On the challenge of building HTTP REST APIs that don’t suck

Here’s a harsh truth: most RESTful HTTP APIs (in the following, APIs) suck, to some degree or another. Including the ones I’ve written.

Now, to an extent, this is not my fault, your fault or indeed anyone’s fault. APIs occupy a strange no man’s land between stuff designed for machines and stuff designed for humans. On one hand, APIs are intended to allow applications and services to communicate with each other. If humans want to interact with some service, they will do so via some wrapper around an API, be it an iOS app, a web application or a desktop client. Indeed, the tools you need to interact with APIs – a HTTP client – are orders of magnitude less well known and less ubiquitous than web browsers. Everybody has a web browser and knows how to use one. Few people have a dedicated desktop HTTP browser like Paw or know how to use something like curl. Quick, how do you do a token auth header in curl?

At the same time, even if the end user of the API is the under-the-hood part of a client rather than a human end user, humans have to deal with the API at some point, when they’re building whatever connects to the API. Tools like Swagger/OpenAPI were intended to somewhat simplify this process, and the idea was good – let’s have APIs generate a schema that they also serve up from which a generic client can then build a specific client. Except that’s not how it ended up working in practice, and in the overwhelming majority of cases, the way an API handler is written involves Dexedrine, coffee and long hours spent poring over the API documentation.

Which is why your API can’t suck completely. There’s no reason why your API can’t be a jumbled mess of methods from the perspective of your end user, who will interact without your API without needing to know what an API even is. That’s the beauty of it all. But if you want people to use your service – which you should very much want! -, you’ll have to have an API that people can get some use out of.

Now, the web is awash with stuff about best practices in developing REST APIs. And, quite frankly, most of these are chock-full of good advice. Yes, use plural nouns. Use HATEOAS. Use the right methods. Don’t create GET methods that can change state. And so on.

But the most important thing to know about rules, as a former CO of mine used to say, is to know when to break them, and what the consequences will be when you do. There’s a philosophy of RESTful API design called pragmatic REST that acknowledges this to an extent, and uses the ideas underlying REST as a guideline, rather than strict, immutable rules. So, the first step of building APIs that don’t suck is knowing the consequences of everything you do. The problem with adhering to doctrine or rules or best practices is that none of that tells you what the consequences of your actions are, whether you follow them or not. That’s especially important when considering the consequences of not following the rules: not pluralizing your nouns and using GET to alter state have vastly different consequences. The former will piss off your colleagues (rightly so), the latter will possibly endanger the safety of your API and lead to what is sometimes referred to in the industry as Some Time Spent Updating Your LinkedIn & Resume.

Secondly, and you can take this from me – no rules are self-explanatory. Even with all the guidance in the world in your hand, there’s a decent chance I’ll have no idea why most of your code is the way it is. The bottom line being: document everything. I’d much rather have an API breaking fifteen rules and giving doctrinaire rule-followers an apoplectic fit but which is well-documented over a super-tidy bit of best practices incarnate (wouldn’t that be incodeate, given that code is not strictly made of meat?) that’s missing any useful documentation, any day of the week. There are several ways to document APIs, and no strictly right one – in fact, I would use several different methods within the same project for different endpoints. So for instance a totally run-of-the-mill DELETE endpoint that takes an object UUID as an argument requires much less documentation than a complex filtering interface that takes fifty different arguments, some of which may be mandatory. A few general principles have served me well in the past when it comes to documenting APIs:

  • Keep as much of the documentation as you can out of the code and in the parts that make it into the documentation. For instance, in Python, this is the docstring.
  • If your documentation allows, put examples into the docstring. An example can easily be drawn from the tests, by the way, which makes it a twofer.
  • Don’t document for documentation’s sake. Document to help people understand. Avoid tedious, wordy explanation for a method that’s blindingly obvious to everyone.
  • Eschew the concept of ‘required’ fields, values, query parameters, and so on. Nothing is ‘required’ – the world will not end if a query parameter is not provided, and you will be able to make the request at the very least. Rather, make it clear what the consequences of not providing the information will be. What happens if you do not enter a ‘required’ parameter? Merely calling it ‘required’ does not really tell me if it will crash, yield a cryptic error message or simply fail silent (which is something you also should try to avoid).
  • Where something must have a particular type of value (e.g. an integer), where a value will have to be provided in a particular way (e.g. a Boolean encoded as o/1 or True/False) or has a limited set of possible values (e.g. in an application tracking high school students, the year query parameter may only take the values ['freshman', 'sophomore', 'junior', 'senior']), make sure this is clearly documented, and make it clear whether the values are case sensitive or not.
  • Only put things into inline comments that would only be required for someone who is reading your code. Anything a user of your methods/endpoints ought to know about them should be in the docstring or otherwise end up in your documentation – your docstring, of course, has the added benefit that it will be visible not only for people reading the documentation but also for whoever is reading your code.
  • If you envisage even the most remote possibility that your API will have to handle Unicode, emojis or other fancy things (basically, anything beyond ASCII), make sure you explain how your API handles such values.

