Mastering Go Series

# Mastering Go Series.md

Table of Contents

1. Worker Pool Explained

worker-pool.go

package main

import (
	"fmt"
	"sync"
	"time"
)

const MAX_WORKER_COUNT = 3

const MAX_JOB_COUNT = 5

// Worker-Job frequency
var wFreq = [MAX_WORKER_COUNT]int{}

func worker(id int, jobs <-chan int, wg *sync.WaitGroup) {
	for j := range jobs {
		wFreq[id-1]++
		fmt.Printf("%d: Worker %d started job %d\n", time.Now().Local().Nanosecond(), id, j)
		time.Sleep(1 * time.Second)
		
        // Simulate random duration for the job to complete
		// time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
        
        // Simulate fixed duration for the job to complete
		time.Sleep(100 * time.Millisecond)
		fmt.Printf("%d: Worker %d finished job %d\n", time.Now().Local().Nanosecond(), id, j)
		wg.Done()
	}
}

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

	// Create workers to distribute jobs
	for w := 0; w < MAX_WORKER_COUNT; w++ {
		go worker(w+1, jobs, &wg)
	}

	startTime := time.Now()
	// Create jobs
	for j := 1; j <= MAX_JOB_COUNT; j++ {
		wg.Add(1)
		jobs <- j
	}

	close(jobs)
	wg.Wait()
	fmt.Printf("All %d jobs completed in %d millis with %d workers\n", MAX_JOB_COUNT, time.Since(startTime).Milliseconds(), MAX_WORKER_COUNT)

	fmt.Println("Worker Distributions")
	for i, v := range wFreq {
		fmt.Printf("Worker %d: %d jobs\n", i+1, v)
	}
}