Ilia Lobsanov nurey

Around 2006-2007, it was a bit of a fashion to hook lava lamps up to the build server. Normally, the green lava lamp would be on, but if the build failed, it would turn off and the red lava lamp would turn on.

By coincidence, I've actually met, about that time, (probably) the first person to hook up a lava lamp to a build server. It was Alberto Savoia, who'd founded a testing tools company (that did some very interesting things around generative testing that have basically never been noticed). Alberto had noticed that people did not react with any urgency when the build broke. They'd check in broken code and go off to something else, only reacting to the breakage they'd caused when some other programmer pulled the change and had problems.

When should you use DateTime and when should you use Time?

It's a common misconception that [William Shakespeare][1] and [Miguel de Cervantes][2] died on the same day in history - so much so that UNESCO named April 23 as [World Book Day because of this fact][3]. However because England hadn't yet adopted [Gregorian Calendar Reform][4] (and wouldn't until [1752][5]) their deaths are actually 10 days apart. Since Ruby's Time class implements a [proleptic Gregorian calendar][6] and has no concept of calendar reform then there's no way to express this. This is where DateTime steps in:

>> shakespeare = DateTime.iso8601('1616-04-23', Date::ENGLAND)
=> Tue, 23 Apr 1616 00:00:00 +0000
>> cervantes = DateTime.iso8601('1616-04-23', Date::ITALY)
=> Sat, 23 Apr 1616 00:00:00 +0000

How to share a folder with a docker container on OSX

Mounting shared folders between OSX and the docker container is tricky due to the intermediate boot2docker VM. You can't use the usual docker -v option as the docker server knows nothing about the OSX filesystem - it can only mount folders from the boot2docker filesystem. Fortunately, you can work around this using SSHFS.

	# This task should be run inside an environment that is already configured to connect to the redis
	# instance that we're transfering AWAY FROM.
	#
	# The task should be handed the URL of the redis instance that we're MOVING TO.
	#
	# To run it and pass in the destination Redis you'd do something like this:
	# rake sidekiq:transfer[redis://...]
	#
	# As jobs are added to the destination Redis, they're deleted from the source Redis. This
	# allows the task to be restarted cleanly if it fails in the middle due to a network error