feat(translator): Implement BTP CircuitBreaker API

internal/gatewayapi/backendtrafficpolicy.go

@@ -244,6 +244,7 @@
 		rl *ir.RateLimit
 		lb *ir.LoadBalancer
 		pp *ir.ProxyProtocol
+		cb *ir.CircuitBreaker
 	)
 
 	// Build IR
@@ -256,6 +257,10 @@
 	if policy.Spec.ProxyProtocol != nil {
 		pp = t.buildProxyProtocol(policy)
 	}
+	if policy.Spec.CircuitBreaker != nil {
+		cb = t.buildCircuitBreaker(policy)
+	}
+
 	// Apply IR to all relevant routes
 	prefix := irRoutePrefix(route)
 	for _, ir := range xdsIR {
@@ -266,6 +271,7 @@
 					r.RateLimit = rl
 					r.LoadBalancer = lb
 					r.ProxyProtocol = pp
+					r.CircuitBreaker = cb
 				}
 			}
 		}
@@ -278,6 +284,7 @@
 		rl *ir.RateLimit
 		lb *ir.LoadBalancer
 		pp *ir.ProxyProtocol
+		cb *ir.CircuitBreaker
 	)
 
 	// Build IR
@@ -290,6 +297,9 @@
 	if policy.Spec.ProxyProtocol != nil {
 		pp = t.buildProxyProtocol(policy)
 	}
+	if policy.Spec.CircuitBreaker != nil {
+		cb = t.buildCircuitBreaker(policy)
+	}
 	// Apply IR to all the routes within the specific Gateway
 	// If the feature is already set, then skip it, since it must be have
 	// set by a policy attaching to the route
@@ -309,6 +319,9 @@
 			if r.ProxyProtocol == nil {
 				r.ProxyProtocol = pp
 			}
+			if r.CircuitBreaker == nil {
+				r.CircuitBreaker = cb
+			}
 		}
 	}
 
@@ -643,3 +656,58 @@
 	}
 	return seconds
 }
+
+func (t *Translator) buildCircuitBreaker(policy *egv1a1.BackendTrafficPolicy) *ir.CircuitBreaker {
+	var cb *ir.CircuitBreaker
+	pcb := policy.Spec.CircuitBreaker
+
+	if pcb != nil {
+		cb = &ir.CircuitBreaker{}
+
+		if pcb.MaxConnections != nil {
+			if ui32, ok := int64ToUint32(*pcb.MaxConnections); ok {
+				cb.MaxConnections = &ui32
+			} else {
+				setCircuitBreakerPolicyErrorCondition(policy, fmt.Sprintf("invalid MaxConnections value %d", *pcb.MaxConnections))
+				return nil
+			}
+		}
+
+		if pcb.MaxParallelRequests != nil {
+			if ui32, ok := int64ToUint32(*pcb.MaxParallelRequests); ok {
+				cb.MaxParallelRequests = &ui32
+			} else {
+				setCircuitBreakerPolicyErrorCondition(policy, fmt.Sprintf("invalid MaxParallelRequests value %d", *pcb.MaxParallelRequests))
+				return nil
+			}
+		}
+
+		if pcb.MaxPendingRequests != nil {
+			if ui32, ok := int64ToUint32(*pcb.MaxPendingRequests); ok {
+				cb.MaxPendingRequests = &ui32
+			} else {
+				setCircuitBreakerPolicyErrorCondition(policy, fmt.Sprintf("invalid MaxPendingRequests value %d", *pcb.MaxPendingRequests))
+				return nil
+			}
+		}
+	}
+
+	return cb
+}
+
+func setCircuitBreakerPolicyErrorCondition(policy *egv1a1.BackendTrafficPolicy, errMsg string) {
+	message := fmt.Sprintf("Unable to translate Circuit Breaker: %s", errMsg)
+	status.SetBackendTrafficPolicyCondition(policy,
+		gwv1a2.PolicyConditionAccepted,
+		metav1.ConditionFalse,
+		gwv1a2.PolicyReasonInvalid,
+		message,
+	)
+}
+
+func int64ToUint32(in int64) (uint32, bool) {
+	if in >= 0 && in <= math.MaxUint32 {
+		return uint32(in), true
+	}
+	return 0, false
+}

internal/gatewayapi/backendtrafficpolicy_test.go

@@ -0,0 +1,52 @@
+// Copyright Envoy Gateway Authors
+// SPDX-License-Identifier: Apache-2.0
+// The full text of the Apache license is available in the LICENSE file at
+// the root of the repo.
+
+package gatewayapi
+
+import (
+	"math"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestInt64ToUint32(t *testing.T) {
+	type testCase struct {
+		Name    string
+		In      int64
+		Out     uint32
+		Success bool
+	}
+
+	testCases := []testCase{
+		{
+			Name:    "valid",
+			In:      1024,
+			Out:     1024,
+			Success: true,
+		},
+		{
+			Name:    "invalid-underflow",
+			In:      -1,
+			Out:     0,
+			Success: false,
+		},
+		{
+			Name:    "invalid-overflow",
+			In:      math.MaxUint32 + 1,
+			Out:     0,
+			Success: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.Name, func(t *testing.T) {
+			out, success := int64ToUint32(tc.In)
+			require.Equal(t, tc.Out, out)
+			require.Equal(t, tc.Success, success)
+		})
+	}
+}

internal/gatewayapi/testdata/backendtrafficpolicy-with-circuitbreakers-error.in.yaml

