Update golangci-lint to v2.12.2 with canonical config (#62)

Updates golangci-lint to v2.12.2 everywhere it is pinned and installs the canonical `.golangci.yml`, then remediates every finding the new linter/config surfaces so `make check` is green.

## Version bump

- `Dockerfile` lint stage: `golangci/golangci-lint:v2.11.3-alpine` -> `v2.12.2-alpine` (digest-pinned, date comment updated)
- `Makefile` `deps` target: `go install` moved from the old v1 module path at `@latest` to the pinned `github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.12.2`
- `.golangci.yml` replaced with the canonical config (v2 schema; settings under `linters.settings` so the thresholds actually apply; `default: all` with the standard six disables)
- `script/bootstrap` installs golangci-lint via the system package manager and carries no version pin, so it is unchanged
- CI (`.gitea/workflows/check.yml`) only runs `script/cibuild`, so it needed no change

## Lint remediation

The canonical config surfaced ~3,300 findings across 56k lines. All are fixed, behavior-preserving; incorporates and supersedes the per-package mechanical passes already merged to `main` (refs #61). Highlights:

- `err113`: dynamic errors replaced with package sentinels + `%w` wrapping; comparisons via `errors.Is`
- `goprintffuncname`: printf-style helpers renamed with an `f` suffix (`ui.Writer` message methods, `cli.ReportErrorf`, `database.Fatalf`) and all call sites updated
- `revive` stutter renames: `blob.Handler`, `blob.WithReader`, `blob.ChunkPosition`, `storage.URL`, `storage.Info`; missing doc comments added
- `contextcheck`/`noctx`: `context.Context` threaded through `blob.Packer` and the scanner call sites; context-aware `exec`/`sql` variants
- `funlen`/`cyclop`/`gocognit`/`dupl`: oversized and duplicated functions split into focused helpers (production and test code)
- tests: `t.Parallel()` added where safe (global logger init kept in the serial phase for `-race`), `t.TempDir()`/`t.Helper()` adopted, several suites converted to external test packages
- `gosec`: bounded integer conversions, `ReadHeaderTimeout` on the test HTTP server; remaining warnings suppressed per-site with justifications
- remaining `nolint` directives are rare, targeted, and each carries a reason (e.g. `nilnil` not-found contract in the repository layer, fx module globals, on-disk snake_case struct tags)
- removed the deprecated `log.LogOptions` alias (callers migrated to `log.Options`)

`make check` (tests with `-race`, lint, fmt-check) passes.

Co-authored-by: sneak <sneak@sneak.berlin>
Reviewed-on: #62
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

internal/database/snapshots.go

@@ -11,19 +11,27 @@ import (
 	"sneak.berlin/go/vaultik/internal/types"
 )
 
+// SnapshotRepository provides access to the snapshots table and its
+// snapshot_files / snapshot_blobs association tables.
 type SnapshotRepository struct {
 	db *DB
 }
 
+// NewSnapshotRepository creates a SnapshotRepository backed by db.
 func NewSnapshotRepository(db *DB) *SnapshotRepository {
 	return &SnapshotRepository{db: db}
 }
 
-func (r *SnapshotRepository) Create(ctx context.Context, tx *sql.Tx, snapshot *Snapshot) error {
+// Create inserts a snapshot row, using tx when non-nil.
+func (r *SnapshotRepository) Create(
+	ctx context.Context, tx *sql.Tx, snapshot *Snapshot,
+) error {
 	query := `
-		INSERT INTO snapshots (id, hostname, vaultik_version, vaultik_git_revision, started_at, completed_at, 
-			file_count, chunk_count, blob_count, total_size, blob_size, blob_uncompressed_size, 
-			compression_ratio, compression_level, upload_bytes, upload_duration_ms)
+		INSERT INTO snapshots (id, hostname, vaultik_version,
+			vaultik_git_revision, started_at, completed_at,
+			file_count, chunk_count, blob_count, total_size, blob_size,
+			blob_uncompressed_size, compression_ratio, compression_level,
+			upload_bytes, upload_duration_ms)
 		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
 	`
 
@@ -34,15 +42,21 @@ func (r *SnapshotRepository) Create(ctx context.Context, tx *sql.Tx, snapshot *S
 		completedAt = &ts
 	}
 
