Cleanup dead code, also add some more comments

Author: rahulgurnani

pkg/epp/backend/metrics/types.go

@@ -75,8 +75,4 @@ func (f *PodMetricsFactory) ReleaseEndpoint(ep PodMetrics) {
 	}
 }
 
-func (f *PodMetricsFactory) GetAttributes() *datalayer.Attributes {
-	return datalayer.NewAttributes()
-}
-
 type PodMetrics = datalayer.Endpoint

pkg/epp/requestcontrol/director.go

@@ -378,6 +378,9 @@ func prepareData(plugin PrepareDataPlugin, ctx context.Context, request *schedul
 	}
 }
 
+// executePluginsAsDAG executes PrepareData plugins as a DAG based on their dependencies asynchronously.
+// So, a plugin is executed only after all its dependencies have been executed.
+// If there is a cycle or other error in the DAG, it returns an error.
 func (d *Director) executePluginsAsDAG(ctx context.Context, request *schedulingtypes.LLMRequest, pods []schedulingtypes.Pod, plugins []PrepareDataPlugin) error {
 	// Build the DAG
 	// The error validation happens on startup when loading the config. So, here there should not be any error.

pkg/epp/requestcontrol/graph_util.go

@@ -26,8 +26,8 @@ func buildDAG(plugins []PrepareDataPlugin) map[string][]string {
 		dag[plugin.TypedName().String()] = []string{}
 	}
 	// Create dependency graph as a DAG.
-	for i := 0; i < len(plugins); i++ {
-		for j := 0; j < len(plugins); j++ {
+	for i := range plugins {
+		for j := range plugins {
 			if i == j {
 				continue
 			}
@@ -50,7 +50,8 @@ func buildDAG(plugins []PrepareDataPlugin) map[string][]string {
 	return dag
 }
 
-// Where will we call prepareData from? How will the data be actually fetched? Can we put the data in DependencyNode?
+// prepareDataGraph builds a DAG of data preparation plugins and checks for cycles.
+// If there is a cycle, it returns an error.
 func prepareDataGraph(plugins []PrepareDataPlugin) (map[string][]string, error) {
 	nameToNode := map[string]PrepareDataPlugin{}