Our Blog

Three Things: Startups, Rails news, jQuery index

By Steph Skardal
March 23, 2012

I recently had a conversation with Jon about End Point blogging, microblogging, and tweeting. Many of us End Pointer’s have tips and tools that we encounter regularly that aren’t worthy of an entire blog post, but are worthy of sharing. Here’s my first attempt at sharing smaller bits of info – stay tuned to see how it works out.

1. Paul Graham’s Ambitious Startup

Here is an interesting recent article by Paul Graham entitled Frighteningly Ambitious Startup Ideas. It’s great. Read it.

2. Rails Vulnerability Hack

If you aren’t up to speed on things going on in the Rails world, check out this recent commit. A GitHub user was able to exploit Rails’ mass-assignment vulnerability to commit to the Rails core. Check out a few more related links at A Fresh Cup’s post on the incident.

3. jQuery’s index method

MWRC Highlights Part 1 of 2

By Brian Gadoury
March 22, 2012

I attended the 2012 Mountain West Ruby Conference in Salt Lake City last week. There were a lot of cool topics presented at this conference, but I’ve been suffering serious analysis paralysis trying to pick one topic to focus on here. So, I’m taking the easy way out. I’m going to run through some of the projects and tools mentioned during the conference that I flagged in my notes to check out further.

Sidekiq, a multi-threaded drop-in replacement for Resque

• Sidekiq requires much less RAM to do the same amount of work as the single-threaded Resque, while providing a very similar API to Resque. It’s been designed to behave like Resque as much as possible and as such, would be a very easy transition for anyone that’s used Resque before.
• By Mike Perham
• Get it at: mperham.github.com/sidekiq
• Recommended by: Tony Arcieri

Book: Growing Object-Oriented Software Guided by Tests (aka GOOS)

• The “GOOS book” was recommended by a number of speakers at the conference. One downside (for me) is that the Auction Sniper app developed in the book is done in Java. However, there are now ports of that code available in Ruby, Scala, C# and Groovy. Check out the book’s website. The table of contents is …

Puppet custom facts and Ruby plugins to set a homedir

By Greg Sabino Mullane
March 21, 2012

Photo of Swedish Chef by A. M. Kuchling

Puppet is an indispensable tool for system admins, but it can be tricky at times to make it work the way you need it to. One such problem one of our clients had recently was that they needed to track a file inside a user’s home directory via Puppet (a common event). However, for various reasons the user’s home directory was not the same on all the servers! As Puppet uses hard-coded paths to track files, this required the use of a custom Puppet “fact” and a helper Ruby script plugin to solve.

Normally, you can use Puppet to track a file by simply adding a file resource section to a puppet manifest. For example, we might control such a file inside a manifest named “foobar” by writing the file puppet/modules/foobar/init.pp as so:

class foobar {

  user {
    "postgres":
      ensure     => present,
      managehome => true;
  }

  file {
    "/home/postgres/.psqlrc":
      ensure      => present,
      owner       => postgres,
      group       => postgres,
      mode        => 644,
      source      => [
                      "puppet:///foobar/$pg_environment/psqlrc", …

Liquid Galaxy in GSoC 2012!

By Benjamin Goldstein
March 20, 2012

Once again The Liquid Galaxy Project has been accepted for the Google Summer of Code! Google Summer of Code is a tremendous program that provides an excellent opportunity for talented undergraduate and graduate students to work developing Open Source software guided by a mentor. Students receive $5000 stipends for successfully completing their summer projects. Last year The Liquid Galaxy Project had three GSoC slots for students. This year we are hoping for at least this number of slots again. I know it is not the point, but did I mention that participation in the program is a very nice credit for students to have on their resumes? ;-)

Right now we are in the “would-be student participants discuss application ideas with mentoring organizations” phase of the program. Interested students should contact the project’s mentors and admins by emailing lg-gsoc@endpoint.com or by jumping into the #liquid-galaxy Freenode IRC channel. Applicants are well advised to take advantage of the opportunity to consult with project mentors in developing their applications. Student applications are being accepted until April 6 and should be emailed to lg-gsoc@endpoint.com.

