High level perspective on the switch from PHP to Python
It may be fatuous to write this post before we’ve actually finished the transition from PHP to Python, but I started writing a different post and this is what came out. Sometimes that happens.
Status Watch: An add-on for noticing HTTP error codes
Often on complex pages with many assets it can be easy to overlook assets which don't load. Usually they are minor JS, CSS, or tracking pixels which aren't noticed until you've spent way too long trying to track down the problem (or a month later you log into your stats dashboard to discover you haven't been collecting stats). With the launch of the new Add-on Builder (still an alpha product, but usable) I decided to make my first Jetpack to fix this. In only about 20 lines of code I was able to look for any 4xx or 5xx errors in the HTTP traffic and show a brief notification to the user about what went wrong and where. The builder was a great development experience (lack of documentation aside) and was a breeze to do something relatively complex. If you've wanted a similar add-on, feel free to use Status Watch. It's a Jetpack so you'll need Firefox 4, but on the bright side, you won't even need to restart the browser. Just click and go. I've had some requests to support a whitelist of sites so you don't get notifications all over the web and I'll add that when I get time. It's surprising how many sites have 403s and 404s though. Update 2011-02-17: Version 2 is on AMO now which supports a whitelist. See the AMO page for details.
A Night in the Emergency Department
Within minutes of my arrival at the Emergency Department a call comes in that an ambulance will arrive shortly transporting a man in cardiac arrest. Orientation can wait. Over the next 20 minutes he is given a regiment of drugs. I follow him to a unit that will try to locate and destroy the clot in his heart. In the next hour his heart stops four times while technicians put two femoral catheters in his legs and follow a dye through his blood stream. Eventually they finish what they can do and ship him to the Cardiac Care Unit. No one knows about permanent damage. On my way back to the Emergency Department I pass a frantic looking woman with a cell phone. She’s just spied her teenage daughter running in and cries, “they say it’s his heart and it’s serious.” I don’t make eye contact.
md5verify: A script to automatically verify file integrity
I have a lot of files on my computer. Email archives, personal documents, stuff for work, photos I've taken...the list goes on - I'm sure most people reading this are in a similar boat. On occasion I've found some files to be missing or corrupt which is disturbing but is probably something to be expected. The bad part is, I keep backups, but I rotate them out when they reach a certain age which means if I don't notice a file is corrupt or missing I'll eventually lose it forever. I stayed up late a few nights ago and wrote a script to raise an alert when something has changed. On its first run the script will recursively walk a directory tree hashing each file and storing the hashes in the directory (in an md5sum compatible formatted file). On subsequent runs it will begin tracking new files automatically but it will also print messages for missing and changed files. By saving the checksums in each directory it becomes portable - you can copy a directory somewhere else and still be able to verify nothing changed (a quick md5sum -c checksums.txt will let you know). By default the script only prints messages when it sees something fishy so it's perfect to drop into cron and it uses exit statuses so it'll work for nagios too. I've been running it for a few months and have found a couple files that have changed - nothing critical yet but it's nice to know it's there.
CLI Split Windows in Vim
I use split windows, both horizontally and vertically, in Vim all the time. I’ve always wanted to be able to split the window and then start a command line shell within that window but up until now that has just been a dream.