Charles Engelke’s Blog

July 23, 2010

Fantastic Friday at OSCON

Filed under: Uncategorized — Charles Engelke @ 3:43 pm
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Well, they saved the best for last.  In general I found this year’s OSCON to be pretty weak in content, but today has been great.  In particular, Simon Wardley’s keynote was excellent (and clearly much longer than it was expected to be, but well worth the time), and Tim Bray’s talk on Practical Concurrency was the best of the conference.

We will close out with what is sure to be an entertaining talk on the world’s worst inventions from Paul Fenwick, and then be on our own for the rest of the day until our red-eye flight home late tonight.

July 22, 2010

Node.js at OSCON

Filed under: Uncategorized — Charles Engelke @ 8:12 pm
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Tom Hughes-Croucher is going to tell us about Node.js, a JavaScript web server.  He starts by offering a doughnut to anyone asking non-awful questions.

Why server-side JavaScript?  Well, first there are a lot of JavaScript programmers.  Pretty much all web programmers use it, because that’s all they have available on the client.  So why not use it on the server, too?  And why write things twice, separately for the server and client sides?  And progressive enhancement is free (close enough to free).

JavaScript runtimes include V8 (Google) in C++, Spider Monkey (Mozilla) in C++, Rhino (Mozilla) in Java, JavaScript Core (Apple) in C++.  V8 is significantly faster than Spider Monkey (at the moment), but Mozilla is coming back with Trace Monkey.  Google’s success with V8 has sparked a speed war among JavaScript and browser builders.

Node.js is a server-side JavaScript process that uses V8.  It runs on anything POSIX-enough. (May be okay on Cygwin on Windows.)  It’s non-blocking and event driven.  It uses the CommonJS module format (we’ll find out soon what that means).  Node is very fast.  It’s almost as fast as nginx, which is all native C and highly optimized.

Here’s some code (I think I got it down right):

var http = require('http');
http.createServer(function (req, res) {
   res.writeHead(200, {'Content-Type': 'text/plain'});
   res.end('Hello, World\n');
}).listen(8124, '127.0.0.1');
console.log('Server started.\n');

There are plenty of packages available for Node.js, which can be installed with NPM, the Node Package Manager.  Which is itself written in JavaScript.

He shows more examples, and explains how to use things.  A very good session.

JavaScript at OSCON

Filed under: Uncategorized — Charles Engelke @ 3:07 pm
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I’m starting day 2 here with session on JavaScript.  First up is Programming Web Sockets by Sean Sullivan, to be followed by a talk on jQuery UI by Mike Hostetler and Jonathan Sharp.

Web sockets are a lightweight way for web servers and clients to communicate instead of using full HTTP.  Think of it as a push technology.  We start with an example of a multi-player game.  There are two specs to learn: the API and the protocol.  As a programmer, we care more about the API, which is how we use the facility.  He gives it all on one slide, which I don’t have time to show here.  Basically, instantiate a new WebSocket object, set some handlers for various events on it (like receiving and handling data: onopen, onmessage, onerror, onclose), and put data into it with a send method.  Eventually, call the close method to stop using the web socket.  It does look quite simple.

But how do I program the server-side?  That’s more fluid right now; the protocol specification is changing in incompatible ways.  On the browser side, we have support in Chrome 4.0.249.0 and later, Safari 5.0, Firefox 4.0.  IE 9?  Still not known.  Apparently (per a tweet from yesterday) Apple used to support web sockets in iOS, but now no longer does.  On the server side, there’s an enhancement request in for Apache httpd.  There’s a Python extension called pywebsocket available, though.  Django supports web sockets, and maybe some Ruby stuff, too.  Jetty has it.

No actual coding examples, which is a disappointment to me.  We’re finishing early, and have a long gap until the jQuery UI talk (which I think may be pretty full).

It is pretty full, but not standing-room only.

We start with effects, which are pretty ways to show changes on elements.  There’s not much meat here.  Now we move on to interactions, which are more functional.  For example, make an element draggable and attach handlers to various events related to that.  There’s also making a list sortable.

This is all great stuff, but I think I see why I have a hard time getting into it.  There isn’t a grand core idea here, but instead an enormous number of small, focused helper tools.  So a talk like this touches on one and then moves on right away.  Forty minutes of that is hard to stay focused on.  But now we’re getting a more complete coding example.  I don’t know; I like the functionality and appearance, but the necessary coding seems very complex for the examples.

It’s convinced me to use it, anyway.

Android Hands-on at OSCON

Filed under: Uncategorized — Charles Engelke @ 12:37 am
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Well, I really didn’t think Google would do it (again) but they handed out free phones to everyone attending this three hour evening session.  We all got a Nexus One, on AT&T frequencies by default, but you could ask for a T-Mobile one.  It only matters for 3G data; 2G data and voice are the same on both.

