go - 即时更改序列化的 protobuf 消息？

Question

是否可以更改(追加、合并等)序列化的 protobuf 消息而无需先对其进行解码？我正在使用 golang/protobuf package .

理想情况下，我希望有一个服务可以接收传入的序列化消息，即时附加一些字段，然后将消息传递给下一个服务——有点像中间件，可以在其中添加额外的信息有效载荷，而不必不断地解码和编码。

一些上下文:系统是实时的，所以我想尽可能地减少开销。

Answer 1

来自documentation on protocol buffers :

As you know, a protocol buffer message is a series of key-value pairs. The binary version of a message just uses the field's number as the key – the name and declared type for each field can only be determined on the decoding end by referencing the message type's definition (i.e. the .proto file).

When a message is encoded, the keys and values are concatenated into a byte stream. When the message is being decoded, the parser needs to be able to skip fields that it doesn't recognize. This way, new fields can be added to a message without breaking old programs that do not know about them. To this end, the "key" for each pair in a wire-format message is actually two values – the field number from your .proto file, plus a wire type that provides just enough information to find the length of the following value.

因此，要将字段附加到编码的 Protocol Buffer 消息，您可以简单地将编码字段附加到字节流/slice 的末尾。