If we knew exactly what code needs to be written, what needs to be done and how it can be done, we would need very little time to write it. It is the discovery of the knowledge what to build and how to build it that takes all the time. Yet non-developers usually see it as an unacceptable waste to write and then throw away - and perhaps rewrite - code.


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Recommended Readings

Some interesting topics this time despite me spending lot of time on the
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A short story about the complexity of magical frameworks and dependency injection with a happy ending, featuring Resteasy, CDI, and JBoss.

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Recommended Readings

• Google engineers insist 20% time is not dead—it’s just turned into 120% time - it is interesting to see how has this evolved; "I have done many engineering/coding 20% projects and other non-engineering projects, with probably 20-40% producing “real” results (which over 7 years I think has been more than worth it for the company). But these projects are generally not rewarded." [highlight mine]
• The Worst Daily Scrum Ever - a story whose bad part is a too common reality; if energy is low, nobody asks for / offers help, and people only report status / plans then you are doing the daily scrum wrong and should stop now (but it also documents a nice example of a good, effective scrum)
• Why Responsive Design is a Waste of Time - a refreshingly critical take on responsive design; the author now aknowledges that it is sometimes worth the pain but the points are still valid - responsive design requires (lot of) extra work, the attempt to create a one-size-fits-all site of course adds considerable complexity (having two separate simple frontends might be better than one that is too complex), also many sites are good enough as they are (especially taking into account the capabilities of mobile browsers)
• How to lose $172,222 a second for 45 minutes - i.e. your bugs are likely not so serious after all :-) A financial company screwed big and ended up bankrupt. The cause? Chaotic DevOps, not removing old unused code, reusing a feature flag instead of creating a new one, lack of monitoring. The story in short: They deployed new trading code but failed to notice that it has not been deployed to one of the 8 servers; due to the flag reuse, the old, 10 years unused code has been activated instead. Due to the lack of monitoring they did not notice the cause, tried to roll back while leaving the flag enabled thus effectively activating the bad code on all the servers. => have proper automated and self-checking deployments, delete old code, do not repurpose old switches.
• 40 Inappropriate Actions to Take Against an Unlocked (Windows) PC - good tips for promoting security and having fun at the same time; I shall keep this at hand :-)
• How to go about 'proving' why dynamically typed languages are better - a cultivated and interesting discussion; as argueed, thinking in this direction is itself wrong and in different contexts, different languages will be more appropriate. I also like Phil Lord's "Programming is a highly fashion-centric occupation for any number of reasons." and "For me, the main advantage is that you are not forced to build complex hierarchies just to support the type system ([..]), and that having only a few abstractions makes it worthwhile adding lots of functions operating over them." and L. Petit's "IMHO, the question is irrelevant. It implicitly assumes that statically typed vs dynamically typed is a black / white choice, and that either 'static wins over dynamic' or 'dynamic wins over static' will be a true statement whatever the context." Also a good observation that types are only a subset of function contract enforcement and one of possible implementations.
  • What to Know Before Debating Type Systems - explanation of common misunderstandings that hinder discussions of static x dynamic typing including a classification of type systems
• The Failure of Governmental IT (Learnings From HealthCare.gov) - links to a few really good articles about the problems with governmental IT in general and my summary of them
• Inside the Arctic Circle, Where Your Facebook Data Lives - the designs of data centers used to be proprietary secrets until Fb developed its own and open-sourced them, enabling many Asian manufactures to start creating cheaper datacenters and thus started a revolution in this domain. Facebook's data centers are not general purpose but suitable ot the kind of work they need, but it is still widely applicable. Cool to see how they use natural conditions to get energy needs down and make HW that fits best their needs - that is what I call innovation!
• Academia.edu (via @RiczWest) - a rich source of free research papers - just register as an independant researcher; also lean/agile/systems thinking and other interesting topics
• Writing Code? Know Your Boundaries - an inspiring way of thinking; we use many technologies in combination (HTML, CSS, JS, SQL, server-side language, ...) and "the risk for picking the wrong tool for the job is strongest near the boundaries"; a discussion of the aforementioned boundaries with examples follows, e.g.: "Avoid putting HTML in JavaScript strings for 'poor man’s templating'", messing up SQL with html ("SELECT '<strong>' + Username + '</strong>' FROM Users"), CSS+HTML: using inline styles, SQL+server-side: string concatenation to create dynamic SQL queries, "writing dynamic JavaScript in a string on the server". I shall keep this in mind!
• Johannes Brodwall: A canonical web test - a simple web app end-to-end smoke test - using an embedded Jetty, a test DB (preferably in-memory), WebDriver to test it (simple: browser.get("/people"), assertThat(browser.findElement(<person id>.contains(<person's name>)); simple, nice, useful

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The failure of Healthcare.Gov has been discussed a lot but the main causes of the failure are unrelated to the project or to technology and apply similarly to other governments / large projects.

