remove group if the target is empty at adapter level

Signed-off-by: Augustin Husson <husson.augustin@gmail.com>

discovery/manager.go

@@ -232,11 +232,6 @@ func (m *Manager) updateGroup(poolKey poolKey, tgs []*targetgroup.Group) {
 				m.targets[poolKey] = make(map[string]*targetgroup.Group)
 			}
 			m.targets[poolKey][tg.Source] = tg
-
-			// Clear the key in the case where the targets is empty.
-			if tg.Targets == nil || len(tg.Targets) <= 0 {
-				delete(m.targets[poolKey], tg.Source)
-			}
 		}
 	}
 }

documentation/examples/custom-sd/adapter/adapter.go

@@ -60,6 +60,12 @@ func (a *Adapter) generateTargetGroups(allTargetGroups map[string][]*targetgroup
 	tempGroups := make(map[string]*customSD)
 	for k, sdTargetGroups := range allTargetGroups {
 		for i, group := range sdTargetGroups {
+
+			// There is no target, so no need to keep it
+			if len(group.Targets) <= 0 {
+				continue
+			}
+
 			newTargets := make([]string, 0)
 			newLabels := make(map[string]string)