Support for gogoproto

[kyessenov]

It seems that this tool only supports the standard goproto code generation output. I have noticed the following deviations for gogo:

• disregard of go_package annotation that allows multiple proto files to be combined into one package, to avoid circular dependencies between packages
• no support for gogoproto code generation optimization annotations:
  • gogoproto.nullable changes a pointer to an embedded struct for fields that are not nullable by construction
  • gogoproto.stdduration changes a duration from ptypes.Duration to time.Duration

What needs to be done to extend PGV with gogo support?

[rodaine]

disregard of go_package annotation that allows multiple proto files to be combined into one package, to avoid circular dependencies between packages

This is probably an oversight in the template, not using the correct package value. I can look into this.

no support for gogoproto code generation optimization annotations:

I haven't worked with gogoproto, so I don't have specifics here, but I'd say we should treat this as a different language target since it deviates in some fundamental ways from the official protoc-gen-go output. A lot could be reused between the two, though.

[freman]

Tis a good start to be sure to be sure, but I have run into an issue with (gogoproto.customname)

./dhcp.pb.validate.go:135:11: m.GetTtl undefined (type *InterfaceConfiguration has no field or method GetTtl, but does have GetTTL)

[kyessenov]

customname is not supported last time I checked.
It should not be hard to add extra handling for customname. Seems like you might need to override accessor here https://github.com/lyft/protoc-gen-validate/blob/master/templates/goshared/register.go#L88.

[rvolosatovs]

I added GoGo support to protoc-gen-star directly: lyft/protoc-gen-star#51
Using that functionality I added full support for customname/customtype/casttype/embeded: TheThingsIndustries@0065aca
And validation of non-nullable messages: TheThingsIndustries@228ba7a

If approach in lyft/protoc-gen-star#51 seems viable and it gets merged, I can open PR to this repo for improving the GoGo support.

FTR, in our fork (https://github.com/TheThingsIndustries/protoc-gen-validate) we added support for fielpaths in validators, so the caller can specify a subset of fields to validate. If no paths are specified - all fields are validated, same as the original plugin.

[coolyrat]

Is there any plan supporting gogoproto.embed? Embed reduce a lot of duplicate codes. Right now I have to skip the embed message.

message AdPrimaryKey {
    string media = 1;
    string name = 2;
}

message Ad {
    AdPrimaryKey pk = 1 [(gogoproto.embed) = true, (validate.rules).message.skip = true];
    AdType type = 2 [(validate.rules).enum.not_in = 0];

    enum AdType {
        NONE = 0;
        OTHERS = 1;
        VIDEO = 2;
    }
}

message UpdateAdRequest {
    AdPrimaryKey pk = 1 [(gogoproto.embed) = true, (validate.rules).message.skip = true];
    Ad ad = 2;
}

[monotone]

care about this too.

[rvolosatovs]

care about this too.

Given that the project is unmaintained for a while gogo/protobuf#691 I would not expect this to happen