feat: support Health Check in BackendTrafficPolicy

api/v1alpha1/backendtrafficpolicy_types.go

@@ -65,6 +65,11 @@ type BackendTrafficPolicySpec struct {
 	//
 	// +optional
 	TCPKeepalive *TCPKeepalive `json:"tcpKeepalive,omitempty"`
+
+	// HealthCheck allows gateway to perform active health checking on backends.
+	//
+	// +optional
+	HealthCheck *HealthCheck `json:"healthCheck,omitempty"`
 }
 
 // BackendTrafficPolicyStatus defines the state of BackendTrafficPolicy

api/v1alpha1/healthcheck_types.go

@@ -0,0 +1,163 @@
+// 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 v1alpha1
+
+import metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+// HealthCheck defines the health check configuration.
+type HealthCheck struct {
+	// Timeout defines the time to wait for a health check response.
+	//
+	// +kubebuilder:validation:Format=duration
+	// +kubebuilder:default="1s"
+	// +optional
+	Timeout *metav1.Duration `json:"timeout"`
+
+	// Interval defines the time between health checks.
+	//
+	// +kubebuilder:validation:Format=duration
+	// +kubebuilder:default="3s"
+	// +optional
+	Interval *metav1.Duration `json:"interval"`
+
+	// UnhealthyThreshold defines the number of unhealthy health checks required before a backend host is marked unhealthy.
+	//
+	// +kubebuilder:validation:Minimum=1
+	// +kubebuilder:default=3
+	// +optional
+	UnhealthyThreshold *uint32 `json:"unhealthyThreshold"`
+
+	// HealthyThreshold defines the number of healthy health checks required before a backend host is marked healthy.
+	//
+	// +kubebuilder:validation:Minimum=1
+	// +kubebuilder:default=1
+	// +optional
+	HealthyThreshold *uint32 `json:"healthyThreshold"`
+
+	// HealthChecker defines the concrete health checker to do health checking.
+	HealthChecker HealthChecker `json:"healthChecker"`
+}
+
+// HealthCheckerType is the type of health checker.
+// +kubebuilder:validation:Enum=HTTP;GRPC;TCP
+type HealthCheckerType string
+
+const (
+	// HealthCheckerTypeHTTP defines the HTTP type of health checking.
+	HealthCheckerTypeHTTP HealthCheckerType = "HTTP"
+	// HealthCheckerTypeGRPC defines the GRPC type of health checking.
+	HealthCheckerTypeGRPC HealthCheckerType = "GRPC"
+	// HealthCheckerTypeTCP defines the TCP type of health checking.
+	HealthCheckerTypeTCP HealthCheckerType = "TCP"
+)
+
+// HealthChecker defines the configuration of concrete health checker.
+// EG supports various types of health checking including HTTP, GRPC, TCP.
+// +union
+//
+// +kubebuilder:validation:XValidation:rule="self.type == 'HTTP' ? has(self.http) : !has(self.http)",message="If Health Checker type is HTTP, http field needs to be set."
+// +kubebuilder:validation:XValidation:rule="self.type == 'GRPC' ? has(self.grpc) : !has(self.grpc)",message="If Health Checker type is GRPC, grpc field needs to be set."
+// +kubebuilder:validation:XValidation:rule="self.type == 'TCP' ? has(self.tcp) : !has(self.tcp)",message="If Health Checker type is TCP, tcp field needs to be set."
+type HealthChecker struct {
+	// Type defines the type of health checker.
+	// +kubebuilder:validation:Enum=HTTP;GRPC;TCP
+	// +unionDiscriminator
+	Type HealthCheckerType `json:"type" yaml:"type"`
+	// HTTP defines the configuration of http health checker.
+	// It's required while the health checker type is HTTP.
+	// +optional
+	HTTP *HTTPHealthChecker `json:"http,omitempty" yaml:"http,omitempty"`
+	// GRPC defines the configuration of grpc health checker.
+	// It's required while the health checker type is GRPC.
+	// +optional
+	GRPC *GRPCHealthChecker `json:"grpc,omitempty" yaml:"grpc,omitempty"`
+	// TCP defines the configuration of tcp health checker.
+	// It's required while the health checker type is TCP.
+	// +optional
+	TCP *TCPHealthChecker `json:"tcp,omitempty" yaml:"tcp,omitempty"`
+}