+	args := []any{
+		snapshot.ID, snapshot.Hostname, snapshot.VaultikVersion,
+		snapshot.VaultikGitRevision, snapshot.StartedAt.Unix(),
+		completedAt, snapshot.FileCount, snapshot.ChunkCount,
+		snapshot.BlobCount, snapshot.TotalSize, snapshot.BlobSize,
+		snapshot.BlobUncompressedSize, snapshot.CompressionRatio,
+		snapshot.CompressionLevel, snapshot.UploadBytes,
+		snapshot.UploadDurationMs,
+	}
+
 	var err error
 	if tx != nil {
-		_, err = tx.ExecContext(ctx, query, snapshot.ID, snapshot.Hostname, snapshot.VaultikVersion, snapshot.VaultikGitRevision, snapshot.StartedAt.Unix(),
-			completedAt, snapshot.FileCount, snapshot.ChunkCount, snapshot.BlobCount, snapshot.TotalSize, snapshot.BlobSize, snapshot.BlobUncompressedSize,
-			snapshot.CompressionRatio, snapshot.CompressionLevel, snapshot.UploadBytes, snapshot.UploadDurationMs)
+		_, err = tx.ExecContext(ctx, query, args...)
 	} else {
-		_, err = r.db.ExecWithLog(ctx, query, snapshot.ID, snapshot.Hostname, snapshot.VaultikVersion, snapshot.VaultikGitRevision, snapshot.StartedAt.Unix(),
-			completedAt, snapshot.FileCount, snapshot.ChunkCount, snapshot.BlobCount, snapshot.TotalSize, snapshot.BlobSize, snapshot.BlobUncompressedSize,
-			snapshot.CompressionRatio, snapshot.CompressionLevel, snapshot.UploadBytes, snapshot.UploadDurationMs)
+		_, err = r.db.ExecWithLog(ctx, query, args...)
 	}
 
 	if err != nil {
@@ -52,7 +66,14 @@ func (r *SnapshotRepository) Create(ctx context.Context, tx *sql.Tx, snapshot *S
 	return nil
 }
 
-func (r *SnapshotRepository) UpdateCounts(ctx context.Context, tx *sql.Tx, snapshotID string, fileCount, chunkCount, blobCount, totalSize, blobSize int64) error {
+// UpdateCounts updates a snapshot's file/chunk/blob counters and sizes,
+// recomputing the compression ratio, using tx when non-nil.
+func (r *SnapshotRepository) UpdateCounts(
+	ctx context.Context,
+	tx *sql.Tx,
+	snapshotID string,
+	fileCount, chunkCount, blobCount, totalSize, blobSize int64,
+) error {
 	compressionRatio := 1.0
 	if totalSize > 0 {
 		compressionRatio = float64(blobSize) / float64(totalSize)
@@ -71,9 +92,13 @@ func (r *SnapshotRepository) UpdateCounts(ctx context.Context, tx *sql.Tx, snaps
 
 	var err error
 	if tx != nil {
-		_, err = tx.ExecContext(ctx, query, fileCount, chunkCount, blobCount, totalSize, blobSize, compressionRatio, snapshotID)
+		_, err = tx.ExecContext(ctx, query,
+			fileCount, chunkCount, blobCount, totalSize, blobSize,
+			compressionRatio, snapshotID)
 	} else {
-		_, err = r.db.ExecWithLog(ctx, query, fileCount, chunkCount, blobCount, totalSize, blobSize, compressionRatio, snapshotID)
+		_, err = r.db.ExecWithLog(ctx, query,
+			fileCount, chunkCount, blobCount, totalSize, blobSize,
+			compressionRatio, snapshotID)
 	}
 
 	if err != nil {
@@ -84,34 +109,23 @@ func (r *SnapshotRepository) UpdateCounts(ctx context.Context, tx *sql.Tx, snaps
 }
 
