19 Feb 2017

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Itamar Turner-Trauring: When AI replaces programmers

The year is 2030, and artificial intelligence has replaced all programmers. Let's see how this brave new world works out:

Hi! I'm John the Software Genie, here to help you with all your software needs.

Hi, I'd like some software to calculate the volume of my house.

Awesome! May I have access to your location?

Why do you need to access my location?

I will look up your house in your city's GIS database and use its dimensions to calculate its volume.

Sorry, I didn't quite state that correctly. I want some software that will calculate the dimensions of any house.

Awesome! What is the address of this house?

No, look, I don't want anything with addresses. You can have multiple apartments in a house, and anyway some structures don't have an address, or are just being designed... and the attic and basement doesn't always count... How about... I want software that calculates the volume of an abstract apartment.

Awesome! What's an abstract apartment?

Grrrr. I want software that calculates the sum of the volumes of some rooms.

Awesome! Which rooms?

You know what, never mind, I'll use a spreadsheet.

I'm sorry Dave, I can't let you do that.

What.

Just a little joke! I'm sorry you decided to go with a spreadsheet. Your usage bill for $153.24 will be charged to your credit card. Have a nice day!

Back to the present: I've been writing software for 20 years, and I find the idea of being replaced by an AI laughable.

Processing large amounts of data? Software's great at that. Figuring out what a human wants, or what a usable UI is like, or what the real problem you need to solve is... those are hard.

Imagine what it would take for John the Software Genie to learn from that conversation. I've made my share of mistakes over the years, but I've learned enough that these days I can gather requirements decently. How do you teach an AI to gather requirements?

We might one day have AI that is as smart as a random human, an AI that can learn a variety of skills, an AI that can understand what those strange and pesky humans are talking about. Until that day comes, I'm not worried about being replaced by an AI, and you shouldn't worry either.

Garbage collection didn't make programmers obsolete just because it automated memory management. In the end automation is a tool to be controlled by human understanding. As a programmer you should focus on building the skills that can't be automated: figuring out the real problems and how to solve them.

19 Feb 2017 5:00am GMT

11 Feb 2017

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Twisted Matrix Laboratories: Twisted 17.1.0 Released

On behalf of Twisted Matrix Laboratories, I am honoured to announce the release of Twisted 17.1!

The highlights of this release are:


For more information, check the NEWS file (link provided below).

You can find the downloads on PyPI (or alternatively our website). The NEWS file is also available on GitHub.

Many thanks to everyone who had a part in this release - the supporters of the Twisted Software Foundation, the developers who contributed code as well as documentation, and all the people building great things with Twisted!

Twisted Regards,
Amber Brown (HawkOwl)

11 Feb 2017 10:08am GMT

10 Feb 2017

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Glyph Lefkowitz: Make Time For Hope

Pandora hastened to replace the lid! but, alas! the whole contents of the jar had escaped, one thing only excepted, which lay at the bottom, and that was HOPE. So we see at this day, whatever evils are abroad, hope never entirely leaves us; and while we have THAT, no amount of other ills can make us completely wretched.

It's been a rough couple of weeks, and it seems likely to continue to be so for quite some time. There are many real and terrible consequences of the mistake that America made in November, and ignoring them will not make them go away. We'll all need to find a way to do our part.

It's not just you - it's legit hard to focus on work right now. This is especially true if, as many people in my community are, you are trying to motivate yourself to work on extracurricular, after-work projects that you used to find exciting, and instead find it hard to get out of bed in the morning.

I have no particular position of authority to advise you what to do about this situation, but I need to give a little pep talk to myself to get out of bed in the morning these days, so I figure I'd share my strategy with you. This is as much in the hope that I'll follow it more closely myself as it is that it will be of use to you.

With that, here are some ideas.

It's not over.

The feeling that nothing else is important any more, that everything must now be a life-or-death political struggle, is exhausting. Again, I don't want to minimize the very real problems that are coming or the need to do something about them, but, life will go on. Remind yourself of that. If you were doing something important before, it's still important. The rest of the world isn't going away.

Make as much time for self-care as you need.

You're not going to be of much use to anyone if you're just a sobbing wreck all the time. Do whatever you can do to take care of yourself and don't feel guilty about it. We'll all do what we can, when we can.1

You need to put on your own oxygen mask first.

Make time, every day, for hope.

"You can stand anything for 10 seconds. Then you just start on a new 10 seconds."

Every day, set aside some time - maybe 10 minutes, maybe an hour, maybe half the day, however much you can manage - where you're going to just pretend everything is going to be OK.2

Once you've managed to securely fasten this self-deception in place, take the time to do the things you think are important. Of course, for my audience, "work on your cool open source code" is a safe bet for something you might want to do, but don't make the mistake of always grimly setting your jaw and nose to the extracurricular grindstone; that would just be trading one set of world-weariness for another.

After convincing yourself that everything's fine, spend time with your friends and family, make art, or heck, just enjoy a good movie. Don't let the flavor of life turn to ash on your tongue.

Good night and good luck.

Thanks for reading. It's going to be a long four years3; I wish you the best of luck living your life in the meanwhile.


  1. I should note that self-care includes just doing your work to financially support yourself. If you have a job that you don't feel is meaningful but you need the wages to survive, that's meaningful. It's OK. Let yourself do it. Do a good job. Don't get fired.

  2. I know that there are people who are in desperate situations who can't do this; if you're an immigrant in illegal ICE or CBP detention, I'm (hopefully obviously) not talking to you. But, luckily, this is not yet the majority of the population. Most of us can, at least some of the time, afford to ignore the ongoing disaster.

  3. Realistically, probably more like 20 months, once the Rs in congress realize that he's completely destroyed their party's credibility and get around to impeaching him for one of his numerous crimes.

10 Feb 2017 7:58am GMT

Itamar Turner-Trauring: Buggy Software, Loyal Users: Why Bug Reporting is Key To User Retention

Your software has bugs. Sorry, mine does too.

Doesn't matter how much you've tested it or how much QA has tested it, some bugs will get through. And unless you're NASA, you probably can't afford to test your software enough anyway.

