# Pattern: Service

## Responsibility

Business rules, authorization, orchestration, transactions.

## Shape

```go
type ReportRepo interface {
    SaveReport(ctx context.Context, r *model.Report) error
}

type ReportService struct {
    repo ReportRepo
}

func (s *ReportService) Decode(ctx context.Context, in DecodeInput) (*DecodeOutput, error) {
    if err := in.Validate(); err != nil {
        return nil, fmt.Errorf("validate decode: %w", err)
    }
    // rules / engine
    // persist via repo
    return out, nil
}
```

## Never

- Import `gin`
- Bypass repo with ad-hoc SQL drivers scattered around