[Feature] Support import external proto in goctl.

[chaozwn]

Is your feature request related to a problem? Please describe.
In some scenarios, we may need to perform automatic validation of rpc parameters. for example, protovalidate-go library is introduced to automatically validate req.

1. This is the proto that I generated. It contains an external proto file and a new validation syntax.
   
   Next, I can verify req by directly generating the code automatically.
   

Describe the solution you'd like

1. In fact, I have tested that it is now perfectly possible to use buf-cli instead of protoc to generate go files for grpc and proto.
   The following is my solution case.

buf.gen.yaml

version: v2

plugins:
  - remote: buf.build/grpc/go
    out: ../
  - remote: buf.build/protocolbuffers/go
    out: ../
  - remote: buf.build/bufbuild/validate-go
    out: ../

buf.yaml

version: v2

name: buf.build/tutorials/lint
breaking:
  use:
    - FILE
lint:
  use:
    - DEFAULT
  except:
    - SERVICE_SUFFIX
    - FIELD_LOWER_SNAKE_CASE
    - PACKAGE_LOWER_SNAKE_CASE
    - PACKAGE_SAME_SWIFT_PREFIX
    - PACKAGE_VERSION_SUFFIX
    - ENUM_NO_ALLOW_ALIAS
    - BASIC
    - RPC_REQUEST_STANDARD_NAME
    - RPC_RESPONSE_STANDARD_NAME

deps:
  - buf.build/bufbuild/protovalidate

update dep

buf dep update

generate grpc & proto file

buf generate --path ./app/todo/cmd/rpc/pb/todo.proto --output ./app/todo/cmd/rpc/pb

In summary, we can get exactly the same grpc file and pb.go file with proto introduced.

But now there is a very fatal problem, I have import other proto files in proto early, resulting in the system's built-in generation function directly reported an error.

Describe alternatives you've considered

So I wonder if this syntax can be supported. goctl rpc buf xx.proto --xxx. If you are OK with my idea, I can try to submit a pr along these lines.

Additional context
Add any other context or screenshots about the feature request here.

[kesonan]

maybe you can try with -I $external_path, goctl rpc protoc $proto ... -I $external_path --zrpc_out $dir --style=goZero --home $home -m

[chaozwn]

maybe you can try with -I $external_path, goctl rpc protoc $proto ... -I $external_path --zrpc_out $dir --style=goZero --home $home -m

first this directive has no way of taking effect, and the external proto code is not compiled by default

[fireice009]

I make it work. You also need -I for the path of .proto file. e.g. goctl rpc protoc -I ../../common/protobuf/ -I api/proto api/proto/user.proto --go_out=api --go-grpc_out=api --zrpc_out=api --client=true -m

[fireice009]

I get a issue on gateway with importing validate.proto.

1. Execute commands and got 3 *.pb files.

	protoc -I ../../common/protobuf/ -I api/proto --descriptor_set_out=api/asset/user.pb api/proto/user.proto
	protoc -I ../../common/protobuf/ --descriptor_set_out=api/asset/validate.pb ../../common/protobuf/validate.proto
	protoc -I ../../common/protobuf/google/protobuf --descriptor_set_out=api/asset/google/protobuf/descriptor.pb ../../common/protobuf/google/protobuf/descriptor.proto   # try 1
	protoc -I ../../common/protobuf/google/protobuf --descriptor_set_out=api/asset/descriptor.pb ../../common/protobuf/google/protobuf/descriptor.proto   # try 2

2. gateway config

      ProtoSets:
        - asset/user.pb
        - asset/validate.pb
        - asset/google/protobuf/descriptor.pb  # try 1
        - asset/descriptor.pb # try 2

3. Run gateway service, and get the error msg no descriptor found for "google/protobuf/descriptor.proto"

[fireice009]

I get a issue on gateway with importing validate.proto.

1. Execute commands and got 3 *.pb files.

	protoc -I ../../common/protobuf/ -I api/proto --descriptor_set_out=api/asset/user.pb api/proto/user.proto
	protoc -I ../../common/protobuf/ --descriptor_set_out=api/asset/validate.pb ../../common/protobuf/validate.proto
	protoc -I ../../common/protobuf/google/protobuf --descriptor_set_out=api/asset/google/protobuf/descriptor.pb ../../common/protobuf/google/protobuf/descriptor.proto   # try 1
	protoc -I ../../common/protobuf/google/protobuf --descriptor_set_out=api/asset/descriptor.pb ../../common/protobuf/google/protobuf/descriptor.proto   # try 2

2. gateway config

      ProtoSets:
        - asset/user.pb
        - asset/validate.pb
        - asset/google/protobuf/descriptor.pb  # try 1
        - asset/descriptor.pb # try 2

3. Run gateway service, and get the error msg no descriptor found for "google/protobuf/descriptor.proto"

forget it. it work by adding --include_imports