feat: concurrent manifest downloads in ListSnapshots

Replace serial getManifestSize() calls with bounded concurrent downloads
using errgroup. For each remote snapshot not in the local DB, manifest
downloads now run in parallel (up to 10 concurrent) instead of one at a
time.

Changes:
- Use errgroup with SetLimit(10) for bounded concurrency
- Collect remote-only snapshot IDs first, pre-add entries with zero size
- Download manifests concurrently, patch sizes from results
- Remove now-unused getManifestSize helper (logic inlined into goroutines)
- Promote golang.org/x/sync from indirect to direct dependency

closes #8

README.md

@@ -194,9 +194,8 @@ vaultik [--config <path>] store info
 * Requires `VAULTIK_AGE_SECRET_KEY` environment variable with age private key
 * Optional path arguments to restore specific files/directories (default: all)
 * Downloads and decrypts metadata, fetches required blobs, reconstructs files
-* Preserves file permissions, mtime, and ownership (ownership requires root)
+* Preserves file permissions, timestamps, and ownership (ownership requires root)
 * Handles symlinks and directories
-* Note: ctime cannot be restored (see [platform notes](#platform-specific-ctime-semantics))
 
 **prune**: Remove unreferenced blobs from remote storage
 * Scans all snapshots for referenced blobs
@@ -248,14 +247,11 @@ Snapshot IDs follow the format `<hostname>_<snapshot-name>_<timestamp>` (e.g., `
 CREATE TABLE files (
   id TEXT PRIMARY KEY,
   path TEXT NOT NULL UNIQUE,
-  source_path TEXT NOT NULL DEFAULT '',
   mtime INTEGER NOT NULL,
-  ctime INTEGER NOT NULL,
   size INTEGER NOT NULL,
   mode INTEGER NOT NULL,
   uid INTEGER NOT NULL,
-  gid INTEGER NOT NULL,
+  gid INTEGER NOT NULL
-  link_target TEXT
 );
 
 CREATE TABLE file_chunks (
@@ -343,25 +339,7 @@ CREATE TABLE snapshot_blobs (
 1. For each file, get ordered chunk list from file_chunks
 1. Download required blobs, decrypt, decompress
 1. Extract chunks and reconstruct files
-1. Restore permissions, mtime, uid/gid (ctime cannot be restored — see platform notes above)
+1. Restore permissions, mtime, uid/gid
-
-### platform-specific ctime semantics
-
-The `ctime` field in the files table stores a platform-dependent timestamp:
-
-* **macOS (Darwin)**: `ctime` is the file's **birth time** — when the file was
-  first created on disk. This value never changes after file creation, even if
-  the file's content or metadata is modified.
-
-* **Linux**: `ctime` is the **inode change time** — the last time the file's
-  metadata (permissions, ownership, link count, etc.) was modified. This is NOT
-  the file creation time. Linux did not expose birth time (via `statx(2)`) until
-  kernel 4.11, and Go's `syscall` package does not yet surface it.
-
-**Restore limitation**: `ctime` cannot be restored on either platform. On Linux,
-the kernel manages the inode change time and userspace cannot set it. On macOS,
-there is no standard POSIX API to set birth time. The `ctime` value is preserved
-in the snapshot database for informational/forensic purposes only.
 
 #### prune
 

go.mod

@@ -24,6 +24,7 @@ require (
 	github.com/spf13/cobra v1.10.1
 	github.com/stretchr/testify v1.11.1
 	go.uber.org/fx v1.24.0
+	golang.org/x/sync v0.18.0
 	golang.org/x/term v0.37.0
 	gopkg.in/yaml.v3 v3.0.1
 	modernc.org/sqlite v1.38.0
@@ -266,7 +267,6 @@ require (
 	golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 // indirect
 	golang.org/x/net v0.47.0 // indirect
 	golang.org/x/oauth2 v0.33.0 // indirect
-	golang.org/x/sync v0.18.0 // indirect
 	golang.org/x/sys v0.38.0 // indirect
 	golang.org/x/text v0.31.0 // indirect
 	golang.org/x/time v0.14.0 // indirect