Finally, eat your own dog food. Writing a wrapper for your API is not only a commercially sound idea (it is much more fun for other developers to just grab an API wrapper for their language of choice than having to homebrew one), it’s also a great way to gauge how painful it is to work with your API. Unless it’s anything above a 6 on the 1-10 Visual Equivalent Scale of Painful and Grumpy Faces, you’ll be fine. And if you need to make changes, make any breaking change part of a new version. An API version string doesn’t necessarily mean the API cannot change at all, but it does mean you may not make breaking changes – this means any method, any endpoint and any argument that worked on day 0 of releasing v1 will have to work on v1, forever.

Following these rules won’t ensure your API won’t suck. But they’ll make sucking much more difficult, which is half the victory. A great marksmanship instructor I used to know said that the essence of ‘technique’, be it in handling a weapon or writing an API, is to reduce the opportunity of making avoidable mistakes. Correct running technique will force you to run in a way that doesn’t even let you injure your ankle unless you deviate from the form. Correct shooting technique eliminates the risk of elevation divergences due to discrepancies in how much air remains in the lungs by simply making you squeeze the trigger at the very end of your expiration. Good API development technique keeps you from creating APIs that suck by restricting you to practices that won’t allow you to commit some of the more egregious sins of writing APIs. And the more you can see beyond the rules and synthesise them into a body of technique that keeps you from making mistakes, the better your code will be, without cramping your creativity.

Using screen to babysit long-running processes

In machine learning, especially in deep learning, long-running processes are quite common. Just yesterday, I finished running an optimisation process that ran for the best part of four days –  and that’s on a 4-core machine with an Nvidia GRID K2, letting me crunch my data on 3,072 GPU cores!  Of course, I did not want to babysit the whole process. Least of all did I want to have to do so from my laptop. There’s a reason we have tools like Sentry, which can be easily adapted from webapp monitoring to letting you know how your model is doing.

One solution is to spin up another virtual machine, ssh into that machine, then from that
ssh into the machine running the code, so that if you drop the connection to the first machine, it will not drop the connection to the second. There is also nohup, which makes sure that the process is not killed when you ‘hang up’ the ssh connection. You will, however, not be able to get back into the process again. There are also reparenting tools like reptyr, but the need they meet is somewhat different. Enter terminal multiplexers.

Terminal multiplexers are old. They date from the era of things like time-sharing systems and other antiquities whose purpose was to allow a large number of users to get their time on a mainframe designed to serve hundreds, even thousands of users. With the advent of personal computers that had decent computational power on their own, terminal multiplexers remained the preserve of universities and other weirdos still using mainframe architectures. Fortunately for us, two great terminal multiplexers, screen (aka GNU Screen ) and tmux , are still being actively developed, and are almost definitely available for your *nix of choice. This gives us a convenient tool to sneak a peek at what’s going on with our long-suffering process. Here’s how.

Step 1
ssh into your remote machine, and launch ssh. You may need to do this as sudo if you encounter the error where screen, instead of starting up a new shell, returns [screen is terminating] and quits. If screen is started up correctly, you should be seeing a slightly different shell prompt (and if you started it as sudo, you will now be logged in as root).
ssh into your machine, and launch screen (screen).
In some scenarios, you may want to ‘name’ your screen session. Typically, this is the case when you want to share your screen with another user, e.g. for pair programming. To create a named screen, invoke screen using the session name parameter -S, as in e.g. screen -S my_shared_screen.
Step 2
In this step, we will be launching the actual script to run. If your script is Python based and you are using virtualenv (as you ought to!), activate the environment now using source /<virtualenv folder>/bin/activate, replacing  virtualenv folderby the name of the folder where your virtualenvs live (for me, that’s the environments folder, often enough it’s something like ~/.virtualenvs) and by the name of your virtualenv (in my case, research). You have to activate your virtualenv even if you have done so outside of screen already (remember, screen means you’re in an entirely new shell, with all environment configurations, settings, aliases &c. gone)!

