syntax = "proto3";

package envoy.config.core.v3;

import "envoy/config/core/v3/address.proto";
import "envoy/config/core/v3/backoff.proto";
import "envoy/config/core/v3/http_uri.proto";
import "envoy/type/v3/percent.proto";
import "envoy/type/v3/semantic_version.proto";

import "google/protobuf/any.proto";
import "google/protobuf/struct.proto";
import "google/protobuf/wrappers.proto";

import "xds/core/v3/context_params.proto";

import "envoy/annotations/deprecation.proto";
import "udpa/annotations/migrate.proto";
import "udpa/annotations/status.proto";
import "udpa/annotations/versioning.proto";
import "validate/validate.proto";

option java_package = "io.envoyproxy.envoy.config.core.v3";
option java_outer_classname = "BaseProto";
option java_multiple_files = true;
option go_package = "github.com/envoyproxy/go-control-plane/envoy/config/core/v3;corev3";
option (udpa.annotations.file_status).package_version_status = ACTIVE;

// [#protodoc-title: Common types]

// Envoy supports :ref:`upstream priority routing
// <arch_overview_http_routing_priority>` both at the route and the virtual
// cluster level. The current priority implementation uses different connection
// pool and circuit breaking settings for each priority level. This means that
// even for HTTP/2 requests, two physical connections will be used to an
// upstream host. In the future Envoy will likely support true HTTP/2 priority
// over a single upstream connection.
enum RoutingPriority {
  DEFAULT = 0;
  HIGH = 1;
}

// HTTP request method.
enum RequestMethod {
  METHOD_UNSPECIFIED = 0;
  GET = 1;
  HEAD = 2;
  POST = 3;
  PUT = 4;
  DELETE = 5;
  CONNECT = 6;
  OPTIONS = 7;
  TRACE = 8;
  PATCH = 9;
}

// Identifies the direction of the traffic relative to the local Envoy.
enum TrafficDirection {
  // Default option is unspecified.
  UNSPECIFIED = 0;

  // The transport is used for incoming traffic.
  INBOUND = 1;

  // The transport is used for outgoing traffic.
  OUTBOUND = 2;
}

// Identifies location of where either Envoy runs or where upstream hosts run.
message Locality {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.Locality";

  // Region this :ref:`zone <envoy_v3_api_field_config.core.v3.Locality.zone>` belongs to.
  string region = 1;

  // Defines the local service zone where Envoy is running. Though optional, it
  // should be set if discovery service routing is used and the discovery
  // service exposes :ref:`zone data <envoy_v3_api_field_config.endpoint.v3.LocalityLbEndpoints.locality>`,
  // either in this message or via :option:`--service-zone`. The meaning of zone
  // is context dependent, e.g. `Availability Zone (AZ)
  // <https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-regions-availability-zones.html>`_
  // on AWS, `Zone <https://cloud.google.com/compute/docs/regions-zones/>`_ on
  // GCP, etc.
  string zone = 2;

  // When used for locality of upstream hosts, this field further splits zone
  // into smaller chunks of sub-zones so they can be load balanced
  // independently.
  string sub_zone = 3;
}

// BuildVersion combines SemVer version of extension with free-form build information
// (i.e. 'alpha', 'private-build') as a set of strings.
message BuildVersion {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.BuildVersion";

  // SemVer version of extension.
  type.v3.SemanticVersion version = 1;

  // Free-form build information.
  // Envoy defines several well known keys in the source/common/version/version.h file
  google.protobuf.Struct metadata = 2;
}

// Version and identification for an Envoy extension.
// [#next-free-field: 7]
message Extension {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.Extension";

  // This is the name of the Envoy filter as specified in the Envoy
  // configuration, e.g. envoy.filters.http.router, com.acme.widget.
  string name = 1;

  // Category of the extension.
  // Extension category names use reverse DNS notation. For instance "envoy.filters.listener"
  // for Envoy's built-in listener filters or "com.acme.filters.http" for HTTP filters from
  // acme.com vendor.
  // [#comment:TODO(yanavlasov): Link to the doc with existing envoy category names.]
  string category = 2;

  // [#not-implemented-hide:] Type descriptor of extension configuration proto.
  // [#comment:TODO(yanavlasov): Link to the doc with existing configuration protos.]
  // [#comment:TODO(yanavlasov): Add tests when PR #9391 lands.]
  string type_descriptor = 3
      [deprecated = true, (envoy.annotations.deprecated_at_minor_version) = "3.0"];

  // The version is a property of the extension and maintained independently
  // of other extensions and the Envoy API.
  // This field is not set when extension did not provide version information.
  BuildVersion version = 4;

  // Indicates that the extension is present but was disabled via dynamic configuration.
  bool disabled = 5;

  // Type URLs of extension configuration protos.
  repeated string type_urls = 6;
}

// Identifies a specific Envoy instance. The node identifier is presented to the
// management server, which may use this identifier to distinguish per Envoy
// configuration for serving.
// [#next-free-field: 13]
message Node {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.Node";

  reserved 5;

  reserved "build_version";

  // An opaque node identifier for the Envoy node. This also provides the local
  // service node name. It should be set if any of the following features are
  // used: :ref:`statsd <arch_overview_statistics>`, :ref:`CDS
  // <config_cluster_manager_cds>`, and :ref:`HTTP tracing
  // <arch_overview_tracing>`, either in this message or via
  // :option:`--service-node`.
  string id = 1;

  // Defines the local service cluster name where Envoy is running. Though
  // optional, it should be set if any of the following features are used:
  // :ref:`statsd <arch_overview_statistics>`, :ref:`health check cluster
  // verification
  // <envoy_v3_api_field_config.core.v3.HealthCheck.HttpHealthCheck.service_name_matcher>`,
  // :ref:`runtime override directory <envoy_v3_api_msg_config.bootstrap.v3.Runtime>`,
  // :ref:`user agent addition
  // <envoy_v3_api_field_extensions.filters.network.http_connection_manager.v3.HttpConnectionManager.add_user_agent>`,
  // :ref:`HTTP global rate limiting <config_http_filters_rate_limit>`,
  // :ref:`CDS <config_cluster_manager_cds>`, and :ref:`HTTP tracing
  // <arch_overview_tracing>`, either in this message or via
  // :option:`--service-cluster`.
  string cluster = 2;

  // Opaque metadata extending the node identifier. Envoy will pass this
  // directly to the management server.
  google.protobuf.Struct metadata = 3;

  // Map from xDS resource type URL to dynamic context parameters. These may vary at runtime (unlike
  // other fields in this message). For example, the xDS client may have a shard identifier that
  // changes during the lifetime of the xDS client. In Envoy, this would be achieved by updating the
  // dynamic context on the Server::Instance's LocalInfo context provider. The shard ID dynamic
  // parameter then appears in this field during future discovery requests.
  map<string, xds.core.v3.ContextParams> dynamic_parameters = 12;

  // Locality specifying where the Envoy instance is running.
  Locality locality = 4;

  // Free-form string that identifies the entity requesting config.
  // E.g. "envoy" or "grpc"
  string user_agent_name = 6;

  oneof user_agent_version_type {
    // Free-form string that identifies the version of the entity requesting config.
    // E.g. "1.12.2" or "abcd1234", or "SpecialEnvoyBuild"
    string user_agent_version = 7;

    // Structured version of the entity requesting config.
    BuildVersion user_agent_build_version = 8;
  }

  // List of extensions and their versions supported by the node.
  repeated Extension extensions = 9;

  // Client feature support list. These are well known features described
  // in the Envoy API repository for a given major version of an API. Client features
  // use reverse DNS naming scheme, for example ``com.acme.feature``.
  // See :ref:`the list of features <client_features>` that xDS client may
  // support.
  repeated string client_features = 10;

  // Known listening ports on the node as a generic hint to the management server
  // for filtering :ref:`listeners <config_listeners>` to be returned. For example,
  // if there is a listener bound to port 80, the list can optionally contain the
  // SocketAddress ``(0.0.0.0,80)``. The field is optional and just a hint.
  repeated Address listening_addresses = 11
      [deprecated = true, (envoy.annotations.deprecated_at_minor_version) = "3.0"];
}

