Is there any way standard way in pants to add some additional validation to proto?

proto3

is very relaxed for the sake of compatibility, but am looking for a way not to have to write validation into the endpoints. I'm looking for something that after we deserialize the proto we can check for what we consider a valid message that is a subset of what proto would allow, string not being empty, int's not being 0 etc. Something like a

jsonschema

validator layer for JSON. I was looking at

protoc-gen-validate

but it seems like I would have to swap out the whole

proto

compiler and give it access to some

go

resources. https://github.com/envoyproxy/protoc-gen-validate wondering if anyone else has found a good solution.

the

--descriptor_set_out=FILE

option to

protoc

will write metadata about the protobufs to FILE (in protobuf format of course)

the --descriptor_set_out=FILE option to protoc will write metadata about the protobufs to FILE

Like the

./pants export-codegen

goal? Not sure how automated you mean by "deserialize"

so the following is one possible solution: 1. add `fmt`/`lint` support for protobuf files 2. write a “protobuf metadata” lint plugin that obtains the descriptor set and then asks the engine to resolve a

ProtobufMetadataLintRequest

using a union rule where particular metadata linters can register. 3. in a particular repo, add a pants plugin to hook

ProtobufMetadataLintRequest

via

UnionRule

and process any of its`ProtobufMetadataLintRequest` subclass that come to it,

I'm not really worried about the current output of the code generation, well might want to modify it at some point. Basically was asking if there is a way to add annotations to

proto

files such that I don't have to write a bunch of code to check fields are not the default. Trying to get grpc off the ground but switching from json with a schema validator to proto if we have to have to hand write the validation might be a tough sell.

Basically was asking if there is a way to add annotations to 

proto

 files such that I don’t have to write a bunch of code to check fields are not the default.

not that I know of. this is a general problem with any user of protobuf.