So now I’ve received four free phones from Google over the last 14 months.  I’m using one as a phone, two others for development and sharing with co-workers, and now I have to figure out whether I’m going to migrate to this fourth one, or pass it on to a co-worker, and use it just for development.  I’m sure not complaining, though.

I took an Android development class at Google IO in May, but it only last an hour and really just gave us time to take an existing app and uncomment code bit by bit to see what it did.  I’m hoping to get a bit deeper tonight.

We’re starting with design principles, not jumping right into programming.  Mobile apps are a bit different from desktop ones, and Google says that they want people to create great ones.  Though I don’t know how much attention folks are paying to the speaker; they’re unboxing and setting up their phones.

Some good UI points: don’t just port your UI from other platforms; your app should behave like other apps on the same platform.  Don’t do positioning and sizing that won’t adjust to different devices.  Don’t overuse modal dialogs.  Of course, DO support different resolutions, handle orientation changes, support non-touch navigation, and make large, obvious tap targets.

[Yes, I swear I'm paying attention.  But I'm also updating my new phone to FroYo!]

Design philosophy: choose clear over “simple”.  Focus on content, not chrome.  Enhance the app through use of the cloud (Yes!).

Show feedback: have at least four states for all interactive UI elements: default, disabled, focused, pressed.

Avoid confirmation dialogs (are you sure?).  Instead, support undo.

(By the way, we’re back on the OSCON_BG wi-fi tonight, and it’s performing very badly again.  Of course, that might be due to everyone downloading FroYo to their phones via wi-fi, since they didn’t come with SIMs.)

Some new UI design patterns: Dashboard, Action Bar, and Quick Actions.  They’ll show them in the context of the new Android twitter app.

This is all good content, but I’m ready for the “hands-on” part.  Let’s build something.

Tim Bray just announced that Android is now shipping 160,000 phones a day, which comes to more than 50 million a year.  So developers should be interested in creating apps for it, and tools to create apps for it.  (Nobody’s mentioned AppInventor yet, though.)

Now we’re going to talk about how to have your app interact with RESTful services.  I missed that session at Google IO (too much competing content there) and I care deeply about this, so I’m really glad to see this.  First issue: why a native REST Client versus a Mobile Web App?  Basically because web apps can’t do all the things a native app can do.  Yet.  Google’s working on it making web apps more and more capable, but there are still things you can’t do on your phone with a web app that you could do with a native app.

First up for REST: how not to do it.  Start up a new thread to talk to the remote server, save results in memory, and then have your main thread take that data out of memory and use it.  Why is this bad?  Well, the OS can shut down the process any time the user navigates away from it (since the device has limited memory).  So if you haven’t finished the fetch, or processed the data fetched to memory, it’s gone and you’ll have to do it over.  Instead, you need to start a service for this, which the OS won’t kill as easily, and if it does kill it, the OS will save and later restore the state.

Now we’ll see step by step how to do that.  There’s a diagram showing with 11 steps involved to have your activity create and use a service to perform a REST method.  The specific example is getting a list of photos in an album, or saving a new photo to an album, accessed via a RESTful web service.  Some other tips:

  • Can use the new built-in JSON parser in FroYo
  • Always enable gzip encoding.  If the server supports it, it will not only download faster, but use the radio (and hence the battery) less.
  • Run the method in a worker thread
  • Use the Apache HTTP client library

The whole thing starts when the Service receives the Intent sent by the Service Helper and starts the correct REST method.  Then the Processor that actually makes the request is done it triggers a callback, and then the Service Helper invoices the “Service Helper binder callback”.  (I think I know what they mean by that.)  It can queue multiple downloads.

That was how the Service responds to the Service Helper.  Where does that come in?  It’s what your Activity actually invokes.  It’s a singleton that exposes a simple (asynchronous) API to be used by the user interface.

(Again, good information.  But where’s the hands-on?  I’ve already created the Hello, Android example and pushed it to the new phone, but I want to create something tonight!)

I’ve been to a couple of short session on programming Android, and created the baby Hello, World app, but I’m barely keeping up at this point.  I strongly suspect that this example is way too complicated for the majority of people here who just don’t have any Android context to put it in yet.

Okay, we’ve finally finished the description of how that would work.  Now we’re going to hear how to use the ContentProvider API.  Which is apparently much simpler.  Okay, now we have the background to understand all the stuff the Content Provider is doing for us.  And finally, the third option is to use something called a Sync adapter.  Those are new in Android 2.0+, and they are important.  Use them!  They’re battery efficient, but not instantaneous due to queueing.

Well, we’re moving on the Android NDK development kit (for native C/C++ code instead of using Java).  I no longer believe that there will be any hands-on this evening.  Good information, though.  However, I have no intention of programming Android in C/C++.  Still, there are nice advances.  You can now debug NDK application on retail devices, starting with Android 2.2.  But we’re now seeing the original Tetris code (from Russia, from a long time ago) running natively on an Android phone using it.  Cool, but I’m still not going to do it myself.

