Today I wanted to be able to watch the PyCon Live Stream while using OS X at work. A quick Google search returned an awesome program: Afloat. It lets me change the window settings for just about any OS X application. Right now I've got the live feed just lingering there in the background, pinned to my desktop. Loving it!
With the recent release of Python 3.0 final, I've had a crazy itch that needed to be scratched. That itch, my friends, was to do a write-up of how to install Python 3.0 alongside my existing Python 2.5.2 installation without borking things up. The reason I thought it would be useful is that I'm running a Debian-based distribution of Linux called sidux right now, and neither Python 2.6 nor Python 3.0 are in the package repositories. I assume that Ubuntu and other Debian-based distributions might be the same way, and that there are others like me who would like to tinker with these new releases.
Just before attempting to install Python 3.0 on my computer, I started getting ready to write this article. Before I knew it, Python 3.0 was installed on my system, and I had no notes to share with you! That is how stinkin easy it is to install Python 3.0 without interfering with an existing install. I mentioned to a good friend that I wasn't sure the process was worth writing an article because it was so simple, but he encouraged me to carry on. Thanks bro.
So, without any further ado, here is what I did to install Python 3.0 from source alongside my Python 2.5 installation:
Note: If you're using a Mac or Windows, you should be able to simply install the packages for your platform to accomplish this same feat. Once the packages are in the repositories it will be just as easy for Linux.
Download Python 3.0 from the official Web site: http://python.org/download/releases/3.0/
I downloaded it this way:
- Unpack the archive:
- Descend into the newly extracted Python-3.0 directory:
- Install libreadline-dev. This step is necessary for the arrow keys to work, as pointed out by jazevec below in the comments. If you are on a Debian-based system, you can execute a command such as this:
$ sudo apt-get install libreadline-dev Other distributions may have different package names, such as ``readline-dev``. If neither one of those package names work for your distribution, try searching your package manager for ``readline`` and install the development files. Alternatively, you should be able to manually install what you need by installing `readline itself <http://directory.fsf.org/project/readline/>`_.
- Configure Python 3.0 for your computer:
- Compile Python 3.0:
$ make **UPDATE** (9 Dec): Depending on your setup, you may or may not see a message such as this after executing the ``make`` command (thanks again to ``jazevec`` for pointing out that this can happen):: Failed to find the necessary bits to build these modules: _dbm _gdbm _hashlib _sqlite3 _ssl _tkinter bz2 zlib To find the necessary bits, look in setup.py in detect_modules() for the module's name. If you need any of those capabilities, you should install the appropriate development files for the missing module(s). For example, above, we installed the ``libreadline-dev`` package. To resolve the missing module problem for each one listed above (except ``_dbm`` because it's apparently borked on Debian right now... possibly other distros too), install these packages: * ``tk-dev`` to satisfy ``_tkinter`` * ``libsqlite3-dev`` to satisfy ``_sqlite3`` * ``libbz2-dev`` to satisfy ``bz2`` * ``zlib1g-dev`` to satisfy ``zlib`` * ``libssl-dev`` to satisfy ``_ssl`` and ``_hashlib`` * ``libgdbm-dev`` to satisfy ``_gdbm``
- Install Python 3.0:
- Test Python 3.0:
$ python3.0 Python 3.0 (r30:67503, Dec 5 2008, 11:05:45) [GCC 4.3.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> print 'Hi' File "<stdin>", line 1 print 'Hi' ^ SyntaxError: invalid syntax >>> print('Hi') Hi >>>
- Make sure that your old version of Python is still around:
$ python Python 2.5.2 (r252:60911, Sep 29 2008, 21:15:13) [GCC 4.3.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> print 'Hi' Hi >>>
That's about it folks! Extremely simple and fast, compared to what it could have been.
If you find yourself in a situation where you don't have access to sudo or straight root-level access, you can install Python 3.0 locally by doing something like this:
- Configure Python 3.0 for your computer:
- Compile Python 3.0:
- Install Python 3.0:
- Symlink to Python 3.0, assuming you have a bin/ directory in your home directory (i.e. /home/[yourusername]/bin), and that said bin directory is on your PATH:
- Test your locally installed Python 3.0:
- Do the dance.
Please comment with any problems you find with this process, or any additional advice you can offer to newbies!
This article is a related to my previously posted article about installing Django, an advanced Web framework for perfectionists, on your own computer. Now we will learn how to install Django on a shared hosting account, using Site5 and fastcgi as an example. Depending on your host, you may or may not have to request additional privileges from the support team in order to execute some of these commands.
Note: Django requires at least Python 2.3. Newer versions of Python are preferred.
Note: This HOWTO assumes familiarity with the UNIX/Linux command line.
Note: If the wget command doesn't work for you (as in you don't have permission to run it), you might try curl [url] -O instead. That's a -O as in upper-case o.
Site5 (and many other shared hosting providers that offer SSH access) already has Python installed, but you will want to have your own copy so you can install various tools without affecting other users. So go ahead and download virtual python:
Virtual Python will make a local copy of the installed Python in your home directory. Now you want to make sure you execute this next command with the newest version of Python available on your host. For example, Site5 offers both Python 2.3.4 and Python 2.4.3. We want to use Python 2.4.3. To verify the version of your Python, execute the following command:
If that displays Python 2.3.x or anything earlier, try using python2.4 -V or python2.5 -V instead. Whichever command renders the most recent version of Python is the one you should use in place of python in the next command. Since python -V currently displays Python 2.4.3 on my Site5 sandbox, I will execute the following command:
Again, this is just making a local copy of the Python installation that you used to run the virtual-python.py script. Your local installation is likely in ~/lib/python2.4/ (version could vary).
