Bind the local index to the s3.* destination too (closes #298)

The local index was bound to its destination only through storage_url.
With the s3.* form nothing was checked, so after s3.bucket or s3.prefix
changed the next backup treated every chunk as already stored, uploaded
nothing, and completed a snapshot that could not be restored.

Without storage_url, the binding now records the destination the s3.*
fields name, written as an s3:// URL from s3.endpoint, s3.bucket and
s3.prefix, and a change is refused with the same error and advice. The
advice line now names the s3.* fields as well as storage_url.

Judgement call: the fields are compared as written, so an equivalent
spelling (a trailing slash on the prefix, a scheme on the endpoint) is
also refused, as it already is for storage_url.

Model: opus-5-5

README.md

@@ -349,11 +349,9 @@ the backup destination store. Blobs are NOT touched — deleting blobs
 requires reading every remaining remote manifest (the destination store
 may hold snapshots this host doesn't know about), which is what
 `vaultik prune` does. On success the command prints the exact `vaultik
-prune` invocation to run as a follow-up. An ID that names no snapshot in
-the local index or on the destination store is an error; with
-`--local-only`, the snapshot must be in the local index. Local row
-cleanup (files, chunks, blobs the snapshot was the last referrer for)
-runs automatically. If the destination store is unreachable, the local-DB
+prune` invocation to run as a follow-up. Local row cleanup (files,
+chunks, blobs the snapshot was the last referrer for) runs
+automatically. If the destination store is unreachable, the local-DB
 removal still completes and a warning is emitted; run `vaultik snapshot
 remove <snapshot-id>` again once the store is reachable to remove the
 snapshot's metadata from it (`vaultik prune` does not). To wipe everything
@@ -414,7 +412,8 @@ destination store.
 entirely. Remote storage is unaffected; the next backup will do a full
 scan and re-deduplicate against existing remote blobs, and the local
 index will re-bind to the currently configured storage destination.
-Use this after changing `storage_url` to a different destination.
+Use this after changing `storage_url`, or `s3.endpoint`, `s3.bucket` or
+`s3.prefix`, to a different destination.
 * `--force`: Skip confirmation prompt
 
 ---

TODO.md

@@ -22,15 +22,14 @@ the tag exists and is exercised; what is left is merging `next` to
 
 # Completed Steps
 
-- 2026-10-13: Made `snapshot remove` fail for a snapshot that does not
-  exist ([issue #293](https://git.eeqj.de/sneak/vaultik/issues/293)).
-  The command never checked the ID: it reported the snapshot removed
-  from the local database and from the destination store and exited 0,
-  under `--json`, `--dry-run` and `--local-only` too. An ID that names
-  no snapshot in the local index or on the destination store is now an
-  error; with `--local-only`, the snapshot must be in the local index.
-  The command now reports a removal from either side only when one
-  happened, and `remote_removed` is true only when metadata was deleted.
+- 2026-10-12: Bound the local index to the destination an `s3.*` config
+  names ([issue #298](https://git.eeqj.de/sneak/vaultik/issues/298)).
+  Only `storage_url` was checked, so after `s3.bucket` or `s3.prefix`
+  changed, the next backup treated every chunk as already stored,
+  uploaded nothing, and completed a snapshot that could not be restored.
+  Without `storage_url`, the local index is now bound to `s3.endpoint`,
+  `s3.bucket` and `s3.prefix`, and a change is refused as a changed
+  `storage_url` is.
 
 - 2026-10-12: Rejected a retention duration longer than about 292 years
   ([issue #289](https://git.eeqj.de/sneak/vaultik/issues/289)). The

internal/cli/snapshot.go

@@ -255,12 +255,8 @@ manifest (the destination store may hold snapshots this host doesn't
 know about), which is what 'vaultik prune' does. On success the command
 prints the exact 'vaultik prune' invocation to run as a follow-up.
 
-An ID that names no snapshot in the local index or on the destination
-store is an error.
-
 Use --local-only to skip the remote half (e.g. when you want to forget a
-snapshot locally without touching the destination store); the snapshot
-must then be in the local index.
+snapshot locally without touching the destination store).
 
