fix(runtime): log service startup errors instead of printing them beside the log

opencloud/pkg/runtime/service/service.go

@@ -389,9 +389,16 @@ func Start(ctx context.Context, o ...Option) error {
 				if ev.Restarting {
 					l = s.Log.Error()
 				}
-				l.Str("event", e.String()).Str("service", ev.ServiceName).Str("supervisor", ev.SupervisorName).
-					Bool("restarting", ev.Restarting).Float64("failures", ev.CurrentFailures).Float64("threshold", ev.FailureThreshold).
-					Interface("error", ev.Err).Msg("service terminated")
+				l = l.Str("event", e.String()).Str("service", ev.ServiceName).Str("supervisor", ev.SupervisorName).
+					Bool("restarting", ev.Restarting).Float64("failures", ev.CurrentFailures).Float64("threshold", ev.FailureThreshold)
+				// ev.Err is an interface{}: marshaling an error yields {} because
+				// its fields are unexported, so the message has to go through Err
+				if err, ok := ev.Err.(error); ok {
+					l = l.Err(err)
+				} else {
+					l = l.Interface("error", ev.Err)
+				}
+				l.Msg("service terminated")
 			case suture.EventBackoff:
 				s.Log.Warn().Str("event", e.String()).Str("supervisor", ev.SupervisorName).Msg("service backoff")
 			case suture.EventResume:

pkg/clihelper/app.go

@@ -14,5 +14,17 @@ func DefaultApp(app *cobra.Command) *cobra.Command {
 	// version info
 	app.Version = fmt.Sprintf("%s (%s <%s>) (%s)", version.String, "OpenCloud GmbH", "support@opencloud.eu", version.Compiled())
 
+	// cobra would print the error on top of what main() already prints
+	app.SilenceErrors = true
+
+	// keep the usage block for flag parse errors, drop it once RunE runs.
+	// Traversing runs the hook even below a subcommand that brings its own,
+	// e.g. every service below ServiceCommand.
+	cobra.EnableTraverseRunHooks = true
+	app.PersistentPreRunE = func(cmd *cobra.Command, _ []string) error {
+		cmd.SilenceUsage = true
+		return nil
+	}
+
 	return app
 }