ankur22

// Step 1: Write a failing test
func TestURLShortner(t *testing.T) {
	var tests = []struct {
		name, in, expected string
		err                error
	}{
		{"NoScheme", "https://google.com", "1", nil},
		{"NoScheme", "google", "", errors.New("invalid")},
	}

ankur22

lines := make(chan string, 1)
go func() {
	defer close(lines)
	for {
		if !scanner.Scan() {
			fmt.Println("Reader: Completed")
			break
		}
		lines <- scanner.Text()

ankur22

ctx, cancel := context.WithCancel(context.Background())

sigs := make(chan os.Signal, 1)
signal.Notify(sigs, syscall.SIGTERM)

go func() {
	sig := <-sigs
	fmt.Printf("Caught %s\n", sig)
	cancel()
}()

ankur22

lines := make(chan string, 1)
go func() {
	defer close(lines)
	for {
		if !scanner.Scan() {
			fmt.Println("Reader: Completed")
			break
		}
		lines <- scanner.Text()

ankur22

var wg sync.WaitGroup
wg.Add(1)
go func() {
	defer func() {
		wg.Done()
		close(lines)
	}()
	for {
		if !scanner.Scan() {
			fmt.Println("Reader: Completed")

ankur22

eg, ctx := errgroup.WithContext(ctx)
eg.Go(func() error {
	defer close(lines)
	for {
		if !scanner.Scan() {
			fmt.Println("Reader: Completed")
			break
		}
		lines <- scanner.Text()

ankur22

eg.Go(func() error {
	defer close(lines)
	for {
		if !scanner.Scan() {
			fmt.Println("Reader: Completed")
			break
		}
		lines <- scanner.Text()
		time.Sleep(time.Second) // To fake the slow writing to the lines channel

ankur22

eg.Go(func() error {
	for l := range lines {
		select {
		case <-ctx.Done():
			fmt.Println("Sender: Context closed")
			return ctx.Err()
		default:
			fmt.Printf("Sender: Sending %s to remote database\n", l)
		}
	}

ankur22

done := ctx.Done()
eg, ctx := errgroup.WithContext(ctx)
eg.Go(func() error {
	defer close(lines)
	for {
		if !scanner.Scan() {
			fmt.Println("Reader: Completed")
			break
		}
		lines <- scanner.Text()

ankur22

timeout := time.Millisecond * 500
timeoutTimer := time.NewTimer(timeout)
defer timeoutTimer.Stop()
eg.Go(func() error {
	for {
		select {
		case <-done():
			fmt.Println("Sender: Context closed")
			return ctx.Err()
		case <-timeoutTimer.C: