perf: improve mem allocation in TruncatePolicyAncestors

internal/gatewayapi/status/policy.go

@@ -6,10 +6,7 @@
 package status
 
 import (
-	"cmp"
-	"fmt"
-	"slices"
-	"strings"
+	"sort"
 	"time"
 
 	gocmp "github.com/google/go-cmp/cmp"
@@ -20,10 +17,6 @@ import (
 	egv1a1 "github.com/envoyproxy/gateway/api/v1alpha1"
 )
 
-const (
-	conditionMessageMaxLength = 32768
-)
-
 type PolicyResolveError struct {
 	Reason  gwapiv1a2.PolicyConditionReason
 	Message string
@@ -113,22 +106,31 @@ func TruncatePolicyAncestors(policyStatus *gwapiv1a2.PolicyStatus, controllerNam
 	// we need to truncate policy ancestor status due to the item limit (max 16).
 	// so we are choosing to preserve the 16 most important ancestors.
 	// negative polarity (Conflicted, Overridden...) should be clearly indicated to the user.
-	slices.SortStableFunc(policyStatus.Ancestors, func(a, b gwapiv1a2.PolicyAncestorStatus) int {
-		if r := cmp.Compare(sortRankForPolicyAncestor(a), sortRankForPolicyAncestor(b)); r != 0 {
-			return r
+	sort.Slice(policyStatus.Ancestors, func(i, j int) bool {
+		a, b := policyStatus.Ancestors[i], policyStatus.Ancestors[j]
+		aRank := sortRankForPolicyAncestor(a)
+		bRank := sortRankForPolicyAncestor(b)
+
+		if aRank != bRank {
+			return aRank < bRank
+		}
+		// First compare by namespace, then by name
+		aNamespace := ""
+		if a.AncestorRef.Namespace != nil {
+			aNamespace = string(*a.AncestorRef.Namespace)
+		}
+		bNamespace := ""
+		if b.AncestorRef.Namespace != nil {
+			bNamespace = string(*b.AncestorRef.Namespace)
 		}
-		return strings.Compare(string(a.AncestorRef.Name), string(b.AncestorRef.Name))
+
+		if aNamespace != bNamespace {
+			return aNamespace < bNamespace
+		}
+		return string(a.AncestorRef.Name) < string(b.AncestorRef.Name)
 	})
 
-	aggregated := make([]string, len(policyStatus.Ancestors)-16)
-	for i, ancestor := range policyStatus.Ancestors[16:] {
-		aggregated[i] = string(ancestor.AncestorRef.Name)
-	}
-	aggregatedMessage := fmt.Sprintf("Ancestors have been aggregated because the number of policy ancestors exceeds 16. "+
-		"The aggregated ancestors: %s", strings.Join(aggregated, ", "))
-	if len(aggregatedMessage) > conditionMessageMaxLength {
-		aggregatedMessage = aggregatedMessage[:conditionMessageMaxLength]
-	}
+	aggregatedMessage := "Ancestors have been truncated because the number of policy ancestors exceeds 16."
 
 	policyStatus.Ancestors = policyStatus.Ancestors[:16]
 	SetConditionForPolicyAncestor(policyStatus,

internal/gatewayapi/testdata/backendtlspolicy-status-conditions-truncated.out.yaml

@@ -179,8 +179,8 @@ backendTLSPolicies:
         status: "True"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated
@@ -365,8 +365,8 @@ backendTLSPolicies:
         status: "False"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated

internal/gatewayapi/testdata/backendtrafficpolicy-status-conditions-truncated.out.yaml

@@ -213,8 +213,8 @@ backendTrafficPolicies:
         status: "True"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-7, gateway-8'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated
@@ -440,8 +440,8 @@ backendTrafficPolicies:
         status: "False"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated
@@ -651,8 +651,8 @@ backendTrafficPolicies:
         status: "True"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated

internal/gatewayapi/testdata/clienttrafficpolicy-status-conditions-truncated.out.yaml

@@ -255,8 +255,8 @@ envoyExtensionPolicies:
         status: "True"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated
@@ -533,8 +533,8 @@ envoyExtensionPolicies:
         status: "False"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated

internal/gatewayapi/testdata/envoyextensionpolicy-status-conditions-truncated.out.yaml

@@ -213,8 +213,8 @@ envoyExtensionPolicies:
         status: "True"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-7, gateway-8'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated
@@ -440,8 +440,8 @@ envoyExtensionPolicies:
         status: "False"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated
@@ -651,8 +651,8 @@ envoyExtensionPolicies:
         status: "True"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated

internal/gatewayapi/testdata/securitypolicy-status-conditions-truncated.out.yaml

@@ -1960,8 +1960,8 @@ securityPolicies:
         status: "True"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-7, gateway-8'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated
@@ -2187,8 +2187,8 @@ securityPolicies:
         status: "False"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated
@@ -2398,8 +2398,8 @@ securityPolicies:
         status: "True"
         type: Accepted
       - lastTransitionTime: null
-        message: 'Ancestors have been aggregated because the number of policy ancestors
-          exceeds 16. The aggregated ancestors: gateway-8, gateway-9'
+        message: Ancestors have been truncated because the number of policy ancestors
+          exceeds 16.
         reason: Aggregated
         status: "True"
         type: Aggregated