Days ago' I was developing a front-end form in order to give users the opportunity to subscribe to a newsletter. I used the django ModelForm class because I didn't need nothing special except from hiding some model fields.

But I run into a problem, the compulsory fileds where handled properly in the sense that the form submission returned an error if such fields weren't filled, but there wasn't any attribute assigned to the label element in order to style it different from non-compulsory fields.

Nothing special here, nor complicated, but it costs me a while to find the reason for this, so I'll share it with you. The simple solution is to add a line ( required_css_class ...

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I think this should be a nice post talking about the substitution of the default multiple select widget used in django admin interface to deal with m2m fields, with a multiple checkbox widget.

Yes I know, you may solve it this way, but I don't like such solution very much, and I think it is just not perfect for some reasons:

• At the time of this writing the add related functionality (+) seems to be broken, throws an error, at least for me
• It just can't be used with the django-mptt application, which is awesome to deal with data which have a tree like structure

So to graphically explain what we want to do here, say we want this ...

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This entry is related to the series "Deploy django applications with nginx, uwsgi, virtualenv, south, git and fabric", the first part here.

So what happens here? Really nothing special, I've changed my working machine and so I had to set up my django projects on the new notebook. This post is only a remainder of the followed steps.

Install all the required system packages

Clearly I had to install some packages in the new machine:

• mysql-server
• python
• python-dev
• python-setuptools
• build-essentials
• libmysqlclient-dev
• git

And also I've installed pip and virtualenv

Create the folder structure and the virtualenv

First of all create a directory which will contain the project, I've created it under /var/www:

$ mkdir /var/www/myproject ...

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I use to use the django-mptt package to deal with tree like models. I also use to have my backoffice autogenerated by django admin.

Now one of the problems I've encountered was to add an inline form of a model which contains a "tree" field in a way the user can deal with a select input well formatted (showing parents and children in a clear way).

This task is easily reached in a normal form by defining the form ...

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I've just discovered a great thing on django. Like in javascript, it is possible to add dynamically properties to a model instance, and use them inside a template. This is extremely useful in my opinion because saves us from creating a new dictionary mapping the object properties with the addition of the properties that we want to add.

Here a short example: I have a model WorkingPlace which is related to a model Case in the sense that every ...

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This is the fifth and last part of the django deploy environment, you may find the fourth part here.

In this part we'll see how to automate the deployment using fabric.

What the hell have fabric to do?

Well, fabric have to do all the work for me in the sense that once I've done some changes to my project and pushed them to the bare repository I want to update the production environment with only one command. I'd like also to setup initially the whole environment with only one command.

How does it work?

First of all install it, so with the virtualenv activated:

$ pip install fabric

Done.

Now reading from the official site:

Fabric is a Python (2.5 or higher) library and command-line tool for streamlining the use of SSH for application deployment or systems administration tasks. It provides a basic suite of operations for executing local or remote shell commands (normally or via sudo) and uploading/downloading files, as well as auxiliary functionality such as prompting the running user for input, or aborting ...

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This is the fourth part of the django deploy environment, you may find the third part here.

In this part we'll see how to freeze the project requirements, use versioning and prepare all in order to automate the deployment in production with fabric (which will be the argument of the last post, part 5).

Create a requirements.txt

As said in all previous posts, all the packages used by our project have been installed in a virtualenv which is strictly connected to our project. And if you were asking yourself why this is a convenient way to approach the django developement issue here comes the answer.

Activate the virtualenv, go inside the container folder of your django project and then perform this simple command

$ pip freeze > requirements.txt

This command simply creates a requirements.txt files which contains all the project dependencies, look at the image illustrating the project folder structure in the part 2, you'll see the same file there.

The nice part here is that you may setup an equivalent environment, with all the dependencies ...

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This is the third part of the django deploy environment, you may find the second part here.

In this part we'll see how to set up nginx and uwsgi to work with our django project.

Let's install and configure uwsgi

Be sure to have the virtualenv activated (see part 2), and then install uwsgi

$ pip install uwsgi

Ok now we have to configure our project to work with uwsgi, open and edit the myproject/myproject/wsgi.py file, mine looks like this:

"""
WSGI config for sic2012 project.

This module contains the WSGI application used by Django's development server
and any production WSGI deployments. It should expose a module-level variable
named ``application``. Django's ``runserver`` and ``runfcgi`` commands discover
this application via the ``WSGI_APPLICATION`` setting.

Usually you will have the standard Django WSGI application here, but it also
might make sense to replace the whole Django WSGI application with a custom one
that later delegates to the Django one. For example, you could introduce WSGI
middleware here, or combine a Django application with an application of another
framework.

"""
import os ...

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Ok, this is the second part of the django deploy environment, you may find the first part here.

In the prevoius post we have seen how to install nginx webserver an some system packages, both in locale and remote, now it's time to start our developement in locale.

Let's create a new virtualenv

The use of virtualenv is incredibly comfortable and lets you keep separated environment for different projects. So first of all create a new virtualenv in the place you prefer

$ mkdir ~/virtualenv
$ cd ~/virtualenv
$ virtualenv --no-site-packages myproject

Done, now we can activate the virtualenv so that every new python package will be installed in it, so

$ source ~/virtualenv/myproject/bin/activate

MySQL as the database server

Why MySQL? Only because I'm easy with it, I know its syntax, I'm accustomed with it and because I use it at work.
But, since the role of mysql in the whole deploy structure finishes here, you may want to use a different db server, more efficient, lightweight and which uses less system resources

In the first post ...

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After googling for a while, asking my guru and some tests I was able to setup a deploy environment for django projects.

The web server is nginx, the database server mysql, I use uwsgi as wsgi server, all the code is versioned using git, the python libraries are installed in a virtualenv, db migration is assured by South and the deploy is automated using fabric.

While writing this post the whole environment is working but I think it may be adjusted in some ways, so let's take what follows as a guideline to improve in many aspects.

I assume we are working in locale and deploying directly to a production server, ignoring the staging phase.

Installing some packages (locale and remote)

To set up the environment we need python >= 2.6, python-dev, python-setuptools, pip and virtualenv, so (in a debian/ubuntu os):

$ sudo apt-get install python python-dev python-setuptools
$ sudo easy_install pip
$ pip install virtualenv

Ok that's all, the other python packages will be installed in the virtualenv, so now let's continue installing git and mysql

$ sudo apt-get install git ...

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