Building from the Inside Out

One of my favorite questions to ask a customer's development or build manager when I go onsite is how often they release a new build process. I usually get long pauses or funny looks and then finally get the answer "Every day." Of course, as you might suspect, I am not talking about releasing a daily build, but a new build process. The fact that so many companies do not release new build processes on a regular basis does not surprise me. This is because traditionally creating a build process is an afterthought when all of the specifications of a project have been written. Many project and program managers think that the actual building of a project is pretty trivial. Their attitude is that they can simply have the developer throw his code over the wall and hire someone to press a Build button, and everything will be fine. At Microsoft, we understand that whether you're building the smallest application or something huge and complicated like Windows, you should plan and think through the process thoroughly in advance.

Again, I recommend that you consider the build process a piece of software that you regularly revise and deploy throughout your product team. You should also add to your project schedule some "cushion time" to allow for unforeseen build breaks or delays, I would at least pad the milestone dates one week for build issues.

The concept of "building from the inside out" tends to confuse customers who are not familiar with a centralized build process. The idea is that the Central Build Team determines what the build process is for a product and then publishes the policies to an internal build site. All development teams in the project must comply with the Central Build Team process; otherwise, their code check-in is not accepted and built. Unfortunately, this concept is usually the complete opposite of how a build system for a project actually evolves over time. The Central Build Team for a project usually goes out of its way to accommodate the way developers build their code. "Building from the inside out" means that the Central Build Team figures out the best way to get daily builds released, and everyone uses that process independently or in parallel with the way his specific development team builds. This total change in development philosophy or religion can be a culture shock to some groups. I talk more about changing a company's culture or philosophy in Chapter 18, "Future Build Tools from Microsoft." For now, let's stay on the topic of builds.

What we did in the past in the Windows group and what they still do today is to deploy new releases of the build process at major milestones in the project life cycle. Sometimes the new releases involve tool changes such as compilers, linkers, and libraries. At other times, there are major changes such as a new source code control tool or a bug tracker.

Because a build lab tends to have some downtime while the build team waits for compiles, links, and tests to finish, it should take advantage of these slow times to work on improvements to the build process. After the lab tests the improvements and confirms they are ready for primetime, it rolls out the changes. One way to deploy a new build process after a shipping cycle is to send a memo to the whole team pointing to an internal Web site that has directions on the new process that the Central Build Team will be using in future product builds.

Microsoft Sidenote: Developers in a Build Lab

Today, the Windows build lab has its own development team working on writing and maintaining new and old project tools. The development team also works on deploying new build processes. Conversely, of the more than 200 customers I've spoken to, only one or two of them have developers working in a build team.

Remember Danny's quote at the beginning of this chapter and notice the date 1991. In 1991, Windows NT had only a few hundred thousand lines of code, unlike the more than 40 million lines of code that Windows XP has today. Even in the early stages of developing Windows NT, Microsoft recognized the importance of a good build process.

Chapter 3, "Daily, Not Nightly, Builds," covers in more detail the importance of the build team being the driving force to successfully ship a product.