That means your users will be finding bugs for you. They will discover that your site doesn't work on IE 8.2. They clicked a button and a blank screen came up. Where is that feature you promised? WHY IS THIS NOT WORKING?!

As you know from personal experience, users don't enjoy finding bugs. Now you have buggy software and unhappy users. What are you going to do about it?

Luckily, in 1970 the economist Albert O. Hirschman came up with an answer to that question.

Exit, Voice and Loyalty

In his classic treatise Exit, Voice and Loyalty, Hirschman points out that users who are unhappy with a product have exactly two options. Just two, no more:

  1. Exiting, i.e. giving up on your product.
  2. Voicing their concerns.

Someone who has given up on your software isn't likely to tell you about their issues. And someone who cares enough to file a bug is less likely to switch away from your software. Finally, loyal users will stick around and use their voice when otherwise they would choose exit.

Now, your software has no purpose without users. So chances are you want to keep them from leaving (though perhaps you're better off without some of them - see item #2).

And here's the thing: there's only two choices, voice or exit. If you can convince your users to use their voice to complain, and they feel heard, your users are going to stick around.

Now at this point you might be thinking, "Itamar, why are you telling me obvious things? Of course users will stick around if we fix their bugs." But that's not how you keep users around. You keep users around by allowing them to express their voice, by making sure they feel heard.

Sometimes you may not fix the bug, and still have satisfied users. And sometimes you may fix a bug and still fail at making them feel heard; better than not fixing the bug, but you can do better.

To make your users feel heard when they encounter bugs you need to make sure:

  1. They can report bugs with as little effort as possible.
  2. They hear back from you.
  3. If you choose to fix the bug, you can actually figure out the problem from their bug report.
  4. The bug fix actually gets delivered to them.

Let's go through these requirements one by one.

Bug reporting

Once your users notice a problem you want them to communicate it to you immediately. This will ensure they choose the path of voice and don't contemplate exiting to your shiny competitor at the domain next door.

Faster communication also makes it much more likely the bug report will be useful. If the bug occurred 10 seconds ago the user will probably remember what happened. If it's a few hours later you're going to hear something about how "there was a flying moose on the screen? or maybe a hyena?" Remember: users are human, just like you and me, and humans have a hard time remembering things (and sometimes we forget that.)

To ensure bugs get reported quickly (or at all) you want to make it as easy as possible for the user to report the problem. Each additional step, e.g. creating an account in an issue tracker, means more users dropping out of the reporting process.

In practice many applications are designed to make it as hard as possible to report bugs. You'll be visiting a website, when suddenly:

"An error has occurred, please refresh your browser."

And of course the page will give no indication of how or where you should report the problem if it reoccurs, and do the people who run this website even care about your problem?

Make sure that's not how you're treating your users when an error occurs.

Improving bug reporting

So let's say you include a link to the bug report page, and let's say the user doesn't have to jump through hoops and email verification to sign up and then fill out the 200 fields that JIRA or Bugzilla think are really important and would you like to tell us about your most common childhood nightmare from the following list? We'll assume that bug reporting is easy to find and easy to fill it out, as it should be.

But... you need some information from the user. Like, what version of the program they were using, the operating system and so on and so forth. And you do actually need that information.

But the user just wants to get this over with, and every additional piece of information you ask for is likely to make them give up and go away. What to do?

Here's one solution: include it for them.

I've been using the rather excellent Spacemacs editor, and as usual when I use new software I had to report a bug. So it goes.

Anyway, to report a bug in Spacemacs you just hit the bug reporting key combo. You get a bug reporting page. In your editor. And it's filled in the Spacemacs version and the Emacs version and all the configuration you made. And then you close the buffer and it pre-populates a new GitHub issue with all this information and you hit Submit and you're done.

This is pretty awesome. No need to find the right web page or copy down every single configuration and environmental parameter to report a bug: just run the error-reporting command.

Spacemacs screenshot

Also, notice that this is a lot better than automatic crash reporting. I got to participate and explain the bits that were important to me, it's not the "yeah we reported the crash info and let's be honest you don't really believe anyone looks at these do you?"-vibe that one gets from certain software.

You can do much the same thing with a command-line tool, or a web-based application. Every time an error occurs or the user is having issues (e.g. the user ran yourcommand --help):

  1. Ask for the user's feedback in the terminal, or within the context of the web page, and then file the bug report for them.
  2. Gather as much information as you can automatically and include it in the bug report, so the user only has to report the part they care about.

Responding to the bug report

The next thing you have to do is actually respond to the bug report. As I write this the Spacemacs issue I filed is sitting there all sad and lonely and unanswered, and it's a little annoying. I do understand, open source volunteer-run project and all. (This is where loyalty comes in.)

But for a commercial product I am paying for I want to know that my problem has been heard. And sometimes the answer might be "sorry, we're not going to fix that this quarter." And that's OK, at least I know where I stand. But silence is not OK.

Respond to your bug reports, and tell your users what you're doing about it. And no, an automated response is not good enough.

Diagnosing the bug

If you've decided to fix the bug you can now proceed to do so... if you can figure out what the actual problem is. If diagnosing problems is impossible, or even just too expensive, you're not going to do fix the problem. And that means your users will continue to be affected by the bug.

Let's look at a common bug report:

I clicked Save, and your program crashed and deleted a day's worth of my hopes and dreams.

This is pretty bad: an unhappy user, and as is often the case the user simply doesn't have the information you need to figure out what's going on.

Even if the bug report is useful it can often be hard to reproduce the problem. Testing happens in controlled environments, which makes investigation and reproduction easier. Real-world use happens out in the wild, so good luck reproducing that crash.

Remember how we talked about automatically including as much information as possible in the bug report? You did that, right? And included all the relevant logs?

If you didn't, now's the time to think about it: try to ensure that logs, core dumps, and so on and so forth will always be available for bug reports. And try to automate submitting them as much as possible, while still giving the user the ability to report their specific take on the problem.

(And don't forget to respect your user's privacy!)

Distributing the fix

So now you've diagnosed and fixed your bug: problem solved! Or rather, problem almost solved. If the user hasn't gotten the bug fix all this work has been a waste of time.

