fix: loading print panic

nft/loading/loading.go

@@ -0,0 +1,123 @@
+package loading
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+type Type int
+
+const (
+	TypeProcessing Type = iota
+	TypeInfo
+	TypeSuccess
+	TypeWarning
+	TypeError
+)
+
+func (t Type) Symbol() string {
+	switch t {
+	case TypeSuccess:
+		return "✔️  "
+	case TypeWarning:
+		return "❗ "
+	case TypeError:
+		return "❌ "
+	case TypeInfo:
+		return "❕ "
+	default:
+		return ""
+	}
+}
+
+type _msg struct {
+	msg string
+	t   Type
+}
+
+var frames = []string{"|", "/", "-", "\\"}
+
+func Do(ctx context.Context, fn func(ctx context.Context, print func(msg string, types ...Type)) error) (err error) {
+	start := time.Now()
+	ch := make(chan *_msg)
+
+	go func() {
+		var (
+			m          *_msg
+			ok         bool
+			processing string
+		)
+
+		defer func() {
+			fmt.Printf("\r\033[K")
+		}()
+
+		for {
+			for _, frame := range frames {
+				select {
+				case <-ctx.Done():
+					return
+				case m, ok = <-ch:
+					if !ok || m == nil {
+						return
+					}
+
+					switch m.t {
+					case TypeProcessing:
+						if m.msg != "" {
+							processing = m.msg
+						}
+					case TypeInfo,
+						TypeSuccess,
+						TypeWarning,
+						TypeError:
+						// Clear the loading animation
+						fmt.Printf("\r\033[K")
+						fmt.Printf("%s%s\n", m.t.Symbol(), m.msg)
+					}
+				default:
+					elapsed := time.Since(start).Seconds()
+					if processing != "" {
+						fmt.Printf("\r\033[K%s  %s (%.2fs)", frame, processing, elapsed)
+					}
+					time.Sleep(100 * time.Millisecond)
+				}
+			}
+		}
+	}()
+
+	printFn := func(msg string, types ...Type) {
+		if msg == "" {
+			return
+		}
+
+		m := &_msg{
+			msg: msg,
+			t:   TypeProcessing,
+		}
+
+		if len(types) > 0 {
+			m.t = types[0]
+		}
+
+		ch <- m
+	}
+
+	done := make(chan struct{})
+	go func() {
+		if err = fn(ctx, printFn); err != nil {
+			ch <- &_msg{msg: err.Error(), t: TypeError}
+		}
+
+		close(ch)
+		done <- struct{}{}
+	}()
+
+	select {
+	case <-ctx.Done():
+	case <-done:
+	}
+
+	return err
+}

nft/loading/loading_test.go

@@ -0,0 +1,25 @@
+package loading
+
+import (
+	"context"
+	"os/signal"
+	"syscall"
+	"testing"
+	"time"
+)
+
+func TestLoadingPrint(t *testing.T) {
+	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
+	defer cancel()
+
+	Do(ctx, func(ctx context.Context, print func(msg string, types ...Type)) error {
+		print("start task 1...")
+		time.Sleep(3 * time.Second)
+
+		print("warning...1", TypeWarning)
+
+		time.Sleep(2 * time.Second)
+
+		return nil
+	})
+}