With your virtualenv activated, launch it as normal — no need to launch it in the background. Indeed, one of the big advantages is the ability to see verbose mode progress indicators. If your script does not have a progress logger to stdout but logs to a logfile, you can start it using nohup, then put it into the background (Ctrl--Z, then bg) and track progress using tail -f logfile.log (where logfile.log is, of course, to be substituted by the filename of the logfile.
Step 3
Press Ctrl--A followed by Ctrl--D to detach from the current screen. This will take you back to your original shell after noting the address of the screen you’re detaching from. These always follow the format <identifier>.<session id>.<hostname>, where hostname is, of course, the hostname of the computer from which the screen session was started, stands for the name you gave your screen if any, and is an autogenerated 4-6 digit socket identifier. In general, as long as you are on the same machine, the screen identifier or the session name will be sufficient – the full canonical name is only necessary when trying to access a screen on another host.

To see a list of all screens running under your current username, enter screen -list. Refer to that listing or the address echoed when you detached from the screen to reattach to the process using screen -r <socket identifier>[.<session identifier>.<hostname>]. This will return you to the script, which keeps executing in the background.
Reattaching to the process running in the background, you can now follow the progress of the script. Use the key combination in Step 3 to step out of the process anytime and the rest of the step to return to it.

There is a known issue, caused by strace, that leads to screen immediately closing, with the message [screen is terminating] upon invoking screen as a non-privileged user.

There are generally two ways to resolve this issue.

The overall effect of both solutions is the same. Notably, both may be undesirable from a security perspective. As always, weigh risks against utility.

Do you prefer screen to staying logged in? Do you have any other cool hacks to make monitoring a machine learning process that takes considerable time to run? Let me know in the comments!

Image credits: Zenith Z-19 by ajmexico on Flickr

Fixing the mysterious Jupyter Tensorflow import bug

There’s a weird bug afoot that you might encounter when setting up a ‘lily white’ (brand new) development environment to play around with Tensorflow.  As it seems to have vexed quite a few people, I thought I’ll put my solution here to help future  tensorflowers find their way.  The problem presents after you have set up your new  virtualenv . You install Jupyter and Tensorflow, and  when importing, you get this:

In [1]:   import tensorflow as tf

ModuleNotFoundError Traceback (most recent call last)
in ()
----> 1 import tensorflow as tf

ModuleNotFoundError: No module named 'tensorflow'


Added perplexion

Say you are a dogged pursuer of bugs, and wish to check if you might have installed Tensorflow and Jupyter into different virtualenvs. One way to do that is to simply activate your virtualenv (using activate or source activate, depending on whether you use virtualenvwrapper), and starting a Python shell. Perplexingly, importing Tensorflow here will work just fine.

The solution

At this time, this works only for CPython aka ‘regular Python’ (if you don’t know what kind of Python you are running, it is in all likelihood CPython).

In general, it is advisable to start fixing these issues by destroying your virtualenv and starting anew, although that’s not strictly necessary. Create a virtualenv, and note the base Python executable’s version (it has to be a version for which there is a Tensorflow wheel for your platform, i.e. 2.7 or 3.3-3.6).

Step 1

Go to the PyPI website to find the Tensorflow installation appropriate to your system and your Python version (e.g. cp36 for Python 3.6). Copy the path of the correct version, then open up a terminal window and declare it as the environment variable TF_BINARY_URL. Use pip to install from the URL you set as the environment variable, then install Jupyter.

