Tag Archives | Ruby

Notes from NH Ruby/Rails, 21-Feb-2011

Eight attendees made it to the February meeting of the New Hampshire Ruby Rails group at the New Hampshire Innovation Commercialization Center. A round of introductions included the usual suspects and several new people with interesting backgrounds and interests.

Brian Turnbull talked about Ruby debugging. He had a sample he created on Github Ruby comes with it’s own debugging library, but you can add a good one with a gem: ruby-debug.
Commands:
list – lists the code currently load
next – steps through the code listed, but skips over subroutines.
step – steps into the code
where – dumps the stack
finish – finishes the current subroutine call
display – dumps a value
(commonly use display value.inspect to make a cleaner display)
pp – pretty print, evaluates any Ruby code you want
edit – launches the EDITOR variable in our shell
catch – catch exceptions
cont – continue
break – set a breakpoint

,,, and so forth. Use the help, it is your friend.

The second example is far more complex, with a Sinatra app using OmniAuth and an LDAP provider. Following the supplied documentation, the app crashes on startup. (That’s what you get for reading the docs!) Debug and another tool – rbtrace to the rescue! Excellent demo of the problem and how the tools can debug them.

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Notes from NH Ruby/Rails, 17-Jan-2011: Brian Turnbull, OmniAuth, Nick Plante, Mirah

Seven members attended the New Hampshire Ruby / Rails group meeting held on 17-January-2011 at the New Hampshire Innovation Commercialization Center (NH-ICC). We had two presentations: Brian Turnbull talked about OmniAuth and Nick Plante showed a project he’s doing with Mirah on the Android platform.
Brian Turnbull is an engineer working for ARRIS and injects Ruby into his build tools whenever he gets the chance. A recent project required authentication against multiple providers and he did some research on OmniAuth. Brian presented a slideshow explaining the basic concepts of authentication and how they’re implemented in OmniAuth. Apparently, OmniAuth was the authentication method of choice during the most recent RailsRumble, used by most of the contestants. Brian outlined the process needed for working with an existing provider and demonstrated it with clear and simple code. He followed that up by showing how to build your own custom provider and authentication strategy. Brian’s sample code can be found on his github account.
Nick Plante has been working on an Android rich client app as part of a web-based social application that’s soon to launch. Nick told us that working on Java for Android has reinforced his love of Ruby. There’s not yet a good port of Ruby to the Android platform, but he has been impressed with the Mirah language, a hybrid solution that compiles to bytecode and runs natively on the JVM. He has developed a Ruby generator called protoform to construct the skeletons of a Mirah app. He gave us a tour of the components and built a simple “Hello, World” app, deployed and ran it on his Android VM.
Thanks to Brian for organizing the meeting and for the OmniAuth presentation, to Nick for talking about his Mirah project and to the NH-ICC for providing the fine facilities.

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Notes from CentraLUG, 6-Dec-2010: David Berube, MySQL Operations

Six people attended the December 2010 meeting of the Central New Hampshire Linux Group, held at the NHTI‘s Library from 7 to 9 PM. David Berube was the featured speaker, talking about his experience with large scale high-performance MySQL applications.

David is an independent software developer and consultant. One of his larger projects over the past couple of years has been an application for scheduling actors for auditions. This involves agents and projects, auditions, roles, videos and a number of other entities in a complex and fast-moving application. He’s used Ruby on Rails, PHP, MySQL, a NOSQL database, Amazon S3, A rack of Mac Minis, BSD, Linux, and a number of other elements. He had some insightful things to say about the development process, managing a client project, handling difficult requirements, scaling up million-row databases for subsecond response times and more. It was a meeting well worth attending.

There were a lot of useful tools and reference sites mentioned, and I was only able to take note of a few: Useful Ruby add-ons: New Relic, Query Reviewer, Percona Operations Day, Cacti for data aggregation. An In-depth discussion of NoSQL (“Not Only SQL”) Databases: what are they, what are they good for, what are the liabilities? A good discussion of the trade-offs of using NoSQL, reference to the NHRuby presentation on Redis a few months ago, and more.

