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Okay, everybody, please welcome Kerri Miller.
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Hey, everybody. Um, how about this? That's a little bit better.
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You know, this is a strange Ruby on Ales conference because it feels like nobody's drinking, and I'm not drinking either.
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So beer me!
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Beer us now.
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I'm not Jim and Rob; I don't always drink on stage. But when I do, it's butterbeer.
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This has been a really fun conference. Is Randall still here by any chance?
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I was so inspired by his talk that I want to do my own mic drop.
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Actually, though, I really love math, although I don't have a real strong grasp of it.
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This is usually my general reaction to real math-heavy talks.
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I feel like I'm right there, like I have to get it. I can get it.
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We'll just let this loop. Thank you, that's my talk.
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I want to give a little disclaimer. When I first said I wanted to talk about Harry Potter and the legacy code base, I had some Harry Potter fans say, 'But Kerri, you've never read any of the books.'
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No problem, that's fine; I watch the movies.
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But if you're not a fan of Harry Potter, you're going to have a bad time.
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There's a little bit of Harry Potter in this talk, so I'd like to welcome you all to Hogwarts Online.
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This is our special convo cave.
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I'm really glad all the other speakers have presented here, but our mutual employer has actually brought us here to tackle a very serious problem.
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And that is the legacy code beasts that are living in the basement of Hogwarts right now.
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Not everybody here knows me, which is strange because usually I blend in a little bit.
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I am a senior software developer from House Minnesota. I uphold the fine traditions of funny gem names and two-space indentation.
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You might think with a hat like mine that I'm from Texas, and then you might think, 'Well, she's wearing tie-dye; maybe she's from Austin,' but I'm actually from Seattle.
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In Seattle, I work for Nerd, one of the sponsors of the conference.
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They have the awesome pint glasses that we've been toting around and only having one drink in.
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We all discovered the bathroom.
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I also spent a lot of time working with the Ada Developers Academy.
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Yes, thank you. I know a number of people, especially here in the Pacific Northwest, have volunteered or donated time and money.
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It's a great program. In fact, we were able to bring four students down who are sitting in the front row, and I hope that they continue to heckle me just like they do in class. This is no different.
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Promises are made on stage.
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Now, a lot of people think it looks a little bit like the Beauxbatons ladies' wizardry school, but it's not.
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This is not a posed shot; this is the classroom, figuring out OAuth.
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One group said, 'Oh, we got it working,' and the others were like, 'What? I look and log in on Twitter. How does this work?'
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But seriously, we're here to talk about monsters—monsters in the basement.
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You're here as representatives of three different groups that have to deal with these monsters.
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This is tough; this is a battle that happens to a lot of us from day one or day 100 or 101.
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Who here has seen a legacy code beast before? Yeah, a whole bunch of you.
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Even new students have seen legacy code. I made them do legacy code last week.
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How are your scars? Do you have any scars to show? Most of my legacy code scars are on the inside.
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These are nasty, nasty beasts that we have to face down.
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So how did these beasts come about?
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Now, all too often, we assume that legacy code is evil. But it's not; it just had a bad childhood.
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It had a bad environment growing up.
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We think of legacy code as being brittle and wrong, but really, we're interpreting that code outside of its context.
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Legacy code is really a storehouse of domain knowledge, a set of decisions made by developers before us.
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It's very strange talking to Mike like this.
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If we take the time to study the history of code, we gain a better understanding of the business we're working for.
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We'll also understand the context in which the code was developed and the context for our future development.
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Because if software is a people problem, legacy software is also a people problem.
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So we've created ideal habitats for legacy code to exist—these beasts rise up out of the depths and attack us.
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You might perceive this assignment as some sort of penalty.
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I mean, there was that incident with the visiting professor and the pumpkin and the Polyjuice potion.
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But rest assured, this is not a penalty assignment.
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In fact, you should see this as an opportunity to earn some vital points for your house.
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Because you know you're a little behind.
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Every behavior we see around us is not illogical for those who are doing it.
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People always make the best decisions they can given the time, resources, and knowledge they have.
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Would people agree to that?
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Okay, a few people agree with that.
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So, those who don't agree, do you actually go out of your way to write bad code, obfuscated code, horrible code?
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Is anybody here doing that?
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I see we have some Perl hackers here; I can say that.
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When we're writing code, we need to take shortcuts sometimes.
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We get sloppy and we tend to focus on implementation details rather than the larger picture.
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Maybe we don't have complete information about what we're writing the code to do.
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This is a bad user story, perhaps, or we're just not experts at it.
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We're trying to set up some sort of DRB distributed crazy card shuffling system and we don't know anything about it.
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We don't set out to write code that is going to decay and get nasty, but it does.
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I prefer to take an evolutionary perspective to it.
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Large events force their way into our code, and it can be as simple as getting a new hire who has a different style.
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Maybe they use Seattle style coding, or we get a new data center.
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Someone out there is shorting parentheses stock right now.
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We get a new data center or our business gets acquired, and now we have to merge with a group of developers.
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Or we hear about Node.js and start working it into our process.
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Something changes, and it's in that change that we start to realize this code is bad.
