syntax = "proto3";

package envoy.api.v2;

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

import "validate/validate.proto";

// [#protodoc-title: Health check]
// * Health checking :ref:`architecture overview <arch_overview_health_checking>`.
// * If health checking is configured for a cluster, additional statistics are emitted. They are
//   documented :ref:`here <config_cluster_manager_cluster_stats>`.

message HealthCheck {
  // The time to wait for a health check response. If the timeout is reached the
  // health check attempt will be considered a failure.
  google.protobuf.Duration timeout = 1 [(validate.rules).duration.required = true];

  // The interval between health checks.
  google.protobuf.Duration interval = 2 [(validate.rules).duration.required = true];

  // An optional jitter amount in millseconds. If specified, during every
  // internal Envoy will add 0 to interval_jitter to the wait time.
  google.protobuf.Duration interval_jitter = 3;

  // The number of unhealthy health checks required before a host is marked
  // unhealthy. Note that for *http* health checking if a host responds with 503
  // this threshold is ignored and the host is considered unhealthy immediately.
  google.protobuf.UInt32Value unhealthy_threshold = 4;

  // The number of healthy health checks required before a host is marked
  // healthy. Note that during startup, only a single successful health check is
  // required to mark a host healthy.
  google.protobuf.UInt32Value healthy_threshold = 5;

  // [#not-implemented-hide:] Non-serving port for health checking.
  google.protobuf.UInt32Value alt_port = 6;

  // Reuse health check connection between health checks. Default is true.
  google.protobuf.BoolValue reuse_connection = 7;

  // Describes the encoding of the payload bytes in the payload.
  message Payload {
    oneof payload {
      option (validate.required) = true;

      // Hex encoded payload. E.g., "000000FF".
      string text = 1 [(validate.rules).string.min_bytes = 1];

      // [#not-implemented-hide:] Binary payload.
      bytes binary = 2;
    }
  }

  message HttpHealthCheck {
    // [#not-implemented-hide:] The value of the host header in the HTTPS health check request. If
    // left empty (default value), the IP on behalf of which this health check is performed will be
    // used.
    string host = 1;

    // Specifies the HTTP path that will be requested during health checking. For example
    // */healthcheck*.
    string path = 2 [(validate.rules).string.min_bytes = 1];

    // [#not-implemented-hide:] HTTP specific payload.
    Payload send = 3;

    // [#not-implemented-hide:] HTTP specific response.
    Payload receive = 4;

    // An optional service name parameter which is used to validate the identity of
    // the health checked cluster. See the :ref:`architecture overview
    // <arch_overview_health_checking_identity>` for more information.
    string service_name = 5;
  }

  message TcpHealthCheck {
    // Empty payloads imply a connect-only health check.
    Payload send = 1;

    // When checking the response, “fuzzy” matching is performed such that each
    // binary block must be found, and in the order specified, but not
    // necessarily contiguous.
    repeated Payload receive = 2;
  }

  message RedisHealthCheck {
  }

  oneof health_checker {
    option (validate.required) = true;

    // HTTP health check.
    HttpHealthCheck http_health_check = 8;

    // TCP health check.
    TcpHealthCheck tcp_health_check = 9;

    // Redis health check.
    RedisHealthCheck redis_health_check = 10;
  }
}

// [#not-implemented-hide:] Part of HDS.
enum HealthStatus {
  // UNKNOWN should be treated by Envoy as HEALTHY.
  UNKNOWN = 0;

  // Healthy.
  HEALTHY = 1;

  // Unhealthy.
  UNHEALTHY = 2;

  // Connection draining in progress. E.g.,
  // https://aws.amazon.com/blogs/aws/elb-connection-draining-remove-instances-from-service-with-care/
  // or
  // https://cloud.google.com/compute/docs/load-balancing/enabling-connection-draining.
  DRAINING = 3;

  // This value is used by HDS Remote server. From Envoy’s perspective
  // TIMEOUT = UNHEALTHY in case EDS returns HealthStatus.
  TIMEOUT = 4;
}