You need fast releases, and you need automated updates where possible. If it takes too long for fixes to reach your users then for for practical purposes your users are not being heard. (There are exceptions, as always: in some businesses your users will value stability over all else.)

A virtuous circle

If you've done this right:

  1. Your users will feel heard, and choose voice over exit.
  2. You will get the occasional useful bug report, allowing you to improve your product.
  3. All your users will quickly benefit from those improvements.

There is more to be done, of course: many bugs can and should be caught in advance. And many users will never tell you their problems unless you ask.

But it's a good start at making your users happy and loyal, even when they encounter the occasional bug.

10 Feb 2017 5:00am GMT

31 Jan 2017

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Jonathan Lange: Announcing haskell-cli-template

Last October, I announced servant-template, a cookiecutter template for creating production-ready Haskell web services.

Almost immediately after making it, I wished I had something for building command-line tools quickly. I know stack comes with a heap of them, but:

So I made haskell-cli-template. It's very simple, it just makes a Haskell command-line project with some tests, command-line parsing, and a CircleCI build.

I wanted to integrate logging-effect, but after a few months away from it my tired little brain wasn't able to figure it out. I like command-line tools with logging controls, so I suspect I'll add it again in the future.

Let me know if you use haskell-cli-template to make anything cool, and please feel free to fork and extend.

31 Jan 2017 12:00am GMT

30 Jan 2017

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Jonathan Lange: Announcing graphql-api: Haskell library for GraphQL

Late last year, my friend Tom tried to convince me that writing REST APIs was boring and repetitive and that I should give this thing called GraphQL a try.

I was initially sceptical. servant, the REST library that I'm most familiar with, is lovely. Its clever use of Haskell's type system means that all the boring boilerplate I'd have to write in other languages just goes away.

However, after watching Lee Byron's Strange Loop talk on GraphQL I began to see his point. Being able to get many resources with the same request is very useful, and as someone who writes & runs servers, I very much want clients to ask only for the data that they need.

The only problem is that there isn't really a way to write GraphQL servers in Haskell-until now.

Introducing graphql-api

Tom and I put together a proof-of-concept GraphQL server implementation called graphql-api, which we released to Hackage today.

It lets you take a GraphQL schema and translate it into a Haskell type that represents the schema. You can then write handlers that accept and return native Haskell types. graphql-api will take care of parsing and validating your user queries, and Haskell's type system will make sure that your handlers handle the right thing.

Using graphql-api

Say you have a simple GraphQL schema, like this:

type Hello {
  greeting(who: String!): String!
}

which defines a single top-level type Hello that contains a single field, greeting, that takes a single, required argument who.

A user would query it with something like this:

{
  greeting("World")
}

And expect to see an answer like:

{
  "data": {
    "greeting": "Hello World!"
  }
}

To do this in Haskell with GraphQL, first we'd define the type:

type Hello = Object "Hello" '[]
  '[ Argument "who" Text :> Field "greeting" Text ]

And then a handler for that type:

hello :: Handler IO Hello
hello = pure greeting
 where
   greeting who = pure ("Hello " <> who <> "!")

We can then run a query like so:

queryHello :: IO Response
queryHello = interpretAnonymousQuery @Hello hello "{ greeting(who: \"World\") }"

And get the output we expect.

There's a lot going on in this example, so I encourage you to check out our tutorial to get the full story.

graphql-api's future

Tom and I put graphql-api together over a couple of months in our spare time because we wanted to actually use it. However, as we dug deeper into the implementation, we found we really enjoyed it and want to make a library that's genuinely good and helps other people do cool stuff.

The only way to do that, however, is to release it and get feedback from our users, and that's what we've done. So please use graphql-api and tell us what you think. If you build something cool with it, let us know.

For our part, we want to improve the error messages, make sure our handling for recursive data types is spot on, and smooth down a few rough edges.

Thanks

Tom and I want to thank J. Daniel Navarro for his great GraphQL parser and encoder, which forms the basis for what we built here.

About the implementation

graphql-api is more-or-less a GraphQL compiler hooked up to type-based executing (aka "resolving") engine that's heavily inspired by Servant and uses various arcane type tricks from GHC 8.

We tried to stick to implementing the GraphQL specification. The spec is very well written, but implementing it has taught us that GraphQL is not at all as simple as it looks at first.

I can't speak very well to the type chicanery, except to point you at the code and at the Servant paper.

The compiler mostly lives in the GraphQL.Internal.Validation module. The main idea is that it takes the AST and translates it into a value that cannot possibly be wrong.

All the syntax stuff is from the original graphql-haskell, with a few fixes, and a tweak to guarantee that Name values are guaranteed to be correct.

30 Jan 2017 12:00am GMT

29 Jan 2017

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Itamar Turner-Trauring: Does your job contradict your beliefs?

As an employee your work is chosen by the owners and managers of the company: you choose the means, they choose the ends. Becoming an employee doesn't mean abdicating your moral responsibility, however. Even if someone else has chosen the goals you are still responsible for your own actions.

As an employee you need to ask yourself if the goals you're working for are worthwhile, and if the people you are working for deserve the power to direct your actions.

Let me tell you about the first time I was forced to ask myself this question.

The past is a different country

I grew up Israel, where as a Jewish citizen I was subject to the draft. The State of Israel is both Zionist and democratic, inherently contradictory ideals: a nation united by ethnicity, language and land versus the natural rights of individual human beings. Most Israeli citizens are indeed Jewish, but a large minority are Arab.

The contradiction is even more acute outside the borders of Israel, in the occupied territories of the West Bank and Gaza, where Israel's Jewish military rules millions of Palestinian Arabs. Whatever their opinion of the Occupation, most Israeli Jews are Zionists. They believe Israel must remain a Jewish state with a Jewish army, a bulwark against Palestinian terrorism and Israel's hostile Arab neighbors.

At age seventeen I had my first contact with the military: I was summoned to an initial screening at the Bakum, a military base that processes new recruits. The base was covered with asphalt, concrete, barbed wire and dirt, which turned to mud when it rained. The buildings were ugly concrete blocks and flimsy metal shacks that had seen better decades. Everything, inside and out, was painted in shades of khaki, gray and rust.

