syntax = "proto3";

package envoy.config.overload.v2alpha;
option go_package = "v2alpha";

import "google/protobuf/duration.proto";
import "google/protobuf/struct.proto";

import "validate/validate.proto";

// [#protodoc-title: Overload Manager]

// The Overload Manager provides an extensible framework to protect Envoy instances
// from overload of various resources (memory, cpu, file descriptors, etc).
// It monitors a configurable set of resources and notifies registered listeners
// when triggers related to those resources fire.

message ResourceMonitor {
  // The name of the resource monitor to instantiate. Must match a registered
  // resource monitor type. The built-in resource monitors are:
  //
  // * :ref:`envoy.resource_monitors.fixed_heap
  //   <envoy_api_msg_config.resource_monitor.fixed_heap.v2alpha.FixedHeapConfig>`
  // * :ref:`envoy.resource_monitors.injected_resource
  //   <envoy_api_msg_config.resource_monitor.injected_resource.v2alpha.InjectedResourceConfig>`
  string name = 1 [(validate.rules).string.min_bytes = 1];

  // Configuration for the resource monitor being instantiated.
  google.protobuf.Struct config = 2;
}

message ThresholdTrigger {
  // If the resource pressure is greater than or equal to this value, the trigger
  // will fire.
  double value = 1 [(validate.rules).double = {gte: 0, lte: 1}];
}

message Trigger {
  // The name of the resource this is a trigger for.
  string name = 1 [(validate.rules).string.min_bytes = 1];

  oneof trigger_oneof {
    option (validate.required) = true;
    ThresholdTrigger threshold = 2;
  }
}

message OverloadAction {
  // The name of the overload action. This is just a well-known string that listeners can
  // use for registering callbacks. Custom overload actions should be named using reverse
  // DNS to ensure uniqueness.
  string name = 1 [(validate.rules).string.min_bytes = 1];

  // A set of triggers for this action. If any of these triggers fire the overload action
  // is activated. Listeners are notified when the overload action transitions from
  // inactivated to activated, or vice versa.
  repeated Trigger triggers = 2 [(validate.rules).repeated .min_items = 1];
}

message OverloadManager {
  // The interval for refreshing resource usage.
  google.protobuf.Duration refresh_interval = 1;

  // The set of resources to monitor.
  repeated ResourceMonitor resource_monitors = 2 [(validate.rules).repeated .min_items = 1];

  // The set of overload actions.
  repeated OverloadAction actions = 3;
}