Thanks to David for an informative presentation, to the attendees for a dynamic interactive session, and to the NHTI Library for the facilities. Future meetings at the Concord location have been suspended, we encourage our regulars to attend the Manchester ManchLUG meetings. If you haven’t already, consider subscribing to the announcement list so you’ll know when there’s an upcoming meeting. (Subscribers to the discussion list will automatically receive the announcements, too.)

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Notes from Ruby SIG, 16-Aug-2010

The New Hampshire Ruby/Rails group met as usual on the 3rd Monday of the month. We met at the New Hampshire Innovation Commercialization Center, a new space near the Pease airfield. Mark Galvin, NHICC’s Managing Director, was kind enough to offer the space for our meeting and tell us about the ICC. Eleven members attended the meeting.

As we often do, we started with a round of introductions. It’s always interesting to find out who’s there and what they’re up to. I mentioned the GNHLUG calendar and Nick plugged the upcoming Rails Rumble. Near the end of the meeting, we plugged the NorthEast RailsCamp, coming up on it’s third meeting, this one in Stowe, VT. 5 alums from previous camps were there, and all loved it. There may still be a ticket or two left, even though the site says zero – you’d better hurry!

We were lucky enough to have two presentations tonight.

Brian Turnbull presented “Interfacing Ruby with C.” He explained he needed to do some automation with a “black box” his company was using, and their documentation consisted of a C API and a DLL. Rather than developing an entire application in C, he used Ruby to interface to the C API and then could develop an easy-to-modify Ruby app. That turned out to be a good idea, as the final product he delivered turned out to be very different from the initial request, and having the ability to rapidly re-develop in Ruby was a success. To show us how to use C to access Ruby and vice-versa, Brian used a simple example of a “leaky bucket stack,” a fixed-length stack that would lose the oldest item as the stack was pushed. It was a great example in that it had enough complex behavior to be useful, while simple enough to explain and translate into C without too much effort. First, we reviewed the pure Ruby implementation. Brian proceeded to build up the equivalent code in C, calling Ruby array functionality and data types where appropriate. He then showed how to configure the C extension from from Ruby, build, compile, debug and run from the ruby command line.

See the example code and slides (I’ll update the URL when available). Also http://github.com/bturnbull/padpaws for his more advanced C example.

Brian Cardarella, @bcardarella, http://bcardarella.com, presented his gem, client-side validation, which he developed while working on the “Raise Your Vote” site for the Democratic National Committee. The Raise Your Vote site is intended to assist in voter registration by collecting data online and generating matching PDFs of the voter application. Naturally, 50 states have fifty different forms, with different requirements. He wanted to avoid duplicating the server-side validations with hand-maintained client side code, as the regular changing of requirements and the difficulty of keeping business rules in synch across the two languages would doom the project. He wrote client-cisde_validations to use the declarative validations within the entity models to generate the equivalent Javascript code. Client-side_validations has remarkable depth and breadth, handling nearly all of the common and exceptional types of valiation (Brian notes the few difficult cases in his slides). You can find the code on GitHub (gem code, examples) and the slides here: client_side_validations.pdf

Thanks to Brian Cardarella for travelling all the way to Portsmouth and thanks to both Brians for their fine presentations. Thanks to Nick Plante and Brian Turnbull for organizing and promoting the meeting and the group. And thanks to Mark Galvin and the New Hampshire Innovation Commercialization Center for providing the fine facilities!

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Notes from New Hampshire Ruby/Rails Group, 19-July-2010: Redis, Resque, Vanity, Mogotest, Nick Plante

The July meeting of the New Hampshire Ruby/Rails group was held as usual on the third Monday of the month at RMC Research in Portsmouth. Nick Plante was the featured speaker, talking about Redis, the NOSQL database, Resque and Vanity. Brian Turnbull ran the meeting and brought pizzas — thanks, Brian and Nick!