At the Bakum I was examined by a doctor. He gave me a physical profile of 97, the highest possible value; urban legend has it that the extra three points are taken off for circumcision. A profile of 97 meant I would be assigned combat duty, known in Israel as kravi.

As a kravi soldier I would have been required, as other Israeli soldiers have, to demolish homes, evict families, delay ambulances at checkpoints, threaten to shoot civilians for violating curfews. I didn't believe these actions protected Israel from Palestinian terrorists.

So I took the easy way out: I signed up for the Academic Reserve. I would go to college as a civilian, studying computer science, then serve in the army as a programmer for six years.

In the summer of 1999, after my first year in college, I went through a month of unstrenuous basic training for non-combatants. I hated every minute of it, the half-hearted brainwashing and the petty sadism. The following year, bored and unmotivated, I dropped out of college and started a software company.

Sooner or later the Academic Reserve office would notice I'd stopped taking classes, and I would be drafted into a kravi unit. My mother suggested I write a letter to the army - via a distant relative who worked for the Department of Defense - explaining my qualifications as a programmer and requesting my skills be put to use. Perhaps I could reach an accommodation allowing me to work on my company in my spare time.

I was summoned to a number of interviews in the following months, at office buildings, anonymous houses in residential areas, even a war monument behind a military base. None of them went well. I thoughtlessly, in retrospect perhaps deliberately, wrecked my chances at getting a security clearance, telling an interviewer my political views: I did not believe in the leadership of the country or the military. It was unlikely I would be trusted with classified material.

My final interview was different: I actually liked the soldiers I met. They were intelligent and sympathetic and I was sure I'd enjoy working with them, but I left the interview feeling miserable. I reached not so much a decision as a self-diagnosis: I could never be a soldier, I could not give up my right and duty to make my own decisions.

In the present

I did manage to get out of military service, but that's a longer story. But before that I spent literally years refusing to admit to myself that this was not a job I was willing to take, whatever the social expectations.

Being an employee is not quite the same as being a soldier. But these days when I'm looking for a job I try to be more aware of what I am willing to do. I won't even bother applying to companies that do anything related to "defense" or the military, for example.

You will have your own criteria, of course, but I would urge you to consider whether your current employment matches your beliefs.

29 Jan 2017 5:00am GMT

26 Jan 2017

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Itamar Turner-Trauring: Coding skills you won't learn in school: Object Ownership

There are many skills you need to acquire as a programmer, and some of them are not part of the standard software engineering curriculum. Instead you're expected to learn them by osmosis, or by working with someone more experienced. David MacIver covers one such skill: tracking which type a value has.

Another skill you need is an understanding object ownership in your code: knowing which part of your code owns a particular object in memory, and what its expectations are for access. Lacking this understanding you might write code that causes your program to crash or to suffer from subtle bugs. Even worse, some programming languages won't even provide you with facilities to help you in this task.

Learning by osmosis

Here's how I learned this skill. When I was in university I was once had to implement a Red-Black Tree in C. I'd basically skipped all the classes for the intro to C class, and still gotten a perfect grade, so as far as the school was concerned I knew how to code in C.

In reality I had no clue what I was doing. I couldn't write a working tree implementation: my code kept segfaulting, I couldn't keep the structure straight. Eventually I turned in a half-broken solution and squeaked by with a grade of 60 out of 100.

I spent the next 5 years writing Python code, and then got a job writing C and C++. I did make some mistakes, e.g. my first project crashed every night (you can hear that story by signing up for my newsletter), but in general I was able to write working code even though I hadn't really written any C or C++ for years.

What changed?

I believe the one of the key skills I learned was object ownership, as a result of all the concurrent Python I was writing, plus the fact that C++ has a better model than C for object ownership. Let's see what I learned over those years.

Object ownership for memory deallocation

Consider the following C function:

char* do_something(char* input);

Someone is going to have deallocate input and someone is going to have to deallocate the returned result of do_something(). But who? If two different functions try to deallocate the same allocation your program's memory will be corrupted. If no one deallocates the memory your program will suffer from memory leaks.

This is where object ownership comes in: you ensure each allocation has only one owner, and only that owner should deallocate it. The GNOME project's developer documentation explains how their codebase makes this work:

Each allocation has exactly one owner; this owner may change as the program runs, by transferring ownership to another piece of code. Each variable is owned or unowned, according to whether the scope containing it is always its owner. Each function parameter and return type either transfers ownership of the values passed to it, or it doesn't. ... By statically calculating which variables are owned, memory management becomes a simple task of unconditionally freeing the owned variables before they leave their scope, and not freeing the unowned variables.

GNOME has a whole set of libraries, conventions and rules for making this happen, because the C programming language doesn't have many built-in facilities to deal with ownership.

C++, on the other hand, has built a broad range of utilities for just this purpose. For example, you can wrap an allocation in a shared_ptr object. Every time it is copied it will increment a counter, every time it is deallocated it will decrement the counter. When the counter hits zero the wrapped allocation will be deallocated. That means you don't need to track ownership for purposes of deallocation: the shared_ptr is the owner, and will deallocate at the right time.

This can be simplified even further by using languages like Java or Python that provide garbage collection: the language runtime will do all the work for you. You never have to track ownership for purposes of deallocating memory.

Object access rights

Even when memory allocation is handled by the language runtime, there are still reasons to think about object ownership. In particular there is the question of mutation: modifying an object's contents. Memory deallocation is the ultimate form of mutation, but normal mutation can also break your program.

Consider the following Python program:

words = ["hello", "there", "another"]
counts = wordcount(words)
print(words)

What do you expect to be printed? Typically you'd expect to see ["hello", "there", "another"], but there is another option. You may also get [] printed if wordcount() was implemented as follows:

def wordcount(words):
    result = Counter()
    while words:
        word = words.pop()
        result[word] += 1
    return result

In this implementation wordcount() is mutating the list it is given. Reintroducing the concept of an object owner makes this clearer: each object is owned by a scope, and that scope might not want to grant write access to the object when it passes it to a function.

Unfortunately in Python, Java and friends there is no real way for a caller to tell whether a function will mutate an input, nor whether a parameter to a function can be mutated. So you need to learn a set of conventions and assumptions about when this will happen and when it's safe to do so: you build a mental model of object ownership and access rights. I suspect most Python programmers wouldn't expect wordcount() to mutate its inputs: it violates the mental model we have for object ownership and access.

