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  Don't Overload #nil?

There’s a popular post on Hacker News about writing confident code by, among other things, overloading Object#nil? and returning “null objects” instead of nil itself.DO NOT DO THIS.In Ruby, all objects (except nil itself) coerce to the boolean value true. Your object will be nil and true at the same time. Bad things will happen. Your coworkers will cry. Sad people from around the world will ask bewildering questions on your mailing list.Here’s what happen...

   Ruby,#nil,Overload,Object     2011-11-10 10:50:22

  When and Where to Use Pointers in Go

When declaring variables in Go, we usually have two syntax options: In some scenarios, pointers; in others, reference; sometimes, either. It’s great to have choices, but it is also confusing sometimes as to which one in which scenario. To be more reasonable in choice-making, I started from pointers, walked through their natures, and summarized some rules in using them in Go. from unsplash, Jordan Ladikos Pointers Go has pointers. A pointer holds the memory address of a ...

   POINTER,GOLANG     2022-05-01 02:24:43

  A mini post on GoLang context

In a GoLang web server, every request coming in will be handled by a goroutine. In the request handler, the logic may also need to create new goroutine to handle other tasks like RPC call. When the request is processed and response is returned, these goroutines created need to be exited so that no goroutine leak should happen. package main import ( "fmt" "log" "net/http" ) func main() { http.HandleFunc("/echo", func(w http.ResponseWriter, r *http.Request) { fmt.Println(&r) w.Write(...

   CONTEXT,GOLANG     2019-12-14 06:21:02

  Python: copying a list the right way

new = old[:] Those proficient in Python know what the previous line do. It copies the list old into new. This is confusing for beginners and should be avoided. Sadly the [:] notation is widely used, probably because most Python programmers don’t know a better way of copying lists.A little bit of pythonic theoryFirst we need to understand how Python manages objects & variables. Python doesn’t have variables like C. In C a variable is not just a name, it ...

   Python,List,Copy,Reference,[:],list()     2011-11-07 08:04:48

  this in JavaScript in detail

this in JavaScript is always confusing, it is one of the most frequently seen traps in JavaScript. this is not a good design in JavaScript(You can refer some other design flaws of JavaScript here), since it's lazy binding feature, it can be a global object, the current object or.... Some people even avoid using this in JavaScript. Actually if you master how this works, then you will know how to stay away from these traps. Let's take a look at what this points to in below situations. 1. In global...

   JavaScript,this,bind     2013-05-09 18:35:12

  Mock Solutions for GoLang Unit Test

In Go development, Unit Test is inevitable. And it is essential to use Mock when writing Unit Tests. Mock can help test isolate the business logic it depends on, enabling it to compile, link, and run independently. Mock needs Stub. Stub function replaces the real business logic function, returns the required result, and assists the test. I involved the related test code for Controllers while writing Kubernetes Operator recently, and there would be mocks for GRPC and HT...

   UNIT TEST,TESTIFY,GOSTUB,GOMOCK     2020-10-31 21:59:15

  Reducing Code Nesting

"This guy’s code sucks!" It’s something we’ve all said or thought when we run into code we don’t like. Sometimes it’s because it’s buggy, sometimes it’s because it conforms to a style we don’t like, and sometimes it’s because it just feels wrong. Recently I found myself thinking this, and automatically jumping to the conclusion that the developer who wrote it was a novice. The code had a distinct property that I dislike: lots of ...

   Code nesting,Readability,Maintainability,Reduction     2012-01-02 08:13:46

  Understanding PGO in GoLang 1.20

Background The Go 1.20 version was officially released in February 2023, it introduced the PGO(Profile Guided Optimization) mechanism. The basic principle of PGO can be divided into the following two steps: First, profiling is performed on the program to collect data about the program's runtime and generate a profiling file. When compiling the program, enable the PGO option, and the compiler will optimize the program's performance based on the content in the .pgo file. When compiling a program...

   GO 1.20,PGO,GOLANG     2023-02-28 04:27:46

  A journey to investigate a goroutine leakage case

In Go, creating goroutines is straightforward, but improper usage may result in a large number of goroutines unable to terminate, leading to resource leakage and memory leaks over time. The key to avoiding goroutine leaks is to manage the lifecycle of goroutines properly. By exporting runtime metrics and utilizing pprof, one can detect and resolve goroutine leakage issues. This post will go through one real case encountered by the author. The author maintains a service that connects to a targe...

   TIMEOUT,SSH,GUIDE,DEBUG,LEAK,GOROUTINE,PPROF,GOLANG     2024-03-16 11:00:23

  Go Error Best Practice

Being indulged in Go for quite a while and having implemented web-related programs, grpc interfaces and Operators, I seem to be an advanced beginner now. However, I am still a raw hand in production-environmental debugging, which is cumbersome if done by querying logs or error messages. Imagine the scenario that a full-text search is called when the specific location of the error log is missing. Then what happens when those error logs are not only in one place? Yes, my error logs can no longer h...

   GO ERROR,ERROR HANDLING     2021-10-07 07:38:28