feat(gogenerate): add optional fields in log with omitempty annotation

Signed-off-by: T M Rezoan Tamal <[email protected]>

pkg/events/events.go

@@ -84,7 +84,7 @@ type HTTPRequest struct {
 	Endpoint   string `log:"http.url_details.endpoint"`
 
 	// Route is the URL path without interpolating the path variables.
-	Route string `log:"http.route"`
+	Route string `log:"http.route,omitempty"`
 }
 
 // FillFieldsFromRequest fills in the standard request fields

tools/logger/logger.go

@@ -54,6 +54,10 @@ if s.{{.name}} != nil {
 }`
 )
 
+const (
+	tagOmitEmpty = ",omitempty"
+)
+
 func main() {
 	flag.Usage = usage
 
@@ -140,6 +144,9 @@ func processStruct(w io.Writer, s *types.Struct, name string) {
 				write(w, nestedNilableMarshalerFormat, args)
 			case field == ".":
 				write(w, nestedMarshalerFormat, args)
+			case strings.HasSuffix(field, tagOmitEmpty):
+				args["key"] = strings.TrimSuffix(field, tagOmitEmpty)
+				write(w, getSimpleOptionalFieldFormat(s.Field(kk).Type()), args)
 			default:
 				write(w, simpleFieldFormat, args)
 			}
@@ -168,3 +175,25 @@ func usage() {
 	fmt.Fprintf(os.Stderr, "Flags:\n")
 	flag.PrintDefaults()
 }
+
+func getSimpleOptionalFieldFormat(p types.Type) string {
+	var defaultValue string
+	switch p.Underlying().String() {
+	case "string":
+		defaultValue = `""`
+	case "int", "int8", "int16", "int32", "int64",
+		"uint", "uint8", "uint16", "uint32", "uint64":
+		defaultValue = "0"
+	case "float32", "float64":
+		defaultValue = "0.0"
+	case "bool":
+		defaultValue = "false"
+	default:
+		defaultValue = "nil"
+	}
+
+	return fmt.Sprintf(`
+if s.{{.name}} != %s {
+	addField("{{.key}}", s.{{.name}})
+}`, defaultValue)
+}

tools/logger/logger_test.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"go/types"
+	"testing"
+)
+
+func TestGetSimpleOptionalFieldFormat(t *testing.T) {
+	newNamedType := func(name string, underlying types.Type) types.Type {
+		return types.NewNamed(
+			types.NewTypeName(0, nil, name, nil),
+			underlying,
+			nil,
+		)
+	}
+
+	tests := []struct {
+		name     string
+		typ      types.Type
+		expected string
+	}{
+		{
+			name:     "string type",
+			typ:      types.Typ[types.String],
+			expected: "\nif s.{{.name}} != \"\" {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+		{
+			name:     "int type",
+			typ:      types.Typ[types.Int],
+			expected: "\nif s.{{.name}} != 0 {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+		{
+			name:     "float64 type",
+			typ:      types.Typ[types.Float64],
+			expected: "\nif s.{{.name}} != 0.0 {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+		{
+			name:     "bool type",
+			typ:      types.Typ[types.Bool],
+			expected: "\nif s.{{.name}} != false {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+		{
+			name:     "custom string type (type Token string)",
+			typ:      newNamedType("Token", types.Typ[types.String]),
+			expected: "\nif s.{{.name}} != \"\" {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+		{
+			name:     "custom int type (type Digits int)",
+			typ:      newNamedType("Digits", types.Typ[types.Int]),
+			expected: "\nif s.{{.name}} != 0 {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+		{
+			name:     "custom float type (type Decimal float64)",
+			typ:      newNamedType("Decimal", types.Typ[types.Float64]),
+			expected: "\nif s.{{.name}} != 0.0 {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+		{
+			name:     "custom bool type (type Truther bool)",
+			typ:      newNamedType("Truther", types.Typ[types.Bool]),
+			expected: "\nif s.{{.name}} != false {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+		{
+			name:     "pointer type",
+			typ:      types.NewPointer(types.Typ[types.Int]),
+			expected: "\nif s.{{.name}} != nil {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+		{
+			name:     "pointer to custom type",
+			typ:      types.NewPointer(newNamedType("Nullable", types.Typ[types.String])),
+			expected: "\nif s.{{.name}} != nil {\n\taddField(\"{{.key}}\", s.{{.name}})\n}",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := getSimpleOptionalFieldFormat(tt.typ)
+			if got != tt.expected {
+				t.Errorf("getSimpleOptionalFieldFormat() =\n%v\nwant:\n%v", got, tt.expected)
+			}
+		})
+	}
+}