Worker pool pattern

This pattern is commonly used to manage concurrency effectively, especially when you have a set of tasks that can be processed concurrently but want to limit the number of goroutines to prevent resource exhaustion or to control the load on a system.

Simple code - A worker simulates an expensive op

package main

import "time"

func worker(input <-chan int, result chan<- int) {
  for val := range input {
    time.Sleep(time.Second)

    result <- val * 2
  }
}

func main() {
  input := make(chan int)
  results := make(chan int)

  for range 2 {
    go worker(input, results)
  }

  go func() {
    for i := range 5 {
      input <- i
    }
    close(input)
  }()

  for range 5 {
    println(<-results)
  }

}