Glimpse of Google: Documentation

Welcome to Glimpse of Google, originally a blog series, this insightful collection is now available as a comprehensive eBook. Written by a former Google software engineer, it offers a firsthand look into the inner workings of one of the most transformative companies of our time. This series will uncover how Google operates from an engineering standpoint and explore the broader company culture, guiding principles, and unique approaches that make it a powerhouse in technology. Whether you're an engineer, a tech enthusiast, or simply curious, Glimpse of Google provides insider insights into what makes Google tick.

At Google, documentation transcends the realm of afterthoughts or neglected chores. Instead, it is elevated to the status of "code." This philosophical shift has profound implications for the quality, usability, and long-term value of their documentation efforts.

Let's unpack what it truly means to treat documentation as code. Firstly, it's about embracing the simplicity and universality of formats like markdown. This ensures documentation can be written, modified, and viewed with the same ease as code, without relying on clunky, proprietary editing tools. More importantly, documentation lives within the codebase. Imagine a developer navigating a complex system – explanations for architecture choices, system interactions, and potential gotchas are woven directly into the code they're viewing. No more frantic searches through outdated wikis or long-forgotten shared drives. This proximity creates frictionless access to vital information that helps engineers understand the code faster and with greater confidence.

Google understands that even the best documentation can decay over time. That's why they've integrated an "expiration date" system. When a new piece of documentation is added or significantly modified, it comes with a clear deadline for review – often six months after its creation. This deadline is not a punishment but rather a gentle mechanism to prevent knowledge rot. After the expiration, the author is notified and either updates the documentation to reflect the current state of the code or, if nothing significant has changed, intentionally extends the expiration date. This built-in safeguard ensures that the documentation remains a reliable and trustworthy companion to the ever-evolving code.

Furthermore, Google's approach integrates seamlessly with its core code review processes. Just as a change to the code requires meticulous peer review, so too must changes to its corresponding documentation. This forces engineers to consider the importance of clarity and communication from the outset, not as an afterthought to be rushed through later. The result is a continuous cycle of quality control, ensuring the documentation reflects the true intention of the code and helps others understand it effortlessly.

Google's internal code search and browsing tool, called Code Search, is where this approach truly shines. This sophisticated system doesn't just index code for quick access. It treats the embedded documentation as first-class citizens, presenting relevant explanations and guides alongside relevant code. The user experience is seamless and intuitive, encouraging engineers to engage with the documentation naturally as they explore and work within the codebase. This streamlines their workflow and minimizes the feeling of being lost in an indecipherable sea of logic.

The benefits extend further than just saving time. By treating documentation as a living, evolving, and thoroughly reviewed part of the code, Google fosters a culture where knowledge sharing is valued and embedded into its daily processes. It promotes a mindset of "writing for the next engineer," knowing that a well-explained piece of code is an investment that pays dividends long after the original author has moved on to new challenges. Additionally, newcomers have a vital resource to support their onboarding experience, allowing them to ramp up faster and make meaningful contributions sooner.

In essence, Google's approach transforms documentation from a mere technicality into a fundamental pillar of its engineering philosophy. It underscores their understanding that truly great software requires not just functioning code but also a clear, well-maintained map that guides both current and future generations of engineers on their journey to build amazing things.