registry: adds more comments

pkg/registry/registry.go

@@ -54,14 +54,17 @@ type CanBeDisabled interface {
 	IsDisabled() bool
 }
 
+// BackgroundService should be implemented for services that have
+// long running tasks in the background.
 type BackgroundService interface {
+
+	// Run starts the background process of the service after `Init` have been called
+	// on all services. The `context.Context` passed into the function should be used
+	// to subscribe to ctx.Done() so the service can be notified when Grafana shuts down.
 	Run(ctx context.Context) error
 }
 
-type HasInitPriority interface {
-	GetInitPriority() Priority
-}
-
+// IsDisabled takes an service and return true if its disabled
 func IsDisabled(srv Service) bool {
 	canBeDisabled, ok := srv.(CanBeDisabled)
 	return ok && canBeDisabled.IsDisabled()