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5 Useful Tricks and Tips for Go You Should Know 🐹

July 21, 2022 ¿Ves algún error? Corregir artículo golang-wallpaper

Go is one of the most useful programming languages for performing different tasks, especially concurrency tasks. Additionally, all the native libraries in this language have many common functions we need daily. In this post, I'll show you 5 tricks I use in my day-to-day work as a remote Go programmer.

1. Code Execution Time

Go excels at great performance and has become one of the most used programming languages. Therefore, one of the things I do every day is measure my Go code's execution time. You can use a function and add it to the defer statement to improve readability.

main.go
  package main

import (
  "log"
  "time"
)

func ExecTime(start time.Time, name string) {
  elapsed := time.Since(start)
  log.Printf("%s took %s", name, elapsed)
}

func main() {
  defer ExecTime(time.Now(), "main")
  time.Sleep(3 * time.Second)
}

2. Marshal a JSON String with an Undefined Struct to an "Object"

This is a common problem in system logs when we save a Response and Request with an undefined struct and need to manipulate the information within this string.

main.go
  package main

import (
  "encoding/json"
  "fmt"
  "time"
)

type LogRegister struct {
  ID            int
  RequestString string
  RequestJson   map[string]interface{}
  CreatedAt     time.Time
  UpdatedAt     time.Time
}

func (c *LogRegister) FormatStringToJson() {
  var request map[string]interface{}

  json.Unmarshal([]byte(c.RequestString), &request)

  c.RequestJson = request
}

func main() {
  logRegister := LogRegister{
	  ID: 1,
	  RequestString: `
	  {
		  "status":200,
		  "message":"ok, now you can use me"
	  }
	  `,
	  CreatedAt: time.Now(),
  }
  logRegister.FormatStringToJson()
  if logRegister.RequestJson["status"] != nil {
	  fmt.Println(logRegister.RequestJson["status"])
  }
  if logRegister.RequestJson["message"] != nil {
	  fmt.Println(logRegister.RequestJson["message"])
  }
}

3. Get Code Coverage Test

You can check your project's test coverage in a nice browser interface and verify which parts of your code need to be tested.

~
go test -coverprofile=coverage.out ./… && go tool cover -html=coverage.out && rm coverage.out
golang-wallpaper

Code that hasn't been tested will appear in red and code that has been tested in green.

4. Check if String is Inside a Slice

Another common situation involves simple search problems for a string within a slice. For example, I want to make a list of fields that can be modified in an endpoint. The search method will depend on the array size. In my case, they're very short arrays, so I use a simple search.

main.go
  package main

func StringInSlice(a string, list []string) bool {
 
  for _, b := range list {
	  if b == a {
		  return true
	  }
  }
  return false
}

func main() {
  permmitedFields := []string{"status", "message"}
  field := "createdAt"

  if StringInSlice(field, permmitedFields) {
	  println("the field is authorized")
  }
  println("the field is not authorized")
}

5. Generate CPU Profiles

Likewise, one of my favorite tools is CPU profiling to get a more extensive analysis of your code's performance.

~
go test -cpuprofile=cpu.out ./… && go tool pprof cpu.out && rm cpu.out
golang-wallpaper