// Copyright 2025 Envoy Project Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package envoy.config.endpoint.v3;

import "envoy/config/core/v3/address.proto";
import "envoy/config/core/v3/base.proto";
import "envoy/config/core/v3/config_source.proto";
import "envoy/config/core/v3/health_check.proto";

import "google/protobuf/wrappers.proto";

import "xds/core/v3/collection_entry.proto";

import "envoy/annotations/deprecation.proto";
import "udpa/annotations/status.proto";
import "udpa/annotations/versioning.proto";
import "validate/validate.proto";

option java_package = "io.envoyproxy.envoy.config.endpoint.v3";
option java_outer_classname = "EndpointComponentsProto";
option java_multiple_files = true;
option go_package = "github.com/envoyproxy/go-control-plane/envoy/config/endpoint/v3;endpointv3";
option (udpa.annotations.file_status).package_version_status = ACTIVE;

// [#protodoc-title: Endpoints]

// Upstream host identifier.
message Endpoint {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.endpoint.Endpoint";

  // The optional health check configuration.
  message HealthCheckConfig {
    option (udpa.annotations.versioning).previous_message_type =
        "envoy.api.v2.endpoint.Endpoint.HealthCheckConfig";

    // Optional alternative health check port value.
    //
    // By default the health check address port of an upstream host is the same
    // as the host's serving address port. This provides an alternative health
    // check port. Setting this with a non-zero value allows an upstream host
    // to have different health check address port.
    uint32 port_value = 1 [(validate.rules).uint32 = {lte: 65535}];

    // By default, the host header for L7 health checks is controlled by cluster level configuration
    // (see: :ref:`host <envoy_v3_api_field_config.core.v3.HealthCheck.HttpHealthCheck.host>` and
    // :ref:`authority <envoy_v3_api_field_config.core.v3.HealthCheck.GrpcHealthCheck.authority>`). Setting this
    // to a non-empty value allows overriding the cluster level configuration for a specific
    // endpoint.
    string hostname = 2;

    // Optional alternative health check host address.
    //
    // .. attention::
    //
    //   The form of the health check host address is expected to be a direct IP address.
    core.v3.Address address = 3;

    // Optional flag to control if perform active health check for this endpoint.
    // Active health check is enabled by default if there is a health checker.
    bool disable_active_health_check = 4;
  }

  message AdditionalAddress {
    // Additional address that is associated with the endpoint.
    core.v3.Address address = 1;
  }

  // The upstream host address.
  //
  // .. attention::
  //
  //   The form of host address depends on the given cluster type. For STATIC or EDS,
  //   it is expected to be a direct IP address (or something resolvable by the
  //   specified :ref:`resolver <envoy_v3_api_field_config.core.v3.SocketAddress.resolver_name>`
  //   in the Address). For LOGICAL or STRICT DNS, it is expected to be hostname,
  //   and will be resolved via DNS.
  core.v3.Address address = 1;

  // The optional health check configuration is used as configuration for the
  // health checker to contact the health checked host.
  //
  // .. attention::
  //
  //   This takes into effect only for upstream clusters with
  //   :ref:`active health checking <arch_overview_health_checking>` enabled.
  HealthCheckConfig health_check_config = 2;

  // The hostname associated with this endpoint. This hostname is not used for routing or address
  // resolution. If provided, it will be associated with the endpoint, and can be used for features
  // that require a hostname, like
  // :ref:`auto_host_rewrite <envoy_v3_api_field_config.route.v3.RouteAction.auto_host_rewrite>`.
  string hostname = 3;

  // An ordered list of addresses that together with ``address`` comprise the
  // list of addresses for an endpoint. The address given in the ``address`` is
  // prepended to this list. It is assumed that the list must already be
  // sorted by preference order of the addresses. This will only be supported
  // for STATIC and EDS clusters.
  repeated AdditionalAddress additional_addresses = 4;
}

// An Endpoint that Envoy can route traffic to.
// [#next-free-field: 6]
message LbEndpoint {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.endpoint.LbEndpoint";

  // Upstream host identifier or a named reference.
  oneof host_identifier {
    Endpoint endpoint = 1;

    // [#not-implemented-hide:]
    string endpoint_name = 5;
  }

  // Optional health status when known and supplied by EDS server.
  core.v3.HealthStatus health_status = 2;

  // The endpoint metadata specifies values that may be used by the load
  // balancer to select endpoints in a cluster for a given request. The filter
  // name should be specified as ``envoy.lb``. An example boolean key-value pair
  // is ``canary``, providing the optional canary status of the upstream host.
  // This may be matched against in a route's
  // :ref:`RouteAction <envoy_v3_api_msg_config.route.v3.RouteAction>` metadata_match field
  // to subset the endpoints considered in cluster load balancing.
  core.v3.Metadata metadata = 3;

