Code Investigation Guide

Quick Start

Proto (API contract) -> Handler -> Usecase -> Repository -> DB

Use this flow to trace any feature. Start from what you know.

Key Locations

| What | Where | |------|-------| | API contracts | schema/proto/rapid/{admin_api,public_api,debug_api}/v1/ | | Handlers | internal/infrastructure/grpc/internal/handler/{admin,public,debug}/ | | Usecases | internal/usecase/*_impl.go | | Domain models | internal/domain/model/ | | Repository interfaces | internal/domain/repository/ | | Repository implementations | internal/infrastructure/{mysql,postgresql,spanner}/repository/ | | DI wiring | internal/infrastructure/dependency/dependency.go | | Auth interceptors | internal/infrastructure/grpc/internal/interceptor/ |

Investigation Patterns

Find an API endpoint

# Find by HTTP path
grep "/admin/v1/tenants" schema/proto/rapid/

# Find by RPC name
grep "CreateTenant" internal/infrastructure/grpc/internal/handler/admin/

Trace request flow

1. Find RPC in schema/proto/rapid/**/api.proto
2. Find handler in internal/infrastructure/grpc/internal/handler/{actor}/
3. Find interactor in internal/usecase/*_impl.go
4. Find repository in internal/domain/repository/ (interface) and internal/infrastructure/*/repository/ (impl)

Find all usages of a type

# Find usages of a domain model
grep "model.Staff" internal/

# Find usages of a repository method
grep "staffRepository.Get" internal/usecase/

Check authorization logic

• Session extraction: internal/infrastructure/grpc/internal/interceptor/session_interceptor/
• Access control: internal/infrastructure/grpc/internal/interceptor/authorization_interceptor/
• Role checks in usecase: look for param.AdminRole.IsRoot() patterns

Impact analysis before changes

1. Find interface definition in internal/domain/repository/
2. Find all implementations in internal/infrastructure/*/repository/
3. Find all callers in internal/usecase/
4. Check mock generation: internal/domain/repository/mock/

Common Search Patterns

| Goal | Search | |------|--------| | Find entity by name | grep "type Staff struct" internal/domain/model/ | | Find error definition | grep "StaffNotFoundErr" internal/domain/errors/ | | Find input validation | grep "type AdminCreateStaff" internal/usecase/input/ | | Find marshaller | grep "StaffToModel\|StaffToPb" internal/ | | Find DI registration | grep "AdminStaffInteractor" internal/infrastructure/dependency/ |

Tips

• Start from proto for API-related investigation
• Start from domain model for business logic investigation
• Check dependency.go to understand how components are wired
• Marshallers exist in two places: repository (DB<->domain) and handler (domain<->proto)