第 3 章 工作代码是不够的

Chapter 3 Working Code Isn’t Enough (Strategic vs. Tactical Programming)

One of the most important elements of good software design is the mindset you adopt when you approach a programming task. Many organizations encourage a tactical mindset, focused on getting features working as quickly as possible. However, if you want a good design, you must take a more strategic approach where you invest time to produce clean designs and fix problems. This chapter discusses why the strategic approach produces better designs and is actually cheaper than the tactical approach over the long run.

好的软件设计中最重要的元素之一是您在执行编程任务时所采用的思维方式。许多组织都鼓励采取战术思维方式，着眼于使功能尽快运行。但是，如果您想要一个好的设计，则必须采取更具战略性的方法，在此上花费时间来制作干净的设计并解决问题。本章讨论了从长远来看，为什么战略方法可以产生更好的设计，而实际上却比战术方法便宜。

3.1 Tactical programming 战术编程

Most programmers approach software development with a mindset I call tactical programming. In the tactical approach, your main focus is to get something working, such as a new feature or a bug fix. At first glance this seems totally reasonable: what could be more important than writing code that works? However, tactical programming makes it nearly impossible to produce a good system design.

大多数程序员以我称为战术编程的心态来进行软件开发（针对大多数的开发人员的编码时的思维方式，作者称之为战术式编码）。在战术方法中，您的主要重点是使某些功能正常工作，例如新功能或错误修复。乍一看，这似乎是完全合理的：还有什么比编写有效的代码更重要的呢？但是，战术编程几乎不可能产生出良好的系统设计。

The problem with tactical programming is that it is short-sighted. If you’re programming tactically, you’re trying to finish a task as quickly as possible. Perhaps you have a hard deadline. As a result, planning for the future isn’t a priority. You don’t spend much time looking for the best design; you just want to get something working soon. You tell yourself that it’s OK to add a bit of complexity or introduce a small kludge or two, if that allows the current task to be completed more quickly.

战术编程的问题是它是短视的。如果您是战术编程人员，那么您将尝试尽快完成任务。也许您有一个艰难的期限。因此，为未来做计划不是优先事项。您不会花费太多时间来寻找最佳设计。您只想尽快使某件事起作用。您告诉自己，可以增加一些复杂性或引入一两个小错误，如果这样可以使当前任务更快地完成，则可以。（多数人还会自我安慰，如果可以让功能尽快上线的话，提高一些复杂度或者引入一两个小问题不是什么大不了的事情）

This is how systems become complicated. As discussed in the previous chapter, complexity is incremental. It’s not one particular thing that makes a system complicated, but the accumulation of dozens or hundreds of small things. If you program tactically, each programming task will contribute a few of these complexities. Each of them probably seems like a reasonable compromise in order to finish the current task quickly. However, the complexities accumulate rapidly, especially if everyone is programming tactically.

这就是系统变得复杂的方式。如上一章所述，复杂度是递增的。不是使系统复杂的特定事物，而是数十或数百个小事物的积累（复杂性的提升，不是由一个特定的事物引起的，而是由数十或成百的小事物积累导致的）。如果您进行战术编程（如果编码时总是使用战术式思维方式），则每个编程任务都会带来一些此类复杂性。为了快速完成当前任务，他们每个人似乎都是一个合理的折衷方案。但是，复杂性迅速累积，尤其是如果每个人都在战术上进行编程的时候。

Before long, some of the complexities will start causing problems, and you will begin to wish you hadn’t taken those early shortcuts. But, you will tell yourself that it’s more important to get the next feature working than to go back and refactor existing code. Refactoring may help out in the long run, but it will definitely slow down the current task. So, you look for quick patches to work around any problems you encounter. This just creates more complexity, which then requires more patches. Pretty soon the code is a mess, but by this point things are so bad that it would take months of work to clean it up. There’s no way your schedule can tolerate that kind of delay, and fixing one or two of the problems doesn’t seem like it will make much difference, so you just keep programming tactically.

