Example 03: Importing Proto from a Subdirectory

This example demonstrates importing a proto file from a subdirectory.

Proto Definition

Two proto files with different go_package values:

• order.proto — Defines the OrderService, imports common/types.proto.

option go_package = "example.com/demo/pb";

• common/types.proto — Defines reusable pagination and sorting messages.

option go_package = "example.com/demo/pb/common";

order.proto imports common/types.proto from a subdirectory:

import "common/types.proto";

Note that the two files have different go_package values, so they compile into separate Go packages.

Generation Commands

First, initialize the output directory with a go.mod:

mkdir -p output && cd output && go mod init example.com/demo && cd ..

Then generate the code:

goctl rpc protoc order.proto \
  --go_out=output \
  --go-grpc_out=output \
  --zrpc_out=output \
  --go_opt=module=example.com/demo \
  --go-grpc_opt=module=example.com/demo \
  --module=example.com/demo \
  -I .

Generated directory structure:

output/
├── etc
│   └── ordersvc.yaml
├── go.mod
├── internal
│   ├── config
│   │   └── config.go
│   ├── logic
│   │   ├── getorderlogic.go
│   │   └── listorderslogic.go
│   ├── server
│   │   └── orderserviceserver.go
│   └── svc
│       └── servicecontext.go
├── orderservice
│   └── orderservice.go
├── ordersvc.go
└── pb
    ├── common
    │   └── types.pb.go
    ├── order.pb.go
    └── order_grpc.pb.go

Key Points

• Two proto files have different go_package values, so they compile into separate Go packages (pb/ and pb/common/).
• order.proto imports common/types.proto from a subdirectory.
• When imported protos have a different go_package, goctl automatically generates cross-package imports.
• The -I . flag tells protoc to search from the current directory, enabling it to find common/types.proto.