End Point Upgrades Liquid Galaxy at Ann Arbor Hands On Museum
By Dave Jenkins
April 5, 2013
End Point has assisted the Ann Arbor Hands On Museum in upgrading their Liquid Galaxy to the latest version of interactive immersive digital viewing experience. The museum has a mission to inspire children to discover the wonder of science, technology, math, art, and engineering, and to be the leader in imaginative and interactive learning experiences. The Liquid Galaxy plays a central part in that mission.
Googlers provided material support in the form of hardware and technical expertise to assemble a Liquid Galaxy based on the open source project information. Hands On Museum staffers coordinated the Exhibits, IT and Administration teams at the Museum to bring the project together in a few months. The result was an exhibit that beautifully blended Liquid Galaxy into the mission of the museum.
In December 2012 The Ann Arbor hands On Museum announced the addition of a Liquid Galaxy to their roster of exhibits. At End Point, we congratulated them, and we also offered any assistance they might need. The Museum was running into some performance issues, and asked if any upgrades or recommendations were available from End Point.
Working closely with Google, and with the great cooperation …
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A DIY Ruby Profiler!
By Mike Farmer
April 4, 2013
A simple profiler can be nice to help detect how often different parts of our code are being run by using some statistical analysis and a few threading tricks. New Relic developer Jason Clark talks about how it’s more efficient to take samples than to use ruby profiler to profile every call and then walks us through building your own profiler.
This was a very insightful talk on how to analyze the backtrace of currently active threads. You can find the code for his DIY profiler on github.
conference ruby
Batteries Included!
By Mike Farmer
April 4, 2013
How many gems does it take to build an app? Many gems duplicate functionality that’s already in ruby core or in the standard library. Daniel Huckstep reviews some goodies that come with ruby that you could probably use to replace some of those gems.
Basics
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Set: Like an array but only allows unique values. Set also optimizes for the include? method so if you are calling include? a lot on your arrays and you don’t require duplicates, Set will be a much better option for you.
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Enumerable: Gives you map, each_with_index, and all the other goodness that comes with the Enumerable class. All you need to implement is each and you get everything else in Enumerable for free.
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Enumerator: Allows you to build your new enomerators on the fly and implement lazy loading.
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SimpleDelegator: Inherit from SimpleDelegator and then set self and it will delegate any missing methods to the underlying class.
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Forwardable: Forward selected methods to another object
Performance
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Benchmark: Allows you to measure the performance of blocks of code. It also has many different outputs and reporting formats.
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RubyVM::InstructionSequence: Set compile options to optimize things like tailcall in recursive …
conference ruby
Code Smells: Your Refactoring Cheat Codes
By Mike Farmer
April 4, 2013
Code smells are heuristics for refactoring. Resistance from our code are hints for refactoring. John Pignata shares some great tips on how to actually go about refactoring a long method. Here are some of the highlights and steps that were covered.
First:
- Wrap entire method in a class
- Promote locals to instance variables
Second:
- Move the work into private methods
Third:
- Look for multiple responsibilities in the class
- Create new classes and adjust interfaces so everything still works
Fourth:
- Wrap your lower levels of abstraction (IO, Sockets).
Fifth:
- Your class may know too much about your lower level abstractions. Find ways to remove that knowledge using design patterns such as Observer/Listener.
Sixth:
- Look for case statements or other big conditionals
- Replace conditionals with polymorphism
- Move the conditional to a factory if applicable
Seventh:
- Remove data clumps such as knowledge of indexes in arrays or arrays of arrays (data[1][2]).
Eighth:
- Remove uncommunicative names such as “data” and “new”
Ninth:
- Look for variables that have same name but different meaning such as local variables that match instance variables.
Tenth:
- Look for nil checks. Look for …
conference ruby
Converting RHEL 5.9 and 6.4 to CentOS
By Jon Jensen
April 4, 2013
CentOS is, by design, an almost identical rebuild of Red Hat Enterprise Linux (RHEL). Any given version of each OS should behave the same as the other and packages and yum repositories built for one should work for the other unchanged. Any exception I would call a bug.
Because Red Hat is the source or origin of packages that ultimately end up in CentOS, there is an inherent delay between when Red Hat releases new packages and when they appear in CentOS. CentOS is financed by optional donations of work, hosting, and money, while Red Hat Enterprise Linux is financed by requiring customers to purchase entitlements to use the software and get various levels of support from Red Hat.
Thanks to this close similarity and the tradeoff between rapidity of updates vs. cost and entitlement tracking, we find reasons to use both RHEL and CentOS, depending on the situation.
Sometimes we want to convert RHEL to CentOS or vice versa, on a running machine, without the expense and destabilizing effect of having to reinstall the operating system. In the past I’ve written on this blog about converting from CentOS 6 to RHEL 6, and earlier about converting from RHEL 5 to CentOS 5.
I recently needed to …
hosting linux redhat
Immutable Ruby by Michael Fairley
By Mike Farmer
April 4, 2013
Michael Fairley is presenting on Immutable objects in ruby.
Immutability is a term used to describe data or objects that can’t be changed. This is a lesser known concept for ruby developers because almost everything in ruby is mutable. Despite this, much of ruby is full of immutable code. Make it explicit. Even in your databases there are some records you don’t want to modify.
One technique to making your database records immutable is to use the readonly? method in ActiveRecord or to revoke the permission to modify at the database level.
Many objects can utilize the freeze method which ensures that objects aren’t being modified. For example, use freeze for configurations. Be aware though that freeze doesn’t freeze objects in an array or hash so you’ll need a gem that provides the ability to deep freeze.
The gem values, provides a set of data structures that are frozen by default. These can be useful in cases where you might use Struct. You can create the object but it doesn’t allow you to change the attributes.
Use value objects in your ActiveRecord object by using composed_of which lets you use an object to combine attributes of the record into a value object. This gives you …
conference ruby
It's Time Once Again for MountainWest RubyConf!
By Mike Farmer
April 4, 2013
It’s one of my favorite times of the year. This will be my third trip to Salt Lake City to attend Mountain West Ruby Conference. One of ther really great things about developing in ruby is the amazing community. Hanging out with fellow developers and enthusiasts is very envigorating and so much fun.
This year I will be blogging on all the talks and reporting on some of the great stuff that will be presented. You can checkout the MWRC Schedule to see some of the great speakers in the lineup. You can follow the #mwrc tag on twitter to follow this amazing conference.
conference ruby
MWRC Ruby 2.0 with Matz
By Mike Farmer
April 4, 2013
Today’s first speaker at MWRC is the one and only Yukihiro Matsumoto, better known as Matz. Matz is the founder and chief architect of Ruby. Matz has a wonderfully friendly personality. His talks are always filled with humor.
Probably not unexpectedly Matz is talking about Ruby 2.0. Ruby 2.0 is the happiest ruby release ever. He outlined some of the new features in Ruby 2.0 as follows:
Features of 2.0
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It’s faster than 1.9
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100% compatible with 1.9
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Keyword Arguments: Keywork arguments provide support for literals at the end of the arguments: log(“hello”, level: “DEBUG”) You can implement keyword arguments in 1.9, but 2.0 makes it simpler to read and write and implement
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Module#prepend: Module#prepend is kind of like alias_method_chain from Rails but it doesn’t use aliases.
The prepend method evaluation comes before the existing methods but after the includes so that you can more easily extend existing methods. And you can package changes into a single module.
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Refinements: Currently, monkey patching is a common practice in ruby. But, monkey patching is difficult to scope because it is global. This often leads to name spacing problems and difficult …
conference ruby rails