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Infrastructure Engineering in the 21st Century

Infrastructure engineering is an inherently treacherous problem space because it’s core to so many things. Systems today are increasingly distributed and increasingly complex but are built on unreliable components and will continue to be. This includes unreliable networks and faulty hardware. The 21st century engineer understands failure is routine.

Naturally, application developers would rather not have to think about low-level failure modes so they can focus on solving the problem at hand. Infrastructure engineers are then tasked with competing goals: provide enough abstraction to make application development tractable and provide enough reliability to make subsystems useful. The second goal often comes with an additional proviso in that there must be sufficient reliability without sacrificing performance to the point of no longer being useful. Anyone who has worked on enterprise messaging systems can tell you that these goals are often contradictory. The result is a wall of sand intended to keep the developer’s feet dry from the incoming tide. The 21st century engineer understands that in order to play in the sand, we all need to be comfortable getting our feet a little wet from time to time.

With the deluge of technology becoming available today, it’s tempting to introduce it all into your stack. Likewise, engineers are never happy. Left unchecked, we will hyper optimize and iterate into oblivion. It’s a problem I call “innovating to a fault.” Relying on “it’s done when it’s done” is a great way to ship vaporware. Have tangible objectives, make them high-level, and realize things change and evolve over time. Frame the concrete things you’re doing today within the context of those objectives. There’s a difference between Agile micromanagey roadmaps and having a clear vision. Determine when to innovate and when not to. Not Invented Here syndrome can be a deadly disease. Take inventory of what’s being built, make sure it ties back to your objectives, and avoid falling prey to tech pop culture. Optimize for the right problems. The 21st century engineer understands that you are not defined by your tools, you are defined by what you produce at the end of the day.

The prevalence of microservice architecture has made production tooling and instrumentation more important than ever. Teams should take ownership of their systems. If you’re not willing to stand by your work, don’t ship it. However, just because something falls outside of your system’s boundaries doesn’t mean it’s not your problem. If you rely on it, own it. Don’t be afraid to roll up your sleeves and dive into someone else’s code. The 21st century engineer understands that they live and die by the code they have in production, and if they don’t run anything in production, they aren’t really an engineer at all.

The way in which we design systems today is different from the way we designed them in the 20th century and the way we will design them in the future. There is a vast amount of research that has gone into computer science and related fields dating back to the invention of the modern computer. Research from the 50’s, 60’s, all the way up to today shows that system design always is an evolving process. Compiling this body of knowledge together provides an invaluable foundation from which we can build. The 21st century engineer understands that without a deeper understanding of that foundation or with a blind trust, we are only as good as our sand castle.

It’s our responsibility as software engineers, as system designers, as programmers to use this knowledge. Our job is not to build systems or write code, our job is to solve problems, of which code is often a byproduct. No one cares about the code you write, they care about the problems you solve. More specifically, they care about the business problems you solve. The 21st century engineer understands that if we’re not thinking about our solutions end to end, we’re not really doing our job.

Engage to Assuage

Abstraction is important. It’s how humans deal with complexity. You shouldn’t have to understand every little intricate detail behind how your system works. It would take years to do so. But abstraction comes at a cost. You agree to the abstraction’s interface, you place your trust in it, and then you remove it from your mind. That is, until it fails—and abstractions of sufficient complexity will fail. After all, we are building atop unreliable components. Also, a layer of abstraction doesn’t provide any guarantees in higher levels above it, which often results in some false assumptions.

We cannot understand how everything will work, but we should have enough understanding of how it will not work. More plainly, we should understand the cost of the abstractions we use so that we can pay for them with confidence. This doesn’t mean giving up on abstraction but engaging with the complexity that it manages.

I’ve written before about how distributed systems are a UX problem. They’re also a design problem. And a development problem. And an ops problem. And a business problem. The point is they are everyone’s problem because they are complex, and things that are sufficiently complex eventually leak. There is no airtight abstraction in this world. Without understanding limitations and trade-offs, without using the knowledge and research that has come before us, without thinking end to end, we set ourselves up for failure. If we’re going to call ourselves engineers, let’s start acting like it. Nothing is a black box to the 21st century engineer.

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Designed to Fail

When it comes to reliability engineering, people often talk about things like fault injection, monitoring, and operations runbooks. These are all critical pieces for building systems which can withstand failure, but what’s less talked about is the need to design systems which deliberately fail.

Reliability design has a natural progression which closely follows that of architectural design. With monolithic systems, we care more about preventing failure from occurring. With service-oriented architectures, controlling failure becomes less manageable, so instead we learn to anticipate it. With highly distributed microservice architectures where failure is all but guaranteed, we embrace it.

