syntax = "proto3";

package envoy.api.v2;

option java_generic_services = true;

import "envoy/api/v2/discovery.proto";
import "envoy/api/v2/endpoint/endpoint.proto";
import "envoy/type/percent.proto";

import "google/api/annotations.proto";

import "validate/validate.proto";
import "gogoproto/gogo.proto";
import "google/protobuf/wrappers.proto";

option (gogoproto.equal_all) = true;

// [#protodoc-title: EDS]

service EndpointDiscoveryService {
  // The resource_names field in DiscoveryRequest specifies a list of clusters
  // to subscribe to updates for.
  rpc StreamEndpoints(stream DiscoveryRequest) returns (stream DiscoveryResponse) {
  }

  rpc FetchEndpoints(DiscoveryRequest) returns (DiscoveryResponse) {
    option (google.api.http) = {
      post: "/v2/discovery:endpoints"
      body: "*"
    };
  }
}

// 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. For a given cluster, the
// effective weight of a host is its load_balancing_weight multiplied by the
// load_balancing_weight of its Locality.
message ClusterLoadAssignment {
  // Name of the cluster. This will be the :ref:`service_name
  // <envoy_api_field_Cluster.EdsClusterConfig.service_name>` value if specified
  // in the cluster :ref:`EdsClusterConfig
  // <envoy_api_msg_Cluster.EdsClusterConfig>`.
  string cluster_name = 1 [(validate.rules).string.min_bytes = 1];

  // List of endpoints to load balance to.
  repeated endpoint.LocalityLbEndpoints endpoints = 2 [(gogoproto.nullable) = false];

  // Load balancing policy settings.
  message Policy {
    reserved 1;

    message DropOverload {
      // Identifier for the policy specifying the drop.
      string category = 1 [(validate.rules).string.min_bytes = 1];

      // Percentage of traffic that should be dropped for the category.
      envoy.type.FractionalPercent drop_percentage = 2;
    }
    // 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.
    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 percentage 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%.
    // 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];
  }

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