The Liquid Galaxy GSoC 2012 …

Firebug in Action: CSS Changes

By Steph Skardal
March 19, 2012

When I work with clients, I encourage them to use tools to improve efficiency for web development. Sometimes my clients want styling (CSS) adjustments like font-size, padding, or orientation changes, but they aren’t sure what they want before they’ve seen it applied to real content. I recommend embracing a tool such as Firebug for examining temporary on-page CSS edits. Here’s a quick video that demonstrates Firebug in action as I try out a few adjustments to End Point’s home page.

Some of the changes I test out in the video include:

• Font-color changes
• Deleting DOM elements
• Padding, margin adjustments
• Background color changes

Firebug offers a lot more functionality but the video covers interactive CSS changes only. Read more about Firebug’s features here. Chrome has similar functionality with the Developer Tools included in the core software. There are similar tools in the other browsers, but I develop in Chrome or Firefox and I’m not familiar with them.

Check JSON responses with Nagios

By Brian Buchalter
March 18, 2012

As the developer’s love affair with JSON continues to grow, the need to monitor successful JSON output does as well. I wanted a Nagios plugin which would do a few things:

• Confirm the content-type of the response header was “application/json”
• Decode the response to verify it is parsable JSON
• Optionally, verify the JSON response against a data file

Verify content of JSON response

For the most part, Perl’s LWP::UserAgent class makes short work of the first requirement. Using $response->header(“content-type”) the plugin is able to check the content-type easily. Next up, we use the JSON module’s decode function to see if we can successfully decode $response->content.

Optionally, we can give the plugin an absolute path to a file which contains a Perl hash which can be iterated through in attempt to find corresponding key/value pairs in the decoded JSON response. For each key/value in the hash it doesn’t find in the JSON response, it will append the expected and actual results to the output string, exiting with a critical status. Currently there’s no way to check a key/value does not appear in the response, but feel free to make a pull request on check_json on my …

A Cache Expiration Strategy in RailsAdmin

By Steph Skardal
March 16, 2012

I’ve been blogging about RailsAdmin a lot lately. You might think that I think it’s the best thing since sliced bread. It’s a great configurable administrative interface compatible with Ruby on Rails 3. It provides a configurable architecture for CRUD (create, update, delete, view) management of resources with many additional user-friendly features like search, pagination, and a flexible navigation. It integrates nicely with CanCan, an authorization library. RailsAdmin also allows you to introduce custom actions such as import, and approving items.

Whenever you are working with a gem that introduces admin functionality (RailsAdmin, ActiveAdmin, etc.), the controllers that provide resource management do not live in your code base. In Rails, typically you will see cache expirations in the controller that provides the CRUD functionality. For example, in the code below, a PagesController will specify caching and sweeping of the page which expires when a page is updated or destroyed:

class PagesController < AdminController
  caches_action :index, :show
  cache_sweeper :page_sweeper, :only => [ :update, :destroy ]

  ...
end

While working with RailsAdmin, I’ve come up with a …

Check HTTP redirects with Nagios

By Brian Buchalter
March 15, 2012

Often times there are critical page redirects on a site that may want to be monitored. Often times, it can be as simple as making sure your checkout page is redirecting from HTTP to HTTPS. Or perhaps you have valuable old URLs which Google has been indexing and you want to make sure these redirects remain in place for your PageRank. Whatever your reason for checking HTTP redirects with Nagios, you’ll find there are a few scripts available, but none (that I found) which are able to follow more than one redirect. For example, let’s suppose we have a redirect chain that looks like this:

http://myshop.com/cart >> http://www.myshop.com/cart >> https://www.mycart.com/cart

Following multiple redirects

In my travels, I found check_http_redirect on Nagios Exchange. It was a well designed plugin, written by Eugene Kovalenja in 2009 and licensed under GPLv2. After experimenting with the plugin, I found it was unable to traverse multiple redirects. Fortunately, Perl’s LWP::UserAgent class provides a nifty little option called max_redirect. By revising Eugene’s work, I’ve exposed additional command arguments that help control how many redirects to follow. Here’s a summary of usage: …