Goroutinelar

Goroutine — Go runtime boshqaradigan yengil oqim (thread). OS thread’laridan ancha arzon: bittasi bor-yo’g’i bir necha kilobayt joy oladi, shuning uchun minglab goroutine bemalol yonma-yon ishlab turaveradi. Funksiyani goroutine sifatida ishga tushirish uchun oldiga go qo’yamiz:

go doSomething()

Shu bitta so’z bilan doSomething alohida goroutine’da ketadi, main esa uni kutmay davom etaveradi.

package main
 
import (
    "fmt"
    "time"
)
 
func say(s string) {
    for i := range 3 {
        fmt.Println(s, i)
    }
}
 
func main() {
    go say("async") // alohida goroutine da
    say("main")     // main goroutine da
 
    time.Sleep(100 * time.Millisecond)
}

$ go run goroutine.go
main 0
async 0
main 1
async 1
main 2
async 2

Chiqish tartibi har safar ishga tushirganda o’zgarishi mumkin — ikki goroutine bir-biridan mustaqil ishlaydi.

Main goroutine hammasidan muhim

main ning o’zi ham bir goroutine. Main tugasa, butun dastur to’xtaydi — qolganlar tugadimi-yo’qmi, ahamiyati yo’q. Yuqoridagi time.Sleep aynan shuning uchun kerak edi: usiz main goroutine’ni ishga tushirishga ham ulgurmay yopilib qolardi. Ammo Sleep bilan “kutish” — taxminga tayanish, ya’ni yaramas usul. To’g’ri yechim — goroutine chindan tugaganini kutadigan sync.WaitGroup (alohida darsda ko’ramiz).

Concurrency va parallelism

Concurrency — ishlarni bir vaqtda boshqarish (dastur tuzilishi): vazifalar bir-birini kutmay navbatma-navbat siljiydi. Bu bitta yadroda ham bo’laveradi. Parallelism — ishlarni bir vaqtda bajarish (apparat): ikki yadro ikki goroutine’ni jismonan yonma-yon ishlatadi. Siz concurrent kod (goroutine + channel) yozasiz, uni yadrolarga taqsimlab parallel ishlatishni esa runtime o’zi hal qiladi.

Qisqasi: go funksiyani yangi goroutine’da ishga tushiradi; main tugasa hammasi to’xtaydi, shuning uchun goroutine’larni kutib olish shart.

Manba / batafsil: go.dev/tour/concurrency , Effective Go — Goroutines 

Goroutine’lar o’zaro channel orqali gaplashadi — keyingi darsda.