 // UpdateExtendedStats updates extended statistics for a snapshot
-func (r *SnapshotRepository) UpdateExtendedStats(ctx context.Context, tx *sql.Tx, snapshotID string, blobUncompressedSize int64, compressionLevel int, uploadDurationMs int64) error {
-	// Calculate compression ratio based on uncompressed vs compressed sizes
-	var compressionRatio float64
-
-	if blobUncompressedSize > 0 {
-		// Get current blob_size from DB to calculate ratio
-		var blobSize int64
-
-		queryGet := `SELECT blob_size FROM snapshots WHERE id = ?`
-		if tx != nil {
-			err := tx.QueryRowContext(ctx, queryGet, snapshotID).Scan(&blobSize)
-			if err != nil {
-				return fmt.Errorf("getting blob size: %w", err)
-			}
-		} else {
-			err := r.db.conn.QueryRowContext(ctx, queryGet, snapshotID).Scan(&blobSize)
-			if err != nil {
-				return fmt.Errorf("getting blob size: %w", err)
-			}
-		}
-
-		compressionRatio = float64(blobSize) / float64(blobUncompressedSize)
-	} else {
-		compressionRatio = 1.0
+func (r *SnapshotRepository) UpdateExtendedStats(
+	ctx context.Context,
+	tx *sql.Tx,
+	snapshotID string,
+	blobUncompressedSize int64,
+	compressionLevel int,
+	uploadDurationMs int64,
+) error {
+	compressionRatio, err := r.extendedCompressionRatio(
+		ctx, tx, snapshotID, blobUncompressedSize,
+	)
+	if err != nil {
+		return err
 	}
 
 	query := `
-		UPDATE snapshots 
+		UPDATE snapshots
 		SET blob_uncompressed_size = ?,
 		    compression_ratio = ?,
 		    compression_level = ?,
@@ -120,11 +134,14 @@ func (r *SnapshotRepository) UpdateExtendedStats(ctx context.Context, tx *sql.Tx
 		WHERE id = ?
 	`
 
-	var err error
 	if tx != nil {
-		_, err = tx.ExecContext(ctx, query, blobUncompressedSize, compressionRatio, compressionLevel, uploadDurationMs, snapshotID)
+		_, err = tx.ExecContext(ctx, query,
+			blobUncompressedSize, compressionRatio, compressionLevel,
+			uploadDurationMs, snapshotID)
 	} else {
-		_, err = r.db.ExecWithLog(ctx, query, blobUncompressedSize, compressionRatio, compressionLevel, uploadDurationMs, snapshotID)
+		_, err = r.db.ExecWithLog(ctx, query,
+			blobUncompressedSize, compressionRatio, compressionLevel,
+			uploadDurationMs, snapshotID)
 	}
 
 	if err != nil {
@@ -134,7 +151,11 @@ func (r *SnapshotRepository) UpdateExtendedStats(ctx context.Context, tx *sql.Tx
 	return nil
 }
 
-func (r *SnapshotRepository) GetByID(ctx context.Context, snapshotID string) (*Snapshot, error) {
+// GetByID returns the snapshot with the given ID, or nil if no such
+// snapshot exists.
+func (r *SnapshotRepository) GetByID(
+	ctx context.Context, snapshotID string,
+) (*Snapshot, error) {
 	query := `
 		SELECT id, hostname, vaultik_version, vaultik_git_revision, started_at, completed_at, 
 			file_count, chunk_count, blob_count, total_size, blob_size, blob_uncompressed_size,
@@ -169,7 +190,7 @@ func (r *SnapshotRepository) GetByID(ctx context.Context, snapshotID string) (*S
 	)
 
 	if errors.Is(err, sql.ErrNoRows) {
-		return nil, nil
+		return nil, nil //nolint:nilnil // nil,nil signals not-found; callers check nil
 	}
 
 	if err != nil {
@@ -185,9 +206,14 @@ func (r *SnapshotRepository) GetByID(ctx context.Context, snapshotID string) (*S
 	return &snapshot, nil
 }
 
-func (r *SnapshotRepository) ListRecent(ctx context.Context, limit int) ([]*Snapshot, error) {
+// ListRecent returns up to limit snapshots, most recently started first.
+func (r *SnapshotRepository) ListRecent(
+	ctx context.Context, limit int,
+) ([]*Snapshot, error) {
 	query := `
-		SELECT id, hostname, vaultik_version, vaultik_git_revision, started_at, completed_at, file_count, chunk_count, blob_count, total_size, blob_size, compression_ratio
+		SELECT id, hostname, vaultik_version, vaultik_git_revision,
+			started_at, completed_at, file_count, chunk_count, blob_count,
+			total_size, blob_size, compression_ratio
 		FROM snapshots
 		ORDER BY started_at DESC
 		LIMIT ?
@@ -199,47 +225,13 @@ func (r *SnapshotRepository) ListRecent(ctx context.Context, limit int) ([]*Snap
 	}
 	defer CloseRows(rows)
 