What does it mean to embrace failure? Anticipating failure is understanding the behavior when things go wrong, building systems to be resilient to it, and having a game plan for when it happens, either manual or automated. Embracing failure means making a conscious decision to purposely fail, and it’s essential for building highly available large-scale systems.

A microservice architecture typically means a complex web of service dependencies. One of SOA’s goals is to isolate failure and allow for graceful degradation. The key to being highly available is learning to be partially available. Frequently, one of the requirements for partial availability is telling the client “no.” Outright rejecting service requests is often better than allowing them to back up because, when dealing with distributed services, the latter usually results in cascading failure across dependent systems.

While designing our distributed messaging service at Workiva, we made explicit decisions to drop messages on the floor if we detect the system is becoming overloaded. As queues become backed up, incoming messages are discarded, a statsd counter is incremented, and a backpressure notification is sent to the client. Upon receiving this notification, the client can respond accordingly by failing fast, exponentially backing off, or using some other flow-control strategy. By bounding resource utilization, we maintain predictable performance, predictable (and measurable) lossiness, and impede cascading failure.

Other techniques include building kill switches into service calls and routers. If an overloaded service is not essential to core business, we fail fast on calls to it to prevent availability or latency problems upstream. For example, a spam-detection service is not essential to an email system, so if it’s unavailable or overwhelmed, we can simply bypass it. Netflix’s Hystrix has a set of really nice patterns for handling this.

If we’re not careful, we can often be our own worst enemy. Many times, it’s our own internal services which cause the biggest DoS attacks on ourselves. By isolating and controlling it, we can prevent failure from becoming widespread and unpredictable. By building in backpressure mechanisms and other types of intentional “failure” modes, we can ensure better availability and reliability for our systems through graceful degradation. Sometimes it’s better to fight fire with fire and failure with failure.

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Service-Disoriented Architecture

“You can have a second computer once you’ve shown you know how to use the first one.” -Paul Barham

The first rule of distributed systems is don’t distribute your system until you have an observable reason to. Teams break this rule on the regular. People have been talking about service-oriented architecture for a long time, but only recently have microservices been receiving the hype.

The problem, as Martin Fowler observes, is that teams are becoming too eager to adopt a microservice architecture without first understanding the inherent overheads. A contributing factor, I think, is you only hear the success stories from companies who did it right, like Netflix. However, what folks often fail to realize is that these companies—in almost all cases—didn’t start out that way. There was a long and winding path which led them to where they are today. The inverse of this, which some refer to as microservice envy, is causing teams to rush into microservice hell. I call this service-disoriented architecture (or sometimes disservice-oriented architecture when the architecture is DOA).

The term “monolith” has a very negative connotation—unscalable, unmaintainable, unresilient. These things are not intrinsically tied to each other, however, and there’s no reason a single system can’t be modular, maintainable, and fault tolerant at reasonable scale. It’s just less sexy. Refactoring modular code is much easier than refactoring architecture, and refactoring across service boundaries is equally difficult. Fowler describes this as monolith-first, and I think it’s the right approach (with some exceptions, of course).

Don’t even consider microservices unless you have a system that’s too complex to manage as a monolith. The majority of software systems should be built as a single monolithic application. Do pay attention to good modularity within that monolith, but don’t try to separate it into separate services.

Service-oriented architecture is about organizational complexity and system complexity. If you have both, you have a case to distribute. If you have one of the two, you might have a case (although if you have organizational complexity without system complexity, you’ve probably scaled your organization improperly). If you have neither, you do not have a case to distribute. State, specifically distributed state, is hell, and some pundits argue SOA is satan—perhaps a necessary evil.

There are a lot of motivations for microservices: anti-fragility, fault tolerance, independent deployment and scaling, architectural abstraction, and technology isolation. When services are loosely coupled, the system as a whole tends to be less fragile. When instances are disposable and stateless, services tend to be more fault tolerant because we can spin them up and down, balance traffic, and failover. When responsibility is divided across domain boundaries, services can be independently developed, deployed, and scaled while allowing the right tools to be used for each.

We also need to acknowledge the disadvantages. Adopting a microservice architecture does not automatically buy you anti-fragility. Distributed systems are incredibly precarious. We have to be aware of things like asynchrony, network partitions, node failures, and the trade-off between availability and data consistency. We have to think about resiliency but also the business and UX implications. We have to consider the boundaries of distributed systems like CAP and exactly-once delivery.

