Common Good: Adding a Creative Commons License button to your Blogspot (Blogger) blog

I have intended to place the contents of this blog under a Creative Commons (CC) license for a long while, especially given that all the attractive photos I love to use in these blog entries come from Creative Commons-licensed content on Flickr. For those unfamiliar with Creative Commons licenses, they explicitly permit re-use of creative works a priori. Provided you follow the criteria of the particular CC license of the work (usually simply attributing the original creator), you may simply use, or even modify the work, without the need to contact the original creator for direct permission to do so. Read the Creative Commons' website for more detail.

I had let this task linger far too long, so, spurred on by a recent email exchange with Mark Hahnel of Science 3.0, I finally felt the inspiration to get this done. Unfortunately, I didn't find the top-ranked pages in Google searches for placing a CC license button on Blogger/Blogspot blogs very helpful, so I decided to just figure it out. It turned out to be a simple process, so I documented it and present it here, in step-by-step format (all under the CC-BY license, of course):

1. Go to the Creative Commons website and choose a license
2. Copy the HTML that CC presents you after you've selected your license
3. Go to your blog's page, and click the "Design" link in the navigation bar at the top. Alternatively, go to your Blogger author page and click the appropriate "Design" link for your blog there.
4. Click the "Add a Gadget" link in the design editor (should be one at the bottom of the area).
5. Click the link to add an "HTML/JavaScript" gadget.
6. Add a title, like "CC License", paste the HTML of your license button that you copied from the CC website into the contents box, and click "Save".
7. Optional: You'll be back at the design editor; double-click the new CC License gadget and move it below your Blog Posts gadget (or some other fitting area).

That's it! Your shiny new CC license button should appear where you placed it.

Cell on Wheels: Famous Scientist Roller Derby Names

This past Sunday I had an exciting first Roller Derby experience when I went out to support the NRV Rollergirls in their bout of against the Mason Dixon Roller Vixens. For those unfamiliar with modern roller derby, it is a contact, point-based sport in which the players of two teams skate in a circuit, trying to help their point-scorer, designated a "jammer", pass the other team, whilst simultaneously using any blunt part of their bodies above the knees to prevent the other team's jammer from passing them. The rest of the details you can pick up as you watch.

Today, roller derby is largely an all-women's sport, where men play supporting roles as coaches and referees, which is sort of an interesting role-reversal. My favorite part of the roller derby culture is that all participants don noms de guerre, which usually involve clever (or even tacky) wordplay, including the use of homophones, oronyms, and portmanteaus, to spin references to pop culture, history, or anything otherwise generally familiar, with a violent, aggressive bent. For example, my favorites for the NRV Rollergirls are Huck Finish Her and Eleanor Blows B. Dealt, but other good examples include Baby Ruthless and Bloody Holly from the enjoyable film "Whip It", or Hyper Lynx, Auntie Christ, Beyonsláy, and Nina Millimeter who have been appeared in various articles in the New York Times.

As I lay awake Monday, unable to sleep with anxieties about upcoming presentations, needing to develop an entirely different computational approaches for research, and general insecurities about my place in life, I started thinking about how amusing derby names are, and then tried inventing some of my own. Then I had a revelation that it would be hilarious if there were derby names based off of (relatively) famous scientists. Once I got a few, I started jotting them down. Here's a list of ones I've come up with, so far:

• Stephen Knocking
• J. Robert Uppyurheimer
• James Swat Some
• Julius Robert von Slayer
• Louis Passed U
• Archimelees
• Aristhrottle
• Kneel Spore
• Mack's Plank
• Carl Satan
• Jonas Shock 'n' Awe
• Alexander Grand Hell
• William Rams Ye
• Earnest Rougher Foot
• Paul D. Rock

I would like to point out the obvious that these are all plays ot men's names, which is ironic given that roller derby is played predominantly by women. This is disheartening for three reasons:

1. I could only come up with four "famous" female scientists offhand: Marie Curie, Jane Goodall, Rosalind Franklin, and Lynn Margulis.
2. I couldn't come up with a clever spin on any of them.
3. Did I mention I could come up with only four famous scientists who are women? This reflects poorly on me, but I think also on the inequality that exists in scientific education and scientific research, both of yesteryear but also today. This is another issue for another blog post.

