add and use event bus for UI progress

internal/ui/common/event_handlers.go

@@ -0,0 +1,22 @@
+package common
+
+import (
+	"fmt"
+	"os"
+
+	imgbomEventParsers "github.com/anchore/imgbom/imgbom/event/parsers"
+	"github.com/wagoodman/go-partybus"
+)
+
+func CatalogerFinishedHandler(event partybus.Event) error {
+	// show the report to stdout
+	pres, err := imgbomEventParsers.ParseCatalogerFinished(event)
+	if err != nil {
+		return fmt.Errorf("bad CatalogerFinished event: %w", err)
+	}
+
+	if err := pres.Present(os.Stdout); err != nil {
+		return fmt.Errorf("unable to show package catalog report: %w", err)
+	}
+	return nil
+}