feat: EnvoyPatchPolicy API (#1410)

* feat: EnvoyPatchPolicy API

Relates to #24

Signed-off-by: Arko Dasgupta <arko@tetrate.io>

* wip design doc

Signed-off-by: Arko Dasgupta <arko@tetrate.io>

* wrap up design

Signed-off-by: Arko Dasgupta <arko@tetrate.io>

* lint

Signed-off-by: Arko Dasgupta <arko@tetrate.io>

* update implementation

Signed-off-by: Arko Dasgupta <arko@tetrate.io>

* address comments

Signed-off-by: Arko Dasgupta <arko@tetrate.io>

* lint

Signed-off-by: Arko Dasgupta <arko@tetrate.io>

* charts

Signed-off-by: Arko Dasgupta <arko@tetrate.io>

---------

Signed-off-by: Arko Dasgupta <arko@tetrate.io>
Co-authored-by: Xunzhuo <bitliu@tencent.com>

api/v1alpha1/envoypatchpolicy_types.go

@@ -0,0 +1,131 @@
+// 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"
+	gwapiv1a2 "sigs.k8s.io/gateway-api/apis/v1alpha2"
+)
+
+const (
+	// KindEnvoyPatchPolicy is the name of the EnvoyPatchPolicy kind.
+	KindEnvoyPatchPolicy = "EnvoyPatchPolicy"
+)
+
+// +kubebuilder:object:root=true
+
+// EnvoyPatchPolicy allows the user to modify the generated Envoy xDS
+// resources by Envoy Gateway using this patch API
+type EnvoyPatchPolicy struct {
+	metav1.TypeMeta   `json:",inline"`
+	metav1.ObjectMeta `json:"metadata,omitempty"`
+
+	// Spec defines the desired state of EnvoyPatchPolicy.
+	Spec EnvoyPatchPolicySpec `json:"spec"`
+
+	// Status defines the current status of EnvoyPatchPolicy.
+	Status EnvoyPatchPolicyStatus `json:"status"`
+}
+
+// EnvoyPatchPolicySpec defines the desired state of EnvoyPatchPolicy.
+// +union
+type EnvoyPatchPolicySpec struct {
+	// Type decides the type of patch.
+	// Valid EnvoyPatchType values are "JSONPatch".
+	//
+	// +unionDiscriminator
+	Type EnvoyPatchType `json:"type"`
+	// JSONPatch defines the JSONPatch configuration.
+	//
+	// +optional
+	JSONPatches []EnvoyJSONPatchConfig `json:"jsonPatches,omitempty"`
+	// TargetRef is the name of the Gateway API resource this policy
+	// is being attached to.
+	// Currently only attaching to Gateway is supported
+	// This Policy and the TargetRef MUST be in the same namespace
+	// for this Policy to have effect and be applied to the Gateway
+	// TargetRef
+	TargetRef gwapiv1a2.PolicyTargetReference `json:"targetRef"`
+	// Priority of the EnvoyPatchPolicy.
+	// If multiple EnvoyPatchPolicies are applied to the same
+	// TargetRef, they will be applied in the ascending order of
+	// the priority i.e. int32.min has the highest priority and
+	// int32.max has the lowest priority.
+	// Defaults to 0.
+	Priority int32 `json:"priority"`
+}
+
+// EnvoyPatchType specifies the types of Envoy patching mechanisms.
+// +kubebuilder:validation:Enum=JSONPatch
+type EnvoyPatchType string
+
+const (
+	// JSONPatchEnvoyPatchType allows the user to patch the generated xDS resources using JSONPatch semantics.
+	// For more details on the semantics, please refer to https://datatracker.ietf.org/doc/html/rfc6902
+	JSONPatchEnvoyPatchType EnvoyPatchType = "JSONPatch"
+)
+
+// EnvoyJSONPatchConfig defines the configuration for patching a Envoy xDS Resource
+// using JSONPatch semantic
+type EnvoyJSONPatchConfig struct {
+	// Type is the typed URL of the Envoy xDS Resource
+	Type EnvoyResourceType `json:"type"`
+	// Name is the name of the resource
+	Name string `json:"name"`
+	// Patch defines the JSON Patch Operation
+	Operation JSONPatchOperation `json:"operation"`
+}
+
+// EnvoyResourceType specifies the type URL of the Envoy resource.
+// +kubebuilder:validation:Enum=type.googleapis.com/envoy.config.listener.v3.Listener;type.googleapis.com/envoy.config.route.v3.RouteConfiguration;type.googleapis.com/envoy.config.cluster.v3.Cluster;type.googleapis.com/envoy.config.endpoint.v3.ClusterLoadAssignment
+type EnvoyResourceType string
+
+const (
+	// ListenerEnvoyResourceType defines the Type URL of the Listener resource
+	ListenerEnvoyResourceType EnvoyResourceType = "type.googleapis.com/envoy.config.listener.v3.Listener"
+	// RouteConfigurationEnvoyResourceType defines the Type URL of the RouteConfiguration resource
+	RouteConfigurationEnvoyResourceType EnvoyResourceType = "type.googleapis.com/envoy.config.route.v3.RouteConfiguration"
+	// ClusterEnvoyResourceType defines the Type URL of the Cluster resource
+	ClusterEnvoyResourceType EnvoyResourceType = "type.googleapis.com/envoy.config.cluster.v3.Cluster"
+	// ClusterLoadAssignmentEnvoyResourceType defines the Type URL of the ClusterLoadAssignment resource
+	ClusterLoadAssignmentEnvoyResourceType EnvoyResourceType = "type.googleapis.com/envoy.config.endpoint.v3.ClusterLoadAssignment"
+)
+
+// JSONPatchOperation defines the JSON Patch Operation as defined in
+// https://datatracker.ietf.org/doc/html/rfc6902
+type JSONPatchOperation struct {
+	// Op is the type of operation to perform
+	Op string `json:"op"`
+	// Path is the location of the target document/field where the operation will be performed
+	// Refer to https://datatracker.ietf.org/doc/html/rfc6901 for more details.
+	Path string `json:"path"`
+	// Value is the new value of the path location.
+	Value string `json:"value"`
+}
+
+// EnvoyPatchPolicyStatus defines the state of EnvoyPatchPolicy
+type EnvoyPatchPolicyStatus struct {
+	// Conditions describe the current conditions of the EnvoyPatchPolicy.
+	//
+	// +optional
+	// +listType=map
+	// +listMapKey=type
+	// +kubebuilder:validation:MaxItems=8
+	Conditions []metav1.Condition `json:"conditions,omitempty"`
+}
+
+//+kubebuilder:object:root=true
+
+// EnvoyPatchPolicyList contains a list of EnvoyPatchPolicy resources.
+type EnvoyPatchPolicyList struct {
+	metav1.TypeMeta `json:",inline"`
+	metav1.ListMeta `json:"metadata,omitempty"`
+	Items           []EnvoyPatchPolicy `json:"items"`
+}
+
+func init() {
+	SchemeBuilder.Register(&EnvoyPatchPolicy{}, &EnvoyPatchPolicyList{})
+}