Posted by Nick Sieger Wed, 10 Dec 2008 14:50:44 GMT
Here’s a nice surprise. My mini-keynote at RailsConf Europe was posted over at blip.tv. It’s only 10 minutes, so give it a watch and let me know what you think. I even watched it myself, without cringing! I laughed (at how I actually sounded credible), I cried (at how I laughed at my own poorly-delivered joke).
Posted by Nick Sieger Sun, 01 Jun 2008 22:07:33 GMT
These are the notes I took during our “panelish” Q & A session on Sunday afternoon at RailsConf.
Exceptions (behavior between ruby and java)
Java integration, mocking, proxying, extension
Multiple VM support
Startup time performance gain recently
Compiling Ruby code to JVM bytecode
Community tasks/actions
Sun’s commitment
Ruby programming language, JRuby is an implementation
How do you pitch JRuby/Rails in a legacy environment?
Testing
Terracotta/DSO
Windows/Mongrel/ImageMagick issues
Rails benchmarks
JSR-292 (“invokedynamic”)
Posted by Nick Sieger Sat, 31 May 2008 23:42:00 GMT
If you already saw my JavaOne slides, these aren’t too different, but I think they’re better and prettier, too.
Update. The slides are pretty lean on explanation. Just in case you’re confused, the narrative goes like this:
config/warble.rb file.Posted by Nick Sieger Thu, 22 May 2008 15:40:00 GMT
Thanks to our friends at LinkedIn, Joyent and Sun, we’re having a hackfest at McMenamins/Kennedy School on Thursday evening, May 29, starting at 6:30pm, complete with food and beverages!
Do stop by and hang out with us! Leave a comment over at Charlie’s announcement if you’re interested in joining us.
Kennedy School
Local: (503) 249-3983
Elsewhere: (888) 249-3983
Posted by Nick Sieger Fri, 18 Apr 2008 17:25:16 GMT
Just a quick note on some upcoming gigs. I’ll be speaking next month at both JavaOne and RailsConf, giving an update on the JRuby deployment situation, which by the way is rapidly improving! Despite my proposal for a hands-on tutorial on JRuby deployment not getting accepted for RailsConf, I’ve been asked to fill one of the Sun-sponsored talk slots again. So, much like RailsConf EU last fall, if you come listen I promise you will not get a heavy sales pitch from me! Do stop by, I may even have a couple goodies in store for you.
I also feel privileged to be speaking at RubyFringe this summer, where I haven’t yet determined exactly what I’ll be talking about (although it will probably have some connection to JRuby).
Hope to see you at one of these upcoming events!
Update: We just re-jiggered the schedule of 3 JRuby-related talks at JavaOne, including mine, so that they flow better from beginning to end of the week. My talk is now on Thursday morning instead of Wednesday morning. In addition, Charlie and Tom’s is on Tuesday, and Ola’s is on Wednesday. If you’re attending JavaOne and are interested in JRuby-related talks, please make sure you log into Schedule Builder and re-check your schedule.
Posted by Nick Sieger Sat, 06 Oct 2007 12:04:00 GMT
On September 19, Craig and I presented our talk at RailsConf, which appears to have been well received. It went off mostly without a hitch, if it wasn’t for a couple of hiccups in the demos. I apparently didn’t practice them enough, because a couple of critical steps were either missed or I did them out of order and confused myself. But that’s ok, because I’m releasing the demo steps, source and slides here so you can try them out for yourself.
So, download the zip and follow along. The contents look like this:
1-active-resource-basics.txt
2-make-resourceful.txt
3-atom-roller.txt
4-service-chatter.txt
RailsConfEurope-Hydra.pdf
demo/
demo-baked/
The demo steps are in the text files; I’d recommend going in the order specified. It turns out the third isn’t really a demo but more of a code review, because it also requires you to have Roller set up and I’m not going into those details for now. If you want to just run the demos, skip to demo-baked, the finished product.
For those of you who didn’t see the talk, here’s the basic message.
Look at your basic MVC Rails app.
Why not consider spliting it into two? ActiveResource allows you to access a RESTful resource in your Rails application like it was just another model.
