Author Archive | Ted Roche

Brian Turnbull and Nick Plante each had excellent presentations for the New Hampshire Ruby Rails Group’s first meeting on the third Monday of the month, our new “regular meeting day.” (We won’t be having a December meeting, however; have a happy Kwanzaa, Hanukkah, Christmas, Saturnalia, Winter Solstice or non-denominational generic shopping holiday of your choice.)

Brian was up first, and talked about rvm, the Ruby Version Manager (slides here: http://www.slideshare.net/bturnbull/rvm-nhruby-nov-2009). RVM doesn’t just allow you to have multiple versions of ruby on your machine; you’ve always been able to do that with side-by-side installs or linking or aliases or other kludges. RVM can be found at https://rvm.io/ and can be installed as a Gem, from the Git repository or as a tarball. It’s not Ruby code, actually, but shell scripts, and it allows not just switching of the current active version of ruby, but much more interestingly, the entire set of gems associated with a version! Multiple gemsets can be assigned an alias that lets you group your gems by function or project or client. RVM also provides a facility to dump the list of gems from one version or gemset and load it into another, allowing you to test out the migration of an existing system to a new version with much less hassle. Finally, rvm also lets you invoke multiple versions serially, passing them a command like “rvm 1.86, 1.8.7, 1.9.1 rake spec” where rvm will run all your tests on multiple versions and report results, even in JSON if specified. This could be the core of a really simple Continuous Integration (CI) server in a single line of code!

Brian cautioned that rvm is early in its development cycle (current as of last night was 0.0.79) and changes are coming fast and furious, but it’s worth taking some time to keep track of this very interesting development!

Brian also mentioned that rvm has some extensions to work with Bundler. Nick mentioned that Bundler, a project from Yehuda Katz (core contributor to both Ruby and jQuery) , is slated to become the default means of managing gems in Rails 3.0. Here’s a good link to learn more: http://yehudakatz.com/2009/11/03/using-the-new-gem-bundler-today/

Nick Plante was up next, with his presentation on EC2 for Rails Development (http://zapnap.github.com/presentations/ec2-rubber/#0). Nick talked about the evolution of deployment of Rails (or Rack) solutions, moving from very painful to much easier with the introduction of Capistrano (http://www.capistranorb.com/). He reviewed how simple it was to deploy an application with Capistrano, and then talked about the power of the Amazon Web Services (AWS) http://aws.amazon.com/ and Cloud Computing in general. Capistrano is focused on general deployment to a server, but the new add-on, Rubber (http://github.com/wr0ngway/rubber),  extends that to work with elastic computing resources like AWS’ Elastic Compute Cloud (EC2). We walked through the basics of the install-configure-deploy scenario and then “Insert Demo Here.” – he did it. Defying the Demo Gods (who had already tortured Brian a bit), Nick grabbed a copy of RedMine (http://www.redmine.org/) from GitHub, did the couple of minor configuration items needed to make it work locally (creating the session key, copying the sample database config to the live one, setting it to use SQLite3 locally and running db:migrate) and then set it up for deployment: first invoking Capistrano (doing some configuring) and then Vulcanizing (how else would you make rubber) the installation, then deploying it to a brand-new AWS instance. The steps flew by lightening-fast: the Amazon instance was up and running a minute after being invoked, then took a couple of minutes to install and configure Apache, Passenger, MySQL, the Redmine application, and sftp the development directory files to the instance. Within a few minutes, Nick could browse the machine and see the running application as well as ssh into the box and make any changes. There are innumerable options, of course, but they are all accessible by reviewing the configuration files and the source to tune it to your particular needs.

While we waited for the installation to complete, I brought up some of the customer’s concerns and practitioner’s insights from last Thursday’s MonadLUG meeting on Cloud Computing and we talked about how those applied. I expressed concerns about how persistent data storage worked, since the cloud images were considered ephemeral. Nick pointed out that the instance, while running could have a local database and it could be in a master-slave replication arrangement with either another instance (within the AWS, there aren’t bandwidth charges) or a hosted or local machine. Also mentioned was the Amazon Relation Database Service (RDS), which can provide a MySQL database instance with backups. So, there are lots of options.

Thanks to Brian and Nick for excellent presentations as well as organizing the meeting and bringing the pizza, to Tim and the folks at RMC Research for providing the excellent facilites and to all eleven who attended and participated in the meeting.

Remember, no Ruby meeting meeting in December. Stay tuned for a January announcement.

Reposting Nick’s announcement from http://nhruby.org/2009/11/8/november-meetup-ec2-and-rvm:

NHRuby is meeting for the last time this year on Monday the 16th at 7pm at RMC Research, 1000 Market Street, Building 2, Portsmouth, NH. Monday?! You say? Yes — due to scheduling conflicts, the regular meeting day for NHRuby is now to the third Monday of the month. Also, since next month’s meeting fell so close to the Christmas holiday, we decided to skip the December meetup and resume in January. So join us for the last meeting of 2009 for two presentations by NHRuby regulars, Nick Plante and Brian Turnbull.

Nick will present EC2, Amazon’s Elastic Compute Cloud. EC2 is a web service which allows customers to rent virtual server instances by the hour. The real power of EC2 is that it allows you to auto-scale your web applications on demand. Expecting heavy load today? Fire up another web app server or two, with no wait time for procurement, while taking advantage of Amazon’s robust infrastructure.

Making EC2 even more attractive are tools like Matt Conway’s Rubber, a set of extensions to Capistrano that allows you to script procurement and provisioning of server instances as well as deployment of your application itself. Need to set up a staging server? Use Rubber to deploy a disk image, install the necessary stack and utilities, and deploy the appropriate version of your application — in moments — all automatically. In this talk, Nick will quickly discuss the basics you need to know and then dive right into a realtime demo.

