{snapshot,backup}: Write machine-readable report

cmd/snapshot.go

@@ -14,6 +14,9 @@ type snapshot struct {
 	Keepalive   bool `short:"k" long:"keepalive" description:"keep instance running while taking a backup. might lead to inconsistent state"`
 	StagingOnly bool `short:"s" long:"staging-only" description:"do not package into a snapshot archive, but only create a staging directory"`
 
+	Parts []string `short:"p" long:"parts" description:"parts to include in snapshots. defaults to all parts, use l to list all available parts"`
+	List  bool     `short:"l" long:"list-parts" description:"list available parts"`
+
 	Positionals struct {
 		Slug string `positional-arg-name:"SLUG" required:"1-1" description:"slug of instance to take a snapshot of"`
 		Dest string "positional-arg-name:\"DEST\" description:\"destination path to write snapshot archive to. defaults to the `snapshots/archives/` directory\""
@@ -43,6 +46,14 @@ var errSnapshotWissKI = exit.Error{
 func (sn snapshot) Run(context wisski_distillery.Context) error {
 	dis := context.Environment
 
+	// list available parts
+	if sn.List {
+		for _, part := range dis.Exporter().Parts() {
+			context.Println(part)
+		}
+		return nil
+	}
+
 	// find the instance!
 	instance, err := dis.Instances().WissKI(context.Context, sn.Positionals.Slug)
 	if err != nil {
@@ -54,6 +65,9 @@ func (sn snapshot) Run(context wisski_distillery.Context) error {
 		Dest:        sn.Positionals.Dest,
 		StagingOnly: sn.StagingOnly,
 
+		SnapshotDescription: exporter.SnapshotDescription{
+			Parts: sn.Parts,
+		},
 		Instance: instance,
 	})