-	var snapshots []*Snapshot
-
-	for rows.Next() {
-		var (
-			snapshot        Snapshot
-			startedAtUnix   int64
-			completedAtUnix *int64
-		)
-
-		err := rows.Scan(
-			&snapshot.ID,
-			&snapshot.Hostname,
-			&snapshot.VaultikVersion,
-			&snapshot.VaultikGitRevision,
-			&startedAtUnix,
-			&completedAtUnix,
-			&snapshot.FileCount,
-			&snapshot.ChunkCount,
-			&snapshot.BlobCount,
-			&snapshot.TotalSize,
-			&snapshot.BlobSize,
-			&snapshot.CompressionRatio,
-		)
-		if err != nil {
-			return nil, fmt.Errorf("scanning snapshot: %w", err)
-		}
-
-		snapshot.StartedAt = time.Unix(startedAtUnix, 0)
-		if completedAtUnix != nil {
-			t := time.Unix(*completedAtUnix, 0)
-			snapshot.CompletedAt = &t
-		}
-
-		snapshots = append(snapshots, &snapshot)
-	}
-
-	return snapshots, rows.Err()
+	return r.scanSnapshotRows(rows)
 }
 
 // MarkComplete marks a snapshot as completed with the current timestamp
-func (r *SnapshotRepository) MarkComplete(ctx context.Context, tx *sql.Tx, snapshotID string) error {
+func (r *SnapshotRepository) MarkComplete(
+	ctx context.Context, tx *sql.Tx, snapshotID string,
+) error {
 	query := `
 		UPDATE snapshots 
 		SET completed_at = ?
@@ -263,7 +255,9 @@ func (r *SnapshotRepository) MarkComplete(ctx context.Context, tx *sql.Tx, snaps
 }
 
 // AddFile adds a file to a snapshot
-func (r *SnapshotRepository) AddFile(ctx context.Context, tx *sql.Tx, snapshotID string, filePath string) error {
+func (r *SnapshotRepository) AddFile(
+	ctx context.Context, tx *sql.Tx, snapshotID string, filePath string,
+) error {
 	query := `
 		INSERT OR IGNORE INTO snapshot_files (snapshot_id, file_id)
 		SELECT ?, id FROM files WHERE path = ?
@@ -284,7 +278,9 @@ func (r *SnapshotRepository) AddFile(ctx context.Context, tx *sql.Tx, snapshotID
 }
 
 // AddFileByID adds a file to a snapshot by file ID
-func (r *SnapshotRepository) AddFileByID(ctx context.Context, tx *sql.Tx, snapshotID string, fileID types.FileID) error {
+func (r *SnapshotRepository) AddFileByID(
+	ctx context.Context, tx *sql.Tx, snapshotID string, fileID types.FileID,
+) error {
 	query := `
 		INSERT OR IGNORE INTO snapshot_files (snapshot_id, file_id)
 		VALUES (?, ?)
@@ -305,12 +301,17 @@ func (r *SnapshotRepository) AddFileByID(ctx context.Context, tx *sql.Tx, snapsh
 }
 
 // AddFilesByIDBatch adds multiple files to a snapshot in batched inserts
-func (r *SnapshotRepository) AddFilesByIDBatch(ctx context.Context, tx *sql.Tx, snapshotID string, fileIDs []types.FileID) error {
+func (r *SnapshotRepository) AddFilesByIDBatch(
+	ctx context.Context, tx *sql.Tx, snapshotID string, fileIDs []types.FileID,
+) error {
 	if len(fileIDs) == 0 {
 		return nil
 	}
 
-	// Each entry has 2 values, so batch at 400 to be safe
+	// Each snapshot_files row binds this many SQL variables.
+	const snapshotFileCols = 2
+
+	// Batch at 400 rows to be safe with SQLite's variable limit.
 	const batchSize = 400
 
 	for i := 0; i < len(fileIDs); i += batchSize {
@@ -320,7 +321,7 @@ func (r *SnapshotRepository) AddFilesByIDBatch(ctx context.Context, tx *sql.Tx,
 
 		query := "INSERT OR IGNORE INTO snapshot_files (snapshot_id, file_id) VALUES "
 
-		args := make([]any, 0, len(batch)*2)
+		args := make([]any, 0, len(batch)*snapshotFileCols)
 
 		var querySb312 strings.Builder
 
@@ -334,7 +335,7 @@ func (r *SnapshotRepository) AddFilesByIDBatch(ctx context.Context, tx *sql.Tx,
 			args = append(args, snapshotID, fileID.String())
 		}
 