// Metadata provides additional inputs to filters based on matched listeners,
// filter chains, routes and endpoints. It is structured as a map, usually from
// filter name (in reverse DNS format) to metadata specific to the filter. Metadata
// key-values for a filter are merged as connection and request handling occurs,
// with later values for the same key overriding earlier values.
//
// An example use of metadata is providing additional values to
// http_connection_manager in the envoy.http_connection_manager.access_log
// namespace.
//
// Another example use of metadata is to per service config info in cluster metadata, which may get
// consumed by multiple filters.
//
// For load balancing, Metadata provides a means to subset cluster endpoints.
// Endpoints have a Metadata object associated and routes contain a Metadata
// object to match against. There are some well defined metadata used today for
// this purpose:
//
// * ``{"envoy.lb": {"canary": <bool> }}`` This indicates the canary status of an
//   endpoint and is also used during header processing
//   (x-envoy-upstream-canary) and for stats purposes.
// [#next-major-version: move to type/metadata/v2]
message Metadata {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.Metadata";

  // Key is the reverse DNS filter name, e.g. com.acme.widget. The ``envoy.*``
  // namespace is reserved for Envoy's built-in filters.
  // If both ``filter_metadata`` and
  // :ref:`typed_filter_metadata <envoy_v3_api_field_config.core.v3.Metadata.typed_filter_metadata>`
  // fields are present in the metadata with same keys,
  // only ``typed_filter_metadata`` field will be parsed.
  map<string, google.protobuf.Struct> filter_metadata = 1
      [(validate.rules).map = {keys {string {min_len: 1}}}];

  // Key is the reverse DNS filter name, e.g. com.acme.widget. The ``envoy.*``
  // namespace is reserved for Envoy's built-in filters.
  // The value is encoded as google.protobuf.Any.
  // If both :ref:`filter_metadata <envoy_v3_api_field_config.core.v3.Metadata.filter_metadata>`
  // and ``typed_filter_metadata`` fields are present in the metadata with same keys,
  // only ``typed_filter_metadata`` field will be parsed.
  map<string, google.protobuf.Any> typed_filter_metadata = 2
      [(validate.rules).map = {keys {string {min_len: 1}}}];
}

// Runtime derived uint32 with a default when not specified.
message RuntimeUInt32 {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.RuntimeUInt32";

  // Default value if runtime value is not available.
  uint32 default_value = 2;

  // Runtime key to get value for comparison. This value is used if defined.
  string runtime_key = 3;
}

// Runtime derived percentage with a default when not specified.
message RuntimePercent {
  // Default value if runtime value is not available.
  type.v3.Percent default_value = 1;

  // Runtime key to get value for comparison. This value is used if defined.
  string runtime_key = 2;
}

// Runtime derived double with a default when not specified.
message RuntimeDouble {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.RuntimeDouble";

  // Default value if runtime value is not available.
  double default_value = 1;

  // Runtime key to get value for comparison. This value is used if defined.
  string runtime_key = 2;
}

// Runtime derived bool with a default when not specified.
message RuntimeFeatureFlag {
  option (udpa.annotations.versioning).previous_message_type =
      "envoy.api.v2.core.RuntimeFeatureFlag";

  // Default value if runtime value is not available.
  google.protobuf.BoolValue default_value = 1 [(validate.rules).message = {required: true}];

  // Runtime key to get value for comparison. This value is used if defined. The boolean value must
  // be represented via its
  // `canonical JSON encoding <https://developers.google.com/protocol-buffers/docs/proto3#json>`_.
  string runtime_key = 2;
}

// Please use :ref:`KeyValuePair <envoy_api_msg_config.core.v3.KeyValuePair>` instead.
// [#not-implemented-hide:]
message KeyValue {
  // The key of the key/value pair.
  string key = 1 [
    deprecated = true,
    (validate.rules).string = {min_len: 1 max_bytes: 16384},
    (envoy.annotations.deprecated_at_minor_version) = "3.0"
  ];

  // The value of the key/value pair.
  //
  // The ``bytes`` type is used. This means if JSON or YAML is used to to represent the
  // configuration, the value must be base64 encoded. This is unfriendly for users in most
  // use scenarios of this message.
  //
  bytes value = 2 [deprecated = true, (envoy.annotations.deprecated_at_minor_version) = "3.0"];
}

message KeyValuePair {
  // The key of the key/value pair.
  string key = 1 [(validate.rules).string = {min_len: 1 max_bytes: 16384}];

