feat: Add content-defined chunking deduplication
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- Gear hash CDC with 92%+ overlap on shifted data
- SHA-256 content-addressed chunk storage
- AES-256-GCM per-chunk encryption (optional)
- Gzip compression (default enabled)
- SQLite index for fast lookups
- JSON manifests with SHA-256 verification

Commands: dedup backup/restore/list/stats/delete/gc

Resistance is futile.
This commit is contained in:
2026-01-07 15:02:41 +01:00
parent b99b05fedb
commit c519f08ef2
9 changed files with 2002 additions and 12 deletions

579
cmd/dedup.go Normal file
View File

@@ -0,0 +1,579 @@
package cmd
import (
"crypto/sha256"
"encoding/hex"
"fmt"
"io"
"os"
"path/filepath"
"strings"
"time"
"dbbackup/internal/dedup"
"github.com/spf13/cobra"
)
var dedupCmd = &cobra.Command{
Use: "dedup",
Short: "Deduplicated backup operations",
Long: `Content-defined chunking deduplication for space-efficient backups.
Similar to restic/borgbackup but with native database dump support.
Features:
- Content-defined chunking (CDC) with Buzhash rolling hash
- SHA-256 content-addressed storage
- AES-256-GCM encryption (optional)
- Gzip compression (optional)
- SQLite index for fast lookups
Storage Structure:
<dedup-dir>/
chunks/ # Content-addressed chunk files
ab/cdef... # Sharded by first 2 chars of hash
manifests/ # JSON manifest per backup
chunks.db # SQLite index`,
}
var dedupBackupCmd = &cobra.Command{
Use: "backup <file>",
Short: "Create a deduplicated backup of a file",
Long: `Chunk a file using content-defined chunking and store deduplicated chunks.
Example:
dbbackup dedup backup /path/to/database.dump
dbbackup dedup backup mydb.sql --compress --encrypt`,
Args: cobra.ExactArgs(1),
RunE: runDedupBackup,
}
var dedupRestoreCmd = &cobra.Command{
Use: "restore <manifest-id> <output-file>",
Short: "Restore a backup from its manifest",
Long: `Reconstruct a file from its deduplicated chunks.
Example:
dbbackup dedup restore 2026-01-07_120000_mydb /tmp/restored.dump
dbbackup dedup list # to see available manifests`,
Args: cobra.ExactArgs(2),
RunE: runDedupRestore,
}
var dedupListCmd = &cobra.Command{
Use: "list",
Short: "List all deduplicated backups",
RunE: runDedupList,
}
var dedupStatsCmd = &cobra.Command{
Use: "stats",
Short: "Show deduplication statistics",
RunE: runDedupStats,
}
var dedupGCCmd = &cobra.Command{
Use: "gc",
Short: "Garbage collect unreferenced chunks",
Long: `Remove chunks that are no longer referenced by any manifest.
Run after deleting old backups to reclaim space.`,
RunE: runDedupGC,
}
var dedupDeleteCmd = &cobra.Command{
Use: "delete <manifest-id>",
Short: "Delete a backup manifest (chunks cleaned by gc)",
Args: cobra.ExactArgs(1),
RunE: runDedupDelete,
}
// Flags
var (
dedupDir string
dedupCompress bool
dedupEncrypt bool
dedupKey string
dedupName string
dedupDBType string
dedupDBName string
dedupDBHost string
)
func init() {
rootCmd.AddCommand(dedupCmd)
dedupCmd.AddCommand(dedupBackupCmd)
dedupCmd.AddCommand(dedupRestoreCmd)
dedupCmd.AddCommand(dedupListCmd)
dedupCmd.AddCommand(dedupStatsCmd)
dedupCmd.AddCommand(dedupGCCmd)
dedupCmd.AddCommand(dedupDeleteCmd)
// Global dedup flags
dedupCmd.PersistentFlags().StringVar(&dedupDir, "dedup-dir", "", "Dedup storage directory (default: $BACKUP_DIR/dedup)")
dedupCmd.PersistentFlags().BoolVar(&dedupCompress, "compress", true, "Compress chunks with gzip")
dedupCmd.PersistentFlags().BoolVar(&dedupEncrypt, "encrypt", false, "Encrypt chunks with AES-256-GCM")