When distributing, the emphasis should be on resilience engineering and adopting loosely coupled, stateless components—not microservices for microservices’ sake. We need to view eventual consistency as a tool, not a side effect. The problem I see is that teams often end up with what is essentially a complex, distributed monolith. Now you have two problems. If you’re building a microservice which doesn’t make sense outside the context of another system or isn’t useful on its own, stop and re-evaluate. If you’re designing something to be fast and correct, realize that distributing it will frequently take away both.

Like anti-fragility, microservices do not automatically buy you better maintainability or even scalability. Adopting them requires the proper infrastructure and organization to be in place. Without these, you are bound to fail. In theory, they are intended to increase development velocity, but in many cases the microservice premium ends up slowing it down while creating organizational dependencies and bottlenecks.

There are some key things which must be in place in order for a microservice architecture to be successful: a proper continuous-delivery pipeline, competent DevOps and Ops teams, and prudent service boundaries, to name a few. Good monitoring is essential. It’s also important we have a thorough testing and integration story. This isn’t even considering the fundamental development complexities associated with SOA mentioned earlier.

The better strategy is a bottom-up approach. Start with a monolith or small set of coarse-grained services and work your way up. Make sure you have the data model right. Break out new, finer-grained services as you need to and as you become more confident in your ability to maintain and deploy discrete services. It’s largely about organizational momentum. A young company jumping straight to a microservice architecture is like a golf cart getting on the freeway.

Microservices offer a number of advantages, but for many companies they are a bit of a Holy Grail. Developers are always looking for a silver bullet, but there is always a cost. What we need to do is minimize this cost, and with microservices, this typically means easing our way into it rather than diving into the deep end. Team autonomy and rapid iteration are noble goals, but if we’re not careful, we can end up creating an impedance. Microservices require organization and system maturity. Otherwise, they end up being a premature architectural optimization with a lot of baggage. They end up creating a service-disoriented architecture.

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Distributed Systems Are a UX Problem

Distributed systems are not strictly an engineering problem. It’s far too easy to assume a “backend” development concern, but the reality is there are implications at every point in the stack. Often the trade-offs we make lower in the stack in order to buy responsiveness bubble up to the top—so much, in fact, that it rarely doesn’t impact the application in some way. Distributed systems affect the user. We need to shift the focus from system properties and guarantees to business rules and application behavior. We need to understand the limitations and trade-offs at each level in the stack and why they exist. We need to assume failure and plan for recovery. We need to start thinking of distributed systems as a UX problem.

The Truth is Prohibitively Expensive

Stop relying on strong consistency. Coordination and distributed transactions are slow and inhibit availability. The cost of knowing the “truth” is prohibitively expensive for many applications. For that matter, what you think is the truth is likely just a partial or outdated version of it.

Instead, choose availability over consistency by making local decisions with the knowledge at hand and design the UX accordingly. By making this trade-off, we can dramatically improve the user’s experience—most of the time.

Failure Is an Option

There are a lot of problems with simultaneity in distributed computing. As Justin Sheehy describes it, there is no “now” when it comes to distributed systems—that article, by the way, is a must-read for every engineer, regardless of where they work in the stack.

While some things about computers are “virtual,” they still must operate in the physical world and cannot ignore the challenges of that world.

Even though computers operate in the real world, they are disconnected from it. Imagine an inventory system. It may place orders to its artificial heart’s desire, but if the warehouse burns down, there’s no fulfilling them. Even if the system is perfect, its state may be impossible. But the system is typically not perfect because the truth is prohibitively expensive. And not only do warehouses catch fire or forklifts break down, as rare as this may be, but computers fail and networks partition—and that’s far less rare.

The point is, stop trying to build perfect systems because one of two things will happen:

1. You have a false sense of security because you think the system is perfect, and it’s not.

or

2. You will never ship because perfection is out of reach or exorbitantly expensive.

Either case can be catastrophic, depending on the situation. With systems, failure is not only an option, it’s an inevitability, so let’s plan for it as such. We have a lot to gain by embracing failure. Eric Brewer articulated this idea in a recent interview:

So the general answer is you allow things to be inconsistent and then you find ways to compensate for mistakes, versus trying to prevent mistakes altogether. In fact, the financial system is actually not based on consistency, it’s based on auditing and compensation. They didn’t know anything about the CAP theorem, that was just the decision they made in figuring out what they wanted, and that’s actually, I think, the right decision.

We can look to ATMs, and banks in general, as the canonical example for how this works. When you withdraw money, the bank could choose to first coordinate your account, calculating your available balance at that moment in time, before issuing the withdrawal. But what happens when the ATM is temporarily disconnected from the bank? The bank loses out on revenue.

