Versioning of gRPC service / breaking changes in gRPC contract

[espjak]

Hi,

What is best way to solve breaking changes in the gRPC contract. I had a case recently where I had to change a model that was used by the gRPC service, as in I changed the datatype of a DataMember but name is the same. The server in this case is a micro service that multiple clients are using. Updating the micro service will require all my clients to also update its contract definition, this is not feasible to do all the time.

So what options are there in these cases?

• I could create a new MicroService, with the updated contract, and in the client update point to this one, but I will have to run multiple MicroServices.
• Introduce a new method in the contract (as far as I understand this is allowed and not BC) which uses the updated models. What I don't like here is that I would have to keep the "broken" model and duplicate a lot of code, also introduces a naming issues.
• I see there are some versioning support in https://docs.microsoft.com/en-us/aspnet/core/grpc/versioning?view=aspnetcore-6.0 via package naming. Is this supported / any way to mimic this in protobuf-net.Grpc? Even if I versioned the service contract though, I do not see what I should do with the models.

Do you have any input on how to solve this? Or point me to a page, code examples etc. so I can read.

[mgravell]

Data member names aren't critical; only the field numbers - so if you have changed a field, one option might be to have the old field and number with a renamed "FooOld" name, marked [Obsolete], and the new field type and new number as "Foo", allowing your server code to check both. Is that an option? I will have to read the link on versioning to check what that is referring to.

[espjak]

That seems to be an okay solution. I will try it next time. Thanks for input.