Agile 101: Automated Build Scripts (ABS) defined

What is ABS?

Automated Build Scripts (ABS) provide an ability to build software in an unattended and machine-independent environment. ABS are generally written and maintained by a special group of developers called configuration managers, or software integrators or just application builders. Some of the tools used to write ABS are Ant, NAnt, Maven, MSBuild, Visual Build Pro, and make.

Automated builds are one of the most important practices for any Agile team. They help developers see the effects of any change immediately and make it possible to deliver working software at the end of each iteration. The need for ABS is even more pronounced in distributed Agile teams because multiple people build simultaneously and in the absence of a common team room it is paramount that every change is properly integrated into the build. This is a fundamental attribute of a well designed automated build system since it helps keep the repository coherent and the code base buildable.

Other important features of good ABS are:

• Allow a system to be built on any machine while requiring minimal (properties) or no changes to the base scripts - in most Agile teams it is more than likely that teams will have different machine settings such as OS, language, IDE. The ABS should be machine- and environment-independent.
• ABS should be easy to plug-in to a Continuous Integration (CI) sever - this is especially important for distributed and offshore Agile teams as the time zone differences make it necessary to build continuously and notify the teams of any problems early. ABS written in Ant or Maven for instance, allow for automated and unattended execution, making them a perfect choice for CI.
• Ability to execute ABS with a simple shell command - both the architect and the developers should be able to trigger a full build with a simple shell command. The best ABS are designed to be simple and guiding the user through the steps so that even relatively non-technical team members such as business analysts and project managers are able to stand-up a system with minimal help from the rest of the team.
• Ability to define and manage project dependencies. These are both compile-time dependencies such as libraries as well-as deploy-time dependencies such database scripts and XML configuration files. In highly collaborative Agile projects the DB servers and XML configurations are likely to change often, so a good ABS should take care of the dependencies in a transparent manner.