And that’s it.  No actual hands-on, except what I’ve done myself during gaps in the talks.  But still a great session (even without the free phone, but FroYo is cool.)

July 21, 2010

OSCON Infrastructure

Filed under: Uncategorized — Charles Engelke @ 5:29 pm
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The wi-fi is working great today.  (Maybe it wasn’t offered as wireless-N yesterday?  The access point was just called OSCONBG.)  But now the air conditioning is no good.  For the first time I’m uncomfortable.  It must be over 80.  The temperature isn’t so bad, but the air is completely stagnant.

Devops

Filed under: Uncategorized — Charles Engelke @ 4:55 pm
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Or is is DevOps?  Regardless, it still looks like an ugly name to me.  I’ve been hearing this word for two days now, and nobody ever bothers to define it, nor give the derivation of the word.  From context, the word is clearly combined from Development and Operations, and seems to refer to managing operations for applications deployed in the cloud.

It seems like a good idea to me.  I know I have long found that developers with some operations experience, or at least perspective, really bring a lot to the creation of easily deployed and managed systems.

Mobile Apps with HTML, CSS, and JavaScript

Filed under: Uncategorized — Charles Engelke @ 4:51 pm
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This morning’s talk by Jonathan Stark was excellent.  In particular, I’m definitely going to be using jQTouch, and probably will use PhoneGap.  In fact, I think I’d like a version of PhoneGap for Windows – let me deploy a web application inside a native wrapper, with extensions that let me manipulate the machine via JavaScript.

OSCON Begins

Filed under: Uncategorized — Charles Engelke @ 1:43 pm
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Yesterday’s Cloud Summit was pretty good.  I didn’t get a lot of detailed, concrete information, but acquired a good overview of what’s going on and how the pieces all need to connect.  But today, the real conference begins.

The morning began with “keynotes”.  I put that in quotes, because they were more like lightning talks.  But since the speakers were mostly executives instead of technical staff, they each needed ten minutes to make their points, not just the five usually allocated to a lightning talk.  The talks were okay, and whenever one dragged it was over soon, but they didn’t add much.  If they just skipped them, and had one or two real, deeply interesting keynotes, for the entire conference, that would be a lot better.  As it is, the conference itself doesn’t get started until nearly 11:00 AM.

For the rest of the morning (actually, the middle of the day) I’m going to attend sessions on programming for mobile devices.  First up is Android, the Whats & Wherefores by Dan Morrill of Google.  I’m already somewhat familiar with Android, so may not see much new.  But the second half the session is about Building Mobile Apps with HTML, CSS, and JavaScript, by Jonathan Stark, and I am very deeply interested in that topic.  I like all mobile platforms, but I don’t want to have to master lots of different technologies.  I think web technologies are mature enough to meet my development needs.

July 20, 2010

Trying OSCON’s Wi-Fi Again

Filed under: Uncategorized — Charles Engelke @ 5:55 pm
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Let’s see if things go better this afternoon.  We’re going to have a few debates in the afternoon, starting with one about the importance of open standards for cloud computing.  Sam Johnston of Google (his blog is here) starts the debate, speaking in favor of the importance of open standards.  After he’s had 15 minutes to present his case, Benjamin Black will have 15 minutes to make the opposite case.  Then there will be 15 minutes of back and forth, between the speakers and with a “jury” and audience members.

The “for” argument isn’t very interesting to me, because I already agree with what he’s saying.  I need to hear some contrary information when the opposition comes on.  Which is now starting.  Black starts by pointing to the dysfunctional processes often behind defining and agreeing to standards with a Monty Python video (the fish-slapping dance).  Then: what’s important?  Utility.  If it doesn’t solve my problem, I don’t care about standards.  Then interoperability.  Then being free of vendor lock-in (independence).  Those three aren’t all equal.

Some problems don’t need go past utility.  For example, SQL (in reality, not in theory).  His point seems to be that there is no meaningful interoperability between SQL implementations, yet we still use SQL.  Well, I don’t think I agree with the premise there.  A lack of perfect interoperability doesn’t mean that there isn’t any interoperability!

Suppose something new comes out with massive utility and a lot of imperfection.  People will adopt it rapidly.  Then you get lots of competition and exploration, and lots of “standards” that are all different from each other (think networking in the early days).  Eventually, the different islands begin to interoperate with each other as demanded by their users.  That’s where the cloud is now.  So it’s too early to define what the correct standards should be.

That happens in the next stage: maturation.  That’s where we worry about independence, not earlier.  Successful standards formalize what is already true.  “Standards are side effects of successful technology.” “All successful standards are de facto standards.”