CVoncsefalvay@orinoco~ $ export TF_BINARY_URL=https://pypi.python.org/packages/b1/74/873a5fc04f1aa8d275ef1349b25c75dd87cbd7fb84fe41fc8c0a1d9afbe9/tensorflow-1.1.0rc2-cp36-cp36m-macosx_10_11_x86_64.whl#md5=c9b6f7741d955d1d3b4991a7942f48b9
CVoncsefalvay@orinoco~ $ pip install --upgrade $TF_BINARY_URL jupyter                 
Collecting tensorflow==1.1.0rc2 from https://pypi.python.org/packages/b1/74/873a5fc04f1aa8d275ef1349b25c75dd87cbd7fb84fe41fc8c0a1d9afbe9/tensorflow-1.1.0rc2-cp36-cp36m-macosx_10_11_x86_64.whl#md5=c9b6f7741d955d1d3b4991a7942f48b9
  Using cached tensorflow-1.1.0rc2-cp36-cp36m-macosx_10_11_x86_64.whl
Collecting jupyter
  Using cached jupyter-1.0.0-py2.py3-none-any.whl

(... lots more installation steps to follow ...)

Successfully installed ipykernel-4.6.1 ipython-6.0.0 jedi-0.10.2 jinja2-2.9.6 jupyter-1.0.0 jupyter-client-5.0.1 jupyter-console-5.1.0 notebook-5.0.0 prompt-toolkit-1.0.14 protobuf-3.2.0 qtconsole-4.3.0 setuptools-35.0.1 tensorflow-1.1.0rc2 tornado-4.5.1 webencodings-0.5.1 werkzeug-0.12.1
Step 2
Now for some magic. If you launch Jupyter now, there’s a good chance it won’t find Tensorflow. Why? Because you just installed Jupyter, your shell might not have updated the jupyter alias to point to that in the virtualenv, rather than your system Python installation.

Enter which jupyter to find out where the Jupyter link is pointing. If it is pointing to a path within your virtualenvs folder, you’re good to go. Otherwise, open a new terminal window and activate your virtualenv. Check where the jupyter command is pointing now – it should point to the virtualenv.

Step 3
Fire up Jupyter, and import tensorflow. Voila – you have a fully working Tensorflow environment!

As always, let me know if it works for you in the comments, or if you’ve found some alternative ways to fix this issue. Hopefully, this helps you on your way to delve into Tensorflow and explore this fantastic deep learning framework!

Header image: courtesy of Jeff Dean, Large Scale Deep Learning for Intelligent Computer Systems, adapted from Untangling invariant object recognition by DiCarlo and Cox (2007).

A deep learning

There are posts that are harder to write than others. This one perhaps has been one of the hardest. It took me the best part of four months and dozens of rewrites.

Because it’s about something I love. And about someone I love. And about something else I love. And how these three came to come into a conflict. And, perhaps, what we all can learn from that.

As many of you might know, deep learning is my jam. Not in a faddish, ‘it’s what cool kids do these days’ sense. Nor, for that matter, in the sense so awfully prevalent in Silicon Valley, whereby the utility of something is measured in how many jobs it will get rid of, presumably freeing off humans to engage in more cerebral pursuits, or how it may someday cure intrinsically human problems if only those pesky humans were to listen to their technocratic betters for once. Rather, I’m a deep learning and AI researcher who believes in what he’s doing. I believe with all I am and all I’ve got that deep learning is right now our best chance to find better ways of curing cancer, producing more with less emissions, building structures that can withstand floods on a dime, identifying terrorists and, heck, create entertaining stuff. I firmly believe that it’s one of the few intellectual pursuits I am somewhat suited for that is also worth my time, not the least because I firmly believe that it will make me have more of it – and if not me, maybe someone equally worthy.

Which is why it was so hard for me to watch this video, of my lifelong idol Hayao Miyazaki ripping a deep learning researcher to shreds.

Now, quite frankly, I have little time for the researcher and his proposition. It’s badly made, dumb and pointless. Why one would inundate Miyazaki-san with it is beyond me. His putdown is completely on point, and not an ounce too harsh. All of his words are well deserved. As someone with a neurological chronic pain disorder that makes me sometimes feel like that creature writhing on the floor, I don’t have a shred of sympathy for this chap.1Least of all because I know how rudimentary and lame his work is. I’ve built evolutionary models of locomotion where the first stages look like this. There’s no cutting edge science here.

Rather, it’s the last few words of Miyazaki-san that have punched a hole in my heart and have held my thoughts captive for months now, coming back into the forefront of my thoughts like a recurring nightmare.