 If the remote is unreachable, the local-database removal still completes
 and a warning is emitted; run 'vaultik snapshot remove <snapshot-id>' again

internal/vaultik/remove_snapshot_test.go

@@ -3,21 +3,17 @@ package vaultik_test
 import (
 	"bytes"
 	"context"
-	"database/sql"
 	"io"
 	"strings"
 	"sync"
 	"testing"
-	"time"
 
 	"github.com/klauspost/compress/zstd"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"sneak.berlin/go/vaultik/internal/database"
 	"sneak.berlin/go/vaultik/internal/log"
 	"sneak.berlin/go/vaultik/internal/snapshot"
 	"sneak.berlin/go/vaultik/internal/storage"
-	"sneak.berlin/go/vaultik/internal/types"
 	"sneak.berlin/go/vaultik/internal/vaultik"
 )
 
@@ -218,37 +214,6 @@ func addBlob(t *testing.T, store *testStorer, hash string) {
 	require.NoError(t, err)
 }
 
-// newLocalIndex returns an in-memory local index holding a completed
-// snapshot row for each of ids.
-func newLocalIndex(t *testing.T, ids ...string) *database.Repositories {
-	t.Helper()
-
-	ctx := context.Background()
-
-	db, err := database.New(ctx, ":memory:")
-	require.NoError(t, err)
-	t.Cleanup(func() { _ = db.Close() })
-
-	repos := database.NewRepositories(db)
-
-	for _, id := range ids {
-		completedAt := time.Now().UTC()
-		snap := &database.Snapshot{
-			ID:          types.SnapshotID(id),
-			Hostname:    snapHostname,
-			StartedAt:   completedAt,
-			CompletedAt: &completedAt,
-		}
-
-		err = repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
-			return repos.Snapshots.Create(ctx, tx, snap)
-		})
-		require.NoError(t, err)
-	}
-
-	return repos
-}
-
 // ============================================================================
 // Unit Tests for RemoveSnapshot
 // ============================================================================
@@ -268,7 +233,6 @@ func TestRemoveSnapshot_LocalOnly_PreservesRemote(t *testing.T) {
 	addBlob(t, store, blobA)
 
 	tv := vaultik.NewForTesting(store)
-	tv.Repositories = newLocalIndex(t, "snapshot-001")
 
 	opts := &vaultik.RemoveOptions{Force: true, LocalOnly: true}
 	result, err := tv.RemoveSnapshot("snapshot-001", opts)
@@ -304,7 +268,6 @@ func TestRemoveSnapshot_DefaultRemovesMetadataNotBlobs(t *testing.T) {
 	addBlob(t, store, blobShared)
 
 	tv := vaultik.NewForTesting(store)
-	tv.Repositories = newLocalIndex(t, "snapshot-001", "snapshot-002")
 
 	opts := &vaultik.RemoveOptions{Force: true}
 	result, err := tv.RemoveSnapshot("snapshot-001", opts)
@@ -353,84 +316,6 @@ func TestRemoveSnapshot_DryRun(t *testing.T) {
 	assert.Contains(t, tv.Stdout.String(), "[Dry run - no changes made]")
 }
 
