add stop watch

error.go

@@ -7,4 +7,5 @@ var (
 	ErrInvalidValue  = errors.New("invalid value")
 	ErrUnknowType    = errors.New("unknow type")
 	ErrInitFactory   = errors.New("init factory")
+	ErrStopWatch     = errors.New("stop watch")
 )

provider.go

@@ -11,7 +11,7 @@ type NamedProvider interface {
 	Provider
 }
 
-type WatchCallback func(ctx context.Context, oldVar, newVar Value)
+type WatchCallback func(ctx context.Context, oldVar, newVar Value) error
 
 type WatchProvider interface {
 	Watch(ctx context.Context, callback WatchCallback, path ...string) error

provider/watcher/provider.go

@@ -2,6 +2,7 @@ package watcher
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log/slog"
 	"time"
@@ -61,7 +62,13 @@ func (p *Provider) Watch(ctx context.Context, callback config.WatchCallback, key
 				if err != nil {
 					p.logger(ctx, "get value%v:%v", key, err.Error())
 				} else if !newVar.IsEquals(oldVar) {
-					callback(ctx, oldVar, newVar)
+					if err := callback(ctx, oldVar, newVar); err != nil {
+						if errors.Is(err, config.ErrStopWatch) {
+							return
+						}
+						p.logger(ctx, "callback %v:%v", key, err)
+
+					}
 					oldVar = newVar
 				}
 			case <-ctx.Done():

provider/watcher/provider_test.go

@@ -31,7 +31,11 @@ func (p *provider) Value(context.Context, ...string) (config.Value, error) {
 func TestWatcher(t *testing.T) {
 	t.Parallel()
 
-	ctx := context.Background()
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second*2)
+	defer func() {
+		cancel()
+	}()
+
 	prov := &provider{}
 
 	w := watcher.New(time.Second, prov)
@@ -42,14 +46,19 @@ func TestWatcher(t *testing.T) {
 
 	err := w.Watch(
 		ctx,
-		func(ctx context.Context, oldVar, newVar config.Value) {
+		func(ctx context.Context, oldVar, newVar config.Value) error {
 			atomic.AddInt32(&cnt, 1)
 			wg.Done()
+			if atomic.LoadInt32(&cnt) == 2 {
+				return config.ErrStopWatch
+			}
+
+			return nil
 		},
 		"tmpname",
 	)
-	require.NoError(t, err)
 	wg.Wait()
 
+	require.NoError(t, err)
 	require.Equal(t, int32(2), cnt)
 }