Recent Interesting Posts- Functional Programming and Dark Launches
posted in Technology, Developers, Software |Back in March Dare Obasanjo said he was going to stop blogging. Luckily it seems like he didn’t carry through his threat very well and has had a ton of great posts recently.
Dare posted on functional programming, Map/Reduce/Filter in C# 3.0 including some nice background on the topic. I’ve been getting into Python lately which has some really elegant support for anonymous functions, list/collection operations, and specifically things like map/reduce/filter. This is also an interesting approach on some similar techniques in PHP.
Dare also did an interesting post on techniques to dark launch / gradually ramp up new features. The idea is that you want to try out a new feature without risking taking down your entire user base at once.
Some other really simple approaches include putting a hidden iframe into existing pages that access the new feature. Its a really easy way to isolate it from the rest of what is going on for your site. One thing to keep in mind is that as you dark-launch a feature its really important to figure out how you can throttle it up/down. If you have 20 front end servers, maybe you can deploy it only on a certain set of them or else your pages can only serve it up a certain random percentage of the time. This way you can start it up on a very low load (say 1% of the requests) and slowly increase it to try it out more. If you start having some performance problems in your data center, just kick it down a couple of notches.
Deploying to only certain specific servers can be especially interesting because it can (if done right) focus the load on those servers. So those servers behave the way the whole system will once the system gets fully turned on, but don’t have the same risk of taking your whole environment down.