This post is a guide for building your own version of Apache’s mod_python as a Universal Binary in order to support a custom Django install containing the Twitter libraries. As you can probably gather, this information is likely only useful to advanced Mac users who are comfortable in Terminal with compiling and installing software from source. If you’re still interested, gird your loins, crack your knuckles, grab some Mountain Dew, and read on.
Mac OS X 10.5 “Leopard” is yet another step forward into the world of 64-bit. At the same time, Apple has to support both PowerPC and Intel architectures. This is no mean feat, and this is where “fat” or Universal binaries come in. Apple also has an explanation of Universal binaries, although it’s heavy on PR. This is all well and good, but there is one problem: once you make this leap, all of your library dependencies must contain the architecture you’re running as. Much software is still built as 32-bit only; while it may be a “fat” binary, containing both Intel and PowerPC machine code, it only has the 32-bit versions thereof. For reference, the names of the various architecture flags:
Huzzah naming conventions! There’s a lot of history in those names. I’ve linked to the relevant Wikipedia articles if you’re curious; these flags will be coming up again later when configuring various builds. The main thing to note is that most build configurations default to i386 on Intel Macs (even though Core 2 and Xeon processors are natively 64-bit), probably because most software is developed for 32-bit versions of Windows and Linux. As you’ll see, we’ll be overriding that default in several places to get this whole mess working.
Unfortunately, Universality is a cancer, which in my case starts with the Apple-shipped version of the Apache web server in 10.5, a universal binary. Everything it touches needs to be Universal as well, so that Apache can run as a 64-bit process by default. I wanted to add Django support on my web server via mod_python, specifically to play with the Twitter API, which meant I also needed to build python-twitter and its dependencies, as well as a MySQL python module to allow Django to talk to my database. None of these are included in the default Leopard version of Python 2.5.1.
After getting all of this set up, and trying to start my test Django app, mod_python was giving me errors about architecture. As it turns out, the included version of Python is only a “fat” 32-bit binary, not a Universal binary… which means all of the new Python modules I just compiled to support Twitter and Django were only 32-bit, which in turn means that the included Universal version of Apache and mod_python couldn’t use them. Yay.
Below the cut you’ll find my complete instructions for compiling all of the relevant components and their dependencies. I also took the opportunity to update to the latest release version of Python 2.6 and MySQL 5.1, and as a side effect my database server is now running as a 64-bit process. Progress has been made here. Feel free to comment or contact me if you have questions.