@@ -0,0 +1,44 @@
+gateways:
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: Gateway
+  metadata:
+    namespace: envoy-gateway
+    name: gateway-1
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - name: http
+      protocol: HTTP
+      port: 80
+      allowedRoutes:
+        namespaces:
+          from: All
+grpcRoutes:
+- apiVersion: gateway.networking.k8s.io/v1alpha2
+  kind: GRPCRoute
+  metadata:
+    namespace: default
+    name: grpcroute-1
+  spec:
+    parentRefs:
+    - namespace: envoy-gateway
+      name: gateway-1
+      sectionName: http
+    rules:
+    - backendRefs:
+      - name: service-1
+        port: 8080
+backendTrafficPolicies:
+- apiVersion: gateway.envoyproxy.io/v1alpha1
+  kind: BackendTrafficPolicy
+  metadata:
+    namespace: envoy-gateway
+    name: policy-for-gateway
+  spec:
+    targetRef:
+      group: gateway.networking.k8s.io
+      kind: Gateway
+      name: gateway-1
+      namespace: envoy-gateway
+    circuitBreaker:
+      maxConnections: -1

internal/gatewayapi/testdata/backendtrafficpolicy-with-circuitbreakers-error.out.yaml

@@ -0,0 +1,141 @@
+backendTrafficPolicies:
+- apiVersion: gateway.envoyproxy.io/v1alpha1
+  kind: BackendTrafficPolicy
+  metadata:
+    creationTimestamp: null
+    name: policy-for-gateway
+    namespace: envoy-gateway
+  spec:
+    circuitBreaker:
+      maxConnections: -1
+    targetRef:
+      group: gateway.networking.k8s.io
+      kind: Gateway
+      name: gateway-1
+      namespace: envoy-gateway
+  status:
+    conditions:
+    - lastTransitionTime: null
+      message: 'Unable to translate Circuit Breaker: invalid MaxConnections value
+        -1'
+      reason: Invalid
+      status: "False"
+      type: Accepted
+gateways:
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: Gateway
+  metadata:
+    creationTimestamp: null
+    name: gateway-1
+    namespace: envoy-gateway
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - allowedRoutes:
+        namespaces:
+          from: All
+      name: http
+      port: 80
+      protocol: HTTP
+  status:
+    listeners:
+    - attachedRoutes: 1
+      conditions:
+      - lastTransitionTime: null
+        message: Sending translated listener configuration to the data plane
+        reason: Programmed
+        status: "True"
+        type: Programmed
+      - lastTransitionTime: null
+        message: Listener has been successfully translated
+        reason: Accepted
+        status: "True"
+        type: Accepted
+      - lastTransitionTime: null
+        message: Listener references have been resolved
+        reason: ResolvedRefs
+        status: "True"
+        type: ResolvedRefs
+      name: http
+      supportedKinds:
+      - group: gateway.networking.k8s.io
+        kind: HTTPRoute
+      - group: gateway.networking.k8s.io
+        kind: GRPCRoute
+grpcRoutes:
+- apiVersion: gateway.networking.k8s.io/v1alpha2
+  kind: GRPCRoute
+  metadata:
+    creationTimestamp: null
+    name: grpcroute-1
+    namespace: default
+  spec:
+    parentRefs:
+    - name: gateway-1
+      namespace: envoy-gateway
+      sectionName: http
+    rules:
+    - backendRefs:
+      - name: service-1
+        port: 8080
+  status:
+    parents:
+    - conditions:
+      - lastTransitionTime: null
+        message: Route is accepted
+        reason: Accepted
+        status: "True"
+        type: Accepted
+      - lastTransitionTime: null
+        message: Resolved all the Object references for the Route
+        reason: ResolvedRefs
+        status: "True"
+        type: ResolvedRefs
+      controllerName: gateway.envoyproxy.io/gatewayclass-controller
+      parentRef:
+        name: gateway-1
+        namespace: envoy-gateway
+        sectionName: http
+infraIR:
+  envoy-gateway/gateway-1:
+    proxy:
+      listeners:
+      - address: null
+        name: envoy-gateway/gateway-1/http
+        ports:
+        - containerPort: 10080
+          name: http
+          protocol: HTTP
+          servicePort: 80
+      metadata:
+        labels:
+          gateway.envoyproxy.io/owning-gateway-name: gateway-1
+          gateway.envoyproxy.io/owning-gateway-namespace: envoy-gateway
+      name: envoy-gateway/gateway-1
+xdsIR:
+  envoy-gateway/gateway-1:
+    accessLog:
+      text:
+      - path: /dev/stdout
+    http:
+    - address: 0.0.0.0
+      hostnames:
+      - '*'
+      isHTTP2: true
+      name: envoy-gateway/gateway-1/http
+      port: 10080
+      routes:
+      - backendWeights:
+          invalid: 0
+          valid: 0
+        destination:
+          name: grpcroute/default/grpcroute-1/rule/0
+          settings:
+          - addressType: IP
+            endpoints:
+            - host: 7.7.7.7
+              port: 8080
+            protocol: GRPC
+            weight: 1
+        hostname: '*'
+        name: grpcroute/default/grpcroute-1/rule/0/match/-1/*