-// TestRemoveSnapshot_UnknownIDIsError checks that an ID naming no
-// snapshot in the local index or on the destination store is an error
-// under every option, and that nothing is reported as removed.
-func TestRemoveSnapshot_UnknownIDIsError(t *testing.T) {
-	log.Initialize(log.Config{})
-	t.Parallel()
-
-	for name, opts := range map[string]vaultik.RemoveOptions{
-		"force":      {Force: true},
-		"json":       {JSON: true},
-		"dry-run":    {Force: true, DryRun: true},
-		"local-only": {Force: true, LocalOnly: true},
-	} {
-		t.Run(name, func(t *testing.T) {
-			t.Parallel()
-
-			store := newTestStorer()
-			addManifest(t, store, "snapshot-001", nil)
-
-			tv := vaultik.NewForTesting(store)
-			tv.Repositories = newLocalIndex(t, "snapshot-001")
-
-			result, err := tv.RemoveSnapshot("snapshot-999", &opts)
-
-			require.ErrorContains(t, err, "snapshot not found")
-			assert.False(t, result.RemoteRemoved)
-			assert.Empty(t, tv.Stdout.String())
-			assert.True(t, store.hasKey(remoteKeyPath("snapshot-001")))
-		})
-	}
-}
-
-// TestRemoveSnapshot_NoMetadataOnDestination checks that removing a
-// snapshot whose metadata is not on the destination store does not
-// report metadata removed from it.
-func TestRemoveSnapshot_NoMetadataOnDestination(t *testing.T) {
-	log.Initialize(log.Config{})
-	t.Parallel()
-
-	tv := vaultik.NewForTesting(newTestStorer())
-	tv.Repositories = newLocalIndex(t, "snapshot-001")
-
-	result, err := tv.RemoveSnapshot("snapshot-001",
-		&vaultik.RemoveOptions{Force: true})
-
-	require.NoError(t, err)
-	assert.False(t, result.RemoteRemoved)
-
-	out := tv.Stdout.String()
-	assert.Contains(t, out, "Removed snapshot 'snapshot-001' from local database")
-	assert.NotContains(t, out, "Removed snapshot metadata from remote storage")
-}
-
-// TestRemoveSnapshot_NotInLocalIndex checks that removing a snapshot
-// only the destination store holds removes its metadata there without
-// reporting a removal from the local database.
-func TestRemoveSnapshot_NotInLocalIndex(t *testing.T) {
-	log.Initialize(log.Config{})
-	t.Parallel()
-
-	store := newTestStorer()
-	addManifest(t, store, "snapshot-001", nil)
-
-	tv := vaultik.NewForTesting(store)
-	tv.Repositories = newLocalIndex(t)
-
-	result, err := tv.RemoveSnapshot("snapshot-001",
-		&vaultik.RemoveOptions{Force: true})
-
-	require.NoError(t, err)
-	assert.True(t, result.RemoteRemoved)
-	assert.False(t, store.hasKey(remoteKeyPath("snapshot-001")))
-
-	out := tv.Stdout.String()
-	assert.NotContains(t, out, "from local database")
-	assert.Contains(t, out, "Removed snapshot metadata from remote storage")
-}
-
 func TestRemoveAllSnapshots_RequiresForce(t *testing.T) {
 	log.Initialize(log.Config{})
 	t.Parallel()

internal/vaultik/snapshot.go

@@ -23,7 +23,6 @@ var (
 	errNoSnapshotsInConfig  = errors.New("no snapshots configured")
 	errSnapshotVerifyFailed = errors.New("verification failed")
 	errRemoveAllNeedsForce  = errors.New("--all requires --force")
-	errSnapshotNotFound     = errors.New("snapshot not found")
 	errInvalidTableName     = errors.New("invalid table name")
 	errNoAgeRecipients      = errors.New(
 		"creating a snapshot needs at least one public key in " +
@@ -644,7 +643,7 @@ func (v *Vaultik) confirmAndExecutePurge(
 				"snapshot_id", snapshotID, "error", err)
 		}
 
-		_, err = v.deleteRemoteSnapshotByKey(snapshot.RemoteSnapshotKey(snapshotID))
+		err = v.deleteRemoteSnapshotByKey(snapshot.RemoteSnapshotKey(snapshotID))
 		if err != nil {
 			return fmt.Errorf("deleting snapshot %s from remote: %w", snapshotID, err)
 		}
@@ -1154,11 +1153,6 @@ func (v *Vaultik) RemoveSnapshot(
 		return result, err
 	}
 
-	inLocalIndex, err := v.findSnapshotToRemove(snapshotID, opts)
-	if err != nil {
-		return result, err
-	}
-
 	if opts.DryRun {
 		return v.removeSnapshotDryRun(result, snapshotID, opts)
 	}
@@ -1167,13 +1161,11 @@ func (v *Vaultik) RemoveSnapshot(
 		return result, nil
 	}
 