This might seem like overkill for a simple application, but what if you had an e-commerce application domain like this?
Splitting up your code into separate Rails applications encourages encapsulation, reduces potential coupling, and gives you more flexible deployment options. Basing interactions upon REST and HTTP means that you can more easily mash up data or create caching strategies, given proper usage of ETags/Last-Modified and/or cache-control headers. The great thing is that existing HTTP reverse proxies can be used without having to mix the caching code in with your application code.
In the application we’re building, we have a number components that are not Rails-based. To expose them to our environment, we’ve taken the strategy of exposing a simple REST web service for the component, and then it can be consumed by the other applications using ActiveResource. The REST web service can either be implemented in the component’s native language/technology, or in some cases we’ve written a wrapper service in Rails since Rails makes it so easy to build REST interfaces. In that case, Rails is pure integration -- RESTful glue.
The idiom that makes this all possible is the uniform interface. In HTTP, this means addressability (each resource gets a unique URI) coupled with the HTTP method verbs HEAD, GET, POST, PUT, and DELETE. Inside your Rails applications, it’s the ActiveRecord interface. If you keep your controllers skinny, you can boil the interface down to the following set of methods (in this case, for the prototypical blog post model):
Post.new/Post.create
Post.find
@post.save
@post.update_attributes
@post.errors
@post.destroy
And in fact, this is precisely what ActiveResource provides, and it’s enabled by duck-typing. Walking through the demos illustrates this pretty well, as you’ll basically swap ActiveRecord for ActiveResource with no noticeable difference, all the way down to validation errors in the scaffolded forms (which I was unable to demo in the talk due to the hiccups).
We’ve found that when you’re making RESTful web services, the controllers largely become boilerplate because of the uniform interface. make_resourceful has been a boon in that regard, as the demos also show. There are several plugins that help you DRY up your controllers (other approaches include resources_controller), so you have some choices there.
We mentioned some drawbacks in our experience with ActiveResource, which have largely been addressed for the upcoming Rails 2.0 release.
Finally, we noted that deployment could be a pain with so many Rails applications to keep running. To that end, we are leveraging JRuby and Glassfish to make this a non-issue, as we simply WAR up our Rails applications with warbler and let Glassfish take care of the rest. Performance is still an open question, but we plan to roll up our sleeves and make sure this combination really hums.
Enjoy the demos! Feel free to drop me an email if you have any questions or troubles with them.
Posted by Nick Sieger Tue, 18 Sep 2007 08:14:00 GMT
Rails is no longer the James Dean character, looking outward, trying to convince you of something. It’s no longer about a rebellion or a revolution. Instead, Rails is settling in as a passionate, inward-looking craftsperson.
After the rebellion, settle in and enjoy the results of your work. David hasn’t been working directly on Rails too much, instead he’s been enjoying it.
And it’s not about David anymore. It’s about You (cue the Time Person of the Year cover). David wants Rails to be more friendly to newcomers.
Report #12: Verified Patches. Encouraging the community to approve patches, rather than limiting the decisions to the core. Opening up Rails. (Also, unfortunately looking a little scarce at the moment. Update: turns out it’s empty because patches are quickly applied, not because there aren’t any submitted!)
David screened the original Rails movie -- showing Apache setup, manually creating databases and tables. He quickly lost patience for it.
Compare to the current state of the art, with everything down to the routes and migrations gets created for you, lowering the barrier to entry (example: a new rake task db:create:all).
Rails 2.0 is largely about continual improvement and removing the cruft:
map.rootscaffold :posts featuremap.namespace and script/generate controller admin::posts*.html.erb files with the MIME type and renderer baked into the filename, since the two are now mutually exclusive.render :partial => @posts resolving to _post.html.erbmop.namespace :admin do |admin|
admin.resources :posts
end
# ...
link_to 'Show', [:admin, post]class Admin::PostsController < ApplicationController