We started off with a round of introductions and speaking a little bit about who we are, what we do, why we’re there. There’s an interesting assortment of backgrounds: a few folks with deep Ruby experience, a number of people transitioning from other languages (Java was mentioned more than once) and some web design folks looking to get a little deeper into the workings. Brian mentioned that the RailsRumble was coming up fast – October 16th – and that seats went quickly once registration for the event was open. Keep an eye out for future announcements.

Nick Plante talked about Redis, Resque and Vanity. You can view the slides here: http://www.scribd.com/doc/34712184/A-Quick-Introduction-to-Redis-NH-rb. Redis (http://github.com/antirez/redis) is a NOSQL (“Not Only SQL”) database that has a simpler API (put/get/list keys) than the complex SQL needed for a relational database. It is a “key-value” store that stores flat values (and/or documents, arrays, lists, etc.) with a great deal of speed, high-performance, reliability and scalability. It is ideal as the primary means of access for data on a demanding web site, acting as a cache for underlying relational data or transient data. Nick talked about how he and his partner used Redis and the Resque
Ruby library (http://github.com/defunkt/resque) to manage a job queue where the front-end servers posted jobs, many background workers processed the jobs, and the front end could display progress or completion. Nick also talked about A/B testing with Vanity, another package which uses Redis as its backend datastore. Vanity lets you present two different interfaces (hence the A/B) and monitor statistics on how the users react to the differences (do green buttons get better conversion than orange?). Nick wrapped up by showing us some of the code used in Mogotest and how they managed backend tasks.

As a bonus, we got the briefest of tours of what Mogotest can do: it will spider a web site, gathering the content, show you validation issues with the code (HTML and CSS), compare how the web pages look in a number of different browsers (side-by-side or a slick overlay). This can be really handy to include as part of testing a web site. Mogotest has just entered into public beta, during which you can test your site for free. Check it out!

Thanks to Nick for a very interesting presentation! Thanks to Brian for coordinating the event and getting pizza! Thanks to RMC for the great facilities.

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HowTo notes: installing REE, Passenger, Ruby on Rails on CentOS5

Recently, I installed Redmine, the Rails-based project tracker,  on an existing virtual private server, running CentOS 5 Linux and an assortment of LAMP applications and web sites using Apache, PHP and MySQL. I chose Ruby Enterprise Edition (REE), an optimized and high-performance version of Ruby, and Passenger, an Apache module to connect to Ruby. Here are the steps I followed, as a reference and in hopes it might help others:

  1. Log onto the box via ssh. As a good practice, I run as an unprivileged user, and use sudo only when superuser rights are needed. So, download the files and un-tar them and read the READMEs and run the processes as a regular user, switching to root via sudo only when the rights are needed.
  2. Download and install Ruby Enterprise Edition. Today, that’s:
    wget http://rubyforge.org/frs/download.php/68719/ruby-enterprise-1.8.7-2010.01.tar.gz

    but follow the instructions you’ll find at http://www.rubyenterpriseedition.com/download.html for the latest. Those instructions will have you un-tar the file and then run the installer.

  3. Install the tools needed to build Ruby Enterprise Edition. If you run the installer, it will prompt you for missing tools. In my case, I needed to:
    sudo yum install gcc-c++ make patch zlib-devel openssl-devel readline-devel
  4. If you’ll be using mysql, you’ll need the native code to build the matching gem. REE attempts to build gems for MySQL, SQLite and PostgreSQL, so choose your flavor and issue the appropriate command like:
    sudo yum install mysql-devel
    

    or postgresql-devel or sqlite-devel as appropriate.

  5. Follow the instructions supplied by the REE installer. They did a nice job on that. To install Passenger when I was done, some additional source code files were required:
    sudo yum install httpd-devel apr-devel
    sudo /opt/ruby-enterprise-1.8.7-2010.01/bin/passenger-install-apache2-module
  6. Once again, follow the prompts to add the proper load module and path commands to your web server configuration, add a configuration file for your site, and you’re ready to start installing your site’s code.

