Installing TeamCity on Gentoo Linux

If you haven’t heard of Continuous Integration yet, it’s the practice of setting up an automated system that rebuilds projects automatically whenever someone commits a new change to your source code repository. It ensures that whatever is in your repository builds and runs: automated builds usually involve compiling, running unit tests and packaging the installer.

Official TeamCity logo depicting a blue T and orange C

To do continuous integration, you need a tool that monitors your source code repository and starts the builds – a continuous integration server. My weapon of choice is TeamCity, a free CI server written in Java with first-class support for .NET and its toolchain (like NAnt, NUnit, NCover or PartCover).

TeamCity is pretty easy to deploy – the Windows package has an installer which leaves you with a fully working server after just a few clicks and even the Linux package is pretty simple to deploy: Download, unzip, run and you’re done. To properly integrate it into a Linux server (so it will come back up after rebooting and can be reached via HTTP without having to run either Apache or TeamCity on a non-standard port), you’ll need to run your own Tomcat server.

This guide will tell you how to do it!

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Mailing Lists with Couriermlm

Courier not only is an excellent mail server, it also ships with a mailing list manager that can be used to build mailing lists without relying on a third party provider (which usually has the bad habit of adding advertising text to the emails being forwarded).

Here’s a small tutorial that explains how to set up a new mailing list using couriermlm.

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Game Architecture Day 2

Logo of the XNA Game Game Architecture tutorial series, three interlocked gears

Stylish logo of two engaged gears with the text XNA Game Architecture

Welcome to day 2 of the XNA Game Architecture series!

I have thought hard about whether I should just assume a certain level of object oriented programming knowledge in this series. People picking up these articles likely already have some knowledge about objects and design, so I settled on a quick run-over of the principles that hopefully won’t bore the seasoned developers and provide a good reference for people just starting out!

If you already know all this, feel free to skip ahead until it becomes interesting again or to the next chapter ;)!

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Integrating SpamAssassin into Courier

Please excuse the current flurry of Linux articles. I’m moving servers and this is my way of writing notes to myself and possibly helping out others. Normal service will resume shortly 😉

This article is a follow-up to my guide on Installing Courier on Gentoo. As long as you have a working Courier installation on your system, there should be no issues following this guide.

Drawing of an arrow piercing through a stack of mail envelopes

Running a mail server without some kind of spam filtering is just insane these days. SpamAssassin is a nice solution, especially if you run SpamAssassin during the SMTP transaction to reject spam while it is being uploaded to your server.

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Installing Courier on Gentoo

On my previous system, I had used qmail (netqmail actually, which is qmail with some patches). Qmail is moderately difficult to set up and in its 3 years lifespan on my system, it has broken down on several occasions. That’s why I decided to use another mail server when I moved my domains to a different system.

Because the Courier IMAP server has never let me down before, I decided to give the Courier Mail Server a chance. Lots of people are using Courier IMAP to access their mail but Exim, Postfix or Qmail to accept incoming emails. Even the Gentoo Wiki contains various HowTos for these combinations, but not a single one for a homogenous Courier setup. After trying out Courier, I don’t see why, so this is my attempt to rectify the situation (and to remember what needs to be done for the next time I’m moving my domains to another system!)

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Installing wTorrent on Gentoo

If you want to download torrents on your Linux system, there are several clients to choose from. One of the nicest and fastest clients is rTorrent. It is full-featured, supports encryption, dynamic host table exchange and achieves fantastic download speeds.

But its best feature probably is that it isn’t bound to any windowing toolkit. You can install one of its GUI frontends to manage it on your fancy KDE 4 desktop machine, but you can also run it on a headless system and manage torrent from a text-only console. And if you happen to run it on a home server like me, there’s wTorrent, a beaufitful AJAX-driven web frontend that allows you to manage your torrents in your browser.

Screenshot of the wTorrent web frontend for rTorrent

Installing wTorrent isn’t the easiest thing to do, so, as when I tried to get the best out of my SSD, I decided to write this small article explaining how to do it. I’m using Gentoo Linux, but it shouldn’t be too hard to apply this article to another Linux distribution.

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Game Architecture Day 1

Logo of the XNA Game Game Architecture tutorial series, three interlocked gears

Stylish logo of two engaged gears with the text XNA Game Architecture

Welcome to day 1 of the XNA Game Architecture series! We’re about to create a small 3D Shoot ’em Up using the principles of modern software architecture.

If you missed the introduction, this series is about the architecture of games. Instead of focusing on a single concept, we’ll be focusing at how it all comes together and how you can keep your game’s code manageable and clean. You’ll be looking over my shoulder as I write a small game and explain why I do things one way and not the other 🙂

Today, I will start the project by creating a development tree that contains the actual XNA project and some third-party libraries I’m going to use within the game. Normally, I would add those libraries as I go, but I’ve got a pretty clear idea for this project and it will be easier for you because I can just package them all in a handy zip archive which you’ll find at the end of this article.

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Aligning an SSD on Linux

I’ve got a small home server with a software RAID-5 for storing my files. It also runs a few virtual machines and acts as a NAT router for internet access. Nothing expensive, just some Frankensteinian patchwork built from old hardware left over when I upgraded my workstation. Nevertheless, I granted it a brand new Intel X25-M SSD last week.

Photo of an Intel X25-M SSD drive, which is a metal box smaller than a CD case

Did I mention that this server is running Gentoo Linux? I thought this would be a good time to do a fresh install and get everything right that might have gone wrong the first time. Besides, installing Linux always is an interesting (and masochistic) experience, especially when your chosen distribution has no installer 🙂

Because getting my partitions and file systems aligned also proved to be difficult task, I thought why not make a small article out of this!

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Game Architecture Series

Stylish logo of two engaged gears with the text XNA Game Architecture


I’m planning to start a short article series:

There are a lot of XNA tutorials out there that explain the basics – how to display a sprite, how to do collision detection and how to render a bunch of colorful particles with additive blending. But there aren’t many articles that explain to you how you’re supposed to put it all together – how to structure a game so that it is easy to extend and remains manageable when the amount of code begins to grow.

The discipline that deals with this issue is called software architecture. Like programming, or any other creative process, it relies a lot on tacit knowledge – finding a good solution without first running down an alley of dead ends (that you can identify using the Principles of Object-Oriented Design) requires a lot of experience.

What I will do in this series is let you look over my shoulder as I design a small game and try to explain my motivations for choosing one design over another while I do so. This will give you a solid starting point and an understanding of the design process that you can apply to your own game projects.

The Meaning of 100% Test Coverage

When I release components, example code or even just helper classes, I often tout 100% test coverage as a feature. Which (as I probably also state often enough :P), means that my unit tests execute 100% of all lines in the source code. But what advantage does this actually bring to a developer, and, just as interesting, what does having complete test coverage not mean?

For people practicing true TDD (test first -> red, green, refactor), 100% coverage is nothing unusual, though even they may decide to not write tests for all invalid inputs possible: if a piece of code satisfies all the tests and the tests cover everything the code should do, it’s enough. If you’re building a library on the other side, the use case of a customer providing invalid inputs will be a valid concern worthy of a test.

I, however, am currently adding unit tests to an existing code base and I decided to go for 100% test coverage. In this short article, I will explain why I see complete test coverage as a worthwhile goal, what effect going for that level of test coverage has on a project and what it says about the code.

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