“I feel like we are nearing the end of times,” he says, the camera gracefully hovering over his shoulder as he sketches through his tears. “We humans are losing faith in ourselves.”

Deep learning is something formidable, something incredible, something so futuristic yet so simple. Deep down (no pun intended), deep learning is really not much more than a combination of a few relatively simple tricks, some the best part of a century old, that together create something fantastic. Let me try to put it into layman’s terms (if you’re one of my fellow ML /AI nerds, you can just jump over this part).

Consider you are facing the arduous and yet tremendously important task of, say, identifying whether an image depicts a cat or a dog. In ML lingo, this is what we call a ‘classification’ task. One traditional approach used to be to define what cats are versus what dogs are, and provide rules. If it’s got whiskers, it’s a cat. If it’s got big puppy eyes, it’s, well, a puppy. If it’s got forward pointing eyes and a roughly circular face, it’s almost definitely a kitty. If it’s on a leash, it’s probably a dog. And so on, ad infinitum, your model of a cat-versus-dog becoming more and more accurate with each rule you add.

This is a fairly feasible approach, and is still used. In fact, there’s a whole school of machine learning called decision trees that relies on this kind of definition of your subjects. But there are three problems with it.

  1. You need to know quite a bit about cats and dogs to be able to do this. At the very least, you need to be able to, and take the time and effort to, describe cats and dogs. It’s not enough to merely feed images of each to the computer.2There’s a whole aspect of the story called feature extraction, which I will ignore for the sake of simplicity, and assume that it just happens. It doesn’t, of course, and it plays a huge role in identifying things, but this story is complex enough already as it is.
  2. You are limited in time and ability to put down distinguishing features – your program cannot be infinitely large, nor do you have infinite time to write it. You must prioritise by identifying the factors with the greatest differentiating potential first. In other words, you need to know, in advance, what the most salient characteristics of cats versus dogs are – that is, what characteristics are almost omnipresent among cats but hardly ever occur among dogs (and vice versa)? All dogs have a snout and no cat has a snout, whereas some cats do have floppy ears and some dogs do have almost catlike triangular ears.
  3. You are limited to what you know. Silly as that may sound, there might be some differentia between cats and dogs that are so arcane, so mathematical that no human would think of it – but which might come trivially evident to a computer.

Deep learning, like friendship, is magic. Unlike most other techniques of machine learning, you don’t need to have the slightest idea of what differentiates cats from dogs. What you need is a few hundred images of each, preferably with a label (although that is not strictly necessary – classifiers can get by just fine without needing to be told what the names of the things they are classifying are: as long as they’re told how many different classes they are to split the images into, they will find differentiating features on their own and split the images into ‘images with thing 1’ versus  ‘images with thing 2’. – magic, right?). Using modern deep learning libraries like TensorFlow and their high level abstractions (e.g. keras, tflearn) you can literally write a classifier that identifies cats versus dogs with a very high accuracy in less than 50 lines of Python that will be able to classify thousands of cat and dog pics in a fraction of a minute, most of which will be taken up by loading the images rather than the actual classification.

Told you it’s magic.

What makes deep learning ‘deep’, though? The origins of deep learning are older than modern computers. In 1943, McCullough and Pitts published a paper3McCulloch, W and Pitts, W (1943). A Logical Calculus of Ideas Immanent in Nervous Activity. Bulletin of Mathematical Biophysics 5 (4): 115–133. doi:10.1007/BF02478259. that posited a model of neural activity based on propositional logic. Spurred by the mid-20th century advances in understanding how the nervous system works, in particular how nerve cells are interconnected, McCulloch and Pitts simply drew the obvious conclusion: there is a way you can represent neural connections using propositional logic (and, actually, vice versa). But it wasn’t until 1958 that this idea was followed up in earnest. Rosenblatt’s ground-breaking paper4Rosenblatt, F. (1958). The Perceptron: A Probabilistic Model For Information Storage And Organization In The Brain. Psych Rev 65 (6): 386–408. doi:10.1037/h0042519 introduced this thing called the perceptron, something that sounds like the ideal robotic boyfriend/therapist but in fact was intended as a mathematical model for how the brain stores and processes information. A perceptron is a network of artificial neurons. Consider the cat/dog example. A simple single-layer perceptron has a list of input neurons   x_1 ,   x_2   and so on. Each of these describe a particular property. Does the animal have a snout? Does it go woof? Depending on how characteristic they are, they’re multiplied by a weight  w_n . For instance, all dogs and no cats have snouts, so   w_1   will be relatively high, while there are cats that don’t have long curly tails and dogs that do, so  w_n   will be relatively low.