不久之后，某些复杂性将开始引起问题，并且您将开始希望您没有采用这些早期的捷径。但是，您会告诉自己，使下一个功能正常工作比返回并重构现有代码更为重要。从长远来看，重构可能会有所帮助，但是肯定会减慢当前的任务。因此，您需要快速修补程序来解决遇到的任何问题。这只会增加复杂性，然后需要更多补丁。很快代码变得一团糟，但是到现在为止，情况已经很糟糕了，清理它需要花费数月的时间。您的日程安排无法容忍这种延迟，解决一个或两个问题似乎并没有太大的区别，因此您只是在战术上保持编程。

If you have worked on a large software project for very long, I suspect you have seen tactical programming at work and have experienced the problems that result. Once you start down the tactical path, it’s difficult to change.

如果您从事大型软件项目的时间很长，我怀疑您在工作中已经看到了战术编程，并且遇到了导致的问题。一旦您沿着战术路线走，就很难改变。

Almost every software development organization has at least one developer who takes tactical programming to the extreme: a tactical tornado. The tactical tornado is a prolific programmer who pumps out code far faster than others but works in a totally tactical fashion. When it comes to implementing a quick feature, nobody gets it done faster than the tactical tornado. In some organizations, management treats tactical tornadoes as heroes. However, tactical tornadoes leave behind a wake of destruction. They are rarely considered heroes by the engineers who must work with their code in the future. Typically, other engineers must clean up the messes left behind by the tactical tornado, which makes it appear that those engineers (who are the real heroes) are making slower progress than the tactical tornado.

几乎每个软件开发组织都有至少一个将战术编程发挥到极致的开发人员：战术龙卷风。战术龙卷风是一位多产的程序员，他抽出代码的速度比其他人快得多，但完全以战术方式工作。实施快速功能时，没有人能比战术龙卷风更快地完成任务。在某些组织中，管理层将战术龙卷风视为英雄。但是，战术龙卷风留下了毁灭的痕迹。他们很少被将来必须使用其代码的工程师视为英雄。通常，其他工程师必须清理战术龙卷风留下的混乱局面，这使得那些工程师（他们是真正的英雄）的进步似乎比战术龙卷风慢。

3.2 Strategic programming 战略规划

The first step towards becoming a good software designer is to realize that working code isn’t enough. It’s not acceptable to introduce unnecessary complexities in order to finish your current task faster. The most important thing is the long-term structure of the system. Most of the code in any system is written by extending the existing code base, so your most important job as a developer is to facilitate those future extensions. Thus, you should not think of “working code” as your primary goal, though of course your code must work. Your primary goal must be to produce a great design, which also happens to work. This is strategic programming.

成为一名优秀的软件设计师的第一步是要意识到 能跑起来的的代码是不够的。引入不必要的复杂性以更快地完成当前任务是不可接受的。最重要的是系统的长期结构。任何系统中的大多数代码都是通过扩展现有代码库编写的，因此，作为开发人员，最重要的工作就是促进这些将来的扩展。因此，尽管您的代码当然必须工作，但您不应将“工作代码”视为主要目标。您的主要目标必须是制作出出色的设计，并且这种设计也会起作用。这是 战略计划。

Strategic programming requires an investment mindset. Rather than taking the fastest path to finish your current project, you must invest time to improve the design of the system. These investments will slow you down a bit in the short term, but they will speed you up in the long term, as illustrated in Figure 3.1.

战略性编程需要一种投资心态。您必须花费时间来改进系统的设计，而不是采取最快的方式来完成当前的项目。这些投资会在短期内让您放慢脚步，但从长远来看会加快您的速度，如图 3.1 所示。

Some of the investments will be proactive. For example, it’s worth taking a little extra time to find a simple design for each new class; rather than implementing the first idea that comes to mind, try a couple of alternative designs and pick the cleanest one. Try to imagine a few ways in which the system might need to be changed in the future and make sure that will be easy with your design. Writing good documentation is another example of a proactive investment.