If you have any suggestions for scientists I've missed (particularly famous women who are or were scientists), or better suggestions for the ones I've attempted to spin, I encourage you to post them in the comments, or put them in your own blog and post the link below.

Update 2011-05-17: Randall Munroe published a relevant comic on the final points on female scientists:

Interactive sandboxes: using IPython with virtualenv

A very helpful blog post on IPython and virtualenv by Pedro Algarvio inspired this one. The advice found there takes you 90% to where you want. I'll recap on that 90% but explain and give the extra 10%. I am indebted to Pedro for laying down all the hard work.

First of all, if you are unfamiliar with Ian Bicking's virtualenv package, you should know two things about it:

1. virtualenv allows you to develop in sane, aseptic, "sandbox" development environments, switch between them seamlessly, and maintain harmonious order in your Python universe.
2. virtualenv is certifiably awesome. Proceed directly to installing it (especially in combination with pip)! Do not pass Go! Do not collect $200!

Arthur Koziel already wrote a really good tutorial on using virtualenv, and, in fact, you'll probably find working with Doug Hellman's excellent virtualenvwrapper more convenient; in this case, Doug already wrote an excellent virtualenvwrapper tutorial, too. I've mentioned IPython in a previous blog post, so I won't cover that here, either. Instead, let's cut to the chase and get IPython and virtualenv playing well together.

Ordinarily, IPython, commonly installed system-wide by your preferred package management system, remains oblivious of an activated virtualenv environment, and will just mill about importing packages and modules from the system, rather than the sandbox. This gives two obvious solutions: either 1) configure the system installation of IPython to work with virtualenv, or 2) install IPython in each virtualenv environment. Doug Hellman wrote a nice tutorial on doing the latter approach; here, we'll focus on the former, which I prefer, since it means having to only install IPython once.

IPython (being a Python program) can read and execute Python scripts during launch; we'll use this mechanism to modify IPython's launch to hook into the virtualenv environment we're currently in. First, we'll tell IPython that we want to execute some code in a at startup. If we go to the $HOME/.ipython/ directory, we'll find a file called ipy_user_conf.py. Open the file in your editor of choice, locate the function main(), and at the within that function (I suggest at the end), insert the following line:

execf('~/.ipython/virtualenv.py')

Next, we need to create this file. Still in the $HOME/.ipython/ directory, create a new file called virtualenv.py and open it with your editor. Next, add these contents to this file:

import site
from os import environ
from os.path import join
import sys

if 'VIRTUAL_ENV' in environ:
    virtual_env = join(environ.get('VIRTUAL_ENV'),
                       'lib',
                       'python%d.%d' % sys.version_info[:2],
                       'site-packages')

    # Remember original sys.path.
    prev_sys_path = list(sys.path)
    site.addsitedir(virtual_env)

    # Reorder sys.path so new directories at the front.
    new_sys_path = []
    for item in list(sys.path):
        if item not in prev_sys_path:
            new_sys_path.append(item)
            sys.path.remove(item)
    sys.path[1:1] = new_sys_path

    print 'VIRTUAL_ENV ->', virtual_env
    del virtual_env

del site, environ, join, sys

If you took a look at Pedro's version of virtualenv.py, you'll recognize most of his code here. The important difference lies in the trickery we play with sys.path in lines 12 through 22. These lines were inspired by a solution to a problem presented by using site.addsitedir(), which adds new paths only to the end of sys.path.

Adding paths to the end of sys.path has, for our purposes, the undesirable side-effect of allowing system-wide packages and modules to preempt locally installed ones, since Python searches through sys.path for modules and packages in first-to-last order. I have filed a feature request for site.addsitedir() to allow inserting new paths at the beginning of sys.path; in the meantime, we'll use this hack inspired by the modwsgi programmers, which keeps track of the paths before and after the call to site.addsitedir(), then swaps the position of the new paths from the end, to just after the first element, '', which represents the current working directory (which should preempt every other path).