internal/database/models.go

@@ -16,8 +16,8 @@ type File struct {
 	ID         types.FileID     // UUID primary key
 	Path       types.FilePath   // Absolute path of the file
 	SourcePath types.SourcePath // The source directory this file came from (for restore path stripping)
-	MTime      time.Time        // Last modification time
+	MTime      time.Time
-	CTime      time.Time        // Creation/change time (platform-specific: birth time on macOS, inode change time on Linux)
+	CTime      time.Time
 	Size       int64
 	Mode       uint32
 	UID        uint32

internal/snapshot/backup_test.go

@@ -345,9 +345,9 @@ func (b *BackupEngine) Backup(ctx context.Context, fsys fs.FS, root string) (str
 			Size:  info.Size(),
 			Mode:  uint32(info.Mode()),
 			MTime: info.ModTime(),
-			CTime: fileCTime(info), // platform-specific: birth time on macOS, inode change time on Linux
+			CTime: info.ModTime(), // Use mtime as ctime for test
-			UID:   1000,            // Default UID for test
+			UID:   1000,           // Default UID for test
-			GID:   1000,            // Default GID for test
+			GID:   1000,           // Default GID for test
 		}
 		err = b.repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
 			return b.repos.Files.Create(ctx, tx, file)

internal/snapshot/ctime_darwin.go

@@ -1,26 +0,0 @@
-package snapshot
-
-import (
-	"os"
-	"syscall"
-	"time"
-)
-
-// fileCTime returns the file creation time (birth time) on macOS.
-//
-// On macOS/Darwin, "ctime" refers to the file's birth time (when the file
-// was first created on disk). This is stored in the Birthtimespec field of
-// the syscall.Stat_t structure.
-//
-// This differs from Linux where "ctime" means inode change time (the last
-// time file metadata was modified). See ctime_linux.go for details.
-//
-// If the underlying stat information is unavailable (e.g. when using a
-// virtual filesystem like afero.MemMapFs), this falls back to mtime.
-func fileCTime(info os.FileInfo) time.Time {
-	stat, ok := info.Sys().(*syscall.Stat_t)
-	if !ok {
-		return info.ModTime()
-	}
-	return time.Unix(stat.Birthtimespec.Sec, stat.Birthtimespec.Nsec).UTC()
-}

internal/snapshot/ctime_linux.go

@@ -1,28 +0,0 @@
-package snapshot
-
-import (
-	"os"
-	"syscall"
-	"time"
-)
-
-// fileCTime returns the inode change time on Linux.
-//
-// On Linux, "ctime" refers to the inode change time — the last time the
-// file's metadata (permissions, ownership, link count, etc.) was modified.
-// This is NOT the file creation time; Linux did not expose birth time until
-// the statx(2) syscall was added in kernel 4.11, and Go's syscall package
-// does not yet surface it.
-//
-// This differs from macOS/Darwin where "ctime" means birth time (file
-// creation time). See ctime_darwin.go for details.
-//
-// If the underlying stat information is unavailable (e.g. when using a
-// virtual filesystem like afero.MemMapFs), this falls back to mtime.
-func fileCTime(info os.FileInfo) time.Time {
-	stat, ok := info.Sys().(*syscall.Stat_t)
-	if !ok {
-		return info.ModTime()
-	}
-	return time.Unix(stat.Ctim.Sec, stat.Ctim.Nsec).UTC()
-}