一些投资将是积极的。例如，值得花一些时间为每个新类找到一个简单的设计。而不是实施想到的第一个想法，请尝试几种替代设计并选择最简洁的设计。试想一下将来可能需要更改系统的几种方式，并确保设计容易。编写好的文档是主动投资的另一个例子。

Other investments will be reactive. No matter how much you invest up front, there will inevitably be mistakes in your design decisions. Over time, these mistakes will become obvious. When you discover a design problem, don’t just ignore it or patch around it; take a little extra time to fix it. If you program strategically, you will continually make small improvements to the system design. This is the opposite of tactical programming, where you are continually adding small bits of complexity that cause problems in the future.

其他投资将是被动的。无论您预先投入多少，设计决策中都不可避免地会出现错误。随着时间的流逝，这些错误将变得显而易见。发现设计问题时，不要只是忽略它或对其进行修补。花一些额外的时间来修复它。如果您进行战略性编程，则将不断对系统设计进行小幅改进。这与战术编程相反，在战术编程中，您不断增加一些复杂性，这些复杂性将来会引起问题。

3.3 How much to invest? 投资多少？

So, what is the right amount of investment? A huge up-front investment, such as trying to design the entire system, won’t be effective. This is the waterfall method, and we know it doesn’t work. The ideal design tends to emerge in bits and pieces, as you get experience with the system. Thus, the best approach is to make lots of small investments on a continual basis. I suggest spending about 10–20% of your total development time on investments. This amount is small enough that it won’t impact your schedules significantly, but large enough to produce significant benefits over time. Your initial projects will thus take 10–20% longer than they would in a purely tactical approach. That extra time will result in a better software design, and you will start experiencing the benefits within a few months. It won’t be long before you’re developing at least 10–20% faster than you would if you had programmed tactically. At this point your investments become free: the benefits from your past investments will save enough time to cover the cost of future investments. You will quickly recover the cost of the initial investment. Figure 3.1 illustrates this phenomenon.

那么，正确的投资额是多少？大量的前期投资（例如尝试设计整个系统）将不会有效。这是瀑布方法，我们知道它不起作用。随着您对系统的了解，理想的设计趋于零碎出现。因此，最好的方法是连续进行大量小额投资 ​​。我建议您将总开发时间的 10％到 20％用于投资。该金额足够小，不会对您的日程安排产生重大影响，但又足够大，可以随着时间的推移产生重大收益。因此，您的初始项目将比纯战术方法花费 10-20％的时间。额外的时间将带来更好的软件设计，并且您将在几个月内开始体验到这些好处。不久之后，您的开发速度将比战术编程快至少 10–20％。在这一点上，您的投资将免费：您过去投资的收益将节省足够的时间来支付未来投资的费用。您将迅速收回初始投资的成本。图 3.1 说明了这种现象。

Figure 3.1: At the beginning, a tactical approach to programming will make progress more quickly than a strategic approach. However, complexity accumulates more rapidly under the tactical approach, which reduces productivity. Over time, the strategic approach results in greater progress. Note: this figure is intended only as a qualitative illustration; I am not aware of any empirical measurements of the precise shapes of the curves.

图 3.1：一开始，战术性的编程方法将比战略性方法更快地取得进展。但是，在战术方法下，复杂性积累得更快，从而降低了生产率。随着时间的流逝，战略方针会带来更大的进步。注意：此图仅用于定性说明；我不知道对曲线精确形状的任何经验测量。

Conversely, if you program tactically, you will finish your first projects 10–20% faster, but over time your development speed will slow as complexity accumulates. It won’t be long before you’re programming at least 10–20% slower. You will quickly give back all of the time you saved at the beginning, and for the rest of system’s lifetime you will be developing more slowly than if you had taken the strategic approach. If you haven’t ever worked in a badly degraded code base, talk to someone who has; they will tell you that poor code quality slows development by at least 20%.