+
+// HTTPHealthChecker defines the settings of http health check.
+type HTTPHealthChecker struct {
+	// Path defines the HTTP path that will be requested during health checking.
+	// +kubebuilder:validation:MinLength=1
+	// +kubebuilder:validation:MaxLength=1024
+	Path string `json:"path" yaml:"path"`
+	// Method defines the HTTP method used for health checking.
+	// Defaults to GET
+	// +optional
+	Method *string `json:"method,omitempty" yaml:"method,omitempty"`
+	// ExpectedStatuses defines a list of HTTP response statuses considered healthy.
+	// +optional
+	ExpectedStatuses []HTTPStatusRange `json:"expectedStatuses,omitempty" yaml:"expectedStatuses,omitempty"`
+	// ExpectedResponses defines a list of HTTP expected responses to match.
+	// +optional
+	ExpectedResponses []HealthCheckPayload `json:"expectedResponses,omitempty" yaml:"expectedResponses,omitempty"`
+}
+
+// GRPCHealthChecker defines the settings of grpc health check.
+type GRPCHealthChecker struct {
+	// ServiceName defines the value of parameter service in the gRPC health check request.
+	// +optional
+	ServiceName *string `json:"serviceName,omitempty" yaml:"omitempty"`
+	// Authority defines the value of :authority header in the gRPC health check request.
+	// +optional
+	Authority *string `json:"authority,omitempty" yaml:"authority,omitempty"`
+	// +optional
+	Metadata map[string]string `json:"metadata,omitempty" yaml:"metadata,omitempty"`
+}
+
+// TCPHealthChecker defines the settings of tcp health check.
+type TCPHealthChecker struct {
+	// Send defines the request payload.
+	// +optional
+	Send *HealthCheckPayload `json:"send,omitempty" yaml:"send,omitempty"`
+	// Receive defines the expected response payloads.
+	// +optional
+	Receive []HealthCheckPayload `json:"receive,omitempty" yaml:"receive,omitempty"`
+}
+
+// HTTPStatusRange defines the start and end of the http status range using half-open interval semantics [start, end). Only statuses in the range [100, 600) are allowed.
+// +kubebuilder:validation:XValidation:rule="self.start <= self.end",message="start should be not greater than end"
+type HTTPStatusRange struct {
+	// Start defines start of the range (inclusive)
+	// +kubebuilder:validation:Minimum=100
+	// +kubebuilder:validation:Maximum=600
+	// +kubebuilder:validation:ExclusiveMaximum=true
+	Start int64 `json:"start" yaml:"start"`
+	// End defines end of the range (exclusive)
+	// +kubebuilder:validation:Minimum=100
+	// +kubebuilder:validation:Maximum=600
+	End int64 `json:"end" yaml:"end"`
+}
+
+// HealthCheckPayloadType is the type of the payload.
+// +kubebuilder:validation:Enum=Text;Binary
+type HealthCheckPayloadType string
+
+const (
+	// HealthCheckPayloadTypeText defines the Text type payload.
+	HealthCheckPayloadTypeText HealthCheckPayloadType = "Text"
+	// HealthCheckPayloadTypeBinary defines the Binary type payload.
+	HealthCheckPayloadTypeBinary HealthCheckPayloadType = "Binary"
+)
+
+// HealthCheckPayload defines the encoding of the payload bytes in the payload.
+// +union
+// +kubebuilder:validation:XValidation:rule="self.type == 'Text' ? has(self.text) : !has(self.text)",message="If payload type is Text, text field needs to be set."
+// +kubebuilder:validation:XValidation:rule="self.type == 'Binary' ? has(self.binary) : !has(self.binary)",message="If payload type is Binary, binary field needs to be set."
+type HealthCheckPayload struct {
+	// Type defines the type of the payload.
+	// +kubebuilder:validation:Enum=Text;Binary
+	// +unionDiscriminator
+	Type HealthCheckPayloadType `json:"type" yaml:"type"`
+	// Text payload in plain text.
+	// +optional
+	Text *string `json:"text,omitempty" yaml:"text,omitempty"`
+	// Binary payload base64 encoded.
+	// +optional
+	Binary []byte `json:"binary,omitempty" yaml:"binary,omitempty"`
+}