Tuesday, August 2, 2016

Tech talk about Pokemon Go



Quick background for people who don't already know: Pokemon Go is a mobile game that launched last month on Android, and more recently on iPhones. It is billed as an "augmented reality game," in that the gameplay incorporates a requirement to walk around in the real world and visit physical locations, and some virtual objects are treated within the game as if they physically exist at those locations. It was immediately popular, and has been plagued with ongoing problems with server response and performance. In this post I will discuss these issues on a level that laymen should be able to understand.

Friday, February 12, 2016

Techie Rant: Mobile apps shouldn't override web browsers

Dear Facebook:

I would like to politely offer feedback on this "instant article" feature that you are so proud to have updated on my mobile device.

I don't want to have to read long articles in the Facebook mobile app.

I don't EVER want to have to read long articles in the Facebook mobile app.

Thursday, January 14, 2016

Thanks for the help, cloud AI!

This is just a quick silly story that illustrates how the "intelligent" programs that monitor our lives can be both funny and creepy.
At my work, we have an intranet application -- something that runs in a web browser, but it's only visible from inside the office -- which tracks change requests and bugs we are working on. I am on the Client Account team, so most of my projects are identified with "CA-" and then a number, such as "CA-1234."
Usually after I have been working on one project for a while, I have memorized the number, and so I just type "CA-1234" into my browser. Since I have visited the feature page often, it automatically fills in the URL to take me there. But sometimes I mistype, or it doesn't work for some other reason, so my browser helpfully pulls up a Google search for CA-1234 instead.
That does not contain any information that is useful to me. However, it does often match a flight number on China Airlines.
So one morning I got an alert on my Android. It was Google's calendar program. It told me "It's time to leave for the airport if you want to catch that flight on China Airlines that you looked up!"

Tuesday, October 27, 2015

Advice for aspiring software engineers

I went for my Master's Degree after living in Austin for several years and working at a low level programming job at a large company. I felt really stuck. The nature of my work hadn't changed significantly in many years, and my team wasn't even trying to keep up with new technology. I was bored and didn't see things changing.

When I completed my degree in 2008, I was now overqualified for my job, but I also lacked the experience to get the kinds of jobs I was aiming for. The economy was also a disaster. I bounced around a number of contract jobs for several years, not managing to get a reliable permanent job until 2011. Three years later, I got a call from a recruiter at Blizzard Entertainment, a company I've been a big fan of since I played Warcraft II in college. I went through two lengthy interviews and joined the web development team. I'm pretty happy with the track my career has taken.

Last December, my cousin David wrote to me on behalf of a friend in college who wanted to know how he should proceed in order to make himself attractive to employers and land a decent job. I sent him the advice below. Due to the nature of my online media activities, a lot of young people write to me with similar questions, so I thought I'd recreate the advice for everyone to read.

Friday, November 14, 2014

Explain like I'm five: DDoS attack

A friend of mine asked me to literally "explain like I'm five" how a DDoS (Distributed Denial of Service) attack works, because World of Warcraft was having troubles yesterday after the launch of Warlords Of Draenor, and he was trying to tell his kid why. My answer:

When you play Warcraft, the computer that represents you is always "talking" through the internet to the computer that has everything in the WoW world. Computers have a limited attention span; they can talk to a lot of people at the same time, but not everybody in the world.

Usually they have enough attention to talk to all the people who are trying to play WoW at the same time. But sometimes bad people don't want the game to work right, so they pretend to be a million people and all try to talk to the computer at once. The world computer doesn't know who's a real person and who's not, so it gets confused and talks to all the million fake people. Then it doesn't have time to talk to you, so the game goes slow because it can't send you information about what's happening fast enough.

Sometimes people do this because they're mad at the company, and sometimes just because they think it's funny. It's against the law, but it's hard for the police to understand, so usually the company that is getting attacked has to deal with it on their own.

