz
cd /srv/python-packages
ln -s ../satchmo-0.8/satchmo

To install the SVN trunk version instead,

cd /srv
svn co svn://satchmoproject.com/satchmo/trunk
mv trunk satchmo_revXXXX
cd /srv/python-packages
ln -s ../satchmo_revXXXX/satchmo

Setup PostgreSQL¶

I followed the instructions at Punteney.com for setting up Django and Postgres on Slicehost.

If you didn't already install Postgres above, run the following as root:
```
apt-get install postgresql
apt-get install python-psycopg2
```
Change the password for the "postgres" Unix user. (run as root or use sudo)
```
passwd -d postgres
su postgres -c passwd
```
Change password for "postgres" user in the database. (From Punteney's article, "It's convenient to have the two passwords match, but not required.")
```
su postgres -c psql template1
```
```
ALTER USER postgres WITH PASSWORD 'postgres_user_password';
template1=\q
```
Create django user:
```
su postgres
createuser -P django_user
```
Punteney says to answer no to all here. Remember the password to put in Django settings.py file. (For this example, I set the password to my_password.)

Create a database. Still su'ed as the "postgres" user:

psql template1

CREATE DATABASE django_db OWNER django_user ENCODING 'UTF8';
\q

exit

(exit from postgres su)

Configure access to the database. Edit /etc/postgresql/8.3/main/pg_hba.conf:

local   all         postgres                          ident sameuser
local   django_db   django_user                       md5

Restart the postgres server:
```
/etc/init.d/postgresql-8.3 restart
```

In your Django project, use the following database settings in settings.py:

DATABASE_ENGINE = 'postgresql_psycopg2'
DATABASE_NAME = 'django_db'
DATABASE_USER = 'django_user'
DATABASE_PASSWORD = 'my_password'
DATABASE_HOST = ''
DATABASE_PORT = ''

Run syncdb:

cd /srv/yourproject
python manage.py syncdb

Setup a domain name

Register for a domain name. Google for "domain registration" for options.
Follow the Slicehost directions for creating DNS records. This includes setting the nameservers at your domain registration service to use Slicehost's nameservers (ns1.slicehost.net, ns2.slicehost.net, ns3.slicehost.net).

6 Comments — Comments feed for this post

#1 Andrew commented on 2008-12-12:

Is there any reason you chose mod_python over mod_wsgi?

#2 Eliot commented on 2008-12-12:

Andrew, is mod_wsgi the preferred way to go? I used mod_python because it was recommended by the Django docs and I had used it in the past. I haven't looked into mod_wsgi but will check it out later.

#3 Andrew commented on 2008-12-12:

I'm no expert on the subject, but there is a page on the mod_wsgi wiki about integration with django. I don't see any reason not to at least check it out, it is in the Ibex repos. Django also has a page on the setup. I've also recently been benchmarking nginx's mod_wsgi (pre-beta code, not ready for production) and it looks quite promising. I have yet to do a comparison with Apache's mod_wsgi (or mod_python), but it is more than twice as fast as paster's internal server (I'm using pylons)

Paster ::

$ ab -n 1000 -c 50 localhost:5000/blog/
Server Software:        PasteWSGIServer/0.5
Server Hostname:        localhost
Server Port:            5000
Document Path:          /blog/
Document Length:        454 bytes
Concurrency Level:      50
Time taken for tests:   52.590574 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      656000 bytes
HTML transferred:       454000 bytes
Requests per second:    19.01 [#/sec] (mean)
Time per request:       2629.529 [ms] (mean)
Time per request:       52.591 [ms] (mean, across all concurrent requests)
Transfer rate:          12.17 [Kbytes/sec] received
Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0  144 918.7      0    9000
Processing:   186 2427 548.2   2638    3318
Waiting:      173 2381 544.2   2591    3228
Total:        199 2571 992.0   2662   11141
 Longest request:  11141 ms

Nginx (2 processes) ::

$ ab -n 1000 -c 50 localhost:5500/blog/
Server Software:        nginx/0.7.26
Server Hostname:        localhost
Server Port:            5500
Document Path:          /blog/
Document Length:        454 bytes
Concurrency Level:      50
Time taken for tests:   17.595767 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      655000 bytes
HTML transferred:       454000 bytes
Requests per second:    56.83 [#/sec] (mean)
Time per request:       879.788 [ms] (mean)
Time per request:       17.596 [ms] (mean, across all concurrent requests)
Transfer rate:          36.32 [Kbytes/sec] received
Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   1.9      0      11
Processing:   213  860 858.5    727    6392
Waiting:      212  860 858.4    726    6391
Total:        221  861 860.0    727    6400
 Longest request:  6400 ms

#4 Eliot commented on 2008-12-13:

Andrew, thanks for the information. I'll check it out.

#5 Nikolay Kolev commented on 2008-12-18:

I've read that WSGI is the recommended approach and even though not officially yet, Phusion Passenger supports it. I'm not sure how it compares to mod_wsgi though, but it's been working great for Ruby frameworks (in production on many high-volume sites) and I've heard nothing but praises about it.

#6 Eliot commented on 2008-12-18:

I may have to start considering alternatives to Apache/mod_python... Even after moving my media files to S3, my site is still slow. I'm not sure if it is Slicehost or if I just need memcached. I briefly looked into nginx and it looks pretty good. I see from their wiki that they have quickly surpassed lighttpd in domains hosted.


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