Use task queue kind instead of name prefix for nexus metrics (#10141)

## What

Use `TASK_QUEUE_KIND_WORKER_COMMANDS` enum check instead of string
prefix matching on the task queue to determine if its internal queue.

## Why

PR #9899 introduced `TASK_QUEUE_KIND_WORKER_COMMANDS`. The original code
(PR #9760) predated this and relied on the `/temporal-sys/` name prefix
as a workaround.

## How did you test it?

Existing tests

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: rkannan82

common/primitives/task_queues.go

@@ -3,6 +3,7 @@ package primitives
 import (
 	"fmt"
 
+	enumspb "go.temporal.io/api/enums/v1"
 	"go.temporal.io/api/serviceerror"
 )
 
@@ -17,6 +18,21 @@ const (
 	DLQActivityTQ                 = "temporal-sys-dlq-activity-tq"
 )
 
+// IsInternalTaskQueueKind returns true if the task queue kind identifies a
+// server-internal task queue (e.g. worker commands queues).
+// All kinds are listed explicitly so that adding a new kind produces a compile error.
+func IsInternalTaskQueueKind(kind enumspb.TaskQueueKind) bool {
+	switch kind {
+	case enumspb.TASK_QUEUE_KIND_WORKER_COMMANDS:
+		return true
+	case enumspb.TASK_QUEUE_KIND_UNSPECIFIED,
+		enumspb.TASK_QUEUE_KIND_NORMAL,
+		enumspb.TASK_QUEUE_KIND_STICKY:
+		return false
+	}
+	return false
+}
+
 func IsInternalPerNsTaskQueue(taskQueue string) bool {
 	return taskQueue == PerNSWorkerTaskQueue
 }

service/matching/handler.go

@@ -2,7 +2,6 @@ package matching
 
 import (
 	"context"
-	"strings"
 	"sync"
 	"time"
 
@@ -21,6 +20,7 @@ import (
 	"go.temporal.io/server/common/persistence"
 	"go.temporal.io/server/common/persistence/serialization"
 	"go.temporal.io/server/common/persistence/visibility/manager"
+	"go.temporal.io/server/common/primitives"
 	"go.temporal.io/server/common/resource"
 	"go.temporal.io/server/common/searchattribute"
 	"go.temporal.io/server/common/testing/testhooks"
@@ -156,18 +156,12 @@ func (h *Handler) opMetricsHandler(
 	)
 }
 
-// internalTaskQueuePrefix identifies server-internal task queues
-// (e.g. /temporal-sys/worker-commands/{namespace}/{worker_grouping_key}).
-// Note: BreakdownMetricsByTaskQueue should NOT be enabled for these queues as
-// they are per-worker and will cause cardinality explosion.
-const internalTaskQueuePrefix = "/temporal-sys/"
-
 // recordNexusTaskRequest emits the nexus_task_requests metric with namespace,
 // operation, client_name, and is_internal tags.
-func (h *Handler) recordNexusTaskRequest(ctx context.Context, namespaceID string, taskQueueName string, operation string) {
+func (h *Handler) recordNexusTaskRequest(ctx context.Context, namespaceID string, taskQueueKind enumspb.TaskQueueKind, operation string) {
 	nsName := h.namespaceName(namespace.ID(namespaceID))
 	clientName, _ := headers.GetClientNameAndVersion(ctx)
-	isInternal := strings.HasPrefix(taskQueueName, internalTaskQueuePrefix)
+	isInternal := primitives.IsInternalTaskQueueKind(taskQueueKind)
 	metrics.NexusTaskRequests.With(h.metricsHandler).Record(1,
 		metrics.NamespaceTag(nsName.String()),
 		metrics.OperationTag(operation),
@@ -531,7 +525,7 @@ func (h *Handler) PollNexusTaskQueue(ctx context.Context, request *matchingservi
 	// Only record on the initial handler call (ForwardedSource == ""), not on
 	// the forwarded call to the root partition, to avoid double-counting.
 	if request.GetForwardedSource() == "" {
-		h.recordNexusTaskRequest(ctx, request.GetNamespaceId(), request.GetRequest().GetTaskQueue().GetName(), "PollNexusTaskQueue")
+		h.recordNexusTaskRequest(ctx, request.GetNamespaceId(), request.GetRequest().GetTaskQueue().GetKind(), "PollNexusTaskQueue")
 	}
 
 	if request.GetForwardedSource() != "" {
@@ -556,7 +550,7 @@ func (h *Handler) RespondNexusTaskCompleted(ctx context.Context, request *matchi
 		enumspb.TASK_QUEUE_TYPE_NEXUS,
 		metrics.MatchingRespondNexusTaskCompletedScope,
 	)
-	h.recordNexusTaskRequest(ctx, request.GetNamespaceId(), request.GetTaskQueue().GetName(), "RespondNexusTaskCompleted")
+	h.recordNexusTaskRequest(ctx, request.GetNamespaceId(), request.GetTaskQueue().GetKind(), "RespondNexusTaskCompleted")
 
 	return h.engine.RespondNexusTaskCompleted(ctx, request, opMetrics)
 }
@@ -569,7 +563,7 @@ func (h *Handler) RespondNexusTaskFailed(ctx context.Context, request *matchings
 		enumspb.TASK_QUEUE_TYPE_NEXUS,
 		metrics.MatchingRespondNexusTaskFailedScope,
 	)
-	h.recordNexusTaskRequest(ctx, request.GetNamespaceId(), request.GetTaskQueue().GetName(), "RespondNexusTaskFailed")
+	h.recordNexusTaskRequest(ctx, request.GetNamespaceId(), request.GetTaskQueue().GetKind(), "RespondNexusTaskFailed")
 
 	return h.engine.RespondNexusTaskFailed(ctx, request, opMetrics)
 }

service/matching/handler_test.go

@@ -178,16 +178,16 @@ func TestNexusHandlersEmitClientNameMetric(t *testing.T) {
 			"should not have client_name tag when header is absent, got: %v", snap)
 	})
 
-	t.Run("is_internal for /temporal-sys/ task queue", func(t *testing.T) {
+	t.Run("is_internal for worker commands task queue kind", func(t *testing.T) {
 		captureHandler := metricstest.NewCaptureHandler()
 		capture := captureHandler.StartCapture()
 		defer captureHandler.StopCapture(capture)
 
 		h, _ := newTestHandler(t, captureHandler)
 		ctx := ctxWithClientName(t, expectedClientName)
 		internalTQ := &taskqueuepb.TaskQueue{
-			Name: "/temporal-sys/worker-commands/ns/grouping-key",
-			Kind: enumspb.TASK_QUEUE_KIND_NORMAL,
+			Name: "some-task-queue",
+			Kind: enumspb.TASK_QUEUE_KIND_WORKER_COMMANDS,
 		}
 
 		_, err := h.PollNexusTaskQueue(ctx, &matchingservice.PollNexusTaskQueueRequest{
@@ -201,7 +201,7 @@ func TestNexusHandlersEmitClientNameMetric(t *testing.T) {
 		snap := capture.Snapshot()
 		require.NotEmpty(t, snap[nexusTaskRequestsMetric])
 		require.True(t, findMetricWithTag(snap, nexusTaskRequestsMetric, "is_internal", "true"),
-			"should have is_internal=true for /temporal-sys/ task queue, got: %v", snap)
+			"should have is_internal=true for worker commands task queue kind, got: %v", snap)
 	})
 }