bug: Make bus Initialize idempotent, add Reload

internal/agent/agent.go

@@ -68,7 +68,7 @@ func Run(opts ...Option) error {
 		}
 
 		// Re-load providers
-		bus.Manager.LoadProviders()
+		bus.Reload()
 		err = machine.CreateSentinel("bundles")
 		if !c.IgnoreBundleErrors && err != nil {
 			return err

internal/bus/bus.go

@@ -10,14 +10,24 @@ import (
 )
 
 // Manager is the bus instance manager, which subscribes plugins to events emitted.
-var Manager = &Bus{
+var Manager = NewBus()
+
+func NewBus() *Bus {
+	return &Bus{
 		Manager: pluggable.NewManager(
 			bus.AllEvents,
 		),
+	}
+}
+
+func Reload() {
+	Manager = NewBus()
+	Manager.Initialize()
 }
 
 type Bus struct {
 	*pluggable.Manager
+	registered bool
 }
 
 func (b *Bus) LoadProviders() {
@@ -26,6 +36,7 @@ func (b *Bus) LoadProviders() {
 }
 
 func (b *Bus) Initialize() {
+	if !b.registered {
 		b.LoadProviders()
 		for i := range b.Manager.Events {
 			e := b.Manager.Events[i]
@@ -51,4 +62,6 @@ func (b *Bus) Initialize() {
 				}
 			})
 		}
+		b.registered = true
+	}
 }