-		query += querySb312.String()
+		query += querySb312.String() //nolint:gosec // G202: appends "?" placeholders only
 
 		var err error
 		if tx != nil {
@@ -361,7 +362,9 @@ func (r *SnapshotRepository) AddFilesByIDBatch(ctx context.Context, tx *sql.Tx,
 // Returns the number of rows inserted (i.e. blobs that were previously
 // referenced indirectly via file_chunks but not yet recorded in
 // snapshot_blobs for this snapshot).
-func (r *SnapshotRepository) PopulateReferencedBlobs(ctx context.Context, tx *sql.Tx, snapshotID string) (int64, error) {
+func (r *SnapshotRepository) PopulateReferencedBlobs(
+	ctx context.Context, tx *sql.Tx, snapshotID string,
+) (int64, error) {
 	query := `
 		INSERT OR IGNORE INTO snapshot_blobs (snapshot_id, blob_id, blob_hash)
 		SELECT DISTINCT ?, blobs.id, blobs.blob_hash
@@ -393,7 +396,13 @@ func (r *SnapshotRepository) PopulateReferencedBlobs(ctx context.Context, tx *sq
 }
 
 // AddBlob adds a blob to a snapshot
-func (r *SnapshotRepository) AddBlob(ctx context.Context, tx *sql.Tx, snapshotID string, blobID types.BlobID, blobHash types.BlobHash) error {
+func (r *SnapshotRepository) AddBlob(
+	ctx context.Context,
+	tx *sql.Tx,
+	snapshotID string,
+	blobID types.BlobID,
+	blobHash types.BlobHash,
+) error {
 	query := `
 		INSERT OR IGNORE INTO snapshot_blobs (snapshot_id, blob_id, blob_hash)
 		VALUES (?, ?, ?)
@@ -414,7 +423,9 @@ func (r *SnapshotRepository) AddBlob(ctx context.Context, tx *sql.Tx, snapshotID
 }
 
 // GetBlobHashes returns all blob hashes for a snapshot
-func (r *SnapshotRepository) GetBlobHashes(ctx context.Context, snapshotID string) ([]string, error) {
+func (r *SnapshotRepository) GetBlobHashes(
+	ctx context.Context, snapshotID string,
+) ([]string, error) {
 	query := `
 		SELECT sb.blob_hash 
 		FROM snapshot_blobs sb
@@ -444,8 +455,11 @@ func (r *SnapshotRepository) GetBlobHashes(ctx context.Context, snapshotID strin
 	return blobs, rows.Err()
 }
 
-// GetSnapshotTotalCompressedSize returns the total compressed size of all blobs referenced by a snapshot
-func (r *SnapshotRepository) GetSnapshotTotalCompressedSize(ctx context.Context, snapshotID string) (int64, error) {
+// GetSnapshotTotalCompressedSize returns the total compressed size of all
+// blobs referenced by a snapshot.
+func (r *SnapshotRepository) GetSnapshotTotalCompressedSize(
+	ctx context.Context, snapshotID string,
+) (int64, error) {
 	query := `
 		SELECT COALESCE(SUM(b.compressed_size), 0)
 		FROM snapshot_blobs sb
@@ -465,7 +479,9 @@ func (r *SnapshotRepository) GetSnapshotTotalCompressedSize(ctx context.Context,
 
 // GetSnapshotUncompressedChunkSize returns the sum of plaintext sizes of all unique
 // chunks referenced by a snapshot (via snapshot_files → file_chunks → chunks).
-func (r *SnapshotRepository) GetSnapshotUncompressedChunkSize(ctx context.Context, snapshotID string) (int64, error) {
+func (r *SnapshotRepository) GetSnapshotUncompressedChunkSize(
+	ctx context.Context, snapshotID string,
+) (int64, error) {
 	query := `
 		SELECT COALESCE(SUM(c.size), 0)
 		FROM (
@@ -491,7 +507,9 @@ func (r *SnapshotRepository) GetSnapshotUncompressedChunkSize(ctx context.Contex
 // referenced by this snapshot but not by any earlier completed snapshot known to
 // the local database. The result is the marginal uncompressed data this snapshot
 // added to the dedup pool — i.e., the delta from prior snapshots.
-func (r *SnapshotRepository) GetSnapshotNewChunkSize(ctx context.Context, snapshotID string) (int64, error) {
+func (r *SnapshotRepository) GetSnapshotNewChunkSize(
+	ctx context.Context, snapshotID string,
+) (int64, error) {
 	query := `
 		WITH this_snap_chunks AS (
 			SELECT DISTINCT fc.chunk_hash
@@ -516,7 +534,9 @@ func (r *SnapshotRepository) GetSnapshotNewChunkSize(ctx context.Context, snapsh
 
