Add: the ability to redact values from Stringer and Error interface.

CHANGELOG.md

@@ -5,7 +5,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
-- No changes yet.
+## Added
+- Redacted annotation provides a mechanism to redact certain struct fields from
+errors messages and log objects.
 
 ## [1.31.0] - 2023-06-09
 ### Changed

gen/field.go

@@ -699,25 +699,38 @@ func (f fieldGroupGenerator) String(g Generator) error {
 			<range .Fields>
 				<- $fname := goName . ->
 				<- $f := printf "%s.%s" $v $fname ->
+				<- $shouldRedact := shouldRedact . ->
+				<- $redactedContent := redactedContent ->
 
 				<- if not .Required ->
 					if <$f> != nil {
-						<if isPrimitiveType .Type ->
-							<$fields>[<$i>] = <$fmt>.Sprintf("<$fname>: %v", *(<$f>))
-						<- else ->
-							<$fields>[<$i>] = <$fmt>.Sprintf("<$fname>: %v", <$f>)
+						<- if $shouldRedact ->
+							<$fields>[<$i>] = "<$fname>: <$redactedContent>"
+						<- else >
+							<if isPrimitiveType .Type ->
+								<$fields>[<$i>] = <$fmt>.Sprintf("<$fname>: %v", *(<$f>))
+							<- else ->
+								<$fields>[<$i>] = <$fmt>.Sprintf("<$fname>: %v", <$f>)
+							<- end>
 						<- end>
 						<$i>++
 					}
 				<- else ->
-					<$fields>[<$i>] = <$fmt>.Sprintf("<$fname>: %v", <$f>)
+					<- if $shouldRedact ->
+						<$fields>[<$i>] = "<$fname>: <$redactedContent>"
+					<- else ->
+						<$fields>[<$i>] = <$fmt>.Sprintf("<$fname>: %v", <$f>)
+					<- end>
 					<$i>++
 				<- end>
 			<end>
 
 			return <$fmt>.Sprintf("<.Name>{%v}", <$strings>.Join(<$fields>[:<$i>], ", "))
 		}
-		`, f)
+		`, f,
+		TemplateFunc("shouldRedact", shouldRedact),
+		TemplateFunc("redactedContent", redactedContent),
+	)
 }
 
 func (f fieldGroupGenerator) ErrorName(g Generator) error {
@@ -779,18 +792,28 @@ func (f fieldGroupGenerator) Zap(g Generator) error {
 			if <$v> == nil {
 				return nil
 			}
+			< $redactedContent := redactedContent ->
 			<range .Fields>
+				<- $shouldRedact := shouldRedact . ->
 				<- if not (zapOptOut .) ->
 					<- $fval := printf "%s.%s" $v (goName .) ->
 					<- if .Required ->
-						<zapEncodeBegin .Type ->
-							<$enc>.Add<zapEncoder .Type>("<fieldLabel .>", <zapMarshaler .Type $fval>)
-						<- zapEncodeEnd .Type>
+						<- if $shouldRedact ->
+								<$enc>.AddString("<fieldLabel .>", "<$redactedContent>")
+						<- else ->
+							<- zapEncodeBegin .Type ->
+								<$enc>.Add<zapEncoder .Type>("<fieldLabel .>", <zapMarshaler .Type $fval>)
+							<- zapEncodeEnd .Type ->
+						<- end ->
 					<- else ->
 						if <$fval> != nil {
-							<zapEncodeBegin .Type ->
-								<$enc>.Add<zapEncoder .Type>("<fieldLabel .>", <zapMarshalerPtr .Type $fval>)
-							<- zapEncodeEnd .Type>
+							<- if $shouldRedact ->
+								<$enc>.AddString("<fieldLabel .>", "<$redactedContent>")
+							<- else ->
+								<- zapEncodeBegin .Type ->
+									<$enc>.Add<zapEncoder .Type>("<fieldLabel .>", <zapMarshalerPtr .Type $fval>)
+								<- zapEncodeEnd .Type ->
+							<- end >
 						}
 					<- end>
 				<- end>
@@ -800,6 +823,8 @@ func (f fieldGroupGenerator) Zap(g Generator) error {
 		`, f,
 		TemplateFunc("zapOptOut", zapOptOut),
 		TemplateFunc("fieldLabel", entityLabel),
+		TemplateFunc("shouldRedact", shouldRedact),
+		TemplateFunc("redactedContent", redactedContent),
 	)
 }
 
