(Cross-posted from the Klotho web site)
This blog post is a high level overview on the reasons to refactor code and systems in a startup setting. We cover risks, approaches and tradeoffs to consider in 2022.
How to judge when the cost is worth the gains
Be honest with yourself
The temptation will always be to refactor: real-world code is messy, and engineers don’t like messy code. Make sure there’s a business case for refactoring by measuring how much time the team is spending on directly customer-visible features.
Our research shows that mid-sized companies and fast-growing startups spend 39% of engineering capacity on undifferentiated work, like infrastructure. Split stories into sub-tasks like infrastructure and refactoring so you can measure where your time is going.
Well-structured is well-maintained
Clear boundaries between modules make them easier to test, deploy, and monitor. Keep an eye on customer-reported bugs, service latency, and how often you have to revert code. On the other end of the software lifecycle, there are multiple indicators that you’re trending towards a bottleneck: how much time it takes to go from design to shipped, the degree of engineering satisfaction and raising infrastructure costs — these can all be leading indicators that you’ve built up debt.
Inflection points in the businesses
Code bases tend to organize themselves on three dimensions: team size, pace of new features, and number of customers. When these numbers change significantly, it may be time to look at splitting up components.
If you’re growing the team or increasing the rate of feature development, the limiting factor will be the code’s readability. Start with targeted, opportunistic refactoring. If your customer base is growing, you may need more scalable technologies or workflows.
Control what you can, plan for the rest
Choosing right won’t prevent re-architecting
Refactoring and re-architecture doesn’t mean you made a bad choice earlier. More often, the driving forces behind re-architecture are tied to requirement changes or external factors. There are at least 4 significant dimensions that will force a re-architecture over the lifetime of a product: new feature development rate, engineering team size, the amount of time spent on undifferentiated work, and customer growth. Each of these is progressively harder to directly control.
Start with the easy dials…
f the four dimensions, the two that are easiest to control are the rate of new features and the engineering team’s size. You can control the rate of new features by being stricter about planning and prioritization. Scaling the team is a slower process, but it’s usually one you can at least plan for.
If both the team and the rate of new features is small, refactoring is unlikely to have a significant impact on the business. At the other end of the spectrum, a large team working on many features may benefit from reorganizing into smaller teams — and you should consider refactoring or re-architecting the code to match. An architecture that enables cleaner organizational and code boundaries will allow the product and company to scale.
…and then move onto the harder ones
The amount of time your team spends on undifferentiated work can be hard to rein in, and customer growth is the hardest measure of all to affect. If these were easy, everyone would minimize undifferentiated work and maximize customer growth! Still, you can
get ahead of problems with a careful and proactive approach to refactoring.
The first step is knowing when not to refactor. If your customer growth and amount of time spent on undifferentiated work is low, don’t spend time on refactoring: focus instead on impactful, customer-visible features. Similarly, if you have good customer growth and low amount of undifferentiated work, your team is doing well. Consider tactical refactoring to avoid the amount of undifferentiated work from growing, but don’t spend too much time on it.
If your team is spending too much time on undifferentiated work, it’s time to revisit the architecture to one that scales better to where your company is today.
If your customer adoption is lower, your priority should be a cheaper architecture that will give you more runway.
If both your customer adoption and the amount of time your team spends on undifferentiated work are high, it may be time to focus on a centralized, optimized solution. This typically takes the form of a dedicated operations team that can efficiently execute on infrastructure tasks. This is a great problem to have — so take a moment to congratulate yourself and your team for getting here!
Have a target, then find shortcuts to get there
Have a plan, even if it’s not perfect
Once you’ve committed to a re-architecture, don’t be afraid to think big. Lean on your engineers to come up with an end-state they’d love, and then pare it down as needed. Chances are, the opportunity for a major re-architecture will only come once or twice in a product’s lifecycle, so be prepared to live with any compromise you make. But by the same token, know that even the best laid plans will go awry as you start implementing.
Make big plans, take little steps
Once you know where you want the code to be, be tactical about how to get it there. Work one one component at a time, or pick components that are as far away as possible from each other. If you haven’t already invested in solid testing, both at the unit and system level, now’s the time. Tests will give you confidence that your changes won’t break existing customer experiences, but they can also help your team come up with its definition of done. When the tests pass, the component is ready!
The best technology is the one you can adapt
The key to reducing the impact of refactoring and re-architecting on startups in particular is to use technology that is adaptable.
Historically, companies choose specific technologies like VMs, serverless, or containers to host their applications. The problem is that switching from one technology to another is prohibitively expensive, and what you need today may not be what you need tomorrow.
An adaptive architecture is one that lets you host your application on any technology equally easily. This lets you adjust the hosting environment on the fly, to match your current needs. Specific technology choices like AWS Lambda, Fargate, Kubernetes, gRPC, Linkerd, Azure/GCP become interchangeable.
By reusing existing programming language constructs like functions and event handlers, as well as interfaces that are idiomatic to each language, adaptive architectures make cloud services easier to use.
Look for abstractions and tools that are lightweight, but flexible enough to let you switch technologies. We think Klotho annotations fit the bill, since they let you separate your architecture’s semantic meaning from the deployment configuration — but with enough investment in runtime libraries and infrastructure automation, you can build out a similar solution yourself.