  // The value of the key/value pair.
  google.protobuf.Value value = 2;
}

// Key/value pair plus option to control append behavior. This is used to specify
// key/value pairs that should be appended to a set of existing key/value pairs.
message KeyValueAppend {
  // Describes the supported actions types for key/value pair append action.
  enum KeyValueAppendAction {
    // If the key already exists, this action will result in the following behavior:
    //
    // - Comma-concatenated value if multiple values are not allowed.
    // - New value added to the list of values if multiple values are allowed.
    //
    // If the key doesn't exist then this will add pair with specified key and value.
    APPEND_IF_EXISTS_OR_ADD = 0;

    // This action will add the key/value pair if it doesn't already exist. If the
    // key already exists then this will be a no-op.
    ADD_IF_ABSENT = 1;

    // This action will overwrite the specified value by discarding any existing
    // values if the key already exists. If the key doesn't exist then this will add
    // the pair with specified key and value.
    OVERWRITE_IF_EXISTS_OR_ADD = 2;

    // This action will overwrite the specified value by discarding any existing
    // values if the key already exists. If the key doesn't exist then this will
    // be no-op.
    OVERWRITE_IF_EXISTS = 3;
  }

  // The single key/value pair record to be appended or overridden. This field must be set.
  KeyValuePair record = 3;

  // Key/value pair entry that this option to append or overwrite. This field is deprecated
  // and please use :ref:`record <envoy_v3_api_field_config.core.v3.KeyValueAppend.record>`
  // as replacement.
  // [#not-implemented-hide:]
  KeyValue entry = 1 [
    deprecated = true,
    (validate.rules).message = {skip: true},
    (envoy.annotations.deprecated_at_minor_version) = "3.0"
  ];

  // Describes the action taken to append/overwrite the given value for an existing
  // key or to only add this key if it's absent.
  KeyValueAppendAction action = 2 [(validate.rules).enum = {defined_only: true}];
}

// Key/value pair to append or remove.
message KeyValueMutation {
  // Key/value pair to append or overwrite. Only one of ``append`` or ``remove`` can be set or
  // the configuration will be rejected.
  KeyValueAppend append = 1;

  // Key to remove. Only one of ``append`` or ``remove`` can be set or the configuration will be
  // rejected.
  string remove = 2 [(validate.rules).string = {max_bytes: 16384}];
}

// Query parameter name/value pair.
message QueryParameter {
  // The key of the query parameter. Case sensitive.
  string key = 1 [(validate.rules).string = {min_len: 1}];

  // The value of the query parameter.
  string value = 2;
}

// Header name/value pair.
message HeaderValue {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.HeaderValue";

  // Header name.
  string key = 1
      [(validate.rules).string =
           {min_len: 1 max_bytes: 16384 well_known_regex: HTTP_HEADER_NAME strict: false}];

  // Header value.
  //
  // The same :ref:`format specifier <config_access_log_format>` as used for
  // :ref:`HTTP access logging <config_access_log>` applies here, however
  // unknown header values are replaced with the empty string instead of ``-``.
  // Header value is encoded as string. This does not work for non-utf8 characters.
  // Only one of ``value`` or ``raw_value`` can be set.
  string value = 2 [
    (validate.rules).string = {max_bytes: 16384 well_known_regex: HTTP_HEADER_VALUE strict: false},
    (udpa.annotations.field_migrate).oneof_promotion = "value_type"
  ];

  // Header value is encoded as bytes which can support non-utf8 characters.
  // Only one of ``value`` or ``raw_value`` can be set.
  bytes raw_value = 3 [
    (validate.rules).bytes = {min_len: 0 max_len: 16384},
    (udpa.annotations.field_migrate).oneof_promotion = "value_type"
  ];
}

// Header name/value pair plus option to control append behavior.
message HeaderValueOption {
  option (udpa.annotations.versioning).previous_message_type =
      "envoy.api.v2.core.HeaderValueOption";

