Add Support for Priority Configuration in HTTPRoute Resource (#734)

* Added unit tests * Added integration tests * Updated advanced configuration documentation * Correct priority queue

Author: rlymbur

docs/guides/advanced-configurations.md

@@ -16,6 +16,38 @@ However, the controller utilizes [IMDS](https://docs.aws.amazon.com/AWSEC2/lates
 
 - **If your cluster cannot access to IMDS.** ensure to specify the[configuration variables](environment.md) when installing the controller.
 
+### Rule Priority Configuration
+
+You can manually assign priorities to rules using the custom annotation `application-networking.k8s.aws/rule-{index}-priority`. This annotation allows you to explicitly set the priority for specific rules in your route configurations.
+
+For example, to set priorities for multiple rules in an HTTPRoute:
+
+```yaml
+apiVersion: gateway.networking.k8s.io/v1beta1
+kind: HTTPRoute
+metadata:
+ name: example-route
+ annotations:
+ application-networking.k8s.aws/rule-0-priority: "200" # First rule gets higher priority
+ application-networking.k8s.aws/rule-1-priority: "100" # Second rule gets lower priority
+spec:
+ rules:
+ - matches: # This is rule[0]
+ - path:
+ type: PathPrefix
+ value: /api/v2
+ - matches: # This is rule[1]
+ - path:
+ type: PathPrefix
+ value: /api
+```
+
+The `{index}` in the annotation corresponds to the zero-based index of the rule in the rules array. In this example:
+- `rule-0-priority: "200"` applies to the first rule matching `/api/v2`
+- `rule-1-priority: "100"` applies to the second rule matching `/api`
+
+Higher priority values indicate higher precedence, so requests to `/api/v2` will be matched by the first rule (priority 200) before the second rule (priority 100) is considered.
+
 ### IPv6 support
 
 IPv6 address type is automatically used for your services and pods if

pkg/gateway/model_build_rule.go

@@ -4,12 +4,14 @@ import (
 "context"
 "errors"
 "fmt"
+"strconv"
 
 apierrors "k8s.io/apimachinery/pkg/api/errors"
 "k8s.io/apimachinery/pkg/types"
 
 anv1alpha1 "github.com/aws/aws-application-networking-k8s/pkg/apis/applicationnetworking/v1alpha1"
 "github.com/aws/aws-application-networking-k8s/pkg/model/core"
+"github.com/aws/aws-application-networking-k8s/pkg/utils"
 
 "github.com/aws/aws-sdk-go/aws"
 
@@ -32,10 +34,59 @@ func (t *latticeServiceModelBuildTask) buildRules(ctx context.Context, stackList
 // note we only build rules for non-deleted routes
 t.log.Debugf(ctx, "Processing %d rules", len(t.route.Spec().Rules()))
 
+// Track rules with and without priority
+rulesWithoutPriority := make([]core.RouteRule, 0)
+priorityQueue := make(utils.PriorityQueue, 0)
+
+// First pass: build all rules and add them to priority queue
 for i, rule := range t.route.Spec().Rules() {
+// Default priority is index + 1
+priority := int64(i + 1)
+
+// Check for priority annotation in format: application-networking.k8s.aws/rule-{index}-priority
+if priorityStr, ok := t.route.K8sObject().GetAnnotations()[fmt.Sprintf("application-networking.k8s.aws/rule-%d-priority", i)]; ok {
+if p, err := strconv.ParseInt(priorityStr, 10, 64); err == nil {
+priority = p
+t.log.Debugf(ctx, "Using priority %d from annotation for rule %d", priority, i)
+} else {
+t.log.Warnf(ctx, "Invalid priority value in annotation for rule %d: %s", i, priorityStr)
+}
+
+priorityQueue.Push(&utils.Item{
+Value: rule,
+Priority: int32(priority),
+})
+
+} else {
+rulesWithoutPriority = append(rulesWithoutPriority, rule)
+}
+}
+
+// Assign rules without a manually assigned priority a priority in sequential order following the greatest
+// manually assigned priority
+for _, ruleSpec := range rulesWithoutPriority {
+// No manually assigned priorities
+topItem, err := priorityQueue.Peek()
+if err == nil {
+t.log.Debugf(ctx, "Setting default rule priority set to: %d", topItem.Priority+1)
+priorityQueue.Push(&utils.Item{
+Value: ruleSpec,
+Priority: topItem.Priority + 1,
+})
+} else {
+t.log.Debugf(ctx, "Setting default rule priority set to: %d", 1)
+priorityQueue.Push(&utils.Item{
+Value: ruleSpec,
+Priority: 1,
+})
+}
+}
+
+for _, item := range priorityQueue {
+rule := item.Value.(core.RouteRule)
 ruleSpec := model.RuleSpec{
 StackListenerId: stackListenerId,
-Priority: int64(i + 1),
+Priority: int64(item.Priority),
 }
 
 if len(rule.Matches()) > 1 {
@@ -62,14 +113,12 @@ func (t *latticeServiceModelBuildTask) buildRules(ctx context.Context, stackList
 return err
 }
 } else {
-
 // Match every traffic on no matches
 ruleSpec.PathMatchValue = "/"
 ruleSpec.PathMatchPrefix = true
 if _, ok := rule.(*core.GRPCRouteRule); ok {
 ruleSpec.Method = string(gwv1.HTTPMethodPost)
 }
-
 }
 
 ruleTgList, err := t.getTargetGroupsForRuleAction(ctx, rule)