Instead, they make a calculated risk. They choose availability and compensate the risk of overdraft with interest and charges. Likewise, banks use double-entry bookkeeping to provide an audit trail. Every credit has a corresponding debit. Mistakes happen—accounts are debited twice, an account is credited without another being debited—the failure modes are virtually endless. But we audit and compensate, detect and recover. Banks are loosely coupled systems. Accountants don’t use erasers. Why should programmers?

When you find yourself saying “this is important data or people’s money, it has to be correct,” consider how the problem was solved before computers. Building on Quicksand by Dave Campbell and Pat Helland is a great read on this topic:

Whenever the authors struggle with explaining how to implement loosely-coupled solutions, we look to how things were done before computers. In almost every case, we can find inspiration in paper forms, pneumatic tubes, and forms filed in triplicate.

Consider the lost request and its idempotent execution. In the past, a form would have multiple carbon copies with a printed serial number on top of them. When a purchase-order request was submitted, a copy was kept in the file of the submitter and placed in a folder with the expected date of the response. If the form and its work were not completed by the expected date, the submitter would initiate an inquiry and ask to locate the purchase-order form in question. Even if the work was lost, the purchase-order would be resubmitted without modification to ensure a lack of confusion in the processing of the work. You wouldn’t change the number of items being ordered as that may cause confusion. The unique serial number on the top would act as a mechanism to ensure the work was not performed twice.

Computers allow us to greatly improve the user experience, but many of the same fail-safes still exist, just slightly rethought.

The idea of compensation is actually a common theme within distributed systems. The Saga pattern is a great example of this. Large-scale systems often have to coordinate resources across disparate services.  Traditionally, we might solve this problem using distributed transactions like two-phase commit. The problem with this approach is it doesn’t scale very well, it’s slow, and it’s not particularly fault tolerant. With 2PC, we have deadlock problems and even 3PC is still susceptible to network partitions.

Sagas split a long-lived transaction into individual, interleaved sub-transactions. Each sub-transaction in the sequence has a corresponding compensating transaction which reverses its effects. The compensating transactions must be idempotent so they can be safely retried. In the event of a partial execution, the compensating transactions are run and the Saga is effectively rolled back.

The commonly used example for Sagas is booking a trip. We need to ensure flight, car rental, and hotel are all booked or none are booked. If booking the flight fails, we cancel the hotel and car, etc. Sagas trade off atomicity for availability while still allowing us to manage failure, a common occurrence in distributed systems.

Compensation has a lot of applications as a UX principle because it’s really the only way to build loosely coupled, highly available services.

Calculated Recovery

Pat Helland describes computing as nothing more than “memories, guesses, and apologies.” Computers always have partial knowledge. Either there is a disconnect with the real world (warehouse is on fire) or there is a disconnect between systems (System A sold a Foo Widget but, unbeknownst to it, System B just sold the last one in inventory—oops!). Systems don’t make decisions, they make guesses. The guess might be good or it might be bad, but rarely is there certainty. We can wait to collect as much information as possible before making a guess, but it means progress can’t be made until the system is confident enough to do so.

Computers have memory. This means they remember facts they have learned and guesses they have made. Memories help systems make better guesses in the future, and they can share those memories with other systems to help in their guesses. We can store more memories at the cost of more money, and we can survey other systems’ memories at the cost of more latency.

It is a business decision how much money, latency, and energy should be spent on reducing forgetfulness. To make this decision, the costs of the increased probability of remembering should be weighed against the costs of occasionally forgetting stuff.

Generally speaking, the more forgetfulness we can tolerate, the more responsive our systems will be, provided we know how to handle the situations where something is forgotten.

Sooner or later, a system guesses wrong. It sucks. It might mean we lose out on revenue; the business isn’t happy. It might mean the user loses out on what they want; the customer isn’t happy. But we calculate the impact of these wrong guesses, we determine when the trade-offs do and don’t make sense, we compensate, and—when shit hits the fan—we apologize.

Business realities force apologies.  To cope with these difficult realities, we need code and, frequently, we need human beings to apologize. It is essential that businesses have both code and people to manage these apologies.

Distributed systems are as much about failure modes and recovery as they are about being operationally correct. It’s critical that we can recover gracefully when something goes wrong, and often that affects the UX.

We could choose to spend extraordinary amounts of money and countless man-hours laboring over a system which provides the reliability we want. We could construct a data center. We could deploy big, expensive machines. We could install redundant fiber and switches. We could drudge over infallible code. Or we could stop, think for a moment, and realize maybe “sorry” is a more effective alternative. Knowing when to make that distinction can be the difference between a successful business and a failed one. The implications of distributed systems may be wider reaching than you thought.