IPython will have access to the contents of the virtualenv sandbox in which you're currently working. For example, if I activate my networkx virtual environment, which has the latest development version of the NetworkX graph library, then fire up IPython, I get the following result (note the line that begins with VIRTUALENV indicating I'm accessing the virtualenv sandbox):

(networkx)$ ipython
VIRTUAL_ENV -> /home/lasher/.virtualenvs/networkx/lib/python2.6/site-packages
Python 2.6.2 (release26-maint, Apr 19 2009, 01:56:41) 
Type "copyright", "credits" or "license" for more information.

IPython 0.9.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object'. ?object also works, ?? prints more.

In [1]: import networkx

In [2]: networkx.__version__
Out[2]: '1.1.dev1518'

When I leave the sandbox (e.g., by using virtualenvwapper's deactivate command), I return to accessing the system-wide default install of NetworkX:

$ ipython
/var/lib/python-support/python2.6/IPython/Magic.py:38: DeprecationWarning: the sets module is deprecated
  from sets import Set
Python 2.6.2 (release26-maint, Apr 19 2009, 01:56:41) 
Type "copyright", "credits" or "license" for more information.

IPython 0.9.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object'. ?object also works, ?? prints more.

In [1]: import networkx

In [2]: networkx.__version__
Out[2]: '0.36'

So there you have it: one IPython to rule all your virtualenv sandboxes!

Time out: deterring brute force SSH attacks with iptables

These are some simple iptables rules I keep around on my firewall to deter brute force SSH attacks. The original idea came from Dominik Borkowski, a sysadmin at VBI.

If the attacker attempts more than 4 connections within a minute, these rules temporarily blacklist them for the next minute—or as I like to say, "put them in time-out". Their packets will be dropped; to them, it will seem that the machine simply disappeared from the intarwebs. The rules will also log such violators to your syslog. I've found them very effective. Most scripts that these crackers run will drop off after one iteration and look for lower hanging fruit.

Of course, if you forget your password, or have a habit of making a couple of simultaneous connections to your computer, the door will shut on you, too, but the good news is that you'll only be blocked for a minute. More draconian methods that append to actual blacklists have a habit of locking their owners out. (Not that I'm speaking from personal experience at all.) The rules escape this pitfall but will prove just as effective.

## Below includes very successful deterrents for SSH brute force
## that allows a maximum of 4 connection attempts within a minute.
iptables -A INPUT -p tcp -m state --state NEW --dport 22 -m recent --name sshattack --set
iptables -A INPUT -m recent --name sshattack --rcheck --seconds 60 --hitcount 4 -m limit --limit 4/minute -j LOG --log-prefix 'SSH attack: '
iptables -A INPUT -m recent --name sshattack --rcheck --seconds 60 --hitcount 4 -j DROP
iptables -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT

I keep this in a firewall (shell) script that controls iptables rules and executes on bootup. If there's sufficient demand, I can make the entire script available.

"Who arrre you?" Getting the hostname back in the Jaunty GDM greeter

The latest Ubuntu release, 9.04, codename "Jaunty Jackelope", has turned out to be one of the best, maybe even on par with the "Gutsy Gibbon" release. The aesthetics definitely got some love; for example, if you're not running the "Dust" theme, you're missing out. [Hint: go to Preferences -> Appearance -> Theme and select "Dust"] The GDM greeter login screen looks the best of any Ubuntu release.

Unfortunately, a little bit of usability got lost along the way; most notably, the hostname no longer appears anywhere on the graphical login. This probably bothers only a minority of people, but our lab, for example, just updated all its machines to Jaunty, and we couldn't tell from the greeters which machine belonged to which hostname without logging in. I sat down this afternoon for a few minutes to figure out how the GDM themes work. It turns out they're just coded as fairly simple XML, and looking at other themes, I eventually figured out what to tweak. This patch will bring back the beloved hostname to the GDM login.

To use this patch, just do

sudo patch -p0 < /path/to/hostname_patch_for_Human.xml.patch

Now you'll no longer have to look at login screens and wonder, "Who arrre you?"

Update (16:17): Apparently Blogger's software won't allow XML in their pre tags, so I just hosted the patch on my server instead. All the more reason why I need to host my own blog with Wordpress or something soon...