-	if inLocalIndex {
-		log.Info("Removing snapshot from local database", "snapshot_id", snapshotID)
+	log.Info("Removing snapshot from local database", "snapshot_id", snapshotID)
 
-		err = v.deleteSnapshotFromLocalDB(snapshotID)
-		if err != nil {
-			return result, fmt.Errorf("removing from local database: %w", err)
-		}
+	err = v.deleteSnapshotFromLocalDB(snapshotID)
+	if err != nil {
+		return result, fmt.Errorf("removing from local database: %w", err)
 	}
 
 	if !opts.LocalOnly {
@@ -1192,9 +1184,7 @@ func (v *Vaultik) RemoveSnapshot(
 		return result, v.outputRemoveJSON(result)
 	}
 
-	if inLocalIndex {
-		v.stdoutf("Removed snapshot '%s' from local database\n", snapshotID)
-	}
+	v.stdoutf("Removed snapshot '%s' from local database\n", snapshotID)
 
 	if !opts.LocalOnly && result.RemoteRemoved {
 		v.printlnStdout("Removed snapshot metadata from remote storage")
@@ -1206,45 +1196,6 @@ func (v *Vaultik) RemoveSnapshot(
 	return result, nil
 }
 
-// findSnapshotToRemove reports whether the local index has a row for
-// snapshotID, and returns errSnapshotNotFound when there is nothing to
-// remove: no row and, unless LocalOnly is set, no metadata on the
-// destination store either. The destination store is consulted only
-// when the local index has no row, so a snapshot in the local index can
-// still be removed from it while the destination store is unreachable.
-func (v *Vaultik) findSnapshotToRemove(
-	snapshotID string, opts *RemoveOptions,
-) (bool, error) {
-	if v.Repositories != nil {
-		snap, err := v.Repositories.Snapshots.GetByID(v.ctx, snapshotID)
-		if err != nil {
-			return false, fmt.Errorf("looking up snapshot in local index: %w", err)
-		}
-
-		if snap != nil {
-			return true, nil
-		}
-	}
-
-	if opts.LocalOnly {
-		return false, fmt.Errorf("%w in the local index: %s",
-			errSnapshotNotFound, snapshotID)
-	}
-
-	objects, err := v.remoteSnapshotObjects(snapshot.RemoteSnapshotKey(snapshotID))
-	if err != nil {
-		return false, fmt.Errorf("looking up snapshot on destination store: %w", err)
-	}
-
-	if len(objects) == 0 {
-		return false, fmt.Errorf(
-			"%w in the local index or on the destination store: %s",
-			errSnapshotNotFound, snapshotID)
-	}
-
-	return false, nil
-}
-
 // removeSnapshotDryRun reports what RemoveSnapshot would do without
 // making changes.
 func (v *Vaultik) removeSnapshotDryRun(
@@ -1304,14 +1255,14 @@ func (v *Vaultik) confirmRemoveSnapshot(snapshotID string, opts *RemoveOptions)
 // didn't finish and to run `vaultik snapshot remove` for the snapshot
 // again once the destination store is reachable (`vaultik prune` never
 // removes snapshot metadata). Returns true when the remote removal
-// succeeded and deleted something.
+// succeeded.
 func (v *Vaultik) removeSnapshotRemote(snapshotID string, opts *RemoveOptions) bool {
 	log.Info("Removing snapshot metadata from remote storage",
 		"snapshot_id", snapshotID)
 
 	remoteKey := snapshot.RemoteSnapshotKey(snapshotID)
 
-	deleted, err := v.deleteRemoteSnapshotByKey(remoteKey)
+	err := v.deleteRemoteSnapshotByKey(remoteKey)
 	if err != nil {
 		log.Warn("Could not remove snapshot metadata from remote storage; "+
 			"run '"+snapshotRemoveCommandHint+"' with the snapshot's ID "+
@@ -1329,7 +1280,7 @@ func (v *Vaultik) removeSnapshotRemote(snapshotID string, opts *RemoveOptions) b
 		return false
 	}
 