before_filter :ensure_administrator
# ...
private
def ensure_administrator
authenticate_or_request_with_http_basic("Blog Admin") do |user,pass|
username == "dhh" && password == "123"
end
end
endindex.iphone.erb.class ApplicationController < ActionController::Base
before_filter :adjust_format_for_iphone
def adjust_format_for_iphone
if request.env["HTTP_USER_AGENT"][/iPhone/]
request.format = :iphone
end
end
end
# initializer
Mime::Type.register "application/x-iphone", :iphone
# In a controller method
respond_to do |format|
format.iphone { render :text => "Hello iPhone", :content => Mime::HTML }
endatom_feed_helper, a new plugin -- builder for Atom specified in index.atom.builder<%= yield :head %>, content_for :head { auto_discovery_link(:atom, formatted_posts_url)}breakpoints in your production code, not that you’d actually want to do that. Dumps you into irb where you can inspect variables, etc. but you can also drop down another level to see the call hierarchy, etc.So when will we see Rails 2.0? The preview release is coming, hopefully before conference end.
Posted by Nick Sieger Tue, 18 Sep 2007 08:08:34 GMT
(Written from Dave’s perspective, in the first person, but paraphrased)
What is a relevant topic in Germany? Engineering. Except there’s no such thing as software engineering. The software equivalent of building a bridge is taking a whole lot of dirt that fills in a hole.
So what makes engineering good? I look for elegance and beauty.
Fred Brooks -- Mythical Man-Month. Not a single thing in software engineering has changed in the 30 years since the book was written. Go out and order it tonight if you haven’t read it.
We are privileged, because we get to start with nothing. Anything we can conceive of, we can create. And so, we suffer the same problems as poets suffer.
Writer’s block: a blank page standing in the way of getting started. Painting: a blank canvas without structure or form. Software project: a blank editor buffer.
Leonardo was commissioned to build a statue. But, having never bronzed in his life, he picked up a scrap of paper and drew sketches. He’s prototyping on paper, but in reality he’s prototyping in his mind, getting his brain thinking about what he’s doing.
We could do more of this experimentation. Whiteboard, index cards, we eschew them for scaffolding or other crutches. But we could think of more ideas if we got away from the familiar and tossed around new, fresh ideas.
The idea that we sit down and start coding the application is crazy. We don’t know what it’s supposed to be. Why should we fool ourselves into thinking that this works?
Artists draw cartoons, often a fully rendered version of a painting. If they don’t like the cartoon, it survives, but the final product probably takes a different form.
With Rails we can do rapid end-to-end prototyping. Scaffolding helps with this, and it probably won’t make it into the end result.
So start anyway, and be prepared to throw it away. Write tests, use them as tracer bullets. And act on worry. Listen to the inner voice that tells you when something is wrong.
Sistine Chapel: brilliant example of modularization. It shows you how to conceive of doing a huge project without the fret of focusing on the entire thing.
Another example: comic books. You’re splitting up the product into time slices. Limit how much you do, and leave open the possibility of continuing at a later day. Know when to stop.
Satisfy the customer. Compare portraits to pictures. The best portraits, while not always faithful to the real image of the subject, still achieve the goal of satisfying the customer.
There is art in engineering, and engineering in art. Neither is an either/or proposition. Art and engineering are mutually supportive, in that you can’t have one without another.
With Ruby and Rails, we have a responsibility to uphold. Rails is a canvas, so be an artist. Create something great. But we also should create something beautiful. Sign your name by your work, and take pride in it.
Posted by Nick Sieger Fri, 14 Sep 2007 05:33:00 GMT
Speaking of keeping busy, I’ll be speaking alongside my colleague Craig McClanahan at RailsConf Europe in Berlin next week.
Sun is a Diamond Sponsor at RailsConf again, just like in Portland last May. Part of that sponsorship money pays for a brief keynote spot (filled by Craig) as well as a session or two. So no, I didn’t get my spot through an accepted proposal submission, but that doesn’t mean that the session is going to be a big marketing shill.
No, actually Craig and I are part of a small group at Sun that’s embracing Rails in a big way, and we’re going to be launching a site built mostly on Rails later this fall. We’re taking what we think are some novel approaches to building a Rails-based application and we thought we’d share some of those thoughts with you rather than drone on for the session about how great Sun is and what snazzy tools we make. (Although expect to see a subtle plug or two for Sun hardware and tools. Call it product placement rather than overt selling.)
