snapshot of https://github.com/ThreeDotsLabs/watermill.git (master, 2026-09-15; blobs > 131072B omitted)

components/cqrs/marshaler_protobuf.go

@@ -0,0 +1,85 @@
+package cqrs
+
+import (
+	"reflect"
+
+	"github.com/ThreeDotsLabs/watermill"
+	"github.com/ThreeDotsLabs/watermill/message"
+	"google.golang.org/protobuf/proto"
+
+	"github.com/pkg/errors"
+)
+
+// ProtoMarshaler is the default Protocol Buffers marshaler.
+type ProtoMarshaler struct {
+	NewUUID      func() string
+	GenerateName func(v interface{}) string
+}
+
+// NoProtoMessageError is returned when the given value does not implement proto.Message.
+type NoProtoMessageError struct {
+	v interface{}
+}
+
+func (e NoProtoMessageError) Error() string {
+	rv := reflect.ValueOf(e.v)
+	if rv.Kind() != reflect.Pointer {
+		return "v is not proto.Message, you must pass pointer value to implement proto.Message"
+	}
+
+	return "v is not proto.Message"
+}
+
+// Marshal marshals the given protobuf's message into watermill's Message.
+func (m ProtoMarshaler) Marshal(v interface{}) (*message.Message, error) {
+	protoMsg, ok := v.(proto.Message)
+	if !ok {
+		return nil, errors.WithStack(NoProtoMessageError{v})
+	}
+
+	b, err := proto.Marshal(protoMsg)
+	if err != nil {
+		return nil, err
+	}
+
+	msg := message.NewMessage(
+		m.newUUID(),
+		b,
+	)
+	msg.Metadata.Set("name", m.Name(v))
+
+	return msg, nil
+}
+
+func (m ProtoMarshaler) newUUID() string {
+	if m.NewUUID != nil {
+		return m.NewUUID()
+	}
+
+	// default
+	return watermill.NewUUID()
+}
+
+// Unmarshal unmarshals given watermill's Message into protobuf's message.
+func (ProtoMarshaler) Unmarshal(msg *message.Message, v interface{}) (err error) {
+	protoV, ok := v.(proto.Message)
+	if !ok {
+		return errors.WithStack(NoProtoMessageError{v})
+	}
+
+	return proto.Unmarshal(msg.Payload, protoV)
+}
+
+// Name returns the command or event's name.
+func (m ProtoMarshaler) Name(cmdOrEvent interface{}) string {
+	if m.GenerateName != nil {
+		return m.GenerateName(cmdOrEvent)
+	}
+
+	return FullyQualifiedStructName(cmdOrEvent)
+}
+
+// NameFromMessage returns the metadata name value for a given Message.
+func (m ProtoMarshaler) NameFromMessage(msg *message.Message) string {
+	return msg.Metadata.Get("name")
+}