 	var totalSize int64
 
-	err := r.db.conn.QueryRowContext(ctx, query, snapshotID, snapshotID, snapshotID).Scan(&totalSize)
+	err := r.db.conn.QueryRowContext(
+		ctx, query, snapshotID, snapshotID, snapshotID,
+	).Scan(&totalSize)
 	if err != nil {
 		return 0, fmt.Errorf("querying new chunk size: %w", err)
 	}
@@ -525,9 +545,13 @@ func (r *SnapshotRepository) GetSnapshotNewChunkSize(ctx context.Context, snapsh
 }
 
 // GetIncompleteSnapshots returns all snapshots that haven't been completed
-func (r *SnapshotRepository) GetIncompleteSnapshots(ctx context.Context) ([]*Snapshot, error) {
+func (r *SnapshotRepository) GetIncompleteSnapshots(
+	ctx context.Context,
+) ([]*Snapshot, error) {
 	query := `
-		SELECT id, hostname, vaultik_version, vaultik_git_revision, started_at, completed_at, file_count, chunk_count, blob_count, total_size, blob_size, compression_ratio
+		SELECT id, hostname, vaultik_version, vaultik_git_revision,
+			started_at, completed_at, file_count, chunk_count, blob_count,
+			total_size, blob_size, compression_ratio
 		FROM snapshots
 		WHERE completed_at IS NULL
 		ORDER BY started_at DESC
@@ -539,49 +563,17 @@ func (r *SnapshotRepository) GetIncompleteSnapshots(ctx context.Context) ([]*Sna
 	}
 	defer CloseRows(rows)
 
-	var snapshots []*Snapshot
-
-	for rows.Next() {
-		var (
-			snapshot        Snapshot
-			startedAtUnix   int64
-			completedAtUnix *int64
-		)
-
-		err := rows.Scan(
-			&snapshot.ID,
-			&snapshot.Hostname,
-			&snapshot.VaultikVersion,
-			&snapshot.VaultikGitRevision,
-			&startedAtUnix,
-			&completedAtUnix,
-			&snapshot.FileCount,
-			&snapshot.ChunkCount,
-			&snapshot.BlobCount,
-			&snapshot.TotalSize,
-			&snapshot.BlobSize,
-			&snapshot.CompressionRatio,
-		)
-		if err != nil {
-			return nil, fmt.Errorf("scanning snapshot: %w", err)
-		}
-
-		snapshot.StartedAt = time.Unix(startedAtUnix, 0)
-		if completedAtUnix != nil {
-			t := time.Unix(*completedAtUnix, 0)
-			snapshot.CompletedAt = &t
-		}
-
-		snapshots = append(snapshots, &snapshot)
-	}
-
-	return snapshots, rows.Err()
+	return r.scanSnapshotRows(rows)
 }
 
 // GetIncompleteByHostname returns all incomplete snapshots for a specific hostname
-func (r *SnapshotRepository) GetIncompleteByHostname(ctx context.Context, hostname string) ([]*Snapshot, error) {
+func (r *SnapshotRepository) GetIncompleteByHostname(
+	ctx context.Context, hostname string,
+) ([]*Snapshot, error) {
 	query := `
-		SELECT id, hostname, vaultik_version, vaultik_git_revision, started_at, completed_at, file_count, chunk_count, blob_count, total_size, blob_size, compression_ratio
+		SELECT id, hostname, vaultik_version, vaultik_git_revision,
+			started_at, completed_at, file_count, chunk_count, blob_count,
+			total_size, blob_size, compression_ratio
 		FROM snapshots
 		WHERE completed_at IS NULL AND hostname = ?
 		ORDER BY started_at DESC
@@ -645,7 +637,9 @@ func (r *SnapshotRepository) Delete(ctx context.Context, snapshotID string) erro
 }
 