NOTE: It wasn’t the case with my particular host, but you may need to adjust your SELinux settings, if you’ve got SELinux enabled. See the post at http://www.catapult-creative.com/2009/02/04/installing-rails-on-centos-5/ and look for “SELinux” for some ideas.

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NHRuby, 17 September: Games in Ruby

The New Hampshire Ruby / Rails Group announces the topic of their September meeting: Games. It sounds like the games are just an excuse for us to have problems to solve by actually writing code in Ruby. Not a bad idea — trick us into coding by having fun? Radical.

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More links from NHRuby.org’s August dinner meeting

I was finally able to decode some of the scrawling notes I took at the NHRuby.org August dinner meeting, and found a couple more resources worth looking at. With our theme of “Where’d you learn that?” I’d recommend you check out these resources:

Dave Thomas, co-author of the original Pragmatic Programmer and proprietor of the same-named shop, has a series of videos called “The Ruby Object Model and Metaprogramming” that one attendee thought was well worth watching.

Another recommendation was to check out Topher Cyll’s book, “Practical Ruby Projects: Ideas for the Eclectic Programmer” for some interesting insights into Ruby.

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Notes from NH Ruby group, 20-Aug-2009, “Where’d you learn that?”

Eight folks enjoyed an excellent dinner at The Rosa Restaurant. We had a private room upstairs where we could woot and yell over each other and tell geek jokes without inhibitions, not that that has ever stopped us before.

Nick Plante mentioned Rails Rumble coming up this weekend. Watch for some incredible apps coming from the Rumble. Can’t wait to see the winners.

Adam Bair brought along two books, Kent Beck’s “Smalltalk Best Practice Patterns” (ISBN 978-0134769042) and Martin Fowler’s “Refactoring” (978-0201485677). Adam credit both books as being very helpful for his practice in the past several years where he has had to refactor a lot of code in rescuing lower-quality Rails projects.

Adam also mentioned an inspirational presentation by Marcel Molina, Jr. at Ruby Hoedown 2007 called “Beautiful Code” (http://rubyhoedown2007.confreaks.com/session09.html) – Adam recommends the higher quality videos as they include video/slides side by side – and also browsing much of the confreaks.com site for some great videos.

Russ talked about Peepcode videos (http://peepcode.com), which he really appreciates. In particular, he mentioned the most recent, Advanced Command Line, helped him debug an unusual problem he was having with one remote client whose shell behaved incorrectly. He’s used inspiration from that video to reconfigure the way he uses his shell. Russ also mentioned Ryan Bates “RailsCasts” (http://railscasts.com/) as very useful, and in particular, thought that the three part series on forms (link updated; thanks, Russ!) changed the way he developed Ruby apps.

I talked a little bit about “The Well Grounded Rubyist” (ISBN 979-1933988658) by David Black, which has helped me fill in some of the background of how and why Ruby behaves the way it does. I also passed around Jason Clinton’s “Ruby Phrasebook” which is a handy book of recipes on how an experienced Rubyist is likely to solve common problems like parsing config files or processing XML.

Nick mentioned that he’s using the unix screen command to do screen-sharing for remote pair-programming and you could see the lightbulbs go off over people’s heads (“That’s my payoff for tonight!” one attendee exclaimed.) He’s also working with EC2 instances and is fired up over how simple and powerful they are. Nick promised a followup, perhaps a demo at a future NHRuby meeting, and Casey mentioned that there’s someone local who’s been doing demos on the Amazon Web Services offerings – we hope to come up with some contact info and see if we can schedule a presentation.

The group also talked about how, as a group, we might contribute to one particular open source project. A couple of ideas were batted around. I look forward to hearing more about this idea.

The night’s theme was “How do you know that?” and I asked about how people are keeping up on all the news about what’s happening. We didn’t really come up with a list of links or blogs or news sites, so if you think of any now (or have your bookmarks handy for sharing), I’d appreciate you passing them on and I’ll include them in the meeting notes.

Thanks all, for a fun dinner amongst friends and some inspiring ideas!

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This work by Ted Roche is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States.