At the end, the output neuron (denoted by the big  \Sigma  ) sums up these results, and gives an estimate as to whether it’s a cat or a dog.

What was initially designed to model the way the brain works has soon shown remarkable utility in applied computation, to the point that the US Navy was roped into building an actual, physical perceptron machine – the first application of computer vision. However, it was a complete bust. It turned out that a single layer perceptron couldn’t really recognise a lot of patterns. What it lacked was depth.

What do we mean by depth? Consider the human brain. The brain actually doesn’t have a single part devoted to vision. Rather, it has six separate areas5Or five, depending on whether you consider the dorsomedial area a separate area of the extrastriate cortex – the striate cortex (V1) and the extrastriate areas (V2-V6). These form a feedforward pathway of sorts, where V1 feeds into V2, which feeds into V3 and so on. To massively oversimplify: V1 detects optical features like edges, which it feeds on to V2, which breaks these down into more complex features: shapes, orientation, colour &c. As you proceed towards the back of the head, the visual centres detect increasingly complex abstractions from the simple visual information. What was found is that by putting layers and layers of neurons after one another, even very complex patterns can be identified accurately. There is a hierarchy of features, as the facial recognition example below shows.

The first hidden layer recognises simple geometries and blobs at different parts of the zone. The second hidden layer fires if it detects particular manifestations of parts of the face – noses, eyes, mouths. Finally, the third layer fires if it ‘sees’ a particular combination of these. Much like an identikit image, a face is recognised because it contains parts of a face, which in turn are recognised because they contain a characteristic spatial alignment of simple geometries.

There’s much more to deep learning than what I have tried to convey in a few paragraphs. The applications are endless. With the cost of computing decreasing rapidly, deep learning applications have now become feasible in just about all spheres where they can be applied. And they excel everywhere, outpacing not only other machine learning approaches (which makes me absolutely stoked about the future!) but, at times, also humans.

Which leads me back to Miyazaki. You see, deep learning can’t just classify things or predict stock prices. It can also create stuff. To put an old misunderstanding to rest quite early: generative neural networks are genuinely creating new things. Rather than merely combining pre-programmed elements, they come as close as anything non-human can come to creativity.

The pinnacle of it all, generating enjoyable music, is still some ways off, and we have yet to enjoy a novel written by a deep learning engine. But to anyone who has been watching the rapid development of deep learning and especially generative algorithms based on deep learning, these are literally just questions of time.

Or perhaps, as Miyazaki said, questions of the ‘end of times’.

What sets a computer-generated piece apart from a human’s composition? Someday, they will be, as far as quality is concerned, indistinguishable. Yet something that will always set them apart is the absence of a creator.

In what is probably one of the worst written essays in  20th century literary criticism, a field already overflowing with bad prose for bad prose’s sake, Roland Barthes’s 1967 essay La mort de l’auteur posited a sort of separation between the author and the text, countering centuries of literary criticism that sought to explain the meaning of the latter by reference to the former.  According to Barthes, texts (and so, compositions, paintings &.) have a life and existence of their own. To liberate works of art of an  ‘interpretive  tyranny’ that is almost self-explanatorily imposed on it, they must be read, interpreted and understood by reference to its audience and not its author. Indeed, Barthes eschews the term in favour of the term ‘scriptor‘, the latter hearkening back to the Medieval monks who copied manuscripts: like them, the scriptor is not in control of the narrative or work of art that he or she composes. Devoid of the author’s authority, the work of art is now free to exist in a liberated state that allows you – the recipient – to establish its essential meaning.

Oddly, that’s not entirely what post-modernism seems to have created. If anything, there is now an increased focus on the author, at the very least in one particular sense. Consider the curious case of Wagner’s works in Israel. Because of his anti-Semitic views, arguably as well as due to the favour his music found during the tragic years of the Third Reich, Wagner’s works – even those that do not even remotely express a political position – are rarely played in Israel. Even in recent years, other than Holocaust survivor Mendi Roman’s performance of Siegfried in 2000, there have been very few instances of Wagner played in Israel – despite the curious fact that Theodor Herzl, founder of Zionism, admired Wagner’s music (if not his vile racial politics). Rather than the death of the author, we more often witness the death of the work. The taint of the author’s life comes to haunt the chords of his composition and the stanzas of his poetry, every brush-stroke of theirs forever imbued with the often very human sins and mistakes of their lives.