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EuroClojure 2013 was a nice, small conference. The talks were mostly interesting and often useful and it was wonderful to meet in reality people I only knew from the virtual life or from stories. You can get an impression what it was like from the #euroclojure tweets.

Below are some noteworthy things from the talks and chats.


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I have built an executable .war with an embedded Jetty and all the dependencies packed in using the Maven Shade and War plugins. When I tried to run it (java -jar <my war>.war) then I got a strange FileNotFoundException during the unpack phase. It was strange because the unpack code actually checks whether a file's parent directory exists and creates it if it doesn't.

The problem was that I use OS X which has a case-insensitive filesystem. A directory contained both the file LICENSE and the directory license/. When Jetty tried to unpack license/LICENSE.base64.txt, the check for the parent directory (license/) incorrectly succeeded (because it checked new File("[..]/license/LICENSE.base64.txt").getParentFile().exists() and that returned true because the file LICENSE already was there, and it wasn't distinguished from the actual directory license; .isDirectory() would have at least failed.) The workaround was to exclude the offensive file from the archive:


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Recommended Readings

• Stuff The Internet Says On Scalability For September 13, 2013 - a collection of interesting performance related articles with summaries (via @_dagi)
• Can you copy a culture? The NUMMI story (audio/transcript) - how the GM factory with the worst workforce has been turned around via a good application of Toyota Production System - "a truly inspiring story of human potential and how systems can be designed to bring the best or worst of of people." And how GM failed to learn from it and to copy Toyota's culture.
• The Reactive Manifesto - why to write reactive SW - "Reactive applications represent a balanced approach to addressing a wide range of contemporary challenges in software development. Building on an event-driven, message-based foundation, they provide the tools needed to ensure scalability and resilience. On top of this they support rich, responsive user interactions. We expect that a rapidly increasing number of systems will follow this blueprint in the years ahead."
• Frameworkless JavaScript – Why Angular, Ember, or Backbone don't work for us [Moot discussion platform] (via JavaScriptWeekly) Me: Frameworks are not always evil, but are likely overused and there are good cases when rolling your own solution is the best way. Why in Moot? Because the want a minimal API (no framework methods), small code size, small and familiar code base, no dependency hell and external package updates, no lock-in to technology that will be gone in few years, need WebSockets not REST. "Moot uses native pushState for managing URLs, John Resig's "micro templating" for views, and internal communication between model and views happens with a custom event library. There is no router or automatic data-binding." The looked at Angular, Ember, Backbone. "As a result of our combined perfectionism and minimalism, Moot is an extremely lightweight, manageable, and independent web application [..]"
• NYT: Eiji Toyoda, Promoter of the Toyota Way and Engineer of Its Growth, Dies at 100 - learn about the life of one of the founders of lean thinking
• Gojko Adzic: How we solved our #1 product management problem - valuable experience of false assumptions, learning from users, and a much helpful UI remake: even if you build a product to scratch your itch, you have to test it with real users

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Use case: Deploy a new version of a webapp so that all new users are sent to the new version while users with open sessions continue using the previous version (so that they don't loose their precious session state). Users of the new version can explicitely ask for the previous version in the case that it doesn't work as expected and vice versa.

Benefits: Get new features to users that need them as soon as possible without affecting anybody negatively and without risking that a defect will prevent users from achieving their goal (thanks to being able to fall back to the previous version).


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Are you using Puppet in the client-server setup and want to test the configuration for a particular node without actually changing it? You can do that by fooling Puppet Master into believing that a Vagrant virtual machine (VM) is that node and applying it there. The process is simple: you essentially only need to get the nodes' cert/private key and supply them to Puppet (and likely make sure that the hostname puppet can be resolved from within the VM). Let's see it in detail.


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Sorry folks, this month it will be very brief. I have many more great stuff in the queue but haven't managed to write it down yet. Next month will be heavy :-)

Recommended Readings

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All Clojure REPL variants (nREPL, REPLy, ..) share some common characteristics, inherited from clojure.main
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This month focuses on languages and approaches (reactive programming, F#, Erlang, FP talks etc.), agile (need for speed, recommended books), Clojure/Linux/cloud tools and libs.

Recommended Readings

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Running a Java/Clojure app as a daemon on Linux used to be hard but is pretty simple with Ubuntu Upstart (docs). The short story:

1. Create an all-in one uberjar via "lein with-profile production ring uberjar" (using the lein-ring plugin; a simple lein uberjar would suffice for an app with a main- method)
2. Create an upstart <service name>.conf file in /etc/init/
3. Run sudo start/stop/status <service name>

And of course it works with Puppet too.


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Setting up the new Google Universal Analytics (still in beta) is not completely obvious. You normally won't be able to send events from localhost and it will claim that "Tracking Not Installed." Here are some tips how to use Analytics from localhost and test it.


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