Wednesday, February 12, 2014

Adventures in junior programming, episode 4

As I've mentioned in previous posts (1, 2, 3), I've been teaching my son Ben a little Python here and there over the last few years. We're not very consistent, and in fact we haven't really done it much at all in a year or so. But that's not too terrible; it sort of reflects my own experience at Ben's age. I tinkered a little bit with BASIC once in a great while, copied some programs out of books and magazines, "hacked" some programs, forgot many things, and didn't really get deeply into program structure at all until I reached high school. So this is not an urgent task for me.

Ben and I did some work over the weekend. I have taught him a few things over the last couple of years, but we do it so sporadically that it's hard to keep the information fresh in his mind. So we started with this exercise: opened several of the programs that he has worked on in the past, then read through each one and predicted what it was going to do, and why. Doing this helped him get back into his headspace from earlier sessions, and also drilled the syntax back into his mind pretty quickly. Speaking for myself, I also find that reading my own code can help to refamiliarize myself with a language much more quickly than reading somebody else's examples.

Up until now it was clear that we'd done a lot of programs that were really brief -- single problem, single solution. Print all the powers of two up to a million. Print out a times table. Create a simple password verification program (which insults you if you fail; that's a ten year old mindset for you). These problems are interesting in their own right, but the real fun of programming is making a project with no immediate end goal, something you can tinker with over a long period.

Ben is very into gaming, just like his dad. We've been playing World of Warcraft together since he was seven. This seemed like a promising starting point, so I had him create a simple system of rules which could represent a fight between a hero and a monster. So we started out with a few basic hard coded numbers: Hero hit points, monster hit points, hero damage value, monster damage value. Then we wrote a loop so that the fight would keep going until one of the hit point values dropped below zero.

The program is pretty predictable at this point; the beauty of the concept is that we can build on the basic concept over time. So the first thing Ben wanted to do was tweak the numbers: The hero should always win, but just barely. So we did some math to figure out how to make that happen, and we saw the outcome change as the starting values got closer to numbers that "felt right."

This was a good time to introduce functions, which I don't think I've explained in detail before. We had a function for printing the current status ("The hero has X hit points! The monster has Y hit points!"); a function called "hithero" and another called "hitmonster". Initially the hit functions removed a fixed amount of damage; then we got a little more sophisticated, passed in the damage as a parameter, and also printed the action to the screen. After that we also added in weapon descriptions, so it then said "The hero hit the monster for 20 damage with his sword of epicness!"

It's a fun exercise and it has Ben's enthusiasm up, so he now thinks of it as "The first program I wrote mostly by myself!" (I did give him a whole lot of guidance, actually, but I've let him steer the creative direction of the program, so he does have plenty to be proud about.)

We now have a bug and feature wish list which is surely going to grow:
  • Make it so hit points can't go negative.
  • Make a "death" message.
  • Have multiple kinds of weapons; enable weapon switching.
  • Randomize damage within a range, like 16-24.
  • Allow the hero to pick a type of action, a la Pokemon, such as a direct damage attack or a debuff attack.
  • At some point we should probably start discussing object-oriented programming, before we get to the point where we bring in multiple monsters.
  • Item drops?
  • Visiting locations?
  • Ben really wants to make graphics, but that is a very advanced topic, and I'd rather he get solid with the fundamentals before touching that one.
  • I'm a web programmer, and putting stuff in web pages is a great way to showcase your work to friends. So maybe that's a better direction to go than graphics.
Obviously the best part of programming, as per the title of this blog, is building castles in the air -- constructing projects which seems to take on their own reality. So I'm looking forward to some more sessions where we make this thing interesting, while keeping it accessible to a kid who will be twelve soon.

Wednesday, October 9, 2013

Affordable Care Act Blues 2

Following up on my post from yesterday, a friend linked me to an article on Salon that attempted to diagnose the problems with the healthcare.gov website. The article is full of bad logic and half-baked assumptions that I couldn't resist correcting.

First of all, the article refers to a discussion on Reddit that was just ridiculous.

“The Redditors picking apart the client code have found some genuine issues with it, but healthcare.gov’s biggest problems are most likely not in the front-end code of the site’s Web pages, but in the back-end, server-side code that handles—or doesn’t handle—the registration process, which no one can see. Consequently, I would be skeptical of any outside claim to have identified the problem with the site.”

