How to Implement the Worker Pool Pattern in Go

Implement a worker pool by creating a fixed number of goroutines that consume tasks from a buffered channel and write results to a result channel.

package main

import (
	"fmt"
	"sync"
)

func worker(id int, jobs <-chan int, results chan<- int, wg *sync.WaitGroup) {
	defer wg.Done()
	for j := range jobs {
		results <- j * 2
	}
}

func main() {
	const numWorkers = 4
	jobs := make(chan int, 100)
	results := make(chan int, 100)
	var wg sync.WaitGroup

	for w := 1; w <= numWorkers; w++ {
		wg.Add(1)
		go worker(w, jobs, results, &wg)
	}

	go func() {
		for i := 1; i <= 10; i++ {
			jobs <- i
		}
		close(jobs)
	}()

	go func() {
		wg.Wait()
		close(results)
	}()

	for r := range results {
		fmt.Println(r)
	}
}

A worker pool is like a team of employees where a manager assigns tasks from a queue. Instead of hiring a new worker for every single task, you keep a fixed team size to save resources. This pattern prevents your application from crashing when too many tasks arrive at once.