  // The optional load balancing weight of the upstream host; at least 1.
  // Envoy uses the load balancing weight in some of the built in load
  // balancers. The load balancing weight for an endpoint is divided by the sum
  // of the weights of all endpoints in the endpoint's locality to produce a
  // percentage of traffic for the endpoint. This percentage is then further
  // weighted by the endpoint's locality's load balancing weight from
  // LocalityLbEndpoints. If unspecified, will be treated as 1. The sum
  // of the weights of all endpoints in the endpoint's locality must not
  // exceed uint32_t maximal value (4294967295).
  google.protobuf.UInt32Value load_balancing_weight = 4 [(validate.rules).uint32 = {gte: 1}];
}

// LbEndpoint list collection. Entries are `LbEndpoint` resources or references.
// [#not-implemented-hide:]
message LbEndpointCollection {
  xds.core.v3.CollectionEntry entries = 1;
}

// A configuration for an LEDS collection.
message LedsClusterLocalityConfig {
  // Configuration for the source of LEDS updates for a Locality.
  core.v3.ConfigSource leds_config = 1;

  // The name of the LbEndpoint collection resource.
  //
  // If the name ends in ``/*``, it indicates an LbEndpoint glob collection,
  // which is supported only in the xDS incremental protocol variants.
  // Otherwise, it indicates an LbEndpointCollection list collection.
  //
  // Envoy currently supports only glob collections.
  string leds_collection_name = 2;
}

// A group of endpoints belonging to a Locality.
// One can have multiple LocalityLbEndpoints for a locality, but only if
// they have different priorities.
// [#next-free-field: 10]
message LocalityLbEndpoints {
  option (udpa.annotations.versioning).previous_message_type =
      "envoy.api.v2.endpoint.LocalityLbEndpoints";

  // [#not-implemented-hide:]
  // A list of endpoints of a specific locality.
  message LbEndpointList {
    repeated LbEndpoint lb_endpoints = 1;
  }

  // Identifies location of where the upstream hosts run.
  core.v3.Locality locality = 1;

  // Metadata to provide additional information about the locality endpoints in aggregate.
  core.v3.Metadata metadata = 9;

  // The group of endpoints belonging to the locality specified.
  // This is ignored if :ref:`leds_cluster_locality_config
  // <envoy_v3_api_field_config.endpoint.v3.LocalityLbEndpoints.leds_cluster_locality_config>` is set.
  repeated LbEndpoint lb_endpoints = 2;

  oneof lb_config {
    // [#not-implemented-hide:]
    // Not implemented and deprecated.
    LbEndpointList load_balancer_endpoints = 7
        [deprecated = true, (envoy.annotations.deprecated_at_minor_version) = "3.0"];

    // LEDS Configuration for the current locality.
    // If this is set, the :ref:`lb_endpoints
    // <envoy_v3_api_field_config.endpoint.v3.LocalityLbEndpoints.lb_endpoints>`
    // field is ignored.
    LedsClusterLocalityConfig leds_cluster_locality_config = 8;
  }

  // Optional: Per priority/region/zone/sub_zone weight; at least 1. The load
  // balancing weight for a locality is divided by the sum of the weights of all
  // localities  at the same priority level to produce the effective percentage
  // of traffic for the locality. The sum of the weights of all localities at
  // the same priority level must not exceed uint32_t maximal value (4294967295).
  //
  // Locality weights are only considered when :ref:`locality weighted load
  // balancing <arch_overview_load_balancing_locality_weighted_lb>` is
  // configured. These weights are ignored otherwise. If no weights are
  // specified when locality weighted load balancing is enabled, the locality is
  // assigned no load.
  google.protobuf.UInt32Value load_balancing_weight = 3 [(validate.rules).uint32 = {gte: 1}];

  // Optional: the priority for this LocalityLbEndpoints. If unspecified this will
  // default to the highest priority (0).
  //
  // Under usual circumstances, Envoy will only select endpoints for the highest
  // priority (0). In the event that enough endpoints for a particular priority are
  // unavailable/unhealthy, Envoy will fail over to selecting endpoints for the
  // next highest priority group. Read more at :ref:`priority levels <arch_overview_load_balancing_priority_levels>`.
  //
  // Priorities should range from 0 (highest) to N (lowest) without skipping.
  uint32 priority = 5 [(validate.rules).uint32 = {lte: 128}];

  // Optional: Per locality proximity value which indicates how close this
  // locality is from the source locality. This value only provides ordering
  // information (lower the value, closer it is to the source locality).
  // This will be consumed by load balancing schemes that need proximity order
  // to determine where to route the requests.
  // [#not-implemented-hide:]
  google.protobuf.UInt32Value proximity = 6;
}