The concept of private attributes (explicit in Java, by convention in Python) is one way access rights are controlled, but it doesn't solve the problem in all cases. When conventions don't help and you're uncertain you have to refer to API docs, or sometimes even the implementation, to know who can or might modify objects. This is similar to how C programmers deal with memory allocation.

Interestingly, C and C++ have a mechanism that can often solve this problem: const. You can define arguments as being const, i.e. unchangeable:

std::map<string,int> wordcount(const vector<string> &words);

If you try to mutate the argument the compiler will complain and prevent you from doing so.

Other approaches: Rust vs. functional languages

Outside of const the C++ features for object ownership management grew over time, as library code. The Rust programming language, in contrast, provides object ownership as a feature within the compiler itself. And this applies both to ownership for purposes of memory allocation but also for purposes of mutation. Rust attempts to provide this features while still providing the full power of C and C++, and in particular control over memory allocation.

Where Rust code requires the programmer to make explicit decisions about object ownership, functional languages take a different approach. In functional languages like Haskell or Clojure if you call a wordcount function you know the arguments you pass in won't be mutated, because objects are immutable and can't be changed. If objects can't be mutated it doesn't matter who owns them: they are the same everywhere.

The need to track object ownership in your head or in code for mutation control is obviated by making objects immutable. Couple this with garbage collection and you need spend much less time thinking about object ownership when writing purely functional code.

Summary: what you need to know

Depending on the programming language you're coding in you need to learn different models of thinking about object ownership:

Next time you're writing some code think about who owns each object, and what guarantees the owner expects when it passes an object to other code. Over time you'll build a better mental model of how ownership works.

And if you're writing in a non-functional language consider using immutable (sometimes known as "persistent") data structures. You can get much of the benefits of a functional language by simply reducing the scope of mutation, and therefore how much you need to track object ownership.

26 Jan 2017 5:00am GMT

19 Jan 2017

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Itamar Turner-Trauring: Specialist vs. Generalist: which is better for your career?

One of the decisions you'll need to make during the course of you career as a software developer is whether you should become:

  1. A specialist, an expert in a certain subject.
  2. A generalist, able to take on a wide variety of different work.

Miquel Beltran argues that specialization is the path to choose. At the end of his essay he suggests:

Stick to one platform, framework or language and your professional career will be better on the long run.

I think he's both right and wrong. Specialization is a great career move... but I don't think being a generalist is bad for your career either. In fact, you can be both and still have a good career, because there are two distinct areas in which this question plays out.

Getting hired is not the same as getting things done

Getting hired and getting things done are two different tasks, and you need different skills to do each.

When you're trying to get hired you are trying to show why you are the best candidate. That means dealing with the company's attitude towards employees, and the reason they are hiring, and the way they approach their work. It's not about how well you'll do or your job, or how good a programmer you are, or any of that: it's just about getting your foot in the door.

Once you're in, once you're an employee or a consultant, what matters is the results you deliver. It doesn't matter if you've only spent a few weeks previously writing iOS apps so long you do a good job writing an iOS app after you've been hired. And if you've spent years as an iOS developer and you fail to deliver, the fact you specialize in the iOS apps isn't going to help you.

Since getting hired and doing the work are separate tasks, that means you need to separate the decision to be a specialist or generalist into two questions: which will help you get hired, and which will make you better at actually doing your job?

Specialization is a marketing technique

If the question is how you should get hired then you are in the realm of marketing, not engineering. Specialization is a marketing technique: it's a way to demonstrate why you should be hired because you are an expert in your specialty.

Because specialization a marketing technique, specialization doesn't necessarily need to map to specialization on an engineering level. Let me give some examples from my career.

In 2001 I started contributing to an open source Python project, a networking framework called Twisted. I have used this experience in a variety of ways:

While all these specializations are related, they are not identical: each job I got involved being a specialist in a different area.

It's not what you can do, it's what you emphasize

Now, you could argue that the reasons I got hired enough are close enough that I am indeed a specialist: in networking or distributed systems. But consider that earlier in my career I did a number of years of web development. So back in 2004 I could have applied to web development jobs, highlighted that part of my resume, and relegated my open source networking work to a sentence at the end.

You likely have many engineering and "soft" skills available to you. Instead of focusing on one particular skillset ("I am an Android developer") you can focus on some other way you are special. E.g. If you're building a consulting pipeline then maybe it's a some business vertical you specialize in, to differentiate yourself from all the other Android developers.

But if you're marketing yourself on a one-off basis, which is certainly the case when you're applying for a job, you can choose a specialty that fits the occasion. Here's how my former colleague Adam Dangoor does it:

Pick one thing from what they talk about that you think is probably the least pitched-to aspect. E.g. if they're a Python shop everyone will say that they know Python well. But you can spot that e.g. they need help with growing a team and you have experience with that. It could very well be that 10 other candidates do too, but you just say that and you're the one candidate who can grow a team.

Specialist or Generalist?

So which should you chose, generalist or specialist?

When it comes to engineering skills, or just learning in general, my bias is towards being a generalist. When I went back to school to finish my degree I focused on the humanities and social science; I didn't take a single programming class. You may have different biases then I do.

But engineering skills are fundamentally different than how you market yourself. You can be a generalist in your engineering skills and market yourself as a specialist. In particular, when applying for jobs, you should try to be a specialist in what the company needs.

Sometimes a technical specialty is exactly what they want: you have some set of skills that are hard to find. But often there's a bit more to it than that. They might say they need an Android expert", but what they really need is someone to ship things fast.

They're looking for "an Android expert" because they don't want a learning curve. So if you emphasize the times you've delivered projects quickly and an on schedule you might get the job even, though another candidate had a couple more years of Android experience than you do..

In short, when it comes to engineering skills I tend towards being a generalist, but that may just be my personal bias. When marketing yourself, be a specialist... but there's nothing keeping you from being a different specialist every time you apply for a new job.