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This code is no longer serving its purpose because it's evolved.
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It has some sort of evolutionary advantage which is no longer advantageous—just like our tails.
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Most of us lost our tails when we migrated from primates to humans.
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Moment of silence for my brother.
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But when we move into these new environments, things that were formerly fine traits become expenses.
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They become messy headaches that we need to clean up.
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These are evolutionary adaptations that have lost their advantage.
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They slow us down, and we get caught by a lion.
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So we're introducing a new class here at Hogwarts this semester: Code Archaeology 101.
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In the context of legacy code, archaeology is a great metaphor.
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It's the study of cultures that came before us by examining artifacts.
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These artifacts can be pottery shards or ruins, and by looking at them, we can understand the cultures that created them.
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We can identify items that still pertain to our modern time.
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When working with legacy code, we have a code artifact.
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We're acting as archaeologists, piecing together how this fits into the larger ground we're excavating.
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How does this pot shard relate to another, or this service, or this comment to this git commit that we don't understand?
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There are several books downstairs in the library, several grimoires that we can look at to glean spells to help us cast these demons out of the basement.
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But we also have to think about these activities in the context of our overarching hypothesis or objective.
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Now, in practice, archaeology is a process carried out through three techniques: surveillance, excavation, and finally analysis and documentation.
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Each of you will eventually be graded on a final presentation for this.
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Unlike the real Hogwarts, here at Hogwarts Online, we do not give extra credit for dioramas.
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I'm sorry, when you're dealing with legacy code it pays to be brave.
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You know, just like Indiana Jones going into that tunnel to face giant rocks and spikes.
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We're digging into things that will scare us, and we'll see code that will scar us.
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It may make us want to take a drink and say, 'No, no, no, I've seen the worst code'.
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Here's a Flog score for you: has anybody seen a Flog score of over a thousand?
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How about 5,000? Do you know who wrote that method?
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No, it wasn't me! Actually, that was a trick question.
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Class names have been changed to protect the innocent.
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When you're dealing with legacy code, you're going to have to perform some mighty feats of computer wizardry.
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And you have to be brave and just take that plunge, like Sandy was saying, that leap of faith.
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It's tempting to dismiss the people who came before us as doddering old fools clinging to the ways of the past.
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We say, 'Oh, man, they were PHP developers; I wrote this Rails app.'
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But that's okay, because really—
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Every line of code tells a story; every commit was a reaction and a choice to something.
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These were requirements or pressures from the environment that the person was working in.
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Documentation such as README files and test cases provide knowledge, but they don't tell the full story.
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It's the wisdom that comes from talking to the people who did it in the first place that really counts.
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Whenever I start a new project or go to a new company, I like to take people to lunch.
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I say, 'Let's go have coffee. Tell me what you hate, tell me what you love.'
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What's great about working here? What's the worst thing that happens?
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I don't limit myself to my co-workers; I talk to developers from other teams.
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What are they caring about, and what are their horror stories and war stories?
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I want them to show me the scars. Sales, support, and marketing teams are great fodder for this as well.
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Take them to lunch.
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Now in this picture, who are you?
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You're the red block; I knew you would be.
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Now, obviously, if I'm asking right, maybe we're Draco—are we the evil person coming to spoil everybody's lunch?
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Or are we the golden hero who's stepping in to save the day? That’s an important distinction to make.
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When you start working with legacy code—which is really legacy people—right? Because we all want to be heroes.
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But, really, what we need is more of Neville Longbottom, the butt of every joke who passes out at the slightest hint of danger or excitement.
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He is ultimately the star, if not the hero, of the Harry Potter series.
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He works hard, he's smart, and he takes responsibility in critical moments.
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Now, I want to discuss surveillance a bit.
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In traditional archaeology, surveillance involves measuring things with sticks and telescopes.
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When we talk about software, we start by taking inventory.
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Where are we starting? What problems do we have in one particular area? What are our code metrics?
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How is our test coverage? Do we have benchmarks? What do our New Relic performance graphs say?
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We should pay attention to what's important.
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I often ask dumb questions, as my students know.
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I also seem to really like Ron Weasley for some reason; it might be a ginger thing.
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We have to stick together; soul stealing is a taxing hobby.
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Ask dumb questions.
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People will move forward, especially when you're joining a new team.
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If you have that one expert who used to work on the code coming over to your team—
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Ask them questions about the assumptions they're making.
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We've all heard people say, 'I wanted to use Redis, but they won't let us.'
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Who are they? Who says we can't use something? Why?
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What are the assumptions? Is it a bad piece of technology, or are there costs associated?
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All too often, we move from the idea of a neat trick to this is how we do things.
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Five years ago, I worked for a tiny online bookstore where we had a rule in the employee handbook.
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'Developers must wear proper undergarments at all times.'
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Every rule like that has someone's name attached to it.
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There is actually a story there; I'll tell it in class on Monday.
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When you do this exploration, there are assumptions that people make about their environment.
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These assumptions can create friction, which is the moment we say, 'Oh, this is going to be expensive. This is a headache to change.'
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Sandy's example of refactoring is that code I would leave alone until I had to make that change.
