Protobuf naming conventions

Question

Besides the rather short Google provided style guide, here are my thoughts on naming Google Protocol Buffer messages.

1. Use "Message" at the end of message types names.

   • This makes it easy to see in source code that a class is a protobuf generated class. This also has the advantage that if I have a rich domain specific class, then it can have the real name, say AddressBookMessage for the protobuf class and AddressBook for the real class.

2. For Java users, it appears that having java_outer_classname end in Protos is standard.

   • I didn't notice this initially, so my current protobuf classes are in com.example.project.protobuf.MyProtos , but I don't see a reason to keep it there given that we need to have a containing class, so it could be moved to com.example.protobuf.MyProtos unless there are no classes in the project's top package.

3. Start enums at 0 to match C/C++.

4. Use a singular name for a repeated field.

   • Most of the generated methods sound better with a singular field name, even if it is repeated, e.g. message->add_child(), instead of message->add_children() if one had a repeated child field.

Are there any other standards people use or differ from these?

Answer 1

Disclaimer: answer from a Googler using protobufs on a daily basis. I'm by no means representing Google in any way.

1. Don't do that. Compiled protocol buffers are just a class definition specified by the language you are using, with some improvements. Adding "Message" is extra verbosity. Normally you just use protocol buffers without other class definitions, and even if you use other class definitions, just import java_outer_classname and do a dot from that. You can even put full path of a thing in code to erase one line of import, no problem.

2. Although not specified officially, it sounds like a good suggestion, because normally you put more than one proto inside a folder.

3. You normally start with 0. See the protocol buffer language guide.

4. Yes. Read the following to get some feeling using it: https://developers.google.com/protocol-buffers/docs/javatutorial