19 Jan 2017 5:00am GMT

18 Jan 2017

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Jack Moffitt: Servo Talk at LCA 2017

My talk from Linux.conf.au was just posted, and you can go watch it. In it I cover some of the features of Servo that make it unique and fast, including the constellation and WebRender.

Servo Architecture: Safety & Performance by Jack Moffitt, LCA 2017, Hobart, Australia.

18 Jan 2017 12:00am GMT

12 Jan 2017

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Jonathan Lange: Announcing grafanalib

Late last year, as part of my work at Weaveworks, I published grafanalib, a Python DSL for building Grafana dashboards.

We use it a lot, and it's made our dashboards much nicer to maintain. I've written a blog post about it that you can find it on the Weaveworks blog.

12 Jan 2017 12:00am GMT

11 Jan 2017

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Itamar Turner-Trauring: Your Job is Not Your Life: staying competitive as a developer

Are you worried about keeping your programming skills up-to-date so you can stay employable? Some programmers believe that to succeed you must spend all of your time learning, practicing and improving your craft. How do you fit all that in and still have a life?

In fact, it's quite possible to limit yourself to programming during work hours and still be employable and successful. If you do it right then staying competitive, if it's even necessary, won't require giving up your life for you job.

What does it mean to be "competitive?"

Before moving on to solutions it's worth understanding the problem a little more. The idea of "competitiveness" presumes that every programmer must continually justify their employment, or they will be replaced by some other more qualified developer.

There are shrinking industries where this is the case, but at the moment at least demand for programmers is quite high. Add on the fact that hiring new employees is always risky and worrying about "competitiveness" seems unnecessary. Yes, you need to do well at your job, but I doubt most programmers are at risk of being replaced a moment's notice.

Instead of worrying about "competitiveness" you should focus on the ability to easily find a new job. For example, there are other ways you improve your chances at finding a new job that have nothing to do with your engineering skills:

Moving on to engineering skills, the idea that you need to put in long hours outside of work is based both on the need to become an expert, and on the need to keep up with changing technology. Both can be done on the job.

Becoming an expert

You've probably heard the line about expertise requiring 10,000 hours of practice. The more hours you practice the better, then, right?

In fact many of the original studies were about number of years, not number of hours (10 years in particular). And the kind of practice matters. What you need is "deliberate practice":

... deliberate practice is a highly structured activity, the explicit goal of which is to improve performance. Specific tasks are invented to overcome weaknesses, and performance is carefully monitored to provide cues for ways to improve it further. We claim that deliberate practice requires effort and is not inherently enjoyable.

Putting aside knowledge of particular technologies, the kinds of things you want to become an expert at are problem solving, debugging, reading unknown code, etc.. And while you could practice them on your own time, the most realistic forms of practice will be at your job. What you need to do is utilize your work as a form of practice.

How should you practice? The key is to know your own weaknesses, and to get feedback on how you're doing so you can improve. Here are two ways to do that:

  1. Code reviews: a good code reviewer will point out holes in your design, in the ways you've tested your code, in the technology you're using. And doing code reviews will also improve your skills as you consider other people's approaches. A job at an organization with a good code review culture will be valuable to your skills and to your career.
  2. Self-critique: whenever you make a mistake, try to think about what you should have noticed, what mental model would have caught the problem, and how you could have chosen better. Notice the critique is not of the result. The key is to critique the process, so that you do better next time.

I write a weekly newsletter about my many mistakes, and while this is ostensibly for the benefit of the readers I've actually found it has helped me become a more insightful programmer. If you want to learn how to make self-critique useful than just an exercise in negativity I recommend the book The Power of Intuition by Gary Klein.

Learning technical skills

Beyond expertise you also need technical skills: programming languages, frameworks, and so on. You will never be able to keep up with all the changing technologies that are continuously being released. Instead, try the following:

Your job is not your life

All of the suggestions above shouldn't require much if any time outside of your job. If you enjoy programming and want to do it for fun, by all means do so. But your job shouldn't be the only thing you spend you life on.

If you would like to learn how to to get a job that doesn't overwhelm your life, join my free 6-part email course.

Join the course: Getting to a Sane Workweek

Don't let your job take over your life. Join over 770 other programmers on the journey to a saner workweek by taking this free 6-part email course. You'll learn how you can work reasonable hours and still succeed in your career a programmer.

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11 Jan 2017 5:00am GMT

06 Jan 2017

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Itamar Turner-Trauring: The fourfold path to software quality

How do you achieve software quality? How do you write software that actually works, software that isn't buggy, software that doesn't result in 4AM wake up calls when things break in production?

There are four different approaches you can take, four paths to the ultimate goal. Which path you choose to take will depend on your personality, skills and the circumstances of your work.

The path of the Yolo Programmer

The first path is that of the Yolo Programmer. As a follower of the famous slogan "You Only Live Once", the Yolo Programmer chooses not to think about software quality. Instead the Yolo Programmer enjoys the pure act of creation; writing code is a joy that would only be diminished by thoughts of maintenance or bugs.

It's easy to look down on the Yolo Programmer, to deride their approach a foolish attitude only suitable for children. As adults we suppress our playfulness because we worry about the future. But even though the future is important, the joy of creation is still a fundamental part of being human.

When you have the opportunity, when you're creating a prototype or some other code that doesn't need to be maintained, embrace the path of the Yolo Programmer. There's no shame in pure enjoyment.

The path of the Rational Optimizer

In contrast to the Yolo Programmer, the Rational Optimizer is well aware of the costs of bugs and mistakes. Software quality is best approached by counter-balancing two measurable costs: the cost of bugs to users and the business vs. the cost of finding and fixing the bugs.

Since bugs are more expensive the later you catch them, the Rational Optimizer invests in catching bugs as early as possible. And since human effort is expensive, the Rational Optimizer loves tools: software can be written once and used many times. Tools to find bugs are thus an eminently rational way to increase software quality.

David R. MacIver's post The Economics of Software Correctness is a great summary of this approach. And he's built some really wonderful tools: your company should hire him if you need to improve your software's quality.

The path of Mastery

The path of Mastery takes a different attitude, which you can see in the title Kate Thompson's book Zero Bugs and Program Faster (note that she sent me a free copy, so I may be biased).

