// 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/endpoint/v3/endpoint_components.proto";
import "envoy/type/v3/percent.proto";

import "google/protobuf/duration.proto";
import "google/protobuf/wrappers.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 = "EndpointProto";
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: Endpoint configuration]
// Endpoint discovery :ref:`architecture overview <arch_overview_service_discovery_types_eds>`

// Each route from RDS will map to a single cluster or traffic split across
// clusters using weights expressed in the RDS WeightedCluster.
//
// With EDS, each cluster is treated independently from a LB perspective, with
// LB taking place between the Localities within a cluster and at a finer
// granularity between the hosts within a locality. The percentage of traffic
// for each endpoint is determined by both its load_balancing_weight, and the
// load_balancing_weight of its locality. First, a locality will be selected,
// then an endpoint within that locality will be chose based on its weight.
// [#next-free-field: 6]
message ClusterLoadAssignment {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.ClusterLoadAssignment";

  // Load balancing policy settings.
  // [#next-free-field: 7]
  message Policy {
    option (udpa.annotations.versioning).previous_message_type =
        "envoy.api.v2.ClusterLoadAssignment.Policy";

    message DropOverload {
      option (udpa.annotations.versioning).previous_message_type =
          "envoy.api.v2.ClusterLoadAssignment.Policy.DropOverload";

      // Identifier for the policy specifying the drop.
      string category = 1 [(validate.rules).string = {min_len: 1}];

      // Percentage of traffic that should be dropped for the category.
      type.v3.FractionalPercent drop_percentage = 2;
    }

    reserved 1, 5;

    reserved "disable_overprovisioning";

    // Action to trim the overall incoming traffic to protect the upstream
    // hosts. This action allows protection in case the hosts are unable to
    // recover from an outage, or unable to autoscale or unable to handle
    // incoming traffic volume for any reason.
    //
    // At the client each category is applied one after the other to generate
    // the 'actual' drop percentage on all outgoing traffic. For example:
    //
    // .. code-block:: json
    //
    //  { "drop_overloads": [
    //      { "category": "throttle", "drop_percentage": 60 }
    //      { "category": "lb", "drop_percentage": 50 }
    //  ]}
    //
    // The actual drop percentages applied to the traffic at the clients will be
    //    "throttle"_drop = 60%
    //    "lb"_drop = 20%  // 50% of the remaining 'actual' load, which is 40%.
    //    actual_outgoing_load = 20% // remaining after applying all categories.
    //
    // Envoy supports only one element and will NACK if more than one element is present.
    // Other xDS-capable data planes will not necessarily have this limitation.
    //
    // In Envoy, this ``drop_overloads`` config can be overridden by a runtime key
    // "load_balancing_policy.drop_overload_limit" setting. This runtime key can be set to
    // any integer number between 0 and 100. 0 means drop 0%. 100 means drop 100%.
    // When both ``drop_overloads`` config and "load_balancing_policy.drop_overload_limit"
    // setting are in place, the min of these two wins.
    repeated DropOverload drop_overloads = 2;

    // Priority levels and localities are considered overprovisioned with this
    // factor (in percentage). This means that we don't consider a priority
    // level or locality unhealthy until the fraction of healthy hosts
    // multiplied by the overprovisioning factor drops below 100.
    // With the default value 140(1.4), Envoy doesn't consider a priority level
    // or a locality unhealthy until their percentage of healthy hosts drops
    // below 72%. For example:
    //
    // .. code-block:: json
    //
    //  { "overprovisioning_factor": 100 }
    //
    // Read more at :ref:`priority levels <arch_overview_load_balancing_priority_levels>` and
    // :ref:`localities <arch_overview_load_balancing_locality_weighted_lb>`.
    google.protobuf.UInt32Value overprovisioning_factor = 3 [(validate.rules).uint32 = {gt: 0}];

    // The max time until which the endpoints from this assignment can be used.
    // If no new assignments are received before this time expires the endpoints
    // are considered stale and should be marked unhealthy.
    // Defaults to 0 which means endpoints never go stale.
    google.protobuf.Duration endpoint_stale_after = 4 [(validate.rules).duration = {gt {}}];

    // If true, use the :ref:`load balancing weight
    // <envoy_v3_api_field_config.endpoint.v3.LbEndpoint.load_balancing_weight>` of healthy and unhealthy
    // hosts to determine the health of the priority level. If false, use the number of healthy and unhealthy hosts
    // to determine the health of the priority level, or in other words assume each host has a weight of 1 for
    // this calculation.
    //
    // .. note::
    //   This is not currently implemented for
    //   :ref:`locality weighted load balancing <arch_overview_load_balancing_locality_weighted_lb>`.
    bool weighted_priority_health = 6;
  }

  // Name of the cluster. This will be the :ref:`service_name
  // <envoy_v3_api_field_config.cluster.v3.Cluster.EdsClusterConfig.service_name>` value if specified
  // in the cluster :ref:`EdsClusterConfig
  // <envoy_v3_api_msg_config.cluster.v3.Cluster.EdsClusterConfig>`.
  string cluster_name = 1 [(validate.rules).string = {min_len: 1}];

  // List of endpoints to load balance to.
  repeated LocalityLbEndpoints endpoints = 2;

  // Map of named endpoints that can be referenced in LocalityLbEndpoints.
  // [#not-implemented-hide:]
  map<string, Endpoint> named_endpoints = 5;

  // Load balancing policy settings.
  Policy policy = 4;
}
