Merge pull request #25400 from jsafrane/devel/operation-error

pkg/util/goroutinemap/goroutinemap.go

@@ -62,7 +62,7 @@ func (grm *goRoutineMap) Run(operationName string, operation func() error) error
 	defer grm.Unlock()
 	if grm.operations[operationName] {
 		// Operation with name exists
-		return fmt.Errorf("Failed to create operation with name %q. An operation with that name already exists.", operationName)
+		return newAlreadyExistsError(operationName)
 	}
 
 	grm.operations[operationName] = true
@@ -86,3 +86,30 @@ func (grm *goRoutineMap) operationComplete(operationName string) {
 func (grm *goRoutineMap) Wait() {
 	grm.wg.Wait()
 }
+
+// alreadyExistsError is specific error returned when NewGoRoutine()
+// detects that operation with given name is already running.
+type alreadyExistsError struct {
+	operationName string
+}
+
+var _ error = alreadyExistsError{}
+
+func (err alreadyExistsError) Error() string {
+	return fmt.Sprintf("Failed to create operation with name %q. An operation with that name already exists", err.operationName)
+}
+
+func newAlreadyExistsError(operationName string) error {
+	return alreadyExistsError{operationName}
+}
+
+// IsAlreadyExists returns true if an error returned from NewGoRoutine indicates
+// that operation with the same name already exists.
+func IsAlreadyExists(err error) bool {
+	switch err.(type) {
+	case alreadyExistsError:
+		return true
+	default:
+		return false
+	}
+}

pkg/util/goroutinemap/goroutinemap_test.go

@@ -125,6 +125,9 @@ func Test_NewGoRoutineMap_Negative_SecondOpBeforeFirstCompletes(t *testing.T) {
 	if err2 == nil {
 		t.Fatalf("NewGoRoutine did not fail. Expected: <Failed to create operation with name \"%s\". An operation with that name already exists.> Actual: <no error>", operationName)
 	}
+	if !IsAlreadyExists(err2) {
+		t.Fatalf("NewGoRoutine did not return alreadyExistsError, got: %v", err2)
+	}
 }
 
 func Test_NewGoRoutineMap_Positive_ThirdOpAfterFirstCompletes(t *testing.T) {
@@ -147,6 +150,9 @@ func Test_NewGoRoutineMap_Positive_ThirdOpAfterFirstCompletes(t *testing.T) {
 	if err2 == nil {
 		t.Fatalf("NewGoRoutine did not fail. Expected: <Failed to create operation with name \"%s\". An operation with that name already exists.> Actual: <no error>", operationName)
 	}
+	if !IsAlreadyExists(err2) {
+		t.Fatalf("NewGoRoutine did not return alreadyExistsError, got: %v", err2)
+	}
 
 	// Act
 	operation1DoneCh <- true // Force operation1 to complete