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Go Is Unapologetically Flawed, Here’s Why We Use It

Go is decidedly polarizing. While many are touting their transition to Go, it has become equally fashionable to criticize and mock the language. As Bjarne Stroustrup so eloquently put it, “There are only two kinds of programming languages: those people always bitch about and those nobody uses.” This adage couldn’t be more true. I apologize in advance for what appears to be just another in a long line of diatribes. I’m not really sorry, though.

I normally don’t advocate promoting or condemning a particular programming language or pontificate on why it is or isn’t used within an organization. They’re just tools for a job.


Today I’m going to be a hypocrite. The truth is we should care about what language and technologies we use to build and standardize on, but those decisions should be local to an organization. We shouldn’t choose a technology because it worked for someone else. Chances are they had a very different problem, different set of requirements, different engineering culture. There are so many factors that go into “success”—technology is probably the least impactful. Someone else’s success doesn’t translate to your success. It’s not the technology that makes or breaks us, it’s how the technology is appropriated, among many other conflating elements.

Now that I’ve prefaced why you shouldn’t choose a technology because it’s trendy, I’m going to talk about why we use Go where I work—yes, that’s meant to be ironic. However, I’m also going to describe why the language is essentially flawed. As I’ve alluded to, there are countless blog posts and articles which describe the shortcomings of Go. On the one hand, I’m apprehensive this doesn’t contribute anything meaningful to the dialogue. On the other hand, I feel the dialogue is important and, when framed in the right context, constructive.

Simplicity Through Indignity

Go is refreshingly simple. It’s what drew me to the language in the first place, and I suspect others feel the same way. There’s a popular quote from Rob Pike which I think is worth reiterating:

The key point here is our programmers are Googlers, they’re not researchers. They’re typically, fairly young, fresh out of school, probably learned Java, maybe learned C or C++, probably learned Python. They’re not capable of understanding a brilliant language but we want to use them to build good software. So, the language that we give them has to be easy for them to understand and easy to adopt.

Granted, it’s taken out of context, but on the surface this kind of does sound like Go is a disservice to intelligent programmers. However, there is value in pursuing a simple, yet powerful, lingua franca of backend systems. Any engineer, regardless of experience, can dive into virtually any codebase and quickly understand how something works. Unfortunately, the notion of programmers not understanding a “brilliant language” is a philosophy carried throughout Go, and it hinders productivity more than it helps.

We use Go because it’s boring. Previously, we worked almost exclusively with Python, and after a certain point, it becomes a nightmare. You can bend Python to your will. You can hack it, you can monkey patch it, and you can write remarkably expressive, terse code. It’s also remarkably difficult to maintain and slow. I think this is characteristic of statically and dynamically typed languages in general. Dynamic typing allows you to quickly build and iterate but lacks the static-analysis tooling needed for larger codebases and performance characteristics required for more real-time systems. In my mind, the curve tends to look something like this:

static vs dynamic 2

Of course, this isn’t particular to Go or Python. As highlighted above, there are a lot of questions you must ask when considering such a transition. Like I mentioned, languages are tools for a job. One might argue, then, why would a company settle on a single language? Use the right tool for the job! This is true in principle, but the reality is there are other factors to consider, the largest of which is momentum. When you commit to a language, you produce reusable libraries, APIs, tooling, and knowledge. If you “use the right tool for the job,” you end up pulling yourself in different directions and throwing away those things. If you’re Google scale, this is less of an issue. Most organizations aren’t Google scale. It’s a delicate balance when choosing a technology.

Go makes it easy to write code that is understandable. There’s no “magic” like many enterprise Java frameworks and none of the cute tricks you’ll find in most Python or Ruby codebases. The code is verbose but readable, unsophisticated but intelligible, tedious but predictable. But the pendulum swings too far. So far, in fact, that it sacrifices one of software development’s most sacred doctrines, Don’t Repeat Yourself, and it does so unapologetically.

The Untype System

To put it mildly, Go’s type system is impaired. It does not lend itself to writing quality, maintainable code at a large scale, which seems to be in stark contrast to the language’s ambitions. The type system is noble in theory, but in practice it falls apart rather quickly. Without generics, programmers are forced to either copy and paste code for each type, rely on code generation which is often clumsy and laborious, or subvert the type system altogether through reflection. Passing around interface{} harks back to the Java-pre-generics days of doing the same with Object. The code gets downright dopey if you want to write a reusable library.