I titled the session “Rails Hydra” because the central idea of the structure of our application is not one Rails app, but many. The UI and views don’t even talk to a database; instead they make use of ActiveResource and RESTful web services, talking to the models living in other Rails applications in the backend. One key point is we’re deploying .war files to JRuby running on Glassfish, thus avoiding headaches of morbidly multiplying Mongrel math. We’ll elaborate on this arrangement and talk about some of the other tools and tricks we’re using.
Also, Charlie, Tom and Ola will be there, so we’ll certainly have a JRuby summit at some point. Stop by and say hello!
Posted by Nick Sieger Sat, 19 May 2007 20:34:00 GMT
Chris is here to talk about games, since he used to work for Gamespot. He coded PHP, which is like training wheels without the bike. He had to sit in a glass cube and help keep the site running during E3 last year. There were 100 gajillion teenage boys during their lunch break hitting refresh, and it all blew up. Couldn’t even gzip the responses, because the servers heated up to much. They served 50M pages in a day, without downtime. They did it with Memcache.
Memcache is a distributed hash -- multiple daemons running on different servers. Developed by Livejournal for their infrastructure, you just put up the servers, and they just work.
Should you use Memcache? No. YAGNI, UYRDNI (unless you really do need it).
Fragments, Actions, Sessions, Objects, cache it all. You can use:
memcache-client (by Robot-coop guys/Eric Hodel). Marshal.unload is 40 times faster than Object.new/loading from the database....or...
cache_fuOr, acts_as_cached. It knows about all the aforementioned objects, with a single YAML config file (config/memcached.yml). Word to the wise: don’t use names in your server config file. Use IPs, avoid BIND and connections to the servers with every connection. Don’t let DNS outages bring down your servers.
get_cacheexpire_cacheThis is all you need -- if you’re using set_cache, you probably don’t understand how the plugin works. Expire cache on the “after save” hook, which allows you to cache ID misses as well.
class Presentation < ActiveRecord::Base
acts_as_cached
after_save :expire_cache
endExample: only cache published items
class Presentation < ActiveRecord::Base
acts_as_cached :conditions => 'published = 1'
endCached-scoped-finders (if somebody thinks of a good name, let Chris know). The idea is to move custom finder logic to a method on your model, and then wrap a cache-scoping thingy around it. cache_fu ties this up nicely by giving you a cached method on AR::Base.
class Topic < ActiveRecord::Base
def self.weekly_popular
Topic.find :all, ...
end
end
Topic.cached(:weekly_popular)Adding date to cache key with alias_method_chain:
def self.cache_key_with_date(id)
...
end
class << self
alias_method_chain :cache_key, :date
endCached loads by ID: Topic.find(1, 2, 3) moves to Topic.get_cache(1, 2, 3), which can parallelize calls to memcached and bring them back as they’re ready.
user_ids = @topic.posts.map(&:user_id).uniq
@users = User.get_cache(user_ids)You can also cache associations, so that you’re navigating associations via Memcache.
Cache overrides
class ApplicationController < ActionController::Base
before_filter :set_cache_override
def set_cache_override
ActsAsCached.skip_cache_gets = !!params[:skip_cache]
end
endreset_cache: Slow, uncached operations can sometimes queue up and wedge a site. Instead, issue cache resets on completion of a request, rather than expiring beforehand. That way, requests that continue to pile up will still use the cached copy until the rebuild is complete.
class Presentation < ActiveRecord::Base
after_save :reset_cache
endVersioning: a way to expire cache on new code releases
class Presentation < ActiveRecord::Base
acts_as_cached :version => 1
endDeployment: Chris recommends using Monit to ensure your Memcache servers are up.
libketama: consistent hashing that gives you the ability to redeploy Memcache servers without invalidating all the keys.
Q: Page caching? A: Nginx with native Memcache page caching, but outside of Rails domains.
Lots of other questions, but dude, Chris talks too fast!