@@ -875,3 +900,23 @@ func verifyUniqueFieldLabels(fs compile.FieldGroup) error {
 	}
 	return nil
 }
+
+// RedactLabel provides a mechanism to redact certain struct fields from
+// the outputs of String(), Error() and MarshalLogObject() methods.
+//
+//	struct Contact {
+//	    1: required string name
+//	    2: required string email (go.redact)
+//	}
+const RedactLabel = "go.redact"
+
+func shouldRedact(spec *compile.FieldSpec) bool {
+	_, ok := spec.Annotations[RedactLabel]
+	return ok
+}
+
+const _redactContent = "<redacted>"
+
+func redactedContent() string {
+	return _redactContent
+}

gen/field_test.go

@@ -25,10 +25,12 @@ import (
 	"strings"
 	"testing"
 
-	"go.uber.org/thriftrw/compile"
-
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"go.uber.org/thriftrw/compile"
+	"go.uber.org/thriftrw/gen/internal/tests/exceptions"
+	ts "go.uber.org/thriftrw/gen/internal/tests/structs"
+	"go.uber.org/zap/zapcore"
 )
 
 func TestFieldLabelConflict(t *testing.T) {
@@ -137,3 +139,70 @@ func TestCompileJSONTag(t *testing.T) {
 		})
 	}
 }
+
+func TestHasRedactedAnnotation(t *testing.T) {
+	foo := &compile.FieldSpec{
+		Name: "foo",
+	}
+	redact := &compile.FieldSpec{
+		Name:        "redact",
+		Annotations: compile.Annotations{RedactLabel: ""},
+	}
+	tests := []struct {
+		name string
+		spec *compile.FieldSpec
+		want bool
+	}{
+		{name: "redact annotation", spec: redact, want: true},
+		{name: "no redact annotation", spec: foo, want: false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equalf(t, tt.want, shouldRedact(tt.spec), "shouldRedact(%v)", tt.spec)
+		})
+	}
+}
+
+func TestRedactedAnnotation(t *testing.T) {
+	age := int32(21)
+	pi := ts.PersonalInfo{
+		Age:  toPtr(age),
+		Race: toPtr("martian"),
+	}
+	redactException := exceptions.DoesNotExistException{
+		Key:      "s",
+		UserName: toPtr("john doe"),
+	}
+	enc := zapcore.NewMapObjectEncoder()
+	require.NoError(t, pi.MarshalLogObject(enc))
+	require.Len(t, enc.Fields, 2)
+	_, ok := enc.Fields["race"]
+	require.True(t, ok)
+
+	eEncoder := zapcore.NewMapObjectEncoder()
+	require.NoError(t, redactException.MarshalLogObject(eEncoder))
+	require.Len(t, eEncoder.Fields, 2)
+	_, ok = eEncoder.Fields["userName"]
+	require.True(t, ok)
+
+	tests := []struct {
+		name string
+		got  any
+		want any
+	}{
+		{name: "struct/string", got: pi.String(), want: "PersonalInfo{Age: 21, Race: <redacted>}"},
+		{name: "struct/MarshalLogObject", got: enc.Fields["race"], want: _redactContent},
+		{name: "exception/string", got: redactException.String(), want: "DoesNotExistException{Key: s, UserName: <redacted>}"},
+		{name: "exception/error", got: redactException.Error(), want: "DoesNotExistException{Key: s, UserName: <redacted>}"},
+		{name: "exception/MarshalLogObject", got: eEncoder.Fields["userName"], want: _redactContent},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.EqualValues(t, tt.want, tt.got)
+		})
+	}
+}
+
+func toPtr[T any](input T) *T {
+	return &input
+}