Concepts
Go goroutine leaks and pprofchannels, mutexes, and exit paths
Starting a goroutine is easy. The hard part was deciding who changes the data, who finishes the work, and when a function may return.
Go 13 posts
Concepts
Go sync.Pool and buffer reuseafter Put, Bytes() isn't yours
In the previous post, total allocations stayed at 256MiB however I set GOGC and GOMEMLIMIT. Reusing short-lived buffers with sync.Pool is one way to shrink it.
Concepts
Go GOMEMLIMIT and GOGCOOMKilled with an 800MB heap
The container limit was 1GB, yet the process was OOMKilled with an 800MB heap. Go has a garbage collector, so how did memory run out?
Concepts
Go GMP and GOMAXPROCScontainer CPU limits and goroutines
Put go in front of a call and it runs concurrently. So do 100,000 goroutines mean 100,000 threads? Does GOMAXPROCS=1 mean one task at a time?
Concepts
Copying structs in Gowhy a shallow copy changes the map too
Interfaces, slices, defer, embedding, context: looking back after five posts, most of the pitfalls came from two axes. One is "everything is copied"; the other is "object orientation without classes."
Troubleshooting
Go ResponseHeaderTimeoutwhy a one-hour timeout died at 30 seconds
I thought putting a one-hour context.WithTimeout on a request meant it would wait up to an hour. It died at 30 seconds. The context made it all the way through; it just wasn't the only timer. And once I fixed the timer, the real problem turned out to be somewhere else.
Concepts
Go context, fully explainedcancellation, time budgets, and four pitfalls
I was already taking ctx as the first argument and passing it along. What I had never checked was whether canceling actually stops the goroutine. After stalling on that question in an interview, I went back to context from the start.
Troubleshooting
From 300 calls to 1how I learned that optimization changes failure modes
Validation was dying on timeouts. Within 30 minutes I had an answer, "it's N+1, batch it," and it was only half right. Reaching the final design took two changes of direction, and since the process taught me more than the code, I'm writing it down.
Concepts
Why Go has no inheritancerebuilding OOP with embedding and interfaces
Go has no classes and no inheritance, yet it's hard to call it non-object-oriented. The official FAQ answers "Is Go an object-oriented language?" with "Yes and no." This post explains why by following what Go put where inheritance used to be.
Concepts
Go defer, Errors, and ClosuresLIFO, Error Wrapping, and the Loop Variable Trap
Go dropped exceptions and filled the gap with defer and errors as values. All three take seconds to learn and keep producing traps for years. I reorganized them around one question: exactly when, and what, does each one hold on to?
Concepts
Why Go's append Changes the OriginalInside Slices, Maps, and Strings
The Go bugs I keep hitting come from holding something different from what I think I'm holding. A slice is a window, not data. A map doesn't guarantee addresses. A string isn't a character array. This post opens up the layout of all three.
Concepts
The Go Interface nil TrapWhy err != nil Is True
You return a nil pointer and err != nil comes out true, because an interface value has two slots: a type and the data. From that two-slot layout to method sets, where interfaces should live, and the cost of dynamic dispatch.
Concepts
How Static Typing and Compilation Affect Runtime Performance (Through Go)
Following how compiled, statically typed code turns into runtime wins, using Go: memory layout, compiler optimizations, escape analysis, the GC, and the scheduler, each checked with tools.