Mastery is an attitude, a set of assumptions about how one should write code. It assumes that the code we create can be understood with enough effort. Or, if the code is not understandable, it can and should be simplified until we can understand it.

The path of Mastery is a fundamentally optimistic point of view: we can, if we choose, master our creations. If we can understand our code we can write quality code. We can do so by proving to ourselves that we've covered all the cases, and by learning to structure our code the right way. With the right knowledge, the right skills and the right attitude we can write code with very few bugs, perhaps even zero bugs.

To learn more about this path you should read Thompson's book; it's idiosyncratic, very personal, and full of useful advice. You'll become a better programmer by internalizing her lessons and attitude.

The path of the Software Clown

The final path is the path of the Software Clown. If Mastery is a 1980s movie training montage, the Software Clown is a tragicomedy: all software is broken, failure is inevitable, and nothing ever works right. There is always another banana peel to slip on, and that would be sad if it weren't so funny.

Since the Software Clown is always finding bugs, the Software Clown makes sure they get fixed, even when they're in someone else's software. Since software is always broken, the Software Clown plans for brokenness. For example, if bugs are inevitable then you should make sure users have an easy time reporting them.

Since banana peels are everywhere, the Software Clown learns how to avoid them. You can't avoid everything, and you won't avoid everything, but you can try to avoid as many as possible.

If you'd like to avoid the many mistakes I've made as a software engineer, sign up for my Software Clown newsletter. You'll get the story of one of my mistakes in your inbox every week and how you can avoid making it.

These are the four paths you can take, but remember: there is no one true answer, no one true path. Try to learn them all, and the skills and attitudes that go along with them; you'll become a better programmer and perhaps even a better person.

Avoid my programming mistakes!

Get a weekly email with one of my many software and career mistakes, and how you can avoid it. Here's what readers are saying:

"Are you reading @itamarst's "Software Clown" newsletter? If not, you should be. There's a gem in every issue." - @glyph

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06 Jan 2017 5:00am GMT

02 Jan 2017

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Itamar Turner-Trauring: When software ecosystems die

How much can you rely on the frameworks, tools and libraries you build your software on? And what can you do to reduce the inherent risk of depending on someone else's software?

Years ago I watched a whole software ecosystem die.

Not the slow decline of a programming language that is losing its users, or a no longer maintained library that has a newer, incompatible replacement. This was perma-death: game over, no resurrection, no second chances.

Here's what happened, and what you can learn from it.

The story of mTropolis

Back in the 1990s the Next Big Thing was multimedia, and in particular multimedia CD-ROMs. The market leader was Macromedia Director, a rather problematic tool.

Macromedia Director started out as an animation tool, using a sequence of frames as its organizing metaphor, which meant using it for hypermedia involved a rather bizarre idiom. Your starting screen would be frame 1 on the timeline, with a redirect to itself on exit, an infinite busy loop. Remember this started as animation tool, so the default was to continue on to later frames automatically.

When you clicked on a button that took you to a new screen it worked by moving you to another frame, let's say frame 100. Frame 100 would have a "go to frame 100" on exit to made sure you didn't continue on to frame 101, and then 102, etc.

Then in 1995 mTropolis showed up, a newer, better competitor to Director. It was considered by many to be the superior alternative, even in its very first release. It had a much more suitable conceptual model, features that were good enough to be copied by Director, and a loyal fan base.

In 1997 mTropolis was bought by Quark, maker of the the QuarkXPress desktop publishing software. A year later in 1998 Quark decided to end development of mTropolis.

mTropolis' users were very upset, of course, so they tried to buy the rights off of Quark and continue development on their own.

The purchase failed. mTropolis died.

Market leader or scrappy competitor?

The story of mTropolis had a strong impression on me as a young programmer: I worked with Director, so I was not affected, but the developers who used mTropolis were dead in the water. All the code they'd built was useless as soon as a new OS release broke mTropolis in even the smallest of ways.

This isn't a unique story, either: spend some time reading Our Incredible Journey. Startups come and go, and software ecosystems die with them.

Professor Beekums has an excellent post about switching costs in software development. He argues that given the choice between equivalent market leader and smaller competitor you should choose the latter, so you don't suffer from monopoly pricing.

But what do you do when they're not equivalent, or it's hard to switch? You still need to pick. I would argue that if they're not equivalent, the market leader is much safer. Macromedia was eventually bought by Adobe, and so Director is now Adobe Director. Director was the market leader in 1998, and it's still being developed and still available for purchase, almost 20 years later.

mTropolis may have been better, but mTropolis wasn't the market leader. And mTropolis is dead, and has been for a very long time.

Making the choice

So which do you go for, when you have the choice?

If you're dealing with open source software, much of the problem goes away. Even if the company sponsoring the software shuts down, access to the source code gives you a way to switch off the software gradually.

With Software-as-a-Service you're back in the realm of choosing between monopoly pricing and chance of software disappearing. And at least with mTropolis the developers still could use their licensed copies; an online SaaS can shut down at any time.

Personally I'd err on the side of choosing the market leader, but it's hard to give a general answer. Just remember: the proprietary software you rely on today might be gone tomorrow. Be prepared.

02 Jan 2017 5:00am GMT

23 Dec 2016

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Ralph Meijer: Changes

For me, Christmas and Jabber/XMPP go together. I started being involved with the Jabber community around the end of 2000. One of the first things that I built was a bot that recorded the availability presence of my online friends, and show this on a Christmas tree. Every light in the tree represents one contact, and if the user is offline, the light is darkened.As we are nearing Christmas, I put the tree up on the frontpage again, as many years before.

Over the years, the tooltips gained insight in User Moods and Tunes, first over regular Publish-Subscribe, later enhanced with the Personal Eventing Protocol. A few years later, Jingle was born, and in 2009, stpeter wrote a great specification that solidifies the relationship between Christmas and Jabber/XMPP.

Many things have changed in those 16 years. I've changed jobs quite a few times, most recently switching from the Mailgun team at Rackspace, to an exciting new job at VimpelCom as Chat Expert last April, working on Veon (more on that later). The instant messaging landscape has changed quite a bit, too. While we, unfortunately, still have a lot of different incompatible systems, a lot of progress has been made as well.

