import sys
sys.path.append("/home/me/mypy")
Monday, January 24, 2011
HOWTO add a directory to your python path
You can add to your python path like this:
The (python) way of the future: pip and virtualenv
I recently discovered the magic of pip and virtualenv. Pip is shaping up as a serious contender for replacement of distutils and easy_install. I haven't used it much yet, and will have to reserve judgement until I package a decent-sized project with pip.
Using pip is easy, although there is a bootstrapping problem that, ironically, I used easy_install to solve. If your distro packages a recent version of pip, you can use it to skip this bit.
This gives you a virtualenv install. Virtualenv is brilliant, and has significantly influenced the way I write python. Virtualenv allows you to build a complete python environment in a directory that you 'activate' by running an in-built shell script that sets your python path environment variables. The are many advantages to this approach, but here are a few I have encountered:
You can even create virtual environments with different versions of the python interpreter using:
So, once you have a virtualenv, activate it and install yolk to give you a picture of what is inside the environment.
Then go ahead and install the other packages you need:
You can also build a requirements file to install exactly the same versions somewhere else:
The holy trinity is apparently pip, virtualenv and fabric. Fabric is something I'll have to play with soon. There is a good tutorial on pip and virtualenv here, and using them with django here.
The only limitation/problem I have run into is that you can't move the virtual environment once it is created. There is a "--relocatable" directive to address this, but the webpage says that it is somewhat experimental at the moment.
Using pip is easy, although there is a bootstrapping problem that, ironically, I used easy_install to solve. If your distro packages a recent version of pip, you can use it to skip this bit.
sudo apt-get install python-setuptools s easy_install pip s pip install virtualenv
This gives you a virtualenv install. Virtualenv is brilliant, and has significantly influenced the way I write python. Virtualenv allows you to build a complete python environment in a directory that you 'activate' by running an in-built shell script that sets your python path environment variables. The are many advantages to this approach, but here are a few I have encountered:
- Simplified testing - test your code against multiple versions of libraries and utilities
- Keep separate dev and production environments on your dev machine, allowing you to test in a production environment without pushing the code to your actual production server.
- The isolation provided by Virtualenv ensures you aren't depending on libraries on your dev box that aren't installed in production, and upgrading libraries won't break other applications
You can even create virtual environments with different versions of the python interpreter using:
virtualenv -p python2.6 2.6ENV
So, once you have a virtualenv, activate it and install yolk to give you a picture of what is inside the environment.
source .testenv/bin/activate ~> pip install yolk ~> yolk -l Python - 2.6.4 - active development (/usr/lib/python2.6/lib-dynload) distribute - 0.6.14 - active pip - 0.8.1 - active wsgiref - 0.1.2 - active development (/usr/lib/python2.6) yolk - 0.4.1 - active
Then go ahead and install the other packages you need:
pip install django
You can also build a requirements file to install exactly the same versions somewhere else:
pip freeze -E .testenv > requirements.txt
The holy trinity is apparently pip, virtualenv and fabric. Fabric is something I'll have to play with soon. There is a good tutorial on pip and virtualenv here, and using them with django here.
The only limitation/problem I have run into is that you can't move the virtual environment once it is created. There is a "--relocatable" directive to address this, but the webpage says that it is somewhat experimental at the moment.
Syntax highlighting code in Blogger
Posting code in Blogger by default results in something that is inexcusably ugly. How can you make code posted in blogger look pretty? For me, syntax highlighting and scrollable text boxes are a must.
The solution is: google-code-prettify, which does the highlighting for code.google.com (you could also consider SyntaxHighlighter). Now the next problem is, how do you distribute the javascript and CSS for prettify? Unfortunately Google doesn't make it available via their CDN like they do for other libraries like jQuery. This would obviously be the best option for users since:
I opted for the last option, which works a treat. Put this in your blogger template, right after the <head> tag:
Then add an onload event to the body tag to call the PrettyPrint function:
and, since the prettyprint CSS doesn't give you a scrolling box by default (!?), add this to the CSS in your template to avoid your code being chopped off:
Once you have done all that, you just need to wrap the code in your posts in:
In summary, much harder than it needs to be. Blogger team, please build this functionality in!
The solution is: google-code-prettify, which does the highlighting for code.google.com (you could also consider SyntaxHighlighter). Now the next problem is, how do you distribute the javascript and CSS for prettify? Unfortunately Google doesn't make it available via their CDN like they do for other libraries like jQuery. This would obviously be the best option for users since:
- it would negate the need for additional hosting; and
- minimise load time since browsers could cache the code across many sites, and if needed download it from the closest CDN node.
I opted for the last option, which works a treat. Put this in your blogger template, right after the <head> tag:
<link type="text/css" rel="stylesheet" href="http://www.gstatic.com/codesite/ph/3799605220899551948/css/ph_core.css"> <link type="text/css" rel="stylesheet" href="http://www.gstatic.com/codesite/ph/3799605220899551948/css/ph_detail.css" > <link type="text/css" rel="stylesheet" href="http://www.gstatic.com/codesite/ph/3799605220899551948/css/d_sb_20080522.css" >
Then add an onload event to the body tag to call the PrettyPrint function:
<body onload="prettyPrint()" >
and, since the prettyprint CSS doesn't give you a scrolling box by default (!?), add this to the CSS in your template to avoid your code being chopped off:
/* Override prettyprint CSS, which doesn't allow scrolling box */
pre.prettyprint {
overflow: auto;
}
Once you have done all that, you just need to wrap the code in your posts in:
<pre class="prettyprint"> </pre>
In summary, much harder than it needs to be. Blogger team, please build this functionality in!
Wednesday, January 19, 2011
List of DNS Providers
Just came across a list of DNS providers I made a while ago, and thought I'd post it here. They all seem to still be in business. The top three I have heard good reports about:
- DNS Made Easy
- changeip.com
- zoneedit.com
- bur.st (non-profit based in Perth)
- dnspark.com
- xname.org
GPG HOWTO
Here is a good, quick intro to using GPG, including generating and publishing keys, encrypting and signing.
Tuesday, January 18, 2011
The Google Apps administrator control panel
The Google Apps administrator control panel for "your_domain.com" can be found at the fairly un-intuitive address:
https://www.google.com/a/your_domain.com
Wednesday, January 12, 2011
Linux boot process digram
Finally got around to converting my RHCE notes on the linux boot process into a diagram.
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