The argument there, I suppose, is to rely on interfaces to specify the behavior needed in a function. In passing, this sounds reasonable, but again, it quickly falls apart for even the most trivial situations. Further, you can’t add methods to types from a different (or standard library) package. Instead, you must effectively alias or wrap the type with a new type, resulting in more boilerplate and code that generally takes longer to grok. You start to realize that Go isn’t actually all that great at what it sets out to accomplish in terms of fostering maintainable, large-scale codebases—boilerplate and code duplication abound. It’s 2015, why in the world are we still writing code like this:

Now repeat for uint32, uint64, int32, etc. In any other modern programming language, this would get you laughed out of a code review. In Go, no one seems to bat an eye, and the alternatives aren’t much better.

Interfaces in Go are interesting because they are implicitly implemented. There are advantages, such as implementing mocks and generally dealing with code you don’t own. They also can cause some subtle problems like accidental implementation. Just because a type matches the signature of an interface doesn’t mean it was intended to implement its contract. Not to mention the confusion caused by storing nil in an interface:

This is a common source of confusion. The basic answer is to never store something in an interface if you don’t expect the methods to be called on it. The language may allow it, but that violates the semantics of the interface. To expound, a nil value should usually not be stored in an interface unless it is of a type that has explicitly handled that case in its pointer-valued methods and has no value-receiver methods.

Go is designed to be simple, but that behavior isn’t simple to me. I know it’s tripped up many others. Another lurking danger to newcomers is the behavior around variable declarations and shadowing. It can cause some nasty bugs if you’re not careful.

Rules Are Meant to Be Broken, Just Not by You

Python relies on a notion of “we’re all consenting adults here.” This is great and all, but it starts to break down when you have to scale your organization. Go takes a very different approach which aligns itself with large development teams. Great! But it’s taken to the extreme, and the language seems to break many of its own rules, which can be both confusing and frustrating.

Go sort of supports generic functions as evidenced by its built-ins. You just can’t implement your own. Go sort of supports generic types as evidenced by slices, maps, and channels. You just can’t implement your own. Go sort of supports function overloading as evidenced again by its built-ins. You just can’t implement your own. Go sort of supports exceptions as evidenced by panic and recover. You just can’t implement your own. Go sort of supports iterators as evidenced by ranging on slices, maps, and channels. You just can’t implement your own.

There are other peculiar idiosyncrasies. Error handling is generally done by returning error values. This is fine, and I can certainly see the motivation coming from the abomination of C++ exceptions, but there are cases where Go doesn’t follow its own rule. For example, map lookups return two values: the value itself (or zero-value/nil if it doesn’t exist) and a boolean indicating if the key was in the map. Interestingly, we can choose to ignore the boolean value altogether—a syntax reserved for certain blessed types in the standard library. Type assertions and channel receives have equally curious behavior.

Another idiosyncrasy is adding an item to a channel which is closed. Instead of returning an error, or a boolean, or whatever, it panics. Perhaps because it’s considered a programmer error? I’m not sure. Either way, these behaviors seem inconsistent to me. I often find myself asking what the “idiomatic” approach would be when designing an API. Go could really use proper algebraic data types.

One of Go’s philosophies is “Share memory by communicating; don’t communicate by sharing memory.” This is another rule the standard library seems to break often. There are roughly 60 channels created in the standard library, excluding tests. If you look through the code, you’ll see that mutexes tend to be preferred and often perform better—more on this in a moment.

By the same token, Go actively discourages the use of the sync/atomic and unsafe packages. In fact, there have been indications sync/atomic would be removed if it weren’t for backward-compatibility requirements:

We want sync to be clearly documented and used when appropriate. We generally don’t want sync/atomic to be used at all…Experience has shown us again and again that very very few people are capable of writing correct code that uses atomic operations…If we had thought of internal packages when we added the sync/atomic package, perhaps we would have used that. Now we can’t remove the package because of the Go 1 guarantee.

Frankly, I’m not sure how you write performant data structures and algorithms without those packages. Performance is relative of course, but you need these primitives if you want to write anything which is lock-free. The irony is once you start writing highly concurrent things, which Go is generally considered good at, mutexes and channels tend to fall short performance-wise.

In actuality, to write high-performance Go, you end up throwing away many of the language’s niceties. Defers add overhead, interface indirection is expensive (granted, this is not unique to Go), and channels are, generally speaking, on the slowish side.

