fix scheduler and provide get-update-by-extender method (#501)

Signed-off-by: Mikhail Scherba <mikhail.scherba@flant.com>

Author: miklezzzz

pkg/module_manager/module_manager.go

@@ -475,11 +475,16 @@ func (mm *ModuleManager) GetEnabledModuleNames() []string {
 	return mm.moduleScheduler.GetEnabledModuleNames()
 }
 
-// IsModuleEnabled ...
+// IsModuleEnabled returns current state of the module according to the scheduler
 func (mm *ModuleManager) IsModuleEnabled(moduleName string) bool {
 	return mm.moduleScheduler.IsModuleEnabled(moduleName)
 }
 
+// GetUpdatedByExtender returns the name of the extender that determined the module's state
+func (mm *ModuleManager) GetUpdatedByExtender(moduleName string) (string, error) {
+	return mm.moduleScheduler.GetUpdatedByExtender(moduleName)
+}
+
 func (mm *ModuleManager) AddExtender(ex extenders.Extender) error {
 	return mm.moduleScheduler.AddExtender(ex)
 }

pkg/module_manager/scheduler/scheduler.go

@@ -351,12 +351,19 @@ func moduleSortFunc(m1, m2 string) bool {
 	return m1 < m2
 }
 
+func (s *Scheduler) GetUpdatedByExtender(moduleName string) (string, error) {
+	vertex, err := s.dag.Vertex(moduleName)
+	if err != nil {
+		return "", err
+	}
+	return vertex.GetUpdatedBy(), err
+}
+
 func (s *Scheduler) IsModuleEnabled(moduleName string) bool {
 	vertex, err := s.dag.Vertex(moduleName)
 	if err != nil {
 		return false
 	}
-
 	return vertex.GetState()
 }
 
@@ -482,18 +489,16 @@ outerCycle:
 					if e.ext.IsTerminator() {
 						// if disabled - terminate filtering
 						if !*moduleStatus {
+							// if so far is enabled OR there are ahead other extenders that could enable the module,
+							// mark the module as disabled by the terminator
 							if vBuf[moduleName].enabled || e.filterAhead {
 								vBuf[moduleName].enabled = *moduleStatus
 								vBuf[moduleName].updatedBy = string(e.ext.Name())
 							}
 							break
 						}
-
-						// if enabled and there are some other filtering extenders ahead - continue filtering
-						if e.filterAhead {
-							continue
-						}
-						break
+						// continue checking extenders
+						continue
 					}
 					vBuf[moduleName].enabled = *moduleStatus
 					vBuf[moduleName].updatedBy = string(e.ext.Name())