Code on jpterry.com

My favorite git alias

Tue, 15 Dec 2015 00:00:00 +0000

When I use git I constantly need to understand the shape of the history graph. And the best way to understand graphs is to visualize them. Maybe you already know about git log --graph --oneline --decorate, but that is a lot to type.

Add this alias to your .bash_profile, or .zshrc. I call it glga for “git-log-graph-author”, you can call it what you want.

alias glga="git log --graph --abbrev-commit --date=short --pretty=format:\
 '%C(yellow)%h%Creset %C(bold blue)(%an)%Creset%C(yellow)%d%Creset %s %Cgreen<%cr, %ar>%Creset'"

Below is a sample screenshot of the output. At a glance you can see how the commits are related in the graph, their shas, their authors, messages, and commit/author dates relative to now.

iptables rule to limit tcp connections per ip address

Fri, 07 Feb 2014 15:24:46 +0000

A vps hosting a service I maintain came under a DOS attack today. The malicious client was opening as many tcp connections as they could. And eventually the service would hit the ulimit of open file descriptors and fail. Of course the service should be more resilient, but this iptables rule solved the problem right away.

It will block an individual IPv4 address from opening any more than 25 connections to the service port. It does so by sending a TCP reset when the the client exceeds 25 connections.

NeoPhonic

Thu, 20 Dec 2012 00:00:00 +0000

Today I am releasing NeoPhonic to the world. It’s a half finished iOS drum machine app. It uses OpenAL for sound playing.

You can find the github repo here.

Update 2014-02-07: I never got around to publishing this post. I intended to spice it up a little more but that was more than a year ago, so I’m releasing it as is.

passing objects to methods as blocks in ruby

Wed, 07 Mar 2012 00:00:00 +0000

Lambda’s can come in handy when you need to apply a similar mutation to a collection of objects.

Here’s an example of a simple operation but the block can be as complicated or generic as you need.

ints_to_floats = lambda { |i| i.to_f }
(0..5).map(&ints_to_floats)
#=> [0.0, 1.0, 2.0, 3.0, 4.0, 5.0]

The urnary ampersand calls the :symbol’s #to_proc method and passes it as a block to the method.

In ruby 1.9.2 and monkey patched in by rails, Symbol#to_proc is defined as:

Proc.new { |*args| args.shift.__send__(self, *args) }