dedupCmd.PersistentFlags().StringVar(&dedupKey, "key", "", "Encryption key (hex) or use DBBACKUP_DEDUP_KEY env")
// Backup-specific flags
dedupBackupCmd.Flags().StringVar(&dedupName, "name", "", "Optional backup name")
dedupBackupCmd.Flags().StringVar(&dedupDBType, "db-type", "", "Database type (postgres/mysql)")
dedupBackupCmd.Flags().StringVar(&dedupDBName, "db-name", "", "Database name")
dedupBackupCmd.Flags().StringVar(&dedupDBHost, "db-host", "", "Database host")
}
func getDedupDir() string {
if dedupDir != "" {
return dedupDir
}
if cfg != nil && cfg.BackupDir != "" {
return filepath.Join(cfg.BackupDir, "dedup")
}
return filepath.Join(os.Getenv("HOME"), "db_backups", "dedup")
}
func getEncryptionKey() string {
if dedupKey != "" {
return dedupKey
}
return os.Getenv("DBBACKUP_DEDUP_KEY")
}
func runDedupBackup(cmd *cobra.Command, args []string) error {
inputPath := args[0]
// Open input file
file, err := os.Open(inputPath)
if err != nil {
return fmt.Errorf("failed to open input file: %w", err)
}
defer file.Close()
info, err := file.Stat()
if err != nil {
return fmt.Errorf("failed to stat input file: %w", err)
}
// Setup dedup storage
basePath := getDedupDir()
encKey := ""
if dedupEncrypt {
encKey = getEncryptionKey()
if encKey == "" {
return fmt.Errorf("encryption enabled but no key provided (use --key or DBBACKUP_DEDUP_KEY)")
}
}
store, err := dedup.NewChunkStore(dedup.StoreConfig{
BasePath: basePath,
Compress: dedupCompress,
EncryptionKey: encKey,
})
if err != nil {
return fmt.Errorf("failed to open chunk store: %w", err)
}
manifestStore, err := dedup.NewManifestStore(basePath)
if err != nil {
return fmt.Errorf("failed to open manifest store: %w", err)
}
index, err := dedup.NewChunkIndex(basePath)
if err != nil {
return fmt.Errorf("failed to open chunk index: %w", err)
}
defer index.Close()
// Generate manifest ID
now := time.Now()
manifestID := now.Format("2006-01-02_150405")
if dedupDBName != "" {
manifestID += "_" + dedupDBName
} else {
base := filepath.Base(inputPath)
ext := filepath.Ext(base)
manifestID += "_" + strings.TrimSuffix(base, ext)
}
fmt.Printf("Creating deduplicated backup: %s\n", manifestID)
fmt.Printf("Input: %s (%s)\n", inputPath, formatBytes(info.Size()))
fmt.Printf("Store: %s\n", basePath)
// Hash the entire file for verification
file.Seek(0, 0)
h := sha256.New()
io.Copy(h, file)
fileHash := hex.EncodeToString(h.Sum(nil))
file.Seek(0, 0)
// Chunk the file
chunker := dedup.NewChunker(file, dedup.DefaultChunkerConfig())
var chunks []dedup.ChunkRef
var totalSize, storedSize int64
var chunkCount, newChunks int
startTime := time.Now()
for {
chunk, err := chunker.Next()
if err == io.EOF {
break
}
if err != nil {
return fmt.Errorf("chunking failed: %w", err)
}
chunkCount++
totalSize += int64(chunk.Length)
// Store chunk (deduplication happens here)
isNew, err := store.Put(chunk)
if err != nil {
return fmt.Errorf("failed to store chunk: %w", err)
}
if isNew {
newChunks++
storedSize += int64(chunk.Length)
// Record in index
index.AddChunk(chunk.Hash, chunk.Length, chunk.Length)
}
chunks = append(chunks, dedup.ChunkRef{
Hash: chunk.Hash,
Offset: chunk.Offset,
Length: chunk.Length,
})
// Progress
if chunkCount%1000 == 0 {
fmt.Printf("\r Processed %d chunks, %d new...", chunkCount, newChunks)
}
}
duration := time.Since(startTime)
// Calculate dedup ratio
dedupRatio := 0.0
if totalSize > 0 {
dedupRatio = 1.0 - float64(storedSize)/float64(totalSize)
}
// Create manifest
manifest := &dedup.Manifest{
ID: manifestID,
Name: dedupName,
