refactor: Flatten Flow Control queue plugin directory structure (#1824)

LukeAVanDrie · web-flow · commit 3e930cb9e533 · 2025-11-06T16:20:52.000-08:00
* refactor: Flatten plugins/queue package structure

Moves queue implementations (ListQueue, MaxMinHeap) directly into the
`plugins/queue` package, removing the unnecessary nested directories.

This simplifies the import paths and project structure.

This is a no-op refactoring.

* chore: Apply some modernization best practices

Changes generated via:
```
go run golang.org/x/tools/gopls/internal/analysis/modernize/cmd/modernize@latest \
-fix \
-test ./pkg/epp/flowcontrol/framework/plugins/queue/...
```
diff --git a/pkg/epp/flowcontrol/framework/plugins/queue/benchmark_test.go b/pkg/epp/flowcontrol/framework/plugins/queue/benchmark_test.go
@@ -14,15 +14,14 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package queue_test
+package queue
 
 import (
 	"fmt"
 	"sync"
 	"testing"
 
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework"
-	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types/mocks"
 )
@@ -31,7 +30,7 @@ var benchmarkFlowKey = types.FlowKey{ID: "benchmark-flow"}
 
 // BenchmarkQueues runs a series of benchmarks against all registered queue implementations.
 func BenchmarkQueues(b *testing.B) {
-	for queueName, constructor := range queue.RegisteredQueues {
+	for queueName, constructor := range RegisteredQueues {
 		b.Run(string(queueName), func(b *testing.B) {
 			// All queue implementations must support the default enqueue time comparator.
 			q, err := constructor(enqueueTimeComparator)
@@ -94,7 +93,7 @@ func benchmarkAddPeekRemove(b *testing.B, q framework.SafeQueue) {
 
 	b.ReportAllocs()
 
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		item := mocks.NewMockQueueItemAccessor(1, "item", benchmarkFlowKey)
 		err := q.Add(item)
 		if err != nil {
@@ -120,7 +119,7 @@ func benchmarkAddPeekRemove(b *testing.B, q framework.SafeQueue) {
 func benchmarkBulkAddThenBulkRemove(b *testing.B, q framework.SafeQueue) {
 	b.ReportAllocs()
 
-	for i := 0; i < b.N; i++ {
+	for i := 0; b.Loop(); i++ {
 		// Add a batch of items
 		items := make([]types.QueueItemAccessor, 100)
 		for j := range items {
@@ -155,7 +154,7 @@ func benchmarkAddPeekTailRemove(b *testing.B, q framework.SafeQueue) {
 
 	b.ReportAllocs()
 
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		item := mocks.NewMockQueueItemAccessor(1, "item", benchmarkFlowKey)
 		err := q.Add(item)
 		if err != nil {
diff --git a/pkg/epp/flowcontrol/framework/plugins/queue/functional_test.go b/pkg/epp/flowcontrol/framework/plugins/queue/functional_test.go
@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package queue_test
+package queue
 
 import (
 	"fmt"
@@ -30,9 +30,6 @@ import (
 
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework"
 	frameworkmocks "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/mocks"
-	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue"
-	_ "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue/listqueue"
-	_ "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue/maxminheap"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types"
 	typesmocks "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types/mocks"
 )
@@ -181,7 +178,7 @@ func testLifecycleAndOrdering(
 func TestQueueConformance(t *testing.T) {
 	t.Parallel()
 
-	for queueName, constructor := range queue.RegisteredQueues {
+	for queueName, constructor := range RegisteredQueues {
 		t.Run(string(queueName), func(t *testing.T) {
 			t.Parallel()
 			flowKey := types.FlowKey{ID: "test-flow-1", Priority: 0}
@@ -511,7 +508,7 @@ func TestQueueConformance(t *testing.T) {
 				handleChan := make(chan types.QueueItemHandle, initialItems+(numGoroutines*opsPerGoroutine))
 
 				// Pre-populate the queue with an initial set of items.
-				for i := 0; i < initialItems; i++ {
+				for i := range initialItems {
 					item := typesmocks.NewMockQueueItemAccessor(1, fmt.Sprintf("%s_conc_init_%d", flowKey, i), flowKey)
 					err := q.Add(item)
 					require.NoError(t, err, "Setup: pre-populating the queue should not fail")
@@ -526,7 +523,7 @@ func TestQueueConformance(t *testing.T) {
 				for i := range numGoroutines {
 					go func(routineID int) {
 						defer wg.Done()
-						for j := 0; j < opsPerGoroutine; j++ {
+						for j := range opsPerGoroutine {
 							opType := (j + routineID) % 4 // Vary operations more across goroutines
 							switch opType {
 							case 0: // Add
diff --git a/pkg/epp/flowcontrol/framework/plugins/queue/listqueue.go b/pkg/epp/flowcontrol/framework/plugins/queue/listqueue.go
@@ -16,15 +16,14 @@ limitations under the License.
 
