CSDS: add new config status ACKED

api/envoy/service/status/v3/csds.proto

@@ -9,6 +9,7 @@ import "envoy/type/matcher/v3/node.proto";
 import "google/api/annotations.proto";
 import "google/protobuf