internal/snapshot/ctime_test.go

@@ -1,133 +0,0 @@
-package snapshot
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-	"time"
-)
-
-func TestFileCTime_RealFile(t *testing.T) {
-	// Create a temporary file
-	dir := t.TempDir()
-	path := filepath.Join(dir, "testfile.txt")
-
-	if err := os.WriteFile(path, []byte("hello"), 0644); err != nil {
-		t.Fatal(err)
-	}
-
-	info, err := os.Stat(path)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	ctime := fileCTime(info)
-
-	// ctime should be a valid time (not zero)
-	if ctime.IsZero() {
-		t.Fatal("fileCTime returned zero time")
-	}
-
-	// ctime should be close to now (within a few seconds)
-	diff := time.Since(ctime)
-	if diff < 0 || diff > 5*time.Second {
-		t.Fatalf("fileCTime returned unexpected time: %v (diff from now: %v)", ctime, diff)
-	}
-
-	// ctime should not equal mtime exactly in all cases, but for a freshly
-	// created file they should be very close
-	mtime := info.ModTime()
-	ctimeMtimeDiff := ctime.Sub(mtime)
-	if ctimeMtimeDiff < 0 {
-		ctimeMtimeDiff = -ctimeMtimeDiff
-	}
-	// For a freshly created file, ctime and mtime should be within 1 second
-	if ctimeMtimeDiff > time.Second {
-		t.Fatalf("ctime and mtime differ by too much for a new file: ctime=%v, mtime=%v, diff=%v",
-			ctime, mtime, ctimeMtimeDiff)
-	}
-}
-
-func TestFileCTime_AfterMtimeChange(t *testing.T) {
-	// Create a temporary file
-	dir := t.TempDir()
-	path := filepath.Join(dir, "testfile.txt")
-
-	if err := os.WriteFile(path, []byte("hello"), 0644); err != nil {
-		t.Fatal(err)
-	}
-
-	// Get initial ctime
-	info1, err := os.Stat(path)
-	if err != nil {
-		t.Fatal(err)
-	}
-	ctime1 := fileCTime(info1)
-
-	// Change mtime to a time in the past
-	pastTime := time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC)
-	if err := os.Chtimes(path, pastTime, pastTime); err != nil {
-		t.Fatal(err)
-	}
-
-	// Get new stats
-	info2, err := os.Stat(path)
-	if err != nil {
-		t.Fatal(err)
-	}
-	ctime2 := fileCTime(info2)
-	mtime2 := info2.ModTime()
-
-	// mtime should now be in the past
-	if mtime2.Year() != 2020 {
-		t.Fatalf("mtime not set correctly: %v", mtime2)
-	}
-
-	// On macOS: ctime (birth time) should remain unchanged since birth time
-	// doesn't change when mtime is updated.
-	// On Linux: ctime (inode change time) will be updated to ~now because
-	// changing mtime is a metadata change.
-	// Either way, ctime should NOT equal the past mtime we just set.
-	if ctime2.Equal(pastTime) {
-		t.Fatal("ctime should not equal the artificially set past mtime")
-	}
-
-	// ctime should still be a recent time (the original creation time or
-	// the metadata change time, depending on platform)
-	_ = ctime1 // used for reference; both platforms will have a recent ctime2
-	if time.Since(ctime2) > 10*time.Second {
-		t.Fatalf("ctime is unexpectedly old: %v", ctime2)
-	}
-}
-
-// TestFileCTime_NonSyscallFileInfo verifies the fallback to mtime when
-// the FileInfo doesn't have a *syscall.Stat_t (e.g. afero.MemMapFs).
-type mockFileInfo struct {
-	name    string
-	size    int64
-	mode    os.FileMode
-	modTime time.Time
-	isDir   bool
-}
-
-func (m *mockFileInfo) Name() string       { return m.name }
-func (m *mockFileInfo) Size() int64        { return m.size }
-func (m *mockFileInfo) Mode() os.FileMode  { return m.mode }
-func (m *mockFileInfo) ModTime() time.Time { return m.modTime }
-func (m *mockFileInfo) IsDir() bool        { return m.isDir }
-func (m *mockFileInfo) Sys() interface{}   { return nil } // No syscall.Stat_t
-
-func TestFileCTime_FallbackToMtime(t *testing.T) {
-	now := time.Now().UTC().Truncate(time.Second)
-	info := &mockFileInfo{
-		name:    "test.txt",
-		size:    100,
-		mode:    0644,
-		modTime: now,
-	}
-
-	ctime := fileCTime(info)
-	if !ctime.Equal(now) {
-		t.Fatalf("expected fallback to mtime %v, got %v", now, ctime)
-	}
-}