 // DeleteSnapshotFiles removes all snapshot_files entries for a snapshot
-func (r *SnapshotRepository) DeleteSnapshotFiles(ctx context.Context, snapshotID string) error {
+func (r *SnapshotRepository) DeleteSnapshotFiles(
+	ctx context.Context, snapshotID string,
+) error {
 	query := `DELETE FROM snapshot_files WHERE snapshot_id = ?`
 
 	_, err := r.db.ExecWithLog(ctx, query, snapshotID)
@@ -657,7 +651,9 @@ func (r *SnapshotRepository) DeleteSnapshotFiles(ctx context.Context, snapshotID
 }
 
 // DeleteSnapshotBlobs removes all snapshot_blobs entries for a snapshot
-func (r *SnapshotRepository) DeleteSnapshotBlobs(ctx context.Context, snapshotID string) error {
+func (r *SnapshotRepository) DeleteSnapshotBlobs(
+	ctx context.Context, snapshotID string,
+) error {
 	query := `DELETE FROM snapshot_blobs WHERE snapshot_id = ?`
 
 	_, err := r.db.ExecWithLog(ctx, query, snapshotID)
@@ -669,7 +665,9 @@ func (r *SnapshotRepository) DeleteSnapshotBlobs(ctx context.Context, snapshotID
 }
 
 // DeleteSnapshotUploads removes all uploads entries for a snapshot
-func (r *SnapshotRepository) DeleteSnapshotUploads(ctx context.Context, snapshotID string) error {
+func (r *SnapshotRepository) DeleteSnapshotUploads(
+	ctx context.Context, snapshotID string,
+) error {
 	query := `DELETE FROM uploads WHERE snapshot_id = ?`
 
 	_, err := r.db.ExecWithLog(ctx, query, snapshotID)
@@ -679,3 +677,77 @@ func (r *SnapshotRepository) DeleteSnapshotUploads(ctx context.Context, snapshot
 
 	return nil
 }
+
+// extendedCompressionRatio computes the compression ratio for a snapshot
+// from its stored blob_size and the given uncompressed size. Returns 1.0
+// when the uncompressed size is zero.
+func (r *SnapshotRepository) extendedCompressionRatio(
+	ctx context.Context,
+	tx *sql.Tx,
+	snapshotID string,
+	blobUncompressedSize int64,
+) (float64, error) {
+	if blobUncompressedSize <= 0 {
+		return 1.0, nil
+	}
+
+	// Get current blob_size from DB to calculate ratio
+	var blobSize int64
+
+	queryGet := `SELECT blob_size FROM snapshots WHERE id = ?`
+
+	var err error
+	if tx != nil {
+		err = tx.QueryRowContext(ctx, queryGet, snapshotID).Scan(&blobSize)
+	} else {
+		err = r.db.conn.QueryRowContext(ctx, queryGet, snapshotID).Scan(&blobSize)
+	}
+
+	if err != nil {
+		return 0, fmt.Errorf("getting blob size: %w", err)
+	}
+
+	return float64(blobSize) / float64(blobUncompressedSize), nil
+}
+
+// scanSnapshotRows scans the standard snapshot column set from a rows
+// iterator into Snapshot records.
+func (r *SnapshotRepository) scanSnapshotRows(rows *sql.Rows) ([]*Snapshot, error) {
+	var snapshots []*Snapshot
+
+	for rows.Next() {
+		var (
+			snapshot        Snapshot
+			startedAtUnix   int64
+			completedAtUnix *int64
+		)
+
+		err := rows.Scan(
+			&snapshot.ID,
+			&snapshot.Hostname,
+			&snapshot.VaultikVersion,
+			&snapshot.VaultikGitRevision,
+			&startedAtUnix,
+			&completedAtUnix,
+			&snapshot.FileCount,
+			&snapshot.ChunkCount,
+			&snapshot.BlobCount,
+			&snapshot.TotalSize,
+			&snapshot.BlobSize,
+			&snapshot.CompressionRatio,
+		)
+		if err != nil {
+			return nil, fmt.Errorf("scanning snapshot: %w", err)
+		}
+
+		snapshot.StartedAt = time.Unix(startedAtUnix, 0)
+		if completedAtUnix != nil {
+			t := time.Unix(*completedAtUnix, 0)
+			snapshot.CompletedAt = &t
+		}
+
+		snapshots = append(snapshots, &snapshot)
+	}
+
+	return snapshots, rows.Err()
+}