  // Describes the supported actions types for header append action.
  enum HeaderAppendAction {
    // If the header already exists, this action will result in:
    //
    // - Comma-concatenated for predefined inline headers.
    // - Duplicate header added in the ``HeaderMap`` for other headers.
    //
    // If the header doesn't exist then this will add new header with specified key and value.
    APPEND_IF_EXISTS_OR_ADD = 0;

    // This action will add the header if it doesn't already exist. If the header
    // already exists then this will be a no-op.
    ADD_IF_ABSENT = 1;

    // This action will overwrite the specified value by discarding any existing values if
    // the header already exists. If the header doesn't exist then this will add the header
    // with specified key and value.
    OVERWRITE_IF_EXISTS_OR_ADD = 2;

    // This action will overwrite the specified value by discarding any existing values if
    // the header already exists. If the header doesn't exist then this will be no-op.
    OVERWRITE_IF_EXISTS = 3;
  }

  // Header name/value pair that this option applies to.
  HeaderValue header = 1 [(validate.rules).message = {required: true}];

  // Should the value be appended? If true (default), the value is appended to
  // existing values. Otherwise it replaces any existing values.
  // This field is deprecated and please use
  // :ref:`append_action <envoy_v3_api_field_config.core.v3.HeaderValueOption.append_action>` as replacement.
  //
  // .. note::
  //   The :ref:`external authorization service <envoy_v3_api_msg_service.auth.v3.CheckResponse>` and
  //   :ref:`external processor service <envoy_v3_api_msg_service.ext_proc.v3.ProcessingResponse>` have
  //   default value (``false``) for this field.
  google.protobuf.BoolValue append = 2
      [deprecated = true, (envoy.annotations.deprecated_at_minor_version) = "3.0"];

  // Describes the action taken to append/overwrite the given value for an existing header
  // or to only add this header if it's absent.
  // Value defaults to :ref:`APPEND_IF_EXISTS_OR_ADD
  // <envoy_v3_api_enum_value_config.core.v3.HeaderValueOption.HeaderAppendAction.APPEND_IF_EXISTS_OR_ADD>`.
  HeaderAppendAction append_action = 3 [(validate.rules).enum = {defined_only: true}];

  // Is the header value allowed to be empty? If false (default), custom headers with empty values are dropped,
  // otherwise they are added.
  bool keep_empty_value = 4;
}

// Wrapper for a set of headers.
message HeaderMap {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.HeaderMap";

  // A list of header names and their values.
  repeated HeaderValue headers = 1;
}

// A directory that is watched for changes, e.g. by inotify on Linux. Move/rename
// events inside this directory trigger the watch.
message WatchedDirectory {
  // Directory path to watch.
  string path = 1 [(validate.rules).string = {min_len: 1}];
}

// Data source consisting of a file, an inline value, or an environment variable.
// [#next-free-field: 6]
message DataSource {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.DataSource";

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

    // Local filesystem data source.
    string filename = 1 [(validate.rules).string = {min_len: 1}];

    // Bytes inlined in the configuration.
    bytes inline_bytes = 2;

    // String inlined in the configuration.
    string inline_string = 3;

    // Environment variable data source.
    string environment_variable = 4 [(validate.rules).string = {min_len: 1}];
  }

  // Watched directory that is watched for file changes. If this is set explicitly, the file
  // specified in the ``filename`` field will be reloaded when relevant file move events occur.
  //
  // .. note::
  //   This field only makes sense when the ``filename`` field is set.
  //
  // .. note::
  //   Envoy only updates when the file is replaced by a file move, and not when the file is
  //   edited in place.
  //
  // .. note::
  //   Not all use cases of ``DataSource`` support watching directories. It depends on the
  //   specific usage of the ``DataSource``. See the documentation of the parent message for
  //   details.
  WatchedDirectory watched_directory = 5;
}

// The message specifies the retry policy of remote data source when fetching fails.
// [#next-free-field: 7]
message RetryPolicy {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.RetryPolicy";