For being one of Go’s hallmarks, channels are a bit disappointing. As I already mentioned, the behavior of panicking on puts to a closed channel is problematic. What about cases where we have producers blocked on a put to a channel and another goroutine calls close on it? They panic. Other annoyances include not being able to peek into the channel or get more than one item from it, common operations on most blocking queues. I can live with that, but what’s harder to stomach are the performance implications, which I hinted at earlier. For this, I turn to my colleague and our resident performance nut, Dustin Hiatt:

Rarely do the Golang devs discuss channel performance, although rumblings were heard last time I was at Gophercon about not using defers or channels. You see, when Rob Pike makes the claim that you can use channels instead of locks, he’s not being entirely honest. Behind the scenes, channels are using locks to serialize access and provide threadsafety. So by using channels to synchronize access to memory, you are, in fact, using locks; locks wrapped in a threadsafe queue. So how do Go’s fancy locks compare to just using mutex’s from their standard library “sync” package? The following numbers were obtained by using Go’s builtin benchmarking functionality to serially call Put on a single set of their respective types.

BenchmarkSimpleSet-8 3000000 391 ns/op
BenchmarkSimpleChannelSet-8 1000000 1699 ns/op

This is with a buffered channel, what happens if we use unbuffered?

BenchmarkSimpleChannelSet-8  1000000          2252 ns/op

Yikes, with light or no multithreading, putting using the mutex is quite a bit faster (go version go1.4 linux/amd64). How well does it do in a multithreaded environment. The following numbers were obtained by inserting the same number of items, but doing so in 4 separate Goroutines to test how well channels do under contention.

BenchmarkSimpleSet-8 2000000 645 ns/op
BenchmarkChannelSimpleSet-8 2000000 913 ns/op
BenchmarkChannelSimpleSet-8 2000000 901 ns/op

Better, but the mutex is still almost 30% faster. Clearly, some of the channel magic is costing us here, and that’s without the extra mental overhead to prevent memory leaks. Golang felt the same way, I think, and that’s why in their standard libraries that get benchmarked, like “net/http,” you’ll almost never find channels, always mutexes.

Clearly, channels are not particularly great for workload throughput, and you’re typically better off using a lock-free ring buffer or even a synchronized queue. Channels as a unit of composition tend to fall short as well. Instead, they are better suited as a coordination pattern, a mechanism for signaling and timing-related code. Ultimately, you must use channels judiciously if you are sensitive to performance.

There are a lot of things in Go that sound great in theory and look neat in demos, but then you start writing real systems and go, “oh wait, that doesn’t actually work.” Once again, channels are a good example of this. The range keyword, which allows you to iterate over a data structure, is reserved to slices, maps, and channels. At first glance, it appears channels provide an elegant way to build your own iterators:

But upon closer inspection, we realize this approach is subtly broken. While it works, if we stop iterating, the loop adding items to the channel will block—the goroutine is leaked. Instead, we must push the onus onto the user to signal the iteration is finished. It’s far less elegant and prone to leaks if not used correctly—so much for channels and goroutines.

Goroutines are nice. They make it incredibly easy to spin off concurrent workers. They also make it incredibly easy to leak things. This shouldn’t be a problem for the intelligent programmer, but for Rob Pike’s beloved Googlers, they can be a double-edged sword.

Dependency Management in Practice

For being a language geared towards Google-sized projects, Go’s approach to managing dependencies is effectively nonexistent. For small projects with little-to-no dependencies, go get works great. But Go is a server language, and we typically have many dependencies which must be pinned to different versions. Go’s package structure and go get do not support this. Reproducible builds and dependency management continue to be a source of frustration for folks trying to build real software with it.

In fairness, dependency management is not an issue with the language per se, but to me, tooling is equally important as the language itself. Go doesn’t actually take an official stance on versioning:

“Go get” does not have any explicit concept of package versions. Versioning is a source of significant complexity, especially in large code bases, and we are unaware of any approach that works well at scale in a large enough variety of situations to be appropriate to force on all Go users. What “go get” and the larger Go toolchain do provide is isolation of packages with different import paths.

Fortunately, the tooling in this area is actively improving. I’m confident this problem can be solved in better ways, but the current state of the art will leave newcomers feeling uneasy.

A Community or a Carousel

Go has an increasingly vibrant community, but it’s profoundly stubborn. My biggest gripe is not with the language itself, but with the community’s seemingly us-versus-them mentality. You’re either with us or against us. It’s almost comical because it seems every criticism of the language, mine included, is prefixed with “I really like Go, but…” to ostensibly diffuse the situation. Parts of the community can seem religious, almost cult-like. The sheer mention of generics is now met with a hearty dismissal. It’s not the Go way.