Make Your Local Python Be Default
To reduce confusion and hassle, let's give our new local installation of Python precedence over the system-wide Python. To do that, open up your ~/.bashrc and make sure it contains a line similar to this:
If you're unfamiliar with UNIX-based text editors such as vi, here is what you would type to use vi to make the appropriate changes:
- vi ~/.bashrc to edit the file
- go to the end of the file by using the down arrow key or the j key
- hit o (the letter) to tell vi you want to start typing stuff on the next line
- type export PATH=$HOME/bin:$PATH
- hit the escape key
- type :x to save the changes and quit. Don't forget the : at the beginning. Alternatively, you can type :wq, which works exactly the same as :x.
Once you've made the appropriate changes to ~/.bashrc, you need to make those changes take effect in your current SSH session:
Now we should verify that our changes actually took place. Type the following command:
If they output of that command is not something like ~/bin/python or /home/[your username]/bin/python, something probably didn't work. If that's the case, you can try again, or simply remember to use ~/bin/python instead of python throughout the rest of this HOWTO.
Install Python's setuptools
Now we should install Python's setuptools to make our lives easier down the road.
This gives us access to a script called easy_install, which makes it easy to install many useful Python tools. We will use this a bit later.
Let's now download the most recent development version of Django. SSH into your account and execute the following commands (all commands shall be executed on your host).
Now we should make a symlink (or shortcut) to Django and put it somewhere on the Python Path. A sure-fire place is your ~/lib/python2.4/site-packages/ directory (again, that location could vary from host to host):
ln -s ~/downloads/django-trunk/django ~/lib/python2.4/site-packages ln -s ~/downloads/django-trunk/django/bin/django-admin.py ~/bin
Now verify that Django is installed and working by executing the following command:
That command should return something like 1.0-final-SVN-8964. If you got something like that, you're good to move onto the next section. If, however, you get something more along the lines of...
Traceback (most recent call last): File "<string>", line 1, in ? ImportError: No module named django
...then your Django installation didn't work. If this is the case, make sure that you have a ~/downloads/django-trunk/django directory, and also verify that ~/lib/python2.4/site-packages actually exists.
In order for your Django projects to become useful, we need to install some other packages: PIL (Python Imaging Library, required if you want to use Django's ImageField), MySQL-python (a MySQL database driver for Python), and flup (a utility for fastcgi-powered sites).
easy_install -f http://www.pythonware.com/products/pil/ Imaging easy_install mysql-python easy_install flup
Sometimes, using easy_install to install PIL doesn't go over too well because of your (lack of) permissions. To circumvent this situation, you can always download the actual PIL source code and install it manually.
cd ~/downloads wget http://effbot.org/downloads/Imaging-1.1.6.tar.gz tar zxf Imaging-1.1.6.tar.gz cd Imaging-1.1.6 ln -s ~/downloads/Imaging-1.1.6/PIL ~/lib/python2.4/site-packages
And to verify, you can try this command:
If that doesn't return anything, you're good to go. If it says something about "ImportError: No module named PIL", it didn't work. In that case, you have to come up with some other way of installing PIL.
Setting Up A Django Project
Let's attempt to setup a sample Django project.
mkdir -p ~/projects/django cd ~/projects/django django-admin.py startproject mysite cd mysite mkdir media templates
If that works, then you should be good to do the rest of your Django development on your server. If not, make sure that ~/downloads/django-trunk/django/bin/django-admin.py exists and that it has a functioning symlink (shortcut) in ~/bin. If not, you'll have to make adjustments according to your setup. Your directory structure should look something like:
Making A Django Project Live
Now we need to make your Django project accessible from the Web. On Site5, I generally use either a subdomain or a brand new domain when setting up a Django project. If you plan on having other projects accessible on the same hosting account, I recommend you do the same. Let's assume you setup a subdomain such as mysite.mydomain.com. On Site5, you would go to ~/public_html/mysite for the next few commands. This could differ from host to host, so I won't go into much more detail than that.
Once you're in the proper place, you need to setup a few things: two symlinks, a django.fcgi, and a custom .htaccess file. Let's begin with the symlinks.
ln -s ~/projects/django/mysite/media ~/public_html/mysite/static ln -s ~/lib/python2.4/site-packages/django/contrib/admin/media ~/public_html/mysite/media
Now for the django.fcgi. This file is what tells the webserver to execute your Django project.
And finally, the .htaccess file:
The .htaccess file makes it so that requests to http://mysite.mydomain.com/ are properly directed to your Django project. So, now you should have a directory structure that something that looks like this:
If that looks good, go ahead and make the django.fcgi executable and non-writable by others:
After that, head over to http://mysite.mydomain.com/ (obviously, replace the mydomain accordingly). If you see a page that says you've successfully setup your Django site, you're good to go!
I've noticed that I need to "restart" my Django sites on Site5 any time I change the .py files. There are a couple methods of doing this. One includes killing off all of your python processes (killall ~/bin/python) and the other simply updates the timestamp on your django.fcgi (touch ~/public_html/mysite/django.fcgi). I find the former to be more destructive and unreliable than the latter. So, my advice is to use the touch method unless it doesn't work, in which case you can try the killall method.