internal/snapshot/scanner.go

@@ -728,7 +728,7 @@ func (s *Scanner) checkFileInMemory(path string, info os.FileInfo, knownFiles ma
 		Path:       types.FilePath(path),
 		SourcePath: types.SourcePath(s.currentSourcePath), // Store source directory for restore path stripping
 		MTime:      info.ModTime(),
-		CTime:      fileCTime(info), // platform-specific: birth time on macOS, inode change time on Linux
+		CTime:      info.ModTime(), // afero doesn't provide ctime
 		Size:       info.Size(),
 		Mode:       uint32(info.Mode()),
 		UID:        uid,

internal/vaultik/restore.go

@@ -411,11 +411,7 @@ func (v *Vaultik) restoreDirectory(file *database.File, targetPath string, resul
 		}
 	}
 
-	// Set mtime (atime is set to mtime as a reasonable default).
+	// Set mtime
-	// Note: ctime cannot be restored. On Linux, ctime (inode change time) is
-	// managed by the kernel and cannot be set by userspace. On macOS, birth
-	// time cannot be set via standard POSIX APIs. The ctime value is preserved
-	// in the snapshot database for informational purposes.
 	if err := v.Fs.Chtimes(targetPath, file.MTime, file.MTime); err != nil {
 		log.Debug("Failed to set directory mtime", "path", targetPath, "error", err)
 	}
@@ -512,11 +508,7 @@ func (v *Vaultik) restoreRegularFile(
 		}
 	}
 
-	// Set mtime (atime is set to mtime as a reasonable default).
+	// Set mtime
-	// Note: ctime cannot be restored. On Linux, ctime (inode change time) is
-	// managed by the kernel and cannot be set by userspace. On macOS, birth
-	// time cannot be set via standard POSIX APIs. The ctime value is preserved
-	// in the snapshot database for informational purposes.
 	if err := v.Fs.Chtimes(targetPath, file.MTime, file.MTime); err != nil {
 		log.Debug("Failed to set file mtime", "path", targetPath, "error", err)
 	}

internal/vaultik/snapshot.go

@@ -8,6 +8,7 @@ import (
 	"regexp"
 	"sort"
 	"strings"
+	"sync"
 	"text/tabwriter"
 	"time"
 
@@ -16,6 +17,7 @@ import (
 	"git.eeqj.de/sneak/vaultik/internal/snapshot"
 	"git.eeqj.de/sneak/vaultik/internal/types"
 	"github.com/dustin/go-humanize"
+	"golang.org/x/sync/errgroup"
 )
 
 // SnapshotCreateOptions contains options for the snapshot create command
@@ -388,17 +390,19 @@ func (v *Vaultik) ListSnapshots(jsonOutput bool) error {
 		}
 	}
 
-	// Build final snapshot list
+	// Build final snapshot list.
+	// Separate local (cheap DB lookup) from remote-only (needs manifest download).
 	snapshots := make([]SnapshotInfo, 0, len(remoteSnapshots))
 
+	// remoteOnly collects snapshot IDs that need a manifest download.
+	var remoteOnly []string
+
 	for snapshotID := range remoteSnapshots {
-		// Check if we have this snapshot locally
 		if localSnap, exists := localSnapshotMap[snapshotID]; exists && localSnap.CompletedAt != nil {
 			// Get total compressed size of all blobs referenced by this snapshot
 			totalSize, err := v.Repositories.Snapshots.GetSnapshotTotalCompressedSize(v.ctx, snapshotID)
 			if err != nil {
 				log.Warn("Failed to get total compressed size", "id", snapshotID, "error", err)
-				// Fall back to stored blob size
 				totalSize = localSnap.BlobSize
 			}
 
