Merge pull request #19 from m-mizutani/feature/tag-key

Add WithCustomTagKey option

README.md

@@ -50,13 +50,13 @@ logger := slog.New(
             ReplaceAttr: masq.New(
                 // By user defined custom type
                 masq.WithType[AccessToken](),
-        
+
                 // By regex of phone number as e164 format
                 masq.WithRegex(regexp.MustCompile(`^\+[1-9]\d{1,14}$`)),
-        
+
                 // By field tag such as masq:"secret"
                 masq.WithTag("secret"),
-        
+
                 // By by field name prefix. Concealing SecureXxx field
                 masq.WithFieldPrefix("Secure"),
             ),
@@ -168,6 +168,30 @@ out.Flush()
 // {"level":"INFO","msg":"Got record","record":{"EMail":"[FILTERED]","ID":"m-mizutani"},"time":"2022-12-25T09:00:00.123456789"}
 ```
 
+You can change the tag key by `masq.WithCustomTagKey` option.
+
+```go
+type myRecord struct {
+    ID    string
+    EMail string `custom:"secret"`
+}
+
+record := myRecord{
+    ID:    "m-mizutani",
+    EMail: "[email protected]",
+}
+
+logger := newLogger(out, masq.New(
+    masq.WithCustomTagKey("custom"),
+    masq.WithTag("secret"),
+))
+
+logger.With("record", record).Info("Got record")
+out.Flush()
+// Output:
+// {"level":"INFO","msg":"Got record","record":{"EMail":"[REDACTED]","ID":"m-mizutani"},"time":"2022-12-25T09:00:00.123456789"}
+```
+
 ### With struct field name
 
 ```go

clone.go

@@ -84,7 +84,7 @@ func (x *masq) clone(ctx context.Context, fieldName string, src reflect.Value, t
 				srcValue = reflect.NewAt(srcValue.Type(), unsafe.Pointer(srcValue.UnsafeAddr())).Elem()
 			}
 
-			tagValue := f.Tag.Get("masq")
+			tagValue := f.Tag.Get(x.tagKey)
 			copied := x.clone(ctx, f.Name, srcValue, tagValue)
 			dstValue.Set(copied)
 		}

masq.go

@@ -8,6 +8,10 @@ import (
 )
 
 const (
+	// DefaultTagKey is a default key name of struct tag for masq. WithCustomTagKey option can change this value.
+	DefaultTagKey = "masq"
+
+	// DefaultRedactMessage is a default message to replace redacted value. WithRedactMessage option can change this value.
 	DefaultRedactMessage = "[REDACTED]"
 )
 
@@ -17,6 +21,7 @@ type masq struct {
 	allowedTypes  map[reflect.Type]struct{}
 
 	defaultRedactor Redactor
+	tagKey          string
 }
 
 type Filter struct {
@@ -30,6 +35,7 @@ func newMasq(options ...Option) *masq {
 	m := &masq{
 		redactMessage: DefaultRedactMessage,
 		allowedTypes:  map[reflect.Type]struct{}{},
+		tagKey:        DefaultTagKey,
 	}
 	m.defaultRedactor = func(src, dst reflect.Value) bool {
 		switch src.Kind() {

options.go

@@ -35,6 +35,17 @@ func WithTag(tag string, redactors ...Redactor) Option {
 	return WithCensor(newTagCensor(tag), redactors...)
 }
 
+// WithCustomTagKey is an option to set the custom tag key. The default tag key is `masq`. If the field has the target tag in the custom tag key AND the field is matched with the target tag specified by WithTag, the field will be redacted. If tagKey is empty, WithCustomTagKey panics.
+func WithCustomTagKey(tagKey string) Option {
+	if tagKey == "" {
+		panic("masq: tag key must not be empty")
+	}
+
+	return func(m *masq) {
+		m.tagKey = tagKey
+	}
+}
+
 // WithFieldName is an option to check if the field name is matched with the target field name. If the field name is the target field name, the field will be redacted.
 func WithFieldName(fieldName string, redactors ...Redactor) Option {
 	return WithCensor(newFieldNameCensor(fieldName), redactors...)

options_test.go

@@ -125,6 +125,40 @@ func ExampleWithTag() {
 	// {"level":"INFO","msg":"Got record","record":{"EMail":"[REDACTED]","ID":"m-mizutani"},"time":"2022-12-25T09:00:00.123456789"}
 }
 
+func ExampleWithCustomTagKey() {
+	out := &fixedTimeWriter{}
+
+	type myRecord struct {
+		ID    string
+		EMail string `custom:"secret"`
+	}
+
+	record := myRecord{
+		ID:    "m-mizutani",
+		EMail: "[email protected]",
+	}
+
+	logger := newLogger(out, masq.New(
+		masq.WithCustomTagKey("custom"),
+		masq.WithTag("secret"),
+	))
+
+	logger.With("record", record).Info("Got record")
+	out.Flush()
+	// Output:
+	// {"level":"INFO","msg":"Got record","record":{"EMail":"[REDACTED]","ID":"m-mizutani"},"time":"2022-12-25T09:00:00.123456789"}
+}
+
+func TestCustomTagKeyPanic(t *testing.T) {
+	defer func() {
+		if recover() == nil {
+			t.Errorf("Failed to panic")
+		}
+	}()
+
+	masq.New(masq.WithCustomTagKey(""))
+}
+
 func ExampleWithFieldName() {
 	out := &fixedTimeWriter{}