-	return deleted > 0
+	return true
 }
 
 // RemoveAllSnapshots removes every snapshot known to the local
@@ -1621,7 +1572,7 @@ func (v *Vaultik) removeAllLocalSnapshots(
 		}
 
 		if !opts.LocalOnly {
-			_, err = v.deleteRemoteSnapshotByKey(
+			err = v.deleteRemoteSnapshotByKey(
 				snapshot.RemoteSnapshotKey(snapshotID))
 			if err != nil {
 				log.Warn("Failed to remove snapshot metadata from remote",
@@ -1647,7 +1598,7 @@ func (v *Vaultik) removeAllOrphanRemotes(
 	for _, key := range orphanRemoteKeys {
 		log.Info("Removing orphan remote snapshot", "remote_key", key)
 
-		_, err := v.deleteRemoteSnapshotByKey(key)
+		err := v.deleteRemoteSnapshotByKey(key)
 		if err != nil {
 			log.Warn("Failed to remove orphan from remote",
 				"remote_key", key, "error", err)
@@ -1694,44 +1645,34 @@ func (v *Vaultik) deleteSnapshotFromLocalDB(snapshotID string) error {
 }
 
 // deleteRemoteSnapshotByKey removes everything under
-// metadata/<remoteKey>/ on the destination store and returns how many
-// objects it deleted. The argument is a remote key (double-SHA256
-// derivation), not a human snapshot ID; callers that have a human ID
-// must hash via snapshot.RemoteSnapshotKey first.
-func (v *Vaultik) deleteRemoteSnapshotByKey(remoteKey string) (int, error) {
-	objectsToDelete, err := v.remoteSnapshotObjects(remoteKey)
-	if err != nil {
-		return 0, err
+// metadata/<remoteKey>/ on the destination store. The argument is a
+// remote key (double-SHA256 derivation), not a human snapshot ID;
+// callers that have a human ID must hash via snapshot.RemoteSnapshotKey
+// first.
+func (v *Vaultik) deleteRemoteSnapshotByKey(remoteKey string) error {
+	prefix := fmt.Sprintf("metadata/%s/", remoteKey)
+	objectCh := v.Storage.ListStream(v.ctx, prefix)
+
+	var objectsToDelete []string
+
+	for object := range objectCh {
+		if object.Err != nil {
+			return fmt.Errorf("listing objects: %w", object.Err)
+		}
+
+		objectsToDelete = append(objectsToDelete, object.Key)
 	}
 
-	for i, key := range objectsToDelete {
-		err = v.Storage.Delete(v.ctx, key)
+	for _, key := range objectsToDelete {
+		err := v.Storage.Delete(v.ctx, key)
 		if err != nil {
-			return i, fmt.Errorf("removing %s: %w", key, err)
+			return fmt.Errorf("removing %s: %w", key, err)
 		}
 
 		log.Debug("Deleted remote object", "key", key)
 	}
 
-	return len(objectsToDelete), nil
-}
-
-// remoteSnapshotObjects lists the keys of every object under
-// metadata/<remoteKey>/ on the destination store.
-func (v *Vaultik) remoteSnapshotObjects(remoteKey string) ([]string, error) {
-	prefix := fmt.Sprintf("metadata/%s/", remoteKey)
-
-	var keys []string
-
-	for object := range v.Storage.ListStream(v.ctx, prefix) {
-		if object.Err != nil {
-			return nil, fmt.Errorf("listing objects: %w", object.Err)
-		}
-
-		keys = append(keys, object.Key)
-	}
-
-	return keys, nil
+	return nil
 }
 
 // outputRemoveJSON outputs the removal result as JSON

internal/vaultik/storage_bind.go

@@ -9,7 +9,7 @@ import (
 )
 
 // errStorageBindingMismatch is returned when the local index database is
-// bound to a different destination than the configured storage_url.
+// bound to a different destination than the configured one.
 var errStorageBindingMismatch = errors.New(
 	"local index is bound to a different backup destination")
 
