Merge pull request #28 from shogo82148/introduce-mark-temporary

introduce MarkTemporary

func.go

@@ -23,8 +23,11 @@ func DoValue[T any](ctx context.Context, policy *Policy, f func() (T, error)) (T
 			return v, nil
 		}
 
-		// short cut for calling isPermanent and Unwrap
-		if err, ok := err.(*permanentError); ok {
+		// short cut for calling Unwrap
+		if err, ok := err.(*myError); ok {
+			if err.temporary {
+				continue
+			}
 			return zero, err.error
 		}
 
@@ -41,5 +44,9 @@ func DoValue[T any](ctx context.Context, policy *Policy, f func() (T, error)) (T
 	if err := retrier.err; err != nil {
 		return zero, err
 	}
+	if err, ok := err.(*myError); ok {
+		// Unwrap the error if it's marked as temporary.
+		return zero, err.error
+	}
 	return zero, err
 }

func_test.go

@@ -30,11 +30,32 @@ func TestDoValue_Success(t *testing.T) {
 
 func TestDoValue_MarkPermanent(t *testing.T) {
 	permanentErr := errors.New("permanent error")
-	policy := &Policy{}
+	policy := &Policy{MaxCount: 10}
+	count := 0
 	_, err := DoValue(context.Background(), policy, func() (int, error) {
+		count++
 		return 0, MarkPermanent(permanentErr)
 	})
 	if err != permanentErr {
 		t.Errorf("want error is %#v, got %#v", err, permanentErr)
 	}
+	if count != 1 {
+		t.Errorf("want %d, got %d", 1, count)
+	}
+}
+
+func TestDoValue_MarkTemporary(t *testing.T) {
+	temporaryErr := errors.New("temporary error")
+	policy := &Policy{MaxCount: 10}
+	count := 0
+	_, err := DoValue(context.Background(), policy, func() (int, error) {
+		count++
+		return 0, MarkTemporary(temporaryErr)
+	})
+	if err != temporaryErr {
+		t.Errorf("want error is %#v, got %#v", err, temporaryErr)
+	}
+	if count != 10 {
+		t.Errorf("want %d, got %d", 10, count)
+	}
 }

retry.go

@@ -70,8 +70,11 @@ func (p *Policy) Do(ctx context.Context, f func() error) error {
 			return nil
 		}
 
-		// short cut for calling isPermanent and Unwrap
-		if err, ok := err.(*permanentError); ok {
+		// short cut for calling Unwrap
+		if err, ok := err.(*myError); ok {
+			if err.temporary {
+				continue
+			}
 			return err.error
 		}
 
@@ -88,34 +91,46 @@ func (p *Policy) Do(ctx context.Context, f func() error) error {
 	if err := retrier.err; err != nil {
 		return err
 	}
+	if err, ok := err.(*myError); ok {
+		// Unwrap the error if it's marked as temporary.
+		return err.error
+	}
 	return err
 }
 
 type temporary interface {
 	Temporary() bool
 }
 
-var _ temporary = (*permanentError)(nil)
+var _ temporary = (*myError)(nil)
 
-type permanentError struct {
+type myError struct {
 	error
+	temporary bool
 }
 
 // implements interface{ Temporary() bool }
 // Inspecting errors https://dave.cheney.net/2014/12/24/inspecting-errors
-func (e *permanentError) Temporary() bool {
-	return false
+func (e *myError) Temporary() bool {
+	return e.temporary
 }
 
 // Unwrap implements errors.Wrapper.
-func (e *permanentError) Unwrap() error {
+func (e *myError) Unwrap() error {
 	return e.error
 }
 
 // MarkPermanent marks err as a permanent error.
 // It returns the error that implements interface{ Temporary() bool } and Temporary() returns false.
 func MarkPermanent(err error) error {
-	return &permanentError{err}
+	return &myError{err, false}
+}
+
+// MarkTemporary wraps an error as a temporary error, allowing retry mechanisms to handle it appropriately.
+// This is especially useful in scenarios where errors may not require immediate termination of a process,
+// but rather can be resolved through retrying operations.
+func MarkTemporary(err error) error {
+	return &myError{err, true}
 }
 
 // Continue returns whether retrying should be continued.

retry_test.go

@@ -266,13 +266,35 @@ func TestDo_Success(t *testing.T) {
 
 func TestDo_MarkPermanent(t *testing.T) {
 	permanentErr := errors.New("permanent error")
-	policy := &Policy{}
+	// TestDo_MarkPermanent checks that a permanent error stops retries after one occurrence as expected.
+	policy := &Policy{MaxCount: 10}
+	count := 0
 	err := policy.Do(context.Background(), func() error {
+		count++
 		return MarkPermanent(permanentErr)
 	})
 	if err != permanentErr {
 		t.Errorf("want error is %#v, got %#v", err, permanentErr)
 	}
+	if count != 1 {
+		t.Errorf("want %d, got %d", 1, count)
+	}
+}
+
+func TestDo_MarkTemporary(t *testing.T) {
+	temporaryErr := errors.New("temporary error")
+	policy := &Policy{MaxCount: 10}
+	count := 0
+	err := policy.Do(context.Background(), func() error {
+		count++
+		return MarkTemporary(temporaryErr)
+	})
+	if err != temporaryErr {
+		t.Errorf("want error is %#v, got %#v", err, temporaryErr)
+	}
+	if count != 10 {
+		t.Errorf("want %d, got %d", 10, count)
+	}
 }
 
 type customError bool