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Most of you probably wouldn't cruise through the codebase looking for things to refactor.
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However, let’s discuss some legacy code.
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We're having some ongoing debate over Seattle-style coding.
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In the basement, the number crunchers in the potion department said we have to remove poison for liability reasons.
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So we did that, but then eventually the market forces changed, and the supply of vascular poison dried up.
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We need to save that stuff; we can't just throw it away.
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So we create a poison barrel class and start to deal with that, and then we remove the poison.
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What's wrong with this piece of code?
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This code is lying to us right now.
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Because this code is not about removing poison.
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If you just count the lines of code, you find that barrels and poison storage consume most of the space.
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We still call it 'remove poison,' and this is a trap waiting to bite us.
00:18:02.160
We take a survey to identify the most likely candidates for fixing problems.
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This is where new hires come in; they aren't burdened with any prior knowledge about how things should be.
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You dig down to find where the code comes from: how does it relate to other layers?
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Is it above or below? How do we assemble these pot shards into something useful?
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We roll up our sleeves and say, 'I'll just do a little refactoring today.'
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You can't blindly charge into refactoring; you have to have a plan.
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It's important to have metrics by which you judge your success.
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If you dive in, you'll distract yourself, because legacy code loves to rear its head and show its scary teeth.
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You need to know what you want to do and get in and out.
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If you see other problems, leave a to-do.
00:19:01.760
Note it and move on, because having a light touch is important.
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Sometimes, yes, they add to complexity, but it's a path.
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The code will evolve and continue to evolve forwards, never backwards.
00:19:18.000
How many people here are familiar with the Zieder Z works?
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They have been draining this inland sea in Holland since the 1930s.
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They didn't just throw a ton of dirt in all at once; they drained pieces over time.
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They said, 'Now we need another 100 hectares of farmland, so let’s drain that.'
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By tackling these things piece by piece, they perform an amazing feat of engineering.
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In our code, as we remove the poison, we leave breadcrumbs to other developers.
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We say, 'We changed this API, and the tests are green, but we don’t know who else is using this.'
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There is definitely more refactoring work to be done.
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This is just me doing bad code on an airplane, but the basic idea is to make small changes.
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Just changing the name of something gives it a different set of powers.
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Now for analysis and documentation.
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Once you determine the physical and logical position of a code artifact, it's time to publish.
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If we don't get published, we won't finish, and we won't get our doctorate.
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Look at implementation details and identify edge cases that are not currently accommodated.
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Document these, whether through tests or announcements.
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I updated the Bacillus class, so look out!
00:21:01.480
As you're doing this documentation, especially if you're starting on a new project, work remains crucial.
00:21:07.440
Periodically going through this process identifies holes in your legacy code.
00:21:13.440
Every project has its own language, acronyms, slang, and ways of defining terms.
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I make dictionaries, wikis, little grimoires that define terms in documentation.
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That way, the next developer will understand because the assumptions may differ.
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A sure way to fix a legacy project is to address naming errors.
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I make a lot of maps; I'm a kinesthetic visual learner.
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I need to touch and see things to understand them.
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I was a stagehand and a glass artist; touching things helps me learn.
00:22:03.440
When I can't create a model, I'll find a giant whiteboard and a veteran coder.
00:22:08.960
We sit down and go through the code together.
00:22:12.960
This is a great way to have that cultural transfer about what's important.
00:22:18.640
Don't let them leave that room.
00:22:24.320
Once you complete the surveillance and excavation of a legacy code beast, it's time to move on.
00:22:32.960
There's always a legacy code beast first to contend with.
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But I have confidence in all of you, especially my students.
00:22:45.680
I forget who said it, but writing shitty code just works.
00:22:51.360
Then it becomes too risky and expensive to change, so it lives forever.
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That’s evolution—it's evolved into something we're afraid of.
00:23:02.560
The only difference between code and a pet project is the pressure of its environment.
00:23:08.640
The legacy code beasts are phantoms, boogeymen we use to scare new developers.
00:23:15.080
By breaking the knowledge down and making it understandable, we can untangle their mysteries.
00:23:22.080
Anyway, that’s me and what I do, but not necessarily in that order.
00:23:27.000
Thank you.
00:23:30.000
That was a little rambling, philosophical talk. What questions do you have right now?
00:23:34.160
Now that I don't have to use the mic, yeah.
00:23:37.440
I'm sorry, thank you.
00:23:41.760
Maybe.
00:23:44.960
Um, I found drinking game versions, but they weren't good enough resolution, so I apologize.
00:23:50.880
Yeah, can I say 'troll in the dungeon'?
00:23:55.680
True, in the dungeon.
00:23:59.360
No problem. Yeah, Stephen.
00:24:03.440
The website is Tie-Dye Everything.
00:24:07.440
If there are any other questions or comments, oh, Pete.
00:24:12.160
I didn't read the books, man; I don't know.
00:24:16.560
Um, I probably could. Yes.
00:24:20.480
Okay.
00:24:23.680
There is one last slide I want to share with you—it's fairly awesome.
00:24:30.160
Isn't this great? There you go, thank you.
00:34:12.000
So.
00:34:31.679
You.