CreatedAt: now,
DatabaseType: dedupDBType,
DatabaseName: dedupDBName,
DatabaseHost: dedupDBHost,
Chunks: chunks,
OriginalSize: totalSize,
StoredSize: storedSize,
ChunkCount: chunkCount,
NewChunks: newChunks,
DedupRatio: dedupRatio,
Encrypted: dedupEncrypt,
Compressed: dedupCompress,
SHA256: fileHash,
}
if err := manifestStore.Save(manifest); err != nil {
return fmt.Errorf("failed to save manifest: %w", err)
}
if err := index.AddManifest(manifest); err != nil {
log.Warn("Failed to index manifest", "error", err)
}
fmt.Printf("\r \r")
fmt.Printf("\nBackup complete!\n")
fmt.Printf(" Manifest: %s\n", manifestID)
fmt.Printf(" Chunks: %d total, %d new\n", chunkCount, newChunks)
fmt.Printf(" Original: %s\n", formatBytes(totalSize))
fmt.Printf(" Stored: %s (new data)\n", formatBytes(storedSize))
fmt.Printf(" Dedup ratio: %.1f%%\n", dedupRatio*100)
fmt.Printf(" Duration: %s\n", duration.Round(time.Millisecond))
fmt.Printf(" Throughput: %s/s\n", formatBytes(int64(float64(totalSize)/duration.Seconds())))
return nil
}
func runDedupRestore(cmd *cobra.Command, args []string) error {
manifestID := args[0]
outputPath := args[1]
basePath := getDedupDir()
encKey := ""
if dedupEncrypt {
encKey = getEncryptionKey()
}
store, err := dedup.NewChunkStore(dedup.StoreConfig{
BasePath: basePath,
Compress: dedupCompress,
EncryptionKey: encKey,
})
if err != nil {
return fmt.Errorf("failed to open chunk store: %w", err)
}
manifestStore, err := dedup.NewManifestStore(basePath)
if err != nil {
return fmt.Errorf("failed to open manifest store: %w", err)
}
manifest, err := manifestStore.Load(manifestID)
if err != nil {
return fmt.Errorf("failed to load manifest: %w", err)
}
fmt.Printf("Restoring backup: %s\n", manifestID)
fmt.Printf(" Created: %s\n", manifest.CreatedAt.Format(time.RFC3339))
fmt.Printf(" Size: %s\n", formatBytes(manifest.OriginalSize))
fmt.Printf(" Chunks: %d\n", manifest.ChunkCount)
// Create output file
outFile, err := os.Create(outputPath)
if err != nil {
return fmt.Errorf("failed to create output file: %w", err)
}
defer outFile.Close()
h := sha256.New()
writer := io.MultiWriter(outFile, h)
startTime := time.Now()
for i, ref := range manifest.Chunks {
chunk, err := store.Get(ref.Hash)
if err != nil {
return fmt.Errorf("failed to read chunk %d (%s): %w", i, ref.Hash[:8], err)
}
if _, err := writer.Write(chunk.Data); err != nil {
return fmt.Errorf("failed to write chunk %d: %w", i, err)
}
if (i+1)%1000 == 0 {
fmt.Printf("\r Restored %d/%d chunks...", i+1, manifest.ChunkCount)
}
}
duration := time.Since(startTime)
restoredHash := hex.EncodeToString(h.Sum(nil))
fmt.Printf("\r \r")
fmt.Printf("\nRestore complete!\n")
fmt.Printf(" Output: %s\n", outputPath)
fmt.Printf(" Duration: %s\n", duration.Round(time.Millisecond))
// Verify hash
if manifest.SHA256 != "" {
if restoredHash == manifest.SHA256 {
fmt.Printf(" Verification: ✓ SHA-256 matches\n")
} else {
fmt.Printf(" Verification: ✗ SHA-256 MISMATCH!\n")
fmt.Printf(" Expected: %s\n", manifest.SHA256)
fmt.Printf(" Got: %s\n", restoredHash)
return fmt.Errorf("integrity verification failed")
}
}
return nil
}
func runDedupList(cmd *cobra.Command, args []string) error {
basePath := getDedupDir()
manifestStore, err := dedup.NewManifestStore(basePath)
if err != nil {
return fmt.Errorf("failed to open manifest store: %w", err)
}
manifests, err := manifestStore.ListAll()
if err != nil {
return fmt.Errorf("failed to list manifests: %w", err)
}
if len(manifests) == 0 {
fmt.Println("No deduplicated backups found.")
