003_waitgroup_with_multiple_waits

Go Sample Example - WaitGroup with Multiple Waits

This repository demonstrates how to use Go's sync.WaitGroup to synchronize different sets of goroutines at various stages of execution. The example showcases how to coordinate goroutines across multiple stages using the same WaitGroup for synchronization.

📖 Information

• This example demonstrates using a single `sync.WaitGroup` to manage synchronization between multiple stages of goroutine execution.
• It covers the use of a WaitGroup in two separate phases, waiting for a set of goroutines to complete before moving on to the next stage.
• The goroutines simulate tasks using sleep timers to mimic real processing time.

💻 Code Example

package main

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

func stageOne(id int, wg *sync.WaitGroup) {
	defer wg.Done()
	fmt.Printf("Stage one: Worker %d starting\n", id)
	time.Sleep(1 * time.Second)
	fmt.Printf("Stage one: Worker %d done\n", id)
}

func stageTwo(id int, wg *sync.WaitGroup) {
	defer wg.Done()
	fmt.Printf("Stage two: Worker %d starting\n", id)
	time.Sleep(1 * time.Second)
	fmt.Printf("Stage two: Worker %d done\n", id)
}

func main() {

	// WaitGroup with Multiple Waits
	// we use a WaitGroup to wait for different sets of goroutines at different stages of execution.

	var wg sync.WaitGroup

	// Stage one
	for i := 1; i <= 3; i++ {
		wg.Add(1)
		go stageOne(i, &wg)
	}
	wg.Wait() // Wait for all workers in stage one to complete
	fmt.Println("Stage one completed.")

	// Stage two
	for i := 1; i <= 3; i++ {
		wg.Add(1)
		go stageTwo(i, &wg)
	}
	wg.Wait() // Wait for all workers in stage two to complete
	fmt.Println("Stage two completed.")
}

🏃 How to Run

1. Make sure you have Go installed. If not, you can download it from here.
2. Clone this repository:

git clone https://github.com/Rapter1990/go_sample_examples.git

3. Navigate to the 023_waitgroup directory:

cd go_sample_examples/023_waitgroup/003_waitgroup_with_multiple_waits

4. Run the Go program:

go run 003_waitgroup_with_multiple_waits.go

📦 Output

When you run the program, you should see the following output:

Stage one: Worker 3 starting
Stage one: Worker 1 starting
Stage one: Worker 2 starting
Stage one: Worker 2 done
Stage one: Worker 1 done    
Stage one: Worker 3 done    
Stage one completed.        
Stage two: Worker 3 starting
Stage two: Worker 1 starting
Stage two: Worker 2 starting
Stage two: Worker 2 done
Stage two: Worker 3 done
Stage two: Worker 1 done
Stage two completed.