syntax = "proto3";

package envoy.api.v3alpha;

option java_outer_classname = "EdsProto";
option java_multiple_files = true;
option java_package = "io.envoyproxy.envoy.api.v3alpha";
option java_generic_services = true;

import "envoy/api/v3alpha/discovery.proto";
import "envoy/api/v3alpha/endpoint/endpoint.proto";
import "envoy/type/percent.proto";

import "google/api/annotations.proto";
import "google/protobuf/duration.proto";
import "google/protobuf/wrappers.proto";

import "validate/validate.proto";

// [#protodoc-title: EDS]
// Endpoint discovery :ref:`architecture overview <arch_overview_service_discovery_types_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 DeltaEndpoints(stream DeltaDiscoveryRequest) returns (stream DeltaDiscoveryResponse) {
  }

  rpc FetchEndpoints(DiscoveryRequest) returns (DiscoveryResponse) {
    option (google.api.http) = {
      post: "/v3alpha/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. 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.
message ClusterLoadAssignment {
  // Load balancing policy settings.
  message Policy {
    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.
      type.FractionalPercent drop_percentage = 2;
    }

    reserved 1;

    // 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%. 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 {}}];

    // The flag to disable overprovisioning. If it is set to true,
    // :ref:`overprovisioning factor
    // <arch_overview_load_balancing_overprovisioning_factor>` will be ignored
    // and Envoy will not perform graceful failover between priority levels or
    // localities as endpoints become unhealthy. Otherwise Envoy will perform
    // graceful failover as :ref:`overprovisioning factor
    // <arch_overview_load_balancing_overprovisioning_factor>` suggests.
    // [#next-major-version: Unify with overprovisioning config as a single message.]
    // [#not-implemented-hide:]
    bool disable_overprovisioning = 5;
  }

  // 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;

  // Map of named endpoints that can be referenced in LocalityLbEndpoints.
  map<string, endpoint.Endpoint> named_endpoints = 5;

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