XMPP's story is long from over, and as such I am happy and honored to serve as Chair of the XMPP Standards Foundation since last month. As every year, my current focus is making another success of the XMPP Summit and our presence with the Realtime Lounge and Devroom at FOSDEM in Brussels in February. This is always the highlight of the year, with many XMPP enthousiasts, as well as our friends of the wider Realtime Communications, showing and discussing everything they are working on, ranging from protocol discussions to WebRTC and IoT applications.

Like last year, one of the topics that really excite me is the specification known as Mediated Information eXchange (MIX). MIX takes the good parts of the Multi User Chat (MUC) protocol, that has been the basis of group chat in XMPP for quite a while, redesigned on top of XMPP Publish-Subscribe. Modern commercial messaging systems, for business use (e.g. Slack and HipChat), as well as for general use (e.g. WhatsApp, WeChat, Google's offerings), have tried various approaches on the ancient model of multi-part text exchange, adding multi-media and other information sources, e.g. using integrations, bots, and cards.

MIX is the community's attempt to provide a building block that goes beyond the tradional approach of a single stream of information (presence and messages) to a collection of orthogonal information streams in the same context. A room participant can select (manually or automatically by the user agent) which information streams are of interest at that time. E.g. for mobile use or with many participants, exchanging the presence information of all participants can be unneeded or even expensive (in terms of bandwidth or battery use). In MIX, presence is available as a separate stream of information that can be disabled.

Another example is Slack's integrations. You can add streams of information (Tweets, continuous integration build results, or pull requests) to any channel. However, all participants have no choice to receive the resulting messages, intermixed with discussion. The client's notification system doesn't make any distinction between the two, so you either suffer getting alerts for every build, or mute the channel and possibly miss interesting discussion. The way around it is to have separate channels for notifications and discussion, possibly muting the former.

Using MIX, however, a client can be smarter about this. It can offer the user different ways to consume these information streams. E.g. notifications on your builds could be in a side bar. Tweets can be disabled, or modeled as a ticker. And it can be different depending on which of the (concurrent) clients you are connected with. E.g. the desktop or browser-based client has more screen real-estate to show such orthogonal information streams at the same time, a mobile client might still show the discussion and notifications interleaved.

All-in-all MIX allows for much richer, multi-modal, and more scalable interactions. Some of the other improvements over MUC include persistent participation in channels (much like IRC bouncers, but integrated), better defined multi-device use (including individual addressing), reconnection, and message archiving. I expect the discussions at the XMPP Summit to tie the loose ends as a prelude to initial implementations.

I am sure that FOSDEM and the XMPP Summit will have many more exciting topics, so I hope to see you there. Until then, Jabber on!

23 Dec 2016 1:28pm GMT

20 Dec 2016

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Itamar Turner-Trauring: The one technology you need to learn in 2017

If you want to become a better programmer or find a better-paying job, you might wonder if there's a particular technology you should learn in the coming year. Once you learn this technology you will become far more productive, and provide far more value to current or future employers.

There is something you can learn, but it's not a new web framework, or a programming language, or an IDE. In fact, it's not a technology at all.

It's better than that.

Much better.

Why you need to learn this

Imagine you're a contractor for an online pet-supplies store, selling supplies for cats and dogs.

One Monday the owner of the store asks you to add a new section to the website, selling supplies for aardvarks. Being a skilled designer as well as a programmer you can update the website design, then change the database, write some new code... By the end of the week you've launched the new Aardvark section.

Next Monday the owner is back. This week you're adding badgers, so you add another section of the design, update the code to support another pet, and again you're done after a week. The next week is crabs, and so on and so forth until by the middle of the year you've added zebras.

Unfortunately by this point your website has 30+ sections, and almost all of them are for pets no one wants or owns. No one can find the cat and dog supplies amid the noise, sales are plummeting, and the owner of the store can't afford to pay you any more.

Knowing a better web framework or a more suitable programming language would have let you code the weekly animal's section faster. But coding the wrong thing faster is just as much a waste of time.

Even if you knew every programming language and web framework under the sun you'd still be missing a key skill.

The skill you need to learn

How could this problem have been prevented? Let's get in our time machine and go back to the beginning. Cars drive backwards, raindrops rush up to the clouds, flowers refold, the sun flies from west to east alternating with darkness...

One Monday the owner of the store asks you to add a new section to the website, selling supplies for aardvarks. And you think for a moment, and ask: "why do you want to do that? most people don't own aardvarks."

With a bit more probing you find out the reason the store owners wants to add aardvarks. Perhaps the store wants to sell supplies for all animals, in which case you can code generic animal support once, instead of adding a new one per week. Perhaps this is a misguided search engine optimization strategy, in which case you can suggest adding a blog.

If you ask and figure out the reason for a task, figure out the goal... that is an immensely useful skill. You can only succeed at a project if you know its goal.

Working towards goals

If you can figure out what your boss really needs, what your client's real problem is, you can actually solve their problem. Otherwise they're the ones who have to solve the problem; you're just a hired hand implementing someone else's solution.

If you can figure out what the real goal is you can make sure you're working towards it. You can avoid the irrelevant work, the nice-to-have work, the attractive but useless work: you can work just on what's needed. You won't be writing coding any faster, but you'll ship sooner and code far more effectively.

Technologies are useful and you need to learn them, but in the end they're just tools. Programming languages come and go, web frameworks come and go: what matters is what you choose to build with them.

Don't learn a technology, learn more fundamental skills. Figuring out root causes and why something needs to be done, discovering the real problem, not just the stated one: these skills will serve you this year, and next year and every year after that.

If you have these core skills, you'll be a far more valuable employee. If you also improve your bargaining position and negotiating skills you will be able to find a job on your own terms: a job with work hours you want, a job you love that doesn't own your life.

Join the course: Getting to a Sane Workweek

Don't let your job take over your life. Join over 770 other programmers on the journey to a saner workweek by taking this free 6-part email course. You'll learn how you can work reasonable hours and still succeed in your career a programmer.

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If you would like to learn the skills you need to get a job that doesn't overwhelm your life, join my free 6-part email course.

20 Dec 2016 5:00am GMT