相反，如果您进行战术编程，则可以将第一个项目完成的速度提高 10％到 20％，但是随着时间的推移，复杂性的累积会降低开发速度。不久之后，您的编程速度至少会降低 10–20％。您将很快退回在开始时节省的所有时间，并且在系统的整个生命周期中，与采用策略性方法相比，您的开发速度将更加缓慢。如果您从未使用过严重降级的代码库，请与有经验的人联系。他们会告诉您不良的代码质量会使开发速度至少降低 20％。

3.4 Startups and investment 创业与投资

In some environments there are strong forces working against the strategic approach. For example, early-stage startups feel tremendous pressure to get their early releases out quickly. In these companies, it might seem that even a 10–20% investment isn’t affordable. As a result, many startups take a tactical approach, spending little effort on design and even less on cleanup when problems pop up. They rationalize this with the thought that, if they are successful, they’ll have enough money to hire extra engineers to clean things up.

在某些环境中，强大的力量与战略方法背道而驰。例如，早期的初创公司感到巨大的压力，需要尽快发布其早期版本。在这些公司中，甚至 10％至 20％的投资似乎也负担不起。结果，许多初创公司采取了战术性的方法，在设计上花费了很少的精力，而在问题出现时则花费了更少的精力进行清理。他们认为，如果成功，他们将有足够的钱聘请额外的工程师来清理问题，从而使其合理化。

If you are in a company leaning in this direction, you should realize that once a code base turns to spaghetti, it is nearly impossible to fix. You will probably pay high development costs for the life of the product. Furthermore, the payoff for good (or bad) design comes pretty quickly, so there’s a good chance that the tactical approach won’t even speed up your first product release.

如果您是一家朝着这个方向发展的公司，则应该意识到，一旦代码库变成了意大利面条，几乎是不可能修复的。您可能会为产品的使用寿命付出高昂的开发成本。此外，好的（或坏的）设计的回报很快就会到来，因此战术方法很有可能甚至不会加快您的首个产品发布的速度。

Another thing to consider is that one of the most important factors for success of a company is the quality of its engineers. The best way to lower development costs is to hire great engineers: they don’t cost much more than mediocre engineers but have tremendously higher productivity. However, the best engineers care deeply about good design. If your code base is a wreck, word will get out, and this will make it harder for you to recruit. As a result, you are likely to end up with mediocre engineers. This will increase your future costs and probably cause the system structure to degrade even more.

要考虑的另一件事是，公司成功的最重要因素之一就是工程师的素质。降低开发成本的最佳方法是聘请优秀的工程师：他们的成本不会比普通工程师高很多，但生产率却高得多。但是，最好的工程师对良好的设计深感兴趣。如果您的代码库很残酷，那么单词会变得毫无用处，这将使您难以招募（如果公司的代码已经无法用言语来表达的糟糕，你的招聘也会相应增加难度）。最终可能还是只能使用普通的工程师。这将增加您的未来成本，并可能导致系统结构进一步退化。

Facebook is an example of a startup that encouraged tactical programming. For many years the company’s motto was “Move fast and break things.” New engineers fresh out of college were encouraged to dive immediately into the company’s code base; it was normal for engineers to push commits into production in their first week on the job. On the positive side, Facebook developed a reputation as a company that empowered its employees. Engineers had tremendous latitude, and there were few rules and restrictions to get in their way.

Facebook 是一个鼓励战术编程的创业公司的例子。多年来，公司的座右铭是“快速行动并打破困境”。鼓励刚大学毕业的新工程师立即深入公司的代码库；工程师在工作的第一周将承诺投入生产是很正常的。从积极的一面来看，Facebook 作为一家赋予员工权力的公司而享有声誉。工程师拥有极大的自由度，并且几乎没有任何规则和限制。

Facebook has been spectacularly successful as a company, but its code base suffered because of the company’s tactical approach; much of the code was unstable and hard to understand, with few comments or tests, and painful to work with. Over time the company realized that its culture was unsustainable. Eventually, Facebook changed its motto to “Move fast with solid infrastructure” to encourage its engineers to invest more in good design. It remains to be seen whether Facebook can successfully clean up the problems that accumulated over years of tactical programming.

