Add 'snapshots' command.

cmd/litestream/main.go

@@ -54,6 +54,8 @@ func (m *Main) Run(ctx context.Context, args []string) (err error) {
 		return (&ReplicateCommand{}).Run(ctx, args)
 	case "restore":
 		return (&RestoreCommand{}).Run(ctx, args)
+	case "snapshots":
+		return (&SnapshotsCommand{}).Run(ctx, args)
 	case "version":
 		return (&VersionCommand{}).Run(ctx, args)
 	default:
@@ -75,9 +77,10 @@ Usage:
 
 The commands are:
 
-	generations  list available generations across all dbs & replicas
+	generations  list available generations for a database
 	replicate    runs a server to replicate databases
 	restore      recovers database backup from a replica
+	snapshots    list available snapshots for a database
 	version      prints the version
 `[1:])
 }

cmd/litestream/snapshots.go

@@ -0,0 +1,121 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+	"text/tabwriter"
+	"time"
+
+	"github.com/benbjohnson/litestream"
+)
+
+type SnapshotsCommand struct{}
+
+func NewSnapshotsCommand() *SnapshotsCommand {
+	return &SnapshotsCommand{}
+}
+
+func (c *SnapshotsCommand) Run(ctx context.Context, args []string) (err error) {
+	var configPath string
+	fs := flag.NewFlagSet("litestream-snapshots", flag.ContinueOnError)
+	registerConfigFlag(fs, &configPath)
+	replicaName := fs.String("replica", "", "replica name")
+	fs.Usage = c.Usage
+	if err := fs.Parse(args); err != nil {
+		return err
+	} else if fs.NArg() == 0 || fs.Arg(0) == "" {
+		return fmt.Errorf("database path required")
+	} else if fs.NArg() > 1 {
+		return fmt.Errorf("too many arguments")
+	}
+
+	// Load configuration.
+	if configPath == "" {
+		return errors.New("-config required")
+	}
+	config, err := ReadConfigFile(configPath)
+	if err != nil {
+		return err
+	}
+
+	// Determine absolute path for database.
+	dbPath, err := filepath.Abs(fs.Arg(0))
+	if err != nil {
+		return err
+	}
+
+	// Instantiate DB.
+	dbConfig := config.DBConfig(dbPath)
+	if dbConfig == nil {
+		return fmt.Errorf("database not found in config: %s", dbPath)
+	}
+	db, err := newDBFromConfig(dbConfig)
+	if err != nil {
+		return err
+	}
+
+	// Find snapshots by db or replica.
+	var infos []*litestream.SnapshotInfo
+	if *replicaName != "" {
+		if r := db.Replica(*replicaName); r == nil {
+			return fmt.Errorf("replica %q not found for database %q", *replicaName, dbPath)
+		} else if infos, err = r.Snapshots(ctx); err != nil {
+			return err
+		}
+	} else {
+		if infos, err = db.Snapshots(ctx); err != nil {
+			return err
+		}
+	}
+
+	// List all snapshots.
+	w := tabwriter.NewWriter(os.Stdout, 0, 8, 1, '\t', 0)
+	fmt.Fprintln(w, "replica\tname\tgeneration\tindex\tcreated")
+	for _, info := range infos {
+		fmt.Fprintf(w, "%s\t%s\t%s\t%d\t%s\n",
+			info.Replica,
+			info.Name,
+			info.Generation,
+			info.Index,
+			info.CreatedAt.Format(time.RFC3339),
+		)
+	}
+	w.Flush()
+
+	return nil
+}
+
+func (c *SnapshotsCommand) Usage() {
+	fmt.Printf(`
+The snapshots command lists all snapshots available for a database.
+
+Usage:
+
+	litestream snapshots [arguments] DB
+
+Arguments:
+
+	-config PATH
+	    Specifies the configuration file.
+	    Defaults to %s
+
+	-replica NAME
+	    Optional, filter by a specific replica.
+
+
+Examples:
+
+	# List all snapshots for a database.
+	$ litestream snapshots /path/to/db
+
+	# List all snapshots on S3.
+	$ litestream snapshots -replica s3 /path/to/db
+
+`[1:],
+		DefaultConfigPath,
+	)
+}