Remove -dry-run flag in restore

This flag is being removed because it's not actually that useful
in practice and it just makes the restoration code more complicated.

cmd/litestream/restore.go

@@ -26,7 +26,6 @@ func (c *RestoreCommand) Run(ctx context.Context, args []string) (err error) {
 	fs.StringVar(&opt.ReplicaName, "replica", "", "replica name")
 	fs.StringVar(&opt.Generation, "generation", "", "generation name")
 	fs.IntVar(&opt.Index, "index", opt.Index, "wal index")
-	fs.BoolVar(&opt.DryRun, "dry-run", false, "dry run")
 	ifReplicaExists := fs.Bool("if-replica-exists", false, "")
 	timestampStr := fs.String("timestamp", "", "timestamp")
 	verbose := fs.Bool("v", false, "verbose output")
@@ -46,11 +45,6 @@ func (c *RestoreCommand) Run(ctx context.Context, args []string) (err error) {
 		}
 	}
 
-	// Verbose output is automatically enabled if dry run is specified.
-	if opt.DryRun {
-		*verbose = true
-	}
-
 	// Instantiate logger if verbose output is enabled.
 	if *verbose {
 		opt.Logger = log.New(os.Stderr, "", log.LstdFlags|log.Lmicroseconds)
@@ -173,10 +167,6 @@ Arguments:
 	    Output path of the restored database.
 	    Defaults to original DB path.
 
-	-dry-run
-	    Prints all log output as if it were running but does
-	    not perform actual restore.
-
 	-if-replica-exists
 	    Returns exit code of 0 if no backups found.
 

db.go

@@ -1455,13 +1455,11 @@ func RestoreReplica(ctx context.Context, r Replica, opt RestoreOptions) error {
 		logPrefix = fmt.Sprintf("%s(%s)", db.Path(), r.Name())
 	}
 
-	// Ensure output path does not already exist (unless this is a dry run).
+	// Ensure output path does not already exist.
-	if !opt.DryRun {
+	if _, err := os.Stat(opt.OutputPath); err == nil {
-		if _, err := os.Stat(opt.OutputPath); err == nil {
+		return fmt.Errorf("cannot restore, output path already exists: %s", opt.OutputPath)
-			return fmt.Errorf("cannot restore, output path already exists: %s", opt.OutputPath)
+	} else if err != nil && !os.IsNotExist(err) {
-		} else if err != nil && !os.IsNotExist(err) {
+		return err
-			return err
-		}
 	}
 
 	// Find lastest snapshot that occurs before timestamp.
@@ -1483,21 +1481,17 @@ func RestoreReplica(ctx context.Context, r Replica, opt RestoreOptions) error {
 
 	// Copy snapshot to output path.
 	logger.Printf("%s: restoring snapshot %s/%08x to %s", logPrefix, opt.Generation, minWALIndex, tmpPath)
-	if !opt.DryRun {
+	if err := restoreSnapshot(ctx, r, pos.Generation, pos.Index, tmpPath); err != nil {
-		if err := restoreSnapshot(ctx, r, pos.Generation, pos.Index, tmpPath); err != nil {
+		return fmt.Errorf("cannot restore snapshot: %w", err)
-			return fmt.Errorf("cannot restore snapshot: %w", err)
-		}
 	}
 
 	// Restore each WAL file until we reach our maximum index.
 	for index := minWALIndex; index <= maxWALIndex; index++ {
-		if !opt.DryRun {
+		if err = restoreWAL(ctx, r, opt.Generation, index, tmpPath); os.IsNotExist(err) && index == minWALIndex && index == maxWALIndex {
-			if err = restoreWAL(ctx, r, opt.Generation, index, tmpPath); os.IsNotExist(err) && index == minWALIndex && index == maxWALIndex {
+			logger.Printf("%s: no wal available, snapshot only", logPrefix)
-				logger.Printf("%s: no wal available, snapshot only", logPrefix)
+			break // snapshot file only, ignore error
-				break // snapshot file only, ignore error
+		} else if err != nil {
-			} else if err != nil {
+			return fmt.Errorf("cannot restore wal: %w", err)
-				return fmt.Errorf("cannot restore wal: %w", err)
-			}
 		}
 
 		if opt.Verbose {
@@ -1507,10 +1501,8 @@ func RestoreReplica(ctx context.Context, r Replica, opt RestoreOptions) error {
 
 	// Copy file to final location.
 	logger.Printf("%s: renaming database from temporary location", logPrefix)
-	if !opt.DryRun {
+	if err := os.Rename(tmpPath, opt.OutputPath); err != nil {
-		if err := os.Rename(tmpPath, opt.OutputPath); err != nil {
+		return err
-			return err
-		}
 	}
 
 	return nil
@@ -1740,10 +1732,6 @@ type RestoreOptions struct {
 	// If zero, database restore to most recent state available.
 	Timestamp time.Time
 
-	// If true, no actual restore is performed.
-	// Only equivalent log output for a regular restore.
-	DryRun bool
-
 	// Logging settings.
 	Logger  *log.Logger
 	Verbose bool