Drain the top level internal.

api/internal/kusterr/yamlformaterror.go

@@ -0,0 +1,35 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package error has contextual error types.
+package kusterr
+
+import (
+	"fmt"
+	"strings"
+)
+
+// YamlFormatError represents error with yaml file name where json/yaml format error happens.
+type YamlFormatError struct {
+	Path     string
+	ErrorMsg string
+}
+
+func (e YamlFormatError) Error() string {
+	return fmt.Sprintf("YAML file [%s] encounters a format error.\n%s\n", e.Path, e.ErrorMsg)
+}
+
+// Handler handles YamlFormatError
+func Handler(e error, path string) error {
+	if isYAMLSyntaxError(e) {
+		return YamlFormatError{
+			Path:     path,
+			ErrorMsg: e.Error(),
+		}
+	}
+	return e
+}
+
+func isYAMLSyntaxError(e error) bool {
+	return strings.Contains(e.Error(), "error converting YAML to JSON") || strings.Contains(e.Error(), "error unmarshaling JSON")
+}

api/internal/kusterr/yamlformaterror_test.go

@@ -0,0 +1,41 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package kusterr
+
+import (
+	"fmt"
+	"testing"
+)
+
+const (
+	filepath = "/path/to/whatever"
+	expected = "YAML file [/path/to/whatever] encounters a format error.\n" +
+		"error converting YAML to JSON: yaml: line 2: found character that cannot start any token\n"
+)
+
+func TestYamlFormatError_Error(t *testing.T) {
+	testErr := YamlFormatError{
+		Path:     filepath,
+		ErrorMsg: "error converting YAML to JSON: yaml: line 2: found character that cannot start any token",
+	}
+	if testErr.Error() != expected {
+		t.Errorf("Expected : %s\n, but found : %s\n", expected, testErr.Error())
+	}
+}
+
+func TestErrorHandler(t *testing.T) {
+	err := fmt.Errorf("error converting YAML to JSON: yaml: line 2: found character that cannot start any token")
+	testErr := Handler(err, filepath)
+	expectedErr := fmt.Errorf("format error message")
+	fmtErr := Handler(expectedErr, filepath)
+	if fmtErr.Error() != expectedErr.Error() {
+		t.Errorf("Expected returning fmt.Error, but found %T", fmtErr)
+	}
+	if _, ok := testErr.(YamlFormatError); !ok {
+		t.Errorf("Expected returning YamlFormatError, but found %T", testErr)
+	}
+	if testErr == nil || testErr.Error() != expected {
+		t.Errorf("Expected : %s\n, but found : %s\n", expected, testErr.Error())
+	}
+}