Brian will introduce RVM, the Ruby Version Manager. RVM is a command line tool which allows us to easily install, manage, and work with multiple Ruby environments and sets of gems. Topics to be covered include:

• Installation of RVM on Linux or OS X.
• Day to day use of RVM to switch between Ruby interpreters
• Managing sets of gems using Named Gem Sets

If you’ve ever been burned by differences between development and production, you should check out RVM — see how easy it is to take control of your Ruby environment.

So join us on Monday, 16 November at RMC Research for the last meeting of the year. Hope to see you there!

I think I saw this written up in one of ACM‘s magazines, but those don’t get a lot of traffic, and they hide much of their best content behind subscriber-only firewalls. NPR did a story over the weekend on a group at Stanford doing “computational photography” – camera hardware with a Linux backend. I’ve been a fan of photography for decades, since Dad and I set up a dark room in the cellar. The Stanford prototypes are ungainly, of course, but the potential is very interesting. Here’s the story and the linked video. While you wouldn’t like to lug the prototype around all day on a neck strap, the idea of a “smart” camera where you could develop (or download) new effects, hacks, etc. and upgrade the capabilities of your camera is very attractive. Like the consumer cellular telephones started out as fixed devices and added uploadable ringtones, then backgrounds, then camera effects, then wide-open platforms like Google’s Android phone, an open hardware platform for photography could create an entire new category of devices.

Fifteen people ranging in age from 4 years old to, well, quite a bit older than that, attended the September meeting of the Dartmouth – Lake Sunapee Linux User Group. DLSLUG meets on the first Thursday of most months somewhere on the Dartmouth campus. Join the announcement list to keep up with the latest news. The meeting consisted of the usual round of announcements, two short presentations, informal quick presentations by the assembled crowd — Nifties! — and discussion that went on until the janitors kicked us out.

Bill Stearns demonstrated the drop-dead simplicity of configuring and launching a virtual machine on the Rackspace Cloud (http://www.rackspacecloud.com/) Computing site. Nearly as quickly as he could describe it, Bill set up a new machine, choose the memory and disk size, the version of operating system, and got the machine up and running (he had previously registered, so he had an account and payment information on file). The costs for machines are based purely on how much you use, the hours the machine is running and the bandwidth consumed. A minimal machine can be deployed at 1.5 cents per hour, and a busy machine can cost less than $60 a month. This is well worth looking into if you’d like to deploy a backup DNS server or your entire online facilities.

Rich Brown of Dartware showed what his company has been up to in extending the reach of the InterMapper (http://www.intermapper.com/) network monitoring software to work on, and with, the Amazon Web Services (AWS), EC2 and S3. AWS is the more mature service and seems to be targeted more at enterprise customers. Amazon offers a cloud monitoring service and APIs that let you launch additional instances of your saved imaged machines as needed. InterMapper is adding some interesting facilities to the service, and have free 5-user licenses available for the asking.

Alan Johnson showed a nifty on the command line pv tool (Progress Viewer) which is a classic small-tools-loosely-joined *nix tool: a  pipe that can display the progress of data through that pipe. Alan showed a simple example of cat’ing /dev/zero to /dev/null and sticking pv in the middle to show the progress. Cognoscenti in the audience pointed out that cat wasn’t necessary, and using pv with directly piped input and output displayed throughput of an order of magnitude increase. Debate ensued as to the many causes likely to contribute to this effect. Nerds are so cute.

P.S. Those interested in testing pv on their own machines should find it part of many Linux distributions. The caution at the end of the discussion section of the man page (http://linux.die.net/man/1/pv) should be taken seriously.

Nifty!

James Murza showed us some code he’d been working on. It looks up words you specify on wiktionary (http://www.wiktionary.org/), finds all of the translations wiktionary offers and calculates a numeric value based on some semantic qualities of the word for each language. Then, James offers a PHP page where you can list the relative differences between any two languages, based on the words you’ve selected. So, for example, French and Spanish words tended to score close together, while Tagalog and Frisian had little in common.

Nifty!

Bill McGonigle demonstrated his Wok-Key login, a very clever Javascript routine for allowing you to log into your SquirrelMail front end from a machine you might not trust to share your password with. Instead of typing your actual password, the Wok-Key code generates a table on the fly (different each time) of two-letter pairs matched to all the keyboard characters, and displays a table to the screen of the letter-pairs laid out like a QWERTY keyboard, upper- and lower-case. Rather than typing your password, you type the equivalent two-letter pairs, and the Javascript on the page converts your choice to the password to be sent to the backend. This means a keystroke logger will never see your password, and it is unlikely to be saved in a cache on the browser.

Nifty!

Lloyd Kvam announced there were two new additions to the library, one book on Erlang (http://www.pragprog.com/titles/jaerlang/programming-erlang) and a DVD on Perl (http://www.informit.com/store/product.aspx?isbn=0137001274). Any GNHLUG member (that’s you!) can check out a book by contacting Lloyd. The list of books in our library can be found at: http://dlslug.org/library.html

Bill McGonigle said that he’s trying to line up the correct facilities for the next meeting, and if we’re able to get a room that will support all our laptops, we’ll go for a session on encryption and a key-signing party. Stay tuned for a confirming announcement.

Thanks to Bill McG for organizing the meeting, to Dartmouth College for the great facilities, to Bill Stearns and Rich Brown and all the Nifties! presenters for the participation.