syntax = "proto3";

package envoy.service.extension.v3;

import "envoy/service/discovery/v3/discovery.proto";

import "google/api/annotations.proto";

import "envoy/annotations/resource.proto";
import "udpa/annotations/status.proto";

option java_package = "io.envoyproxy.envoy.service.extension.v3";
option java_outer_classname = "ConfigDiscoveryProto";
option java_multiple_files = true;
option go_package = "github.com/envoyproxy/go-control-plane/envoy/service/extension/v3;extensionv3";
option (udpa.annotations.file_status).package_version_status = ACTIVE;

// [#protodoc-title: Extension config discovery service (ECDS)]

// A service that supports dynamic configuration updates for a specific filter.
// Currently, ECDS is supported for network filters, HTTP filters, UDP session filters and Listener filters.
// Please check :ref:`Extension Config Discovery Service (ECDS) API <config_overview_extension_discovery>`.
// The overall extension config discovery service works as follows:
//
// 1. A filter (:ref:`Downstream Network <envoy_v3_api_field_config.listener.v3.Filter.config_discovery>`,
//    :ref:`Upstream Network <envoy_v3_api_field_config.cluster.v3.Filter.config_discovery>`,
//    :ref:`Listener <envoy_v3_api_field_config.listener.v3.ListenerFilter.config_discovery>`,
//    :ref:`UDP Session <envoy_v3_api_field_extensions.filters.udp.udp_proxy.v3.UdpProxyConfig.SessionFilter.config_discovery>`,
//    or :ref:`HTTP <envoy_v3_api_field_extensions.filters.network.http_connection_manager.v3.HttpFilter.config_discovery>`)
//    contains a :ref:`config_discovery <envoy_v3_api_msg_config.core.v3.ExtensionConfigSource>` configuration. This configuration
//    includes a :ref:`config_source <envoy_v3_api_field_config.core.v3.ExtensionConfigSource.config_source>`,
//    from which the filter configuration will be fetched.
// 2. The client then registers for a resource using the filter name as the resource_name.
// 3. The xDS server sends back the filter's configuration.
// 4. The client stores the configuration that will be used in the next instantiation of the filter chain,
//    i.e., for the next requests. Whenever an updated filter configuration arrives, it will be taken into
//    account in the following instantiation of the filter chain.
//
// Note: Filters that are configured using ECDS are warmed. For more details see
// :ref:`ExtensionConfigSource <envoy_v3_api_msg_config.core.v3.ExtensionConfigSource>`.

// Return extension configurations.
service ExtensionConfigDiscoveryService {
  option (envoy.annotations.resource).type = "envoy.config.core.v3.TypedExtensionConfig";

  rpc StreamExtensionConfigs(stream discovery.v3.DiscoveryRequest)
      returns (stream discovery.v3.DiscoveryResponse) {
  }

  rpc DeltaExtensionConfigs(stream discovery.v3.DeltaDiscoveryRequest)
      returns (stream discovery.v3.DeltaDiscoveryResponse) {
  }

  rpc FetchExtensionConfigs(discovery.v3.DiscoveryRequest)
      returns (discovery.v3.DiscoveryResponse) {
    option (google.api.http).post = "/v3/discovery:extension_configs";
    option (google.api.http).body = "*";
  }
}

// [#not-implemented-hide:] Not configuration. Workaround c++ protobuf issue
// with importing services: https://github.com/google/protobuf/issues/4221 and
// protoxform to upgrade the file.
message EcdsDummy {
}
