1  # Version Wrapper Implementation
  2  
  3  ## Overview
  4  
  5  The version wrapper implementation provides a robust abstraction for adding file versioning capabilities to any storage provider. This implementation follows a wrapper pattern where a standard provider can be wrapped with versioning capabilities.
  6  
  7  ## Core Components
  8  
  9  ### 1. Version Wrapper Adapter
 10  
 11  The `VersionedProviderAdapter` in `internal/cloud/provider/v2/wrappers/version_wrapper_adapter.go` serves as a bridge between the standard provider interface and the versioned provider. It adapts the Provider interface to the versioned functionality, maintaining compatibility with the existing provider system.
 12  
 13  Key features:
 14  - Adapts standard Provider interface to versioned operations
 15  - Maintains all original provider operations
 16  - Adds version-specific metadata handling
 17  - Ensures compatibility with provider factory system
 18  
 19  ### 2. Version Wrapper Factory
 20  
 21  The `VersionWrapperFactory` in `internal/cloud/provider/v2/wrappers/version_wrapper_factory.go` provides factory methods for creating versioned provider instances from existing providers.
 22  
 23  Key features:
 24  - Easy provider wrapping with `WrapProvider` method
 25  - Configuration customization with `WithConfig`
 26  - Integration with the provider factory system
 27  - Provider creation and initialization support
 28  
 29  ### 3. Storage Interfaces
 30  
 31  The storage interfaces in `internal/cloud/provider/v2/wrappers/storage_interfaces.go` define the underlying abstractions for file operations that support versioning, including metadata handling and file representations.
 32  
 33  ### 4. Demo Implementation
 34  
 35  A self-contained demo in `cmd/version-wrapper-demo/main.go` demonstrates the versioning capabilities, including:
 36  - Version creation during file updates
 37  - File history tracking
 38  - Delete markers
 39  - Version listing
 40  - Version metadata handling
 41  
 42  ## Implementation Features
 43  
 44  1. **Transparent Versioning**: Files are versioned automatically when changed, with minimal impact on client code.
 45  
 46  2. **Delete Markers**: When files are deleted, a delete marker is created instead of actually removing version history.
 47  
 48  3. **Version History**: Full version history is maintained, allowing for retrieval of any previous version.
 49  
 50  4. **Efficient Storage**: Only changed files are versioned, with identical content detection to avoid unnecessary versions.
 51  
 52  5. **Version Metadata**: Each version includes rich metadata like timestamps, checksums, and custom user metadata.
 53  
 54  6. **Provider Compatibility**: Works with any provider that implements the basic Provider interface.
 55  
 56  ## Usage Pattern
 57  
 58  ```go
 59  // Create a provider
 60  baseProvider := someProvider.NewProvider()
 61  
 62  // Create a version wrapper factory
 63  factory := wrappers.NewVersionWrapperFactory()
 64  
 65  // Optionally configure versioning
 66  factory.WithConfig(wrappers.VersionConfig{
 67      Enabled: true,
 68      RetentionDays: 30,
 69      MaxVersionsPerFile: 10,
 70  })
 71  
 72  // Wrap the provider with versioning
 73  versionedProvider := factory.WrapProvider(baseProvider)
 74  
 75  // Initialize the versioned provider
 76  err := versionedProvider.Initialize(ctx)
 77  if err != nil {
 78      log.Fatalf("failed to initialize: %v", err)
 79  }
 80  
 81  // Use the versioned provider as you would a regular provider
 82  err = versionedProvider.Put(ctx, "path/to/file.txt", reader)
 83  ```
 84  
 85  ## Future Enhancements
 86  
 87  1. **Retention Policies**: Implement automated version pruning based on age or count.
 88  
 89  2. **Version Tagging**: Allow specific versions to be tagged for retention.
 90  
 91  3. **Bulk Version Operations**: Add efficient operations for bulk version management.
 92  
 93  4. **Version Compression**: Implement delta compression between versions.
 94  
 95  5. **Cross-Provider Migration**: Enable version history transfer between different providers.
 96  
 97  6. **Enhanced Security**: Add version-specific encryption and verification.
 98  
 99  ## Test Coverage
100  
101  The versioning system includes comprehensive tests covering:
102  - Basic versioning operations
103  - Delete markers and restoration
104  - Version metadata handling
105  - Edge cases like empty files and conflicts