Why is goroutine not doing its job?

Question

go

After reading the theory of how goroutines work, in principle, nothing is difficult, I solve a practical problem to understand them, but I ran into a problem, I would like to get advice on a live example, rather than in the output "Hello wordl!" goroutines in a loop.

package main

import (
  "bufio"
  "bytes"
  "fmt"
  "golang.org/x/crypto/bcrypt"
  "io"
  "os"
  "strings"
  "sync"
)

var (
  hash_target = "$2y$10$Jk2gOsrCgYKaVutj9JIVYuXlinrpzeqxdXng/Nm96O7t5AvVBir/a"
  dict = "/home/supreme/rockyou.txt"
  r io.Reader
  err error

)
func main(){

  r, err := os.Open(dict)
  if err != nil{
    fmt.Println(err)
  }
  defer r.Close()

  var wg sync.WaitGroup
  var reader *bufio.Reader = bufio.NewReader(r)
  var  pasw string

  wg.Add(1)
  for {
    pasw, err = reader.ReadString('\n')
    if err == io.EOF {
      fmt.Printf("File %s end detected", dict)
    } else {
      pasw = strings.Replace(pasw, "\n", "", -1)
      go hack_pass(pasw, hash_target, &wg)
    }
  }
  wg.Wait()
  }





func hack_pass(str string,hash_target string, wg *sync.WaitGroup){
  fmt.Println("----------------------------------")
    if CheckPasswordHash(str,hash_target){
      fmt.Println("----------------------------------")
      fmt.Println("[SUCCESS]:", str)
      fmt.Println("----------------------------------")
      os.Exit(0)
    }else{
      fmt.Println("[FAILURE]:", str)
    }
    wg.Done()
    return
  }



func CheckPasswordHash(password string, hash string)bool{
  err := bcrypt.CompareHashAndPassword([]byte(hash),[]byte(password))
  return err == nil
}

Answer 1

You add a unit to wg, the first executing goroutine subtracts this unit, wg.Wait() unblocks the thread and main ends. wg.Add needs to be done for every goroutine you want to wait
. Also os.Exit ends the whole process. That is, the first goroutine that stumbles upon it will end everything
. Still, you are absolutely uncontrollably spawning goroutines in an endless loop. Use an adequate number of goroutines that work at the same time and throw them tasks through channels Read the
theory a couple more times Here is another great article
that will help you understand goroutines and typical examples of their use