Less dramatic, perhaps, than Wagner’s case are the increasingly frequent boycotts, outbursts and protests against works of art solely based on the character of the author or composer. One must only look at the recent past to see protests, for instance, against the works of HP Lovecraft, themselves having to do more with eldritch horrors than racist horridness, due to the author’s admittedly reprehensible views on matters of race. Outrages about one author or another, one artist or the next, are commonplace, acted out on a daily basis on the Twitter gibbets and the Facebook  pillory. Rather than the death of the author, we experience the death of art, amidst an increasingly intolerant culture towards  the works of flawed or sinful creators.

This is, of course, not to excuse any of those sins or flaws. They should not, and cannot, be excused. Rather, perhaps, it is to suggest that part of a better understanding of humanity is that artists are a cross-section of us as a species, equally prone to be misled and deluded into adopting positions that, as the famous German anti-Fascist and children’s book author Erich Kästner said, ‘feed the animal within man’. Nor is this to condone or justify art that actively expresses those reprehensible views – an entirely different issue. Rather, I seek merely to draw attention to the increased tendency to condemn works of art for the artist’s political sins. In many cases, these sins are far from being as straightforward as Lovecraft’s bigotry and Wagner’s anti-Semitism. In many cases, these sins can be as subtle as going against the drift of public opinion, the Orwellian sin of ‘wrongthink’. With the internet having become a haven of mob mentality (something I personally was subjected to a few years ago), the threshold of what sins  of the creator shall be visited upon their creations has significantly decreased. It’s not the end of days, but you can see it from here.

In which case perhaps Miyazaki is right.

Perhaps what we need is art produced by computers.

As Miyazaki-san said, we are losing faith in ourselves. Not in our ability to create wonderful works of art, but in our ability to measure up to some flawless ethos, to some expectation of the artist as the flawless being. We are losing faith in our artists. We are losing faith in our creators, our poets and painters and sculptors and playwrights and composers, because we fear that with the inevitable revelation of greater – or perhaps lesser – misdeeds or wrongful opinions from their past shall not merely taint them: they shall no less taint us, the fans and aficionados and cognoscenti. Put not your faith in earthly artists, for they are fickle, and prone to having opinions that might be unacceptable, or be seen as such someday. Is it not a straightforward response then to  declare one’s love for the intolerable synthetic Baroque of Stanford machine learning genius Cary Kaiming Huang’s research? In a society where the artist’s sins taint the work of art and through that, all those who confessed to enjoy his works, there’s no other safe bet. Only the AI can cast the first stone.

And if the cost of that is truly the chirps of Cary’s synthetic Baroque generator, Miyazaki is right on the other point, too. It truly is the end of days.

References   [ + ]

1. Least of all because I know how rudimentary and lame his work is. I’ve built evolutionary models of locomotion where the first stages look like this. There’s no cutting edge science here.
2. There’s a whole aspect of the story called feature extraction, which I will ignore for the sake of simplicity, and assume that it just happens. It doesn’t, of course, and it plays a huge role in identifying things, but this story is complex enough already as it is.
3. McCulloch, W and Pitts, W (1943). A Logical Calculus of Ideas Immanent in Nervous Activity. Bulletin of Mathematical Biophysics 5 (4): 115–133. doi:10.1007/BF02478259.
4. Rosenblatt, F. (1958). The Perceptron: A Probabilistic Model For Information Storage And Organization In The Brain. Psych Rev 65 (6): 386–408. doi:10.1037/h0042519
5. Or five, depending on whether you consider the dorsomedial area a separate area of the extrastriate cortex

cookiecutter-flask-ask: a quick(er) start to Alexa skills!

If you develop for Amazon’s Alexa-powered devices, you must at some point have come across Flask-Ask, a project by John Wheeler that lets you quickly and easily build Python-based Skills for Alexa. It’s so easy, in fact, that John’s quickstart video, showing the creation of a Flask-Ask based Skill from zero to hero, takes less than five minutes! How awesome is that? Very awesome.