All good points.  But is there nothing in cloud computing ready to benefit from the independence?  His next point is that, even if so, it’s too early.  Because as things become more standardized, the rate of innovation has to drop, and we aren’t ready for that to happen in the cloud.  Very good quote: Standardize too soon, and you lock in to the wrong thing.

Excellent speaker, and I agree with his points.  But not necessarily all his conclusions.  Mainly, I think some cloud issues are more mature that he seems to be saying, and are ready to improve interoperability, and perhaps even independence.  But he makes a great case.

There’s some back and forth and questions next.  It seems that they favor the “against” position.  But it seems that the question has changed a bit over the talk.  Now people are agreeing that a priori standards are bad.  But the question was about whether any standards were needed.

The next debate is on whether Open APIs are enough to prevent vendor lock-in.  George Reese will argue that they are; James Duncan will say that they aren’t.  Of course, the question starts with trying to determine just what would make an API “open”.  But that’s dismissed early on as not the core question.  It seems that the “pro” advocate is arguing against it: even if the APIs are open, if the platform itself isn’t, then you can’t take your top layer and move it elsewhere.

I don’t find this debate very interesting, though.  Nothing really new or useful for me.  But the first debate was excellent.  It’s a good format.

On the plus side, the conference Wi-fi is kind of working now.  It’s not great, but not dead, either.  I notice a lot of non-conference access points are now gone; I wonder if interference, rather than bandwidth, was the major problem.

No more blogging at OSCON

Filed under: Uncategorized — Charles Engelke @ 2:13 pm
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I’ve had to switch to my phone because wifi is unusable. They say they have 60Mb/s, which sounds like a lot until you divide it by a few thousand users.

Swype on android is great, but requires too much attention while trying to listen.

OSCON Cloud Summit

Filed under: Uncategorized — Charles Engelke @ 1:31 pm
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It’s my first day at OSCON, and I’m starting off with the Cloud Summit.  This post isn’t going to be real reporting or notes on the entire session.  Much of the material isn’t new to me, so I’m just going to record things new to me that I want to be able to remember and find more about later.

The introduction is by Simon Wardley, giving background and introducing the speakers and topics we’ll see the rest of the day.  He compares Cloud Computing to the evolution of electricity as a utility, and references Douglas Parkhill’s 1966 book The Challenge of the Computer Utility.

Mark Masterson is talking about cloud computing and the enterprise.  Risk is the likelihood of failure times the cost of failure.  Business has almost totally focused on the first term in the equation, trying to reduce the likelihood of failure, because they viewed the cost of failure is more or less a fixed amount.  But it’s not, and cloud computing is one thing that can reduce that cost.  If you focus on reducing the odds of failure, you have to lock in your decisions very early, and can’t explore some options.  If instead you accept a higher chance of failure, and pursue options that have a low cost of failure instead, you give yourself more options.  And you manage your risk just as well as the other way.  (This sounds a lot like agile development methodologies to me; don’t try so hard to not fail, instead fail early and cheaply and correct your path as you go.)

Subar Kumaraswamy of eBay is talking next, about Security and Identity in Cloud.  He starts with a slide showing a frightened manager, surrounded by scary orange dangers of using cloud computing: Compliance, Rogue Administrator, Governance, and many others.  But this is followed by a slide of a focused and contented developer, surrounded by soothing green virtues of cloud computing: iterative in hours, self service, empowered developers, and more.  The rest of his talk is focused on one key area: identity management.

On to John Willis.  “Cloudy Operations.”  In a cloudy world, the prime constraint should be the time it takes to restore your data.  Because you can rebuild all the infrastructure on demand, even in case of a disaster.  But you can’t be up and running until your instance data is live.

“Cloud Myths, Schemes and Dirty Little Secrets” by Patrick Kerpan up next.  Focus has been on making the physical virtual – Citrix on the desktop, VMWare on the server or Amazon EC2.  Dirty little secrets.  Ephemeral versus persistent images.  Ephemeral images disappear, but persistent ones too easy to treat like metal, errors accumulate, history of changes lost.  If you have a lot of data in the cloud, you can’t get it out quickly.  State is the monster (sounds like the last talk).

What is generally happening around us now is the beginning of the long, slow migration of the traditional enterprise to agile infrastructure; whether public, private or hybrid cloud.

The last talk before the break is called “Curing Addiction is Easier” by Stephen O’Grady.  Everybody has an API, but what about interoperability?  He mentioned Delta Cloud initiative (or maybe that’s δ-cloud), which is a layer on top of the API, for that reason.  No one has portability, but it’s not really a problem.  Most businesses want a solution now, and will defer worrying about tomorrow if they can solve their problem today.

That concludes the Cloud Scene theme for the day.  Not a lot of new stuff for me, but it’s supposed to set the scene and get us all on the same level.  Between the break and lunch we’ll see some Future Thinking.

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