 // Package listqueue provides a high-performance, concurrent-safe FIFO (First-In, First-Out) implementation of
 // implementation of the `framework.SafeQueue` based on the standard library's `container/list`.
-package listqueue
+package queue
 
 import (
 	"container/list"
 	"sync"
 	"sync/atomic"
 
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework"
-	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types"
 )
 
@@ -53,7 +52,7 @@ import (
 const ListQueueName = "ListQueue"
 
 func init() {
-	queue.MustRegisterQueue(queue.RegisteredQueueName(ListQueueName),
+	MustRegisterQueue(RegisteredQueueName(ListQueueName),
 		func(_ framework.ItemComparator) (framework.SafeQueue, error) {
 			// The list queue is a simple FIFO queue and does not use a comparator.
 			return newListQueue(), nil
diff --git a/pkg/epp/flowcontrol/framework/plugins/queue/maxminheap.go b/pkg/epp/flowcontrol/framework/plugins/queue/maxminheap.go
@@ -23,23 +23,22 @@ limitations under the License.
 //
 // The core heap maintenance logic (up, down, and grandchild finding) is adapted from the public domain implementation
 // at https://github.com/esote/minmaxheap, which is licensed under CC0-1.0.
-package maxminheap
+package queue
 
 import (
 	"math"
 	"sync"
 	"sync/atomic"
 
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework"
-	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types"
 )
 
 // MaxMinHeapName is the name of the max-min heap queue implementation.
 const MaxMinHeapName = "MaxMinHeap"
 
 func init() {
-	queue.MustRegisterQueue(queue.RegisteredQueueName(MaxMinHeapName),
+	MustRegisterQueue(RegisteredQueueName(MaxMinHeapName),
 		func(comparator framework.ItemComparator) (framework.SafeQueue, error) {
 			return newMaxMinHeap(comparator), nil
 		})
diff --git a/pkg/epp/flowcontrol/framework/plugins/queue/maxminheap_test.go b/pkg/epp/flowcontrol/framework/plugins/queue/maxminheap_test.go
@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package maxminheap
+package queue
 
 import (
 	"math"
@@ -23,19 +23,10 @@ import (
 
 	"github.com/stretchr/testify/require"
 
-	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/mocks"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types"
 	typesmocks "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types/mocks"
 )
 
-// enqueueTimeComparator orders items by their enqueue time (earlier first).
-var enqueueTimeComparator = &mocks.MockItemComparator{
-	ScoreTypeV: "enqueue_time_ns_asc",
-	FuncV: func(a, b types.QueueItemAccessor) bool {
-		return a.EnqueueTime().After(b.EnqueueTime())
-	},
-}
-
 // TestMaxMinHeap_InternalProperty validates that the max-min heap property is maintained after a series of `Add` and
 // `Remove` operations. This is a white-box test to ensure the internal data structure is always in a valid state.
 func TestMaxMinHeap_InternalProperty(t *testing.T) {
diff --git a/pkg/epp/flowcontrol/registry/config.go b/pkg/epp/flowcontrol/registry/config.go
@@ -28,7 +28,6 @@ import (
 	intra "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/policies/intraflow/dispatch"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/policies/intraflow/dispatch/fcfs"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue"
-	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue/listqueue"
 )
 
 // =============================================================================
@@ -44,7 +43,7 @@ const (
 	// defaultInterFlowDispatchPolicy is the default policy for selecting which flow's queue to service next.
 	defaultInterFlowDispatchPolicy inter.RegisteredPolicyName = besthead.BestHeadPolicyName
 	// defaultQueue is the default queue implementation for flows.
-	defaultQueue queue.RegisteredQueueName = listqueue.ListQueueName
+	defaultQueue queue.RegisteredQueueName = queue.ListQueueName
 	// defaultInitialShardCount is the default number of parallel shards to create when the registry is initialized.
 	defaultInitialShardCount int = 1
 	// defaultFlowGCTimeout is the default duration of inactivity after which an idle flow is garbage collected.
diff --git a/pkg/epp/flowcontrol/registry/config_test.go b/pkg/epp/flowcontrol/registry/config_test.go
@@ -32,7 +32,6 @@ import (
 	intra "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/policies/intraflow/dispatch"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/policies/intraflow/dispatch/fcfs"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue"
-	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue/listqueue"
 )
 
 func TestConfig_ValidateAndApplyDefaults(t *testing.T) {
@@ -84,7 +83,7 @@ func TestConfig_ValidateAndApplyDefaults(t *testing.T) {
 					PriorityName:            "Critical",
 					IntraFlowDispatchPolicy: fcfs.FCFSPolicyName,
 					InterFlowDispatchPolicy: besthead.BestHeadPolicyName,
-					Queue:                   listqueue.ListQueueName,
+					Queue:                   queue.ListQueueName,
 					MaxBytes:                500,
 				}},
 			},
@@ -195,7 +194,7 @@ func TestConfig_ValidateAndApplyDefaults(t *testing.T) {
 					Priority:                1,
 					PriorityName:            "High",
 					IntraFlowDispatchPolicy: intra.RegisteredPolicyName("policy-with-req"),
-					Queue:                   listqueue.ListQueueName,
+					Queue:                   queue.ListQueueName,
 				}},
 			},
 			opts: []configOption{withIntraFlowDispatchPolicyFactory(
diff --git a/pkg/epp/flowcontrol/registry/managedqueue_test.go b/pkg/epp/flowcontrol/registry/managedqueue_test.go
@@ -30,7 +30,6 @@ import (
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework"
 	frameworkmocks "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/mocks"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue"
-	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/framework/plugins/queue/listqueue"
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types"
 	typesmocks "sigs.k8s.io/gateway-api-inference-extension/pkg/epp/flowcontrol/types/mocks"
 )
@@ -56,7 +55,7 @@ func newMockedMqHarness(t *testing.T, queue *frameworkmocks.MockSafeQueue, key t
 // This is essential for integration and concurrency tests.
 func newRealMqHarness(t *testing.T, key types.FlowKey) *mqTestHarness {
 	t.Helper()
-	q, err := queue.NewQueueFromName(listqueue.ListQueueName, nil)
+	q, err := queue.NewQueueFromName(queue.ListQueueName, nil)
 	require.NoError(t, err, "Test setup: creating a real ListQueue implementation should not fail")
 	return newMqHarness(t, q, key, false)
 }
