What is a worker pool in Go and when would you use it?

Worker pool in Go is a pattern for organizing parallel task processing with a limited number of goroutines (workers), which take tasks from a shared queue and process them.

Reasons to use:

• Control over the number of concurrently running goroutines to avoid creating too many and overwhelming the system.
• Increase performance through reuse of goroutines.
• Simplify task management and distribution.

Example of usage:

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 {
		// Process task
		fmt.Printf("Worker %d processing job %d\n", id, j)
		results <- j * 2
	}
}

func main() {
	jobs := make(chan int, 5)
	results := make(chan int, 5)
	var wg sync.WaitGroup

	// Launch 3 workers
	for w := 1; w <= 3; w++ {
		wg.Add(1)
		go worker(w, jobs, results, &wg)
	}

	// Send 5 tasks
	for j := 1; j <= 5; j++ {
		jobs <- j
	}
	close(jobs)

	wg.Wait()
	close(results)

	// Read results
	for r := range results {
		fmt.Println("Result:", r)
	}
}

In this example, three workers process tasks from the jobs channel in parallel. This approach is effective for limited parallelism and resource management.