Bootstrapping a Flask-Ask project is not difficult – in fact, it’s pretty easy, but also pretty repetitive. And so, being the ingenious lazy developer I am, I’ve come up with a (somewhat opinionated) cookiecutter template for Flask-Ask.


Using the Flask-Ask cookiecutter should be trivial.  Make sure you have cookiecutter installed, either in a virtualenv that you have activated or your system installation of Python. Then, simply use  cookiecutter gh:chrisvoncsefalvay/cookiecutter-flask-ask to get started. Answer the friendly assistant’s questions, and voila! You have the basics of a Flask-Ask project all scaffolded.

Once you have scaffolded your project, you will have to create a virtualenv for your project and install dependencies by invoking pip install -r requirements.txt. You will also need ngrok to test your skill from your local device.

What’s in the box?

The cookiecutter has been configured with my Flask-Ask development preferences in mind, which in turn borrow heavily from John Wheeler‘s. The cookiecutter provides a scaffold of a Flask application, including not only session start handlers and an example intention but also a number of handlers for built-in Alexa intents, such as Yes, No and Help.

There is also a folder structure you might find useful, including an intent schema for some basic Amazon intents and a corresponding empty sample_utterances.txt file, as well as a gitkeep’d folder for custom slot types. Because I’m a huge fan of Sphinx documentation and strongly believe that voice apps need to be assiduously documented to live up to their potential, there is also a docs/ folder with a Makefile and an opinionated conf.py configuration file.

Is that all?!

Blissfully, yes, it is. Thanks to John’s extremely efficient and easy-to-use Flask-Ask project, you can discourse with your very own skill less than twenty minutes after starting the scaffolding!

You can find the cookiecutter-flask-ask project here. Issues, bugs and other woes are welcome, as are contributions (simply raise a pull request). For help and advice, you can find me on the Flask-Ask Gitter a lot during daytime CET.

cookiecutter-flask-ask is, of course, Swabware.

In which my awesome father-in-law has taken care of my bedtime reading

In which my awesome father-in-law has taken care of my bedtime reading for the foreseeable future... :) thank you so so much! ️ I've only had an hour or so to go through them but can already see the difference between these books and the rest of the SDR literature out there. Instead of clobbering the reader with heavy maths out of the gate or reading like something written by radio anoraks for radio anoraks, the Clarks' books read easy while going deep. If you have any interest in #sdr #radio or are as lucky as I was to have picked up a #HackRF for Christmas, you MUST get these books!

I only had an hour or so to go through them but can already see the difference between these books and the rest of the SDR literature out there. Instead of clobbering the reader with heavy maths out of the gate or reading like something written by radio anoraks for radio anoraks, the Clarks’ books read easy while going deep. If you have any interest in sdr radio or are as lucky as I was to have picked up a HackRF for Christmas, you MUST get these books!


One of the best things about my job is traveling to new (or in this case, old) places. And yet it wasn't until I had a home to go home to that I began to appreciate the wide world. Always on the road, existence is a sort of fleeting limbo. But if you have an Ithaca to yearn home for, a Penelope whose arms await you, you suddenly understand. It's in being away that we discover our home. It is in home that we discover away.

One of the best things about my job is traveling to new (or in this case, old) places. And yet it wasn’t until I had a home to go home to that I began to appreciate the wide world. Always on the road, existence is a sort of fleeting limbo. But if you have an Ithaca to yearn home for, a Penelope whose arms await you, you suddenly understand. It’s in being away that we discover our home. It is in home that we discover away.

“Next stop: Leiden University Faculty of Law!”

Returning to a place from one’s old life is always a complex experience. I’ve spent a year studying in this town, a mere decade ago: yet today, it feels like an eternity or a past life. So much has changed since then, and I barely recognise the man I was.

Back when I lived in Leiden, I was attached to the law faculty, housed in Kammerlingh Onnes’s old lab. If you had told me then that a decade and a bit later I would be back, but as a data scientist working with a client nearby, I would have laughed. Data science wasn’t even a thing back then, and while I was always into statistics and maths, I never saw myself doing it as a career until (relatively) quite recently. And so, to return to a town that holds all these memories from a past life is strange to say the least. Strange – but not necessarily unpleasant!