publish: check if storage exists

cmd/publish_snapshot.go

@@ -198,9 +198,11 @@ func aptlyPublishSnapshotOrRepo(cmd *commander.Command, args []string) error {
 
 	context.Progress().Printf("\n%s been successfully published.\n", message)
 
-	if localStorage, ok := context.GetPublishedStorage(storage).(aptly.FileSystemPublishedStorage); ok {
-		context.Progress().Printf("Please setup your webserver to serve directory '%s' with autoindexing.\n",
-			localStorage.PublicPath())
+	if ps, err := context.GetPublishedStorage(storage); err == nil {
+		if localStorage, ok := ps.(aptly.FileSystemPublishedStorage); ok {
+			context.Progress().Printf("Please setup your webserver to serve directory '%s' with autoindexing.\n",
+				localStorage.PublicPath())
+		}
 	}
 
 	context.Progress().Printf("Now you can add following line to apt sources:\n")

cmd/serve.go

@@ -97,7 +97,11 @@ func aptlyServe(cmd *commander.Command, args []string) error {
 		}
 	}
 
-	publicPath := context.GetPublishedStorage("").(aptly.FileSystemPublishedStorage).PublicPath()
+	ps, err := context.GetPublishedStorage("")
+	if err != nil {
+		return err
+	}
+	publicPath := ps.(aptly.FileSystemPublishedStorage).PublicPath()
 	ShutdownContext()
 
 	fmt.Printf("\nStarting web server at: %s (press Ctrl+C to quit)...\n", listen)