Advanced Usage

Working with Multiple Proto Files

Project Structure Example

src/proto  
├── common  
│   └── address.proto  # Shared definitions  
└── user  
    └── user.proto     # Main service

Docker Compose Configuration

services:  
  gripmock:  
    image: bavix/gripmock  
    volumes:  
      - ./src/proto:/proto:ro  
      - ./mocks/user:/stubs:ro  
    command: --stub=/stubs --imports=/proto /proto/user/user.proto /proto/common/address.proto

Key Points

• Use --imports=/proto to define the root directory for imports
• Explicitly list all required .proto files in the command to avoid File not found errors
• Ensure volume mappings (./src/proto:/proto) match the paths in your proto imports

---

Stub Configuration for Special Cases

Stub for Parameterless Methods
For RPC methods with no input (e.g., rpc GetData(Empty)):

{  
  "service": "user.UserService",  
  "method": "GetData",  
  "input": { "matches": {} },  // Empty input matcher  
  "output": { "data": "test" }  
}

Notes

• Use { "matches": {} } to match empty input
• Avoid omitting input field to prevent validation errors

---

Troubleshooting

Common Issues & Fixes

1. Import Errors

   • Error: common/address.proto: File not found
     Fix:
     • Add --imports=/proto to specify the root directory
     • Verify proto files are listed in the command

2. Docker Command Syntax

   • Error: unknown flag or invalid syntax
     Fix: Use one of these formats in docker-compose.yml:

     # Single-line  
     command: --stub=/stubs --imports=/proto /proto/user/user.proto  
     
     # Multi-line  
     command: |  
       --stub=/stubs \  
       --imports=/proto \  
       /proto/user/user.proto

3. Proto Path Mismatch

   • Error: File does not reside within any path specified using --proto_path
     Fix: Ensure all imported files are under directories specified in --imports

Validation Steps

1. Check Docker logs: docker logs <container_id>
2. Verify proto files compile locally with protoc