This is WAY too charitable. I’m not “skeptical.” I think the Redditors are dumb as rocks for wasting any time on this at all.

Server side (back end) code handles pretty much everything that is important about a web application's internal logic. The client side (front end) stuff -- which you can see printed out if you right-click on any page in your browser and select "View Source" -- handles cosmetic stuff. How the website looks, what kind of warning messages you get if you enter bad data, etc. It's possible for a site to break because of bad front end code, but that were true then it would almost certain be broken for everybody, not up and down sporadically.

I passed along the article to a friend who is the architect of our software at my job. His explanation is more thorough than mine, so I'm reprinting it with his permission.

Here’s how I would have written the same article but with my speculation….

I think the biggest and most important challenge is the overall architecture. From an architectural standpoint you need to ensure that your system is
  1. Secure
  2. Can scale appropriately
  3. Handles the scenario where it is overloaded
Secondly, for the end user experience, from a UI perspective you need to be
  1. User Friendly
  2. Ensure proper feedback
  3. Have as much client side validation as possible
Once you go live you are in a situation where you have to deal with all types of scenarios quickly. One issue that I see referenced a lot is the fact that the security question dropdowns aren’t populating. Maybe they load tested this but didn’t verify the contents of the actual html rendered. If you rely on older back ends then that needs to be part of your load testing and you need to reduce talking to those systems the least amount possible.

As far as server load there are 3 types of congestion you need to deal with. Memory, CPU and information I/O (Network and Drive). The dropdown thing might be related to either one of those three.

This, of course, is informed speculation about the nature of the problem itself, drawing on real experience about how websites are designed, and how to go about debugging the problem. The Salon author, David Auerbach, doesn't do this sort of thing. Instead, he casts about wildly to find a place to assign blame. He claims that he can identify it as an Oracle problem based on a single error message:

“Error from: https%3A//www.healthcare.gov/oberr.cgi%3Fstatus%253D500%2520errmsg%253DErrEngineDown%23signUpStepOne.” 
To translate, that’s an Oracle database complaining that it can’t do a signup because its “engine” server is down.

What? It is? How did he know that? I looked up “ErrEngineDown” to see if it might be a standard Oracle message. It is not. So my reading is that it’s simply the name that the developers themselves chose to assign to this particular error. There is literally nothing you can determine from this one status result, as far as identifying what kind of database they used, or why the database failed.

After that, Auerbach goes on to state that

That is, the front-end static website and the back-end servers (and possibly some dynamic components of the Web pages) were developed by two different contractors. Coordination between them appears to have been nonexistent, or else front-end architect Development Seed never would have given this interview to the Atlantic a few months back, in which they embrace open-source and envision a new world of government agencies sharing code with one another.

It's true, apparently there are at least two different developers who've had their hands on the system: Development Seed and CGI Federal. This is not a legitimate criticism of the process. The federal government is big. The ACA is big. It is routine and normal to have multiple companies working with one set of data. After all, each individual state seemingly has their own website which has to connect to the ACA. In that case, you typically have a web service host on the back end, which processes results, and the results come from many different clients -- i.e., the state's web site, which was probably developed at least partially by someone in the state.

And that's all we know. There is no evidence I can find in any of those links, that "coordination between them appears to have been nonexistent." Auerbach simply made that up. He also makes up a cute little fictional dialogue that has no grounding in reality whatsoever. That conclusion also does not follow from the fact that they use open source code and are enthusiastic about promoting open source principles, unless I’m missing some other piece of information cited. It may be the case, but it’s not demonstrated at all. Open source is just a model of developing something with transparency. It doesn't say anything at all about the process which the two developers followed.

To reiterate: We're talking about a website that is not working, for some people, some of the time. A friend posted just today that he successfully created his account and is done with the process. This is not a site that is fundamentally broken or flawed; it is a server that is sometimes overloaded by a very high volume of traffic. That's it. That's the whole problem.