@@ -408,24 +412,78 @@ func (v *Vaultik) ListSnapshots(jsonOutput bool) error {
 				CompressedSize: totalSize,
 			})
 		} else {
-			// Remote snapshot not in local DB - fetch manifest to get size
 			timestamp, err := parseSnapshotTimestamp(snapshotID)
 			if err != nil {
 				log.Warn("Failed to parse snapshot timestamp", "id", snapshotID, "error", err)
 				continue
 			}
-
+			// Pre-add with zero size; will be filled by concurrent downloads.
-			// Try to download manifest to get size
-			totalSize, err := v.getManifestSize(snapshotID)
-			if err != nil {
-				return fmt.Errorf("failed to get manifest size for %s: %w", snapshotID, err)
-			}
-
 			snapshots = append(snapshots, SnapshotInfo{
 				ID:             types.SnapshotID(snapshotID),
 				Timestamp:      timestamp,
-				CompressedSize: totalSize,
+				CompressedSize: 0,
 			})
+			remoteOnly = append(remoteOnly, snapshotID)
+		}
+	}
+
+	// Download manifests concurrently for remote-only snapshots.
+	if len(remoteOnly) > 0 {
+		// maxConcurrentManifestDownloads bounds parallel manifest fetches to
+		// avoid overwhelming the S3 endpoint while still being much faster
+		// than serial downloads.
+		const maxConcurrentManifestDownloads = 10
+
+		type manifestResult struct {
+			snapshotID string
+			size       int64
+		}
+
+		var (
+			mu      sync.Mutex
+			results []manifestResult
+		)
+
+		g, gctx := errgroup.WithContext(v.ctx)
+		g.SetLimit(maxConcurrentManifestDownloads)
+
+		for _, sid := range remoteOnly {
+			g.Go(func() error {
+				manifestPath := fmt.Sprintf("metadata/%s/manifest.json.zst", sid)
+				reader, err := v.Storage.Get(gctx, manifestPath)
+				if err != nil {
+					return fmt.Errorf("downloading manifest for %s: %w", sid, err)
+				}
+				defer func() { _ = reader.Close() }()
+
+				manifest, err := snapshot.DecodeManifest(reader)
+				if err != nil {
+					return fmt.Errorf("decoding manifest for %s: %w", sid, err)
+				}
+
+				mu.Lock()
+				results = append(results, manifestResult{
+					snapshotID: sid,
+					size:       manifest.TotalCompressedSize,
+				})
+				mu.Unlock()
+				return nil
+			})
+		}
+
+		if err := g.Wait(); err != nil {
+			return fmt.Errorf("fetching manifest sizes: %w", err)
+		}
+
+		// Build a lookup from results and patch the pre-added entries.
+		sizeMap := make(map[string]int64, len(results))
+		for _, r := range results {
+			sizeMap[r.snapshotID] = r.size
+		}
+		for i := range snapshots {
+			if sz, ok := sizeMap[string(snapshots[i].ID)]; ok {
+				snapshots[i].CompressedSize = sz
+			}
 		}
 	}
 
@@ -731,23 +789,6 @@ func (v *Vaultik) outputVerifyJSON(result *VerifyResult) error {
 
 // Helper methods that were previously on SnapshotApp
 
-func (v *Vaultik) getManifestSize(snapshotID string) (int64, error) {
-	manifestPath := fmt.Sprintf("metadata/%s/manifest.json.zst", snapshotID)
-
-	reader, err := v.Storage.Get(v.ctx, manifestPath)
-	if err != nil {
-		return 0, fmt.Errorf("downloading manifest: %w", err)
-	}
-	defer func() { _ = reader.Close() }()
-
-	manifest, err := snapshot.DecodeManifest(reader)
-	if err != nil {
-		return 0, fmt.Errorf("decoding manifest: %w", err)
-	}
-
-	return manifest.TotalCompressedSize, nil
-}
-
 func (v *Vaultik) downloadManifest(snapshotID string) (*snapshot.Manifest, error) {
 	manifestPath := fmt.Sprintf("metadata/%s/manifest.json.zst", snapshotID)