Facebook 作为一家公司已经取得了令人瞩目的成功，但是由于该公司的战术方法，其代码库受到了影响（同样由于公司的战术编程推广，Facebook 的代码库深受其害）。许多代码不稳定且难以理解，几乎没有注释或测试，并且使用起来很痛苦。随着时间的流逝，该公司意识到其文化是不可持续的。最终，Facebook 改变了座右铭，即“以坚实的基础架构快速移动”，以鼓励其工程师在良好的设计上进行更多的投资。Facebook 是否能够成功清除多年来战术编程中积累的问题还有待观察。

In fairness to Facebook, I should point out that Facebook’s code probably isn’t much worse than average among startups. Tactical programming is commonplace among startups; Facebook just happens to be a particularly visible example.

为了公平起见，我应该指出，Facebook 的代码可能并不比初创公司的平均水平差很多。战术编程在初创企业中司空见惯。Facebook 恰好是一个特别明显的例子。

Fortunately, it is also possible to succeed in Silicon Valley with a strategic approach. Google and VMware grew up around the same time as Facebook, but both of these companies embraced a more strategic approach. Both companies placed a heavy emphasis on high quality code and good design, and both companies built sophisticated products that solved complex problems with reliable software systems. The companies’ strong technical cultures became well known in Silicon Valley. Few other companies could compete with them for hiring the top technical talent.

幸运的是，通过战略方法也有可能在硅谷取得成功。Google 和 VMware 与 Facebook 差不多同时成长，但是这两家公司都采用了更具战略意义的方法。两家公司都非常重视高质量的代码和良好的设计，并且两家公司都开发了复杂的产品，这些产品通过可靠的软件系统解决了复杂的问题。公司的强大技术文化在硅谷广为人知。很少有其他公司可以与他们竞争聘请顶级技术人才。

These examples show that a company can succeed with either approach. However, it’s a lot more fun to work in a company that cares about software design and has a clean code base.

这些例子表明，一家公司可以成功使用任何一种方法。但是，在一家关心软件设计并拥有清晰代码基础的公司中工作会有趣得多。

3.5 Conclusion 结论

Good design doesn’t come for free. It has to be something you invest in continually, so that small problems don’t accumulate into big ones. Fortunately, good design eventually pays for itself, and sooner than you might think.

好的设计不是免费的。它必须是您不断投资的东西，这样小问题才不会累积成大问题。幸运的是，好的设计最终会收回成本，而且比您想象的要早。

It’s crucial to be consistent in applying the strategic approach and to think of investment as something to do today, not tomorrow. When you get in a crunch it will be tempting to put off cleanups until after the crunch is over. However, this is a slippery slope; after the current crunch there will almost certainly be another one, and another after that. Once you start delaying design improvements, it’s easy for the delays to become permanent and for your culture to slip into the tactical approach. The longer you wait to address design problems, the bigger they become; the solutions become more intimidating, which makes it easy to put them off even more. The most effective approach is one where every engineer makes continuous small investments in good design.

始终如一地运用战略方法并将投资视为今天而不是明天要做的事情至关重要。当您陷入危机时，很容易推迟清理，直到危机结束之后。但是，这是一个湿滑的斜坡。在当前紧缩之后，几乎肯定会再出现一次。一旦开始延迟设计改进，就很容易使延迟永久化，并使您的文化陷入战术方法中。您等待解决设计问题的时间越长，问题就会变得越大；解决方案变得更加令人生畏，这使得轻松推迟解决方案变得更加容易。最有效的方法是，每位工程师都对良好的设计进行连续的少量投资。