fmt.Printf("Store: %s\n", basePath)
return nil
}
fmt.Printf("Deduplicated Backups (%s)\n\n", basePath)
fmt.Printf("%-30s %-12s %-10s %-10s %s\n", "ID", "SIZE", "DEDUP", "CHUNKS", "CREATED")
fmt.Println(strings.Repeat("-", 80))
for _, m := range manifests {
fmt.Printf("%-30s %-12s %-10.1f%% %-10d %s\n",
truncateStr(m.ID, 30),
formatBytes(m.OriginalSize),
m.DedupRatio*100,
m.ChunkCount,
m.CreatedAt.Format("2006-01-02 15:04"),
)
}
return nil
}
func runDedupStats(cmd *cobra.Command, args []string) error {
basePath := getDedupDir()
index, err := dedup.NewChunkIndex(basePath)
if err != nil {
return fmt.Errorf("failed to open chunk index: %w", err)
}
defer index.Close()
stats, err := index.Stats()
if err != nil {
return fmt.Errorf("failed to get stats: %w", err)
}
store, err := dedup.NewChunkStore(dedup.StoreConfig{BasePath: basePath})
if err != nil {
return fmt.Errorf("failed to open chunk store: %w", err)
}
storeStats, err := store.Stats()
if err != nil {
log.Warn("Failed to get store stats", "error", err)
}
fmt.Printf("Deduplication Statistics\n")
fmt.Printf("========================\n\n")
fmt.Printf("Store: %s\n", basePath)
fmt.Printf("Manifests: %d\n", stats.TotalManifests)
fmt.Printf("Unique chunks: %d\n", stats.TotalChunks)
fmt.Printf("Total raw size: %s\n", formatBytes(stats.TotalSizeRaw))
fmt.Printf("Stored size: %s\n", formatBytes(stats.TotalSizeStored))
fmt.Printf("Dedup ratio: %.1f%%\n", stats.DedupRatio*100)
fmt.Printf("Space saved: %s\n", formatBytes(stats.TotalSizeRaw-stats.TotalSizeStored))
if storeStats != nil {
fmt.Printf("Disk usage: %s\n", formatBytes(storeStats.TotalSize))
fmt.Printf("Directories: %d\n", storeStats.Directories)
}
return nil
}
func runDedupGC(cmd *cobra.Command, args []string) error {
basePath := getDedupDir()
index, err := dedup.NewChunkIndex(basePath)
if err != nil {
return fmt.Errorf("failed to open chunk index: %w", err)
}
defer index.Close()
store, err := dedup.NewChunkStore(dedup.StoreConfig{
BasePath: basePath,
Compress: dedupCompress,
})
if err != nil {
return fmt.Errorf("failed to open chunk store: %w", err)
}
// Find orphaned chunks
orphans, err := index.ListOrphanedChunks()
if err != nil {
return fmt.Errorf("failed to find orphaned chunks: %w", err)
}
if len(orphans) == 0 {
fmt.Println("No orphaned chunks to clean up.")
return nil
}
fmt.Printf("Found %d orphaned chunks\n", len(orphans))
var freed int64
for _, hash := range orphans {
if meta, _ := index.GetChunk(hash); meta != nil {
freed += meta.SizeStored
}
if err := store.Delete(hash); err != nil {
log.Warn("Failed to delete chunk", "hash", hash[:8], "error", err)
continue
}
if err := index.RemoveChunk(hash); err != nil {
log.Warn("Failed to remove chunk from index", "hash", hash[:8], "error", err)
}
}
fmt.Printf("Deleted %d chunks, freed %s\n", len(orphans), formatBytes(freed))
// Vacuum the index
if err := index.Vacuum(); err != nil {
log.Warn("Failed to vacuum index", "error", err)
}
return nil
}
func runDedupDelete(cmd *cobra.Command, args []string) error {
manifestID := args[0]
basePath := getDedupDir()
manifestStore, err := dedup.NewManifestStore(basePath)
if err != nil {
return fmt.Errorf("failed to open manifest store: %w", err)
}
index, err := dedup.NewChunkIndex(basePath)
if err != nil {
return fmt.Errorf("failed to open chunk index: %w", err)
}
defer index.Close()
// Load manifest to decrement chunk refs
manifest, err := manifestStore.Load(manifestID)
if err != nil {
return fmt.Errorf("failed to load manifest: %w", err)
}
// Decrement reference counts
for _, ref := range manifest.Chunks {
index.DecrementRef(ref.Hash)
}
// Delete manifest
if err := manifestStore.Delete(manifestID); err != nil {
return fmt.Errorf("failed to delete manifest: %w", err)
}
if err := index.RemoveManifest(manifestID); err != nil {
log.Warn("Failed to remove manifest from index", "error", err)
}
fmt.Printf("Deleted backup: %s\n", manifestID)
fmt.Println("Run 'dbbackup dedup gc' to reclaim space from unreferenced chunks.")
return nil
}
// Helper functions
func formatBytes(b int64) string {
const unit = 1024
if b < unit {
return fmt.Sprintf("%d B", b)
}
div, exp := int64(unit), 0
for n := b / unit; n >= unit; n /= unit {
div *= unit
exp++
}
return fmt.Sprintf("%.1f %cB", float64(b)/float64(div), "KMGTPE"[exp])
}
func truncateStr(s string, max int) string {
if len(s) <= max {
return s
}
return s[:max-3] + "..."
}