Consolidate PrefillFilter and DecodeFilter to one class

pkg/scheduling/pd/scheduler.go

@@ -71,13 +71,13 @@ func NewScheduler(ctx context.Context, schedCfg *config.Config, ds Datastore) (*
 	scheduler.prefill = scheduling.NewSchedulerWithConfig(
 		ds,
 		scheduler.generateSchedulerConfig(ctx, schedCfg.PrefillSchedulerPlugins,
-			&filter.PrefillFilter{}),
+			filter.NewPrefillFilter()),
 	)
 
 	scheduler.decode = scheduling.NewSchedulerWithConfig(
 		ds,
 		scheduler.generateSchedulerConfig(ctx, schedCfg.DecodeSchedulerPlugins,
-			&filter.DecodeFilter{}),
+			filter.NewDecodeFilter()),
 	)
 
 	return scheduler, nil

pkg/scheduling/plugins/filter/pd_role_filter.go

@@ -1,12 +1,11 @@
 package filter
 
 import (
-	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/scheduling/plugins"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/scheduling/types"
 )
 
 const (
-	// RoleLabel name
+	// RoleLabel name of the label that contains the pod's role
 	RoleLabel = "llm-d.ai/role"
 	// RolePrefill set for designated prefill workers
 	RolePrefill = "prefill"
@@ -16,46 +15,48 @@ const (
 	RoleBoth = "both"
 )
 
-// PrefillFilter - filters out pods that are not marked with role Prefill
-type PrefillFilter struct{}
+// RoleBasedFilter - filters out pods based on the role defiled by RoleLabel
+type RoleBasedFilter struct {
+	validRoles map[string]struct{}
+	name       string
+}
 
-var _ plugins.Filter = &PrefillFilter{} // validate interface conformance
+// NewPrefillFilter creates and returns instance of RoleBasedFilter configured for prefill
+func NewPrefillFilter() *RoleBasedFilter {
+	// TODO: doesn't RoleBoth also imply Prefill?
+	return NewRoleBasedFilter("prefill-filter", RolePrefill)
+}
 
-// Name returns the name of the filter
-func (pf *PrefillFilter) Name() string {
-	return "prefill-filter"
+// NewDecodeFilter creates and returns instance of RoleBasedFilter configured for decode
+func NewDecodeFilter() *RoleBasedFilter {
+	return NewRoleBasedFilter("decode-filter", RoleDecode, RoleBoth)
 }
 
-// Filter filters out all pods that are not marked as "prefill"
-func (pf *PrefillFilter) Filter(_ *types.SchedulingContext, pods []types.Pod) []types.Pod {
-	filteredPods := []types.Pod{}
+// NewRoleBasedFilter creates and returns instance of RoleBasedFilter based on input parameters
+// name - the filter name
+// rolesArr - list of valid roles
+func NewRoleBasedFilter(name string, rolesArr ...string) *RoleBasedFilter {
+	roles := map[string]struct{}{}
 
-	for _, pod := range pods {
-		role := pod.GetPod().Labels[RoleLabel]
-		if role == RolePrefill { // TODO: doesn't RoleBoth also imply Prefill?
-			filteredPods = append(filteredPods, pod)
-		}
+	for _, role := range rolesArr {
+		roles[role] = struct{}{}
 	}
-	return filteredPods
-}
 
-// DecodeFilter - filters out pods that are not marked with role Decode or Both
-type DecodeFilter struct{}
-
-var _ plugins.Filter = &DecodeFilter{} // validate interface conformance
+	return &RoleBasedFilter{name: name, validRoles: roles}
+}
 
 // Name returns the name of the filter
-func (df *DecodeFilter) Name() string {
-	return "decode-filter"
+func (f *RoleBasedFilter) Name() string {
+	return f.name
 }
 
-// Filter removes all pods that are not marked as "decode" or "both"
-func (df *DecodeFilter) Filter(_ *types.SchedulingContext, pods []types.Pod) []types.Pod {
+// Filter filters out all pods that are not marked with one of roles from the validRoles collection
+func (f *RoleBasedFilter) Filter(_ *types.SchedulingContext, pods []types.Pod) []types.Pod {
 	filteredPods := []types.Pod{}
 
 	for _, pod := range pods {
-		role, defined := pod.GetPod().Labels[RoleLabel]
-		if !defined || role == RoleDecode || role == RoleBoth {
+		role := pod.GetPod().Labels[RoleLabel]
+		if _, exists := f.validRoles[role]; exists {
 			filteredPods = append(filteredPods, pod)
 		}
 	}