@@ -24,8 +24,9 @@ var errStorageBindingMismatch = errors.New(
 //
 // Behaviour:
 //   - On first use (empty stored value), record the configured
-//     storage_url and log the binding.
-//   - When the stored value matches the configured storage_url, do
+//     destination (storage_url, or the s3.* endpoint, bucket and
+//     prefix) and log the binding.
+//   - When the stored value matches the configured destination, do
 //     nothing and return nil.
 //   - When the two differ, refuse with an error that tells the user
 //     how to recover (revert the config, or run `vaultik database
@@ -46,12 +47,10 @@ func (v *Vaultik) EnsureStorageBinding() error {
 
 	configured := v.Config.StorageURL
 	if configured == "" {
-		// Some legacy configs still use the split s3.* keys instead of
-		// storage_url. Falling back to a synthetic URL for those would
-		// hide the fact that the binding is loose. Instead, treat
-		// unset as "nothing to bind against" — the check is
-		// necessarily best-effort for those configs.
-		return nil
+		// The s3.* form: bind on its endpoint, bucket and prefix,
+		// written the way storage_url would name the same destination.
+		s3 := v.Config.S3
+		configured = "s3://" + s3.Bucket + "/" + s3.Prefix + "?endpoint=" + s3.Endpoint
 	}
 
 	stored, err := v.Repositories.LocalMeta.Get(v.ctx, database.LocalMetaKeyStorageURL)
@@ -96,7 +95,8 @@ func buildBindingMismatchMessage(stored, configured string) string {
 		"future snapshots referencing blobs that don't exist at the new destination.\n" +
 		"\n" +
 		"To proceed, either:\n" +
-		"  - revert storage_url in your config to the bound destination, or\n" +
+		"  - revert storage_url (or the s3.* endpoint, bucket and prefix) in your\n" +
+		"    config to the bound destination, or\n" +
 		"  - run 'vaultik database delete' to discard the local index and rebuild it\n" +
 		"    from a fresh full backup against the new destination"
 }

internal/vaultik/storage_bind_test.go

@@ -76,3 +76,51 @@ func TestEnsureStorageBinding_MismatchRefuses(t *testing.T) {
 	assert.Contains(t, err.Error(), "file:///mnt/backups/new")
 	assert.Contains(t, err.Error(), "vaultik database delete")
 }
+
+// A config with no storage_url names its destination with s3.endpoint,
+// s3.bucket and s3.prefix; a change to any of them must be refused just
+// as a changed storage_url is.
+func TestEnsureStorageBinding_S3FieldsChangeRefuses(t *testing.T) {
+	log.Initialize(log.Config{})
+	t.Parallel()
+
+	bound := config.S3Config{
+		Endpoint: "https://s3.example.com",
+		Bucket:   "bucket-a",
+		Prefix:   "backups",
+	}
+
+	tests := []struct {
+		name    string
+		changed config.S3Config
+	}{
+		{"bucket", config.S3Config{
+			Endpoint: bound.Endpoint, Bucket: "bucket-b", Prefix: bound.Prefix,
+		}},
+		{"prefix", config.S3Config{
+			Endpoint: bound.Endpoint, Bucket: bound.Bucket, Prefix: "other",
+		}},
+		{"endpoint", config.S3Config{
+			Endpoint: "https://s3.other.com", Bucket: bound.Bucket, Prefix: bound.Prefix,
+		}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			tv, _ := buildBindTestVaultik(t, "")
+
+			tv.Config.S3 = bound
+			require.NoError(t, tv.EnsureStorageBinding(), "first use binds")
+			require.NoError(t, tv.EnsureStorageBinding(), "same destination passes")
+
+			tv.Config.S3 = tt.changed
+			err := tv.EnsureStorageBinding()
+			require.Error(t, err)
+			assert.Contains(t, err.Error(),
+				"local index is bound to a different backup destination")
+			assert.Contains(t, err.Error(), "vaultik database delete")
+		})
+	}
+}