  // See :ref:`RetryPriority <envoy_v3_api_field_config.route.v3.RetryPolicy.retry_priority>`.
  message RetryPriority {
    string name = 1 [(validate.rules).string = {min_len: 1}];

    oneof config_type {
      google.protobuf.Any typed_config = 2;
    }
  }

  // See :ref:`RetryHostPredicate <envoy_v3_api_field_config.route.v3.RetryPolicy.retry_host_predicate>`.
  message RetryHostPredicate {
    string name = 1 [(validate.rules).string = {min_len: 1}];

    oneof config_type {
      google.protobuf.Any typed_config = 2;
    }
  }

  // Specifies parameters that control :ref:`retry backoff strategy <envoy_v3_api_msg_config.core.v3.BackoffStrategy>`.
  // This parameter is optional, in which case the default base interval is 1000 milliseconds. The
  // default maximum interval is 10 times the base interval.
  BackoffStrategy retry_back_off = 1;

  // Specifies the allowed number of retries. This parameter is optional and
  // defaults to 1.
  google.protobuf.UInt32Value num_retries = 2
      [(udpa.annotations.field_migrate).rename = "max_retries"];

  // For details, see :ref:`retry_on <envoy_v3_api_field_config.route.v3.RetryPolicy.retry_on>`.
  string retry_on = 3;

  // For details, see :ref:`retry_priority <envoy_v3_api_field_config.route.v3.RetryPolicy.retry_priority>`.
  RetryPriority retry_priority = 4;

  // For details, see :ref:`RetryHostPredicate <envoy_v3_api_field_config.route.v3.RetryPolicy.retry_host_predicate>`.
  repeated RetryHostPredicate retry_host_predicate = 5;

  // For details, see :ref:`host_selection_retry_max_attempts <envoy_v3_api_field_config.route.v3.RetryPolicy.host_selection_retry_max_attempts>`.
  int64 host_selection_retry_max_attempts = 6;
}

// The message specifies how to fetch data from remote and how to verify it.
message RemoteDataSource {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.RemoteDataSource";

  // The HTTP URI to fetch the remote data.
  HttpUri http_uri = 1 [(validate.rules).message = {required: true}];

  // SHA256 string for verifying data.
  string sha256 = 2 [(validate.rules).string = {min_len: 1}];

  // Retry policy for fetching remote data.
  RetryPolicy retry_policy = 3;
}

// Async data source which support async data fetch.
message AsyncDataSource {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.AsyncDataSource";

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

    // Local async data source.
    DataSource local = 1;

    // Remote async data source.
    RemoteDataSource remote = 2;
  }
}

// Configuration for transport socket in :ref:`listeners <config_listeners>` and
// :ref:`clusters <envoy_v3_api_msg_config.cluster.v3.Cluster>`. If the configuration is
// empty, a default transport socket implementation and configuration will be
// chosen based on the platform and existence of tls_context.
message TransportSocket {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.TransportSocket";

  reserved 2;

  reserved "config";

  // The name of the transport socket to instantiate. The name must match a supported transport
  // socket implementation.
  string name = 1 [(validate.rules).string = {min_len: 1}];

  // Implementation specific configuration which depends on the implementation being instantiated.
  // See the supported transport socket implementations for further documentation.
  oneof config_type {
    google.protobuf.Any typed_config = 3;
  }
}

// Runtime derived FractionalPercent with defaults for when the numerator or denominator is not
// specified via a runtime key.
//
// .. note::
//
//   Parsing of the runtime key's data is implemented such that it may be represented as a
//   :ref:`FractionalPercent <envoy_v3_api_msg_type.v3.FractionalPercent>` proto represented as JSON/YAML
//   and may also be represented as an integer with the assumption that the value is an integral
//   percentage out of 100. For instance, a runtime key lookup returning the value "42" would parse
//   as a ``FractionalPercent`` whose numerator is 42 and denominator is HUNDRED.
message RuntimeFractionalPercent {
  option (udpa.annotations.versioning).previous_message_type =
      "envoy.api.v2.core.RuntimeFractionalPercent";

  // Default value if the runtime value's for the numerator/denominator keys are not available.
  type.v3.FractionalPercent default_value = 1 [(validate.rules).message = {required: true}];

  // Runtime key for a YAML representation of a FractionalPercent.
  string runtime_key = 2;
}

// Identifies a specific ControlPlane instance that Envoy is connected to.
message ControlPlane {
  option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.core.ControlPlane";

  // An opaque control plane identifier that uniquely identifies an instance
  // of control plane. This can be used to identify which control plane instance,
  // the Envoy is connected to.
  string identifier = 1;
}