The attitude of the decision making around the language is unfortunate, and I think Go could really take a page from Rust’s book with respect to its governance model. I agree entirely with the sentiment of “it is a poor craftsman who blames their tools,” but it is an even poorer craftsman who doesn’t choose the best tools at their disposal. I’m not partial to any of my tools. They’re a means to an end, but we should aim to improve them and make them more effective. Community should not breed complacency. With Go, I fear both are thriving.

Despite your hand wringing over the effrontery of Go’s designers to not include your prerequisite features, interest in Go is sky rocketing. Rather than finding new ways to hate a language for reasons that will not change, why not invest that time and join the growing number of programmers who are using the language to write real software today.

This is dangerous reasoning, and it hinders progress. Yes, programmers are using Go to write real software today. They were also writing real software with Java circa 2004. I write Go every day for a living. I work with smart people who do the same. Most of my open-source projects on GitHub are written in Go. I have invested countless hours into the language, so I feel qualified to point out its shortcomings. They are not irreparable, but let’s not just brush them off as people toying with Go and “finding ways to hate it”—it’s insulting and unproductive.

The Good Parts

Alas, Go is not beyond reproach. But at the same time, the language gets a lot of things right. The advantages of a single, self-contained binary are real, and compilation is fast. Coming from C or C++, the compilation speed is a big deal. Cross-compile allows you to target other platforms, and it’s getting even better with Go 1.5.

The garbage collector, while currently a pain point for performance-critical systems, is the focus of a lot of ongoing effort. Go 1.5 will bring about an improved garbage collector, and more enhancements—including generational techniques—are planned for the future. Compared to current cutting-edge garbage collectors like HotSpot, Go’s is still quite young—lots of room for improvement here.

Over the last couple of months, I dipped my toes back in Java. Along with C#, Java used to be my modus operandi. Going back gave me a newfound appreciation for Go’s composability. In Go, the language and libraries are designed to be composable, à la Unix. In Java, everyone brings their own walled garden of classes.

Java is really a ghastly language in retrospect. Even the simplest of tasks, like reading a file, require a wildly absurd amount of hoop-jumping. This is where Go’s simplicity nails it. Building a web application in Java generally requires an application server, which often puts you in J2EE-land. It’s not a place I recommend you visit. In contrast, building a web server in Go takes a couple lines of code using the standard library—no overhead whatsoever. I just wish Java shared some of its generics Kool-Aid. C# does generics even better, implementing them all the way down to the byte-code level without type erasure.

Beyond go get, Go’s toolchain is actually pretty good. Testing and benchmarking are built in, and the data-race detector is super handy for debugging race conditions in your myriad of goroutines. The gofmt command is brilliant—every language needs something like this—as are vet and godoc. Lastly, Go provides a solid set of profiling tools for analyzing memory, CPU utilization, and other runtime behavior. Sadly, CPU profiling doesn’t work on OSX due to a kernel bug.

Although channels and goroutines are not without their problems, Go is easily the best “concurrent” programming language I’ve used. Admittedly, I haven’t used Erlang, so I suspect that statement made some Erlangers groan. Combined with the select statement, channels allow you to solve some problems which would otherwise be solved in a much more crude manner.

Go fits into your stack as a language for backend services. With the work being done by Docker, CoreOS, HashiCorp, Google, and others, it clearly is becoming the language of Infrastructure as a Service, cloud orchestration, and DevOps as well. Go is not a replacement for C/C++ but a replacement for Java, Python, and the like—that much is clear.

Moving Forward

Ultimately, we use Go because it’s boring. We don’t use it because Google uses it. We don’t use it because it’s trendy. We use it because it’s no-frills and, hey, it usually gets the job done assuming you’ve found the right nail. But Go is still in its infancy and has a lot of room for growth and improvement.

I’m cautiously optimistic about Go’s future. I don’t consider myself a hater, I consider myself a hopeful. As it continues to gain a critical mass, I’m hopeful that the language will continue to improve but fearful of its relentless dogma. Go needs to let go of this attitude of “you don’t need that” or “it’s too complicated” or “programmers won’t know how to use it.” It’s toxic. It’s not all that different from your users requesting features after you release a product and telling those users they aren’t smart enough to use them. It’s not on your users, it’s on you to make the UX good.

A language can have considerable depth while still retaining its simplicity. I wish this were the ideal Go embraced, not one of negativity, of pessimism, of “no.” The question is not how can we protect developers from themselves, it’s how can we make them more productive? How can we enable them to solve problems? But just because people are solving problems with Go today does not mean we can’t do better. There is always room for improvement. There is never room for complacency.

My thanks to Dustin Hiatt for reviewing this and his efforts in benchmarking and profiling various parts of the Go runtime. It’s largely Dustin’s work that has helped pave the way for building performance-critical systems in Go.