Refactor snapshot module into subcommands.

cmd/snapshot_drop.go

@@ -0,0 +1,82 @@
+package cmd
+
+import (
+	"fmt"
+	"github.com/gonuts/commander"
+	"github.com/gonuts/flag"
+	"github.com/smira/aptly/debian"
+)
+
+func aptlySnapshotDrop(cmd *commander.Command, args []string) error {
+	var err error
+	if len(args) != 1 {
+		cmd.Usage()
+		return err
+	}
+
+	name := args[0]
+
+	snapshotCollection := debian.NewSnapshotCollection(context.database)
+	snapshot, err := snapshotCollection.ByName(name)
+	if err != nil {
+		return fmt.Errorf("unable to drop: %s", err)
+	}
+
+	publishedRepoCollection := debian.NewPublishedRepoCollection(context.database)
+	published := publishedRepoCollection.BySnapshot(snapshot)
+
+	if len(published) > 0 {
+		fmt.Printf("Snapshot `%s` is published currently:\n", snapshot.Name)
+		for _, repo := range published {
+			err = publishedRepoCollection.LoadComplete(repo, snapshotCollection)
+			if err != nil {
+				return fmt.Errorf("unable to load published: %s", err)
+			}
+			fmt.Printf(" * %s\n", repo)
+		}
+
+		return fmt.Errorf("unable to drop: snapshot is published")
+	}
+
+	force := cmd.Flag.Lookup("force").Value.Get().(bool)
+	if !force {
+		snapshots := snapshotCollection.BySnapshotSource(snapshot)
+		if len(snapshots) > 0 {
+			fmt.Printf("Snapshot `%s` was used as a source in following snapshots:\n", snapshot.Name)
+			for _, snap := range snapshots {
+				fmt.Printf(" * %s\n", snap)
+			}
+
+			return fmt.Errorf("won't delete snapshot that was used as source for other snapshots, use -force to override")
+		}
+	}
+
+	err = snapshotCollection.Drop(snapshot)
+	if err != nil {
+		return fmt.Errorf("unable to drop: %s", err)
+	}
+
+	fmt.Printf("Snapshot `%s` has been dropped.\n", snapshot.Name)
+
+	return err
+}
+
+func makeCmdSnapshotDrop() *commander.Command {
+	cmd := &commander.Command{
+		Run:       aptlySnapshotDrop,
+		UsageLine: "drop <name>",
+		Short:     "delete snapshot",
+		Long: `
+Drop removes information about snapshot. If snapshot is published,
+it can't be dropped.
+
+ex.
+    $ aptly snapshot drop wheezy-main
+`,
+		Flag: *flag.NewFlagSet("aptly-snapshot-drop", flag.ExitOnError),
+	}
+
+	cmd.Flag.Bool("force", false, "remove snapshot even if it was used as source for other snapshots")
+
+	return cmd
+}