Sort match conditions based on Gateway API Spec

internal/gatewayapi/sort.go

@@ -0,0 +1,69 @@
+package gatewayapi
+
+import (
+	"sort"
+
+	"github.com/envoyproxy/gateway/internal/ir"
+)
+
+type XdsIRRoutes []*ir.HTTPRoute
+
+func (x XdsIRRoutes) Len() int      { return len(x) }
+func (x XdsIRRoutes) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+func (x XdsIRRoutes) Less(i, j int) bool {
+	// 1. Sort based on characters in a matching path.
+	pCountI := pathMatchCount(x[i].PathMatch)
+	pCountJ := pathMatchCount(x[j].PathMatch)
+	if pCountI < pCountJ {
+		return true
+	}
+	if pCountI > pCountJ {
+		return false
+	}
+	// Equal case
+
+	// 2. Sort based on the number of Header matches.
+	hCountI := len(x[i].HeaderMatches)
+	hCountJ := len(x[j].HeaderMatches)
+	if hCountI < hCountJ {
+		return true
+	}
+	if hCountI > hCountJ {
+		return false
+	}
+	// Equal case
+
+	// 3. Sort based on the number of Query param matches.
+	qCountI := len(x[i].QueryParamMatches)
+	qCountJ := len(x[j].QueryParamMatches)
+	return qCountI < qCountJ
+}
+
+// sortXdsIR sorts the xdsIR based on the match precedence
+// defined in the Gateway API spec.
+// https://gateway-api.sigs.k8s.io/references/spec/#gateway.networking.k8s.io/v1beta1.HTTPRouteRule
+func sortXdsIRMap(xdsIR XdsIRMap) {
+	for _, ir := range xdsIR {
+		ir := ir
+		sort.SliceStable(ir.HTTP, func(i, j int) bool { return ir.HTTP[i].Name < ir.HTTP[j].Name })
+		for _, http := range ir.HTTP {
+			// descending order
+			sort.Sort(sort.Reverse(XdsIRRoutes(http.Routes)))
+		}
+	}
+}
+
+func pathMatchCount(pathMatch *ir.StringMatch) int {
+	if pathMatch != nil {
+		if pathMatch.Exact != nil {
+			return len(*pathMatch.Exact)
+		}
+		if pathMatch.Prefix != nil {
+			return len(*pathMatch.Prefix)
+		}
+		if pathMatch.SafeRegex != nil {
+			return len(*pathMatch.SafeRegex)
+		}
+	}
+	return 0
+}

internal/gatewayapi/testdata/httproutes-with-multiple-matches.in.yaml

@@ -0,0 +1,129 @@
+gateways:
+- apiVersion: gateway.networking.k8s.io/v1beta1
+  kind: Gateway
+  metadata:
+    namespace: envoy-gateway
+    name: gateway-1
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - name: http
+      protocol: HTTP
+      port: 80
+      allowedRoutes:
+        namespaces:
+          from: Same
+httpRoutes:
+- apiVersion: gateway.networking.k8s.io/v1beta1
+  kind: HTTPRoute
+  metadata:
+    namespace: envoy-gateway
+    name: httproute-1
+  spec:
+    parentRefs:
+    - namespace: envoy-gateway
+      name: gateway-1
+    rules:
+    - matches:
+      - path:
+          value: "/"
+      backendRefs:
+      - name: service-1
+        port: 8080
+- apiVersion: gateway.networking.k8s.io/v1beta1
+  kind: HTTPRoute
+  metadata:
+    namespace: envoy-gateway
+    name: httproute-2
+  spec:
+    parentRefs:
+    - namespace: envoy-gateway
+      name: gateway-1
+    hostnames:
+    - example.com
+    rules:
+    - matches:
+      - path:
+          value: "/v1/example"
+        queryParams:
+        - name: "debug"
+          value: "yes"
+      backendRefs:
+      - name: service-1
+        port: 8080
+- apiVersion: gateway.networking.k8s.io/v1beta1
+  kind: HTTPRoute
+  metadata:
+    namespace: envoy-gateway
+    name: httproute-3
+  spec:
+    parentRefs:
+    - namespace: envoy-gateway
+      name: gateway-1
+    hostnames:
+    - example.com
+    rules:
+    - matches:
+      - path:
+          value: "/v1/example"
+      backendRefs:
+      - name: service-2
+        port: 8080
+- apiVersion: gateway.networking.k8s.io/v1beta1
+  kind: HTTPRoute
+  metadata:
+    namespace: envoy-gateway
+    name: httproute-4
+  spec:
+    parentRefs:
+    - namespace: envoy-gateway
+      name: gateway-1
+    hostnames:
+    - example.net
+    rules:
+    - matches:
+      - path:
+          value: "/v1/status"
+        headers:
+        - name: "version"
+          value: "one"
+      backendRefs:
+      - name: service-1
+        port: 8080
+- apiVersion: gateway.networking.k8s.io/v1beta1
+  kind: HTTPRoute
+  metadata:
+    namespace: envoy-gateway
+    name: httproute-5
+  spec:
+    parentRefs:
+    - namespace: envoy-gateway
+      name: gateway-1
+    hostnames:
+    - example.net
+    rules:
+    - matches:
+      - path:
+          value: "/v1/status"
+      backendRefs:
+      - name: service-2
+        port: 8080
+services:
+- apiVersion: v1
+  kind: Service
+  metadata:
+    namespace: envoy-gateway
+    name: service-1
+  spec:
+    clusterIP: 7.7.7.7
+    ports:
+    - port: 8080
+- apiVersion: v1
+  kind: Service
+  metadata:
+    namespace: envoy-gateway
+    name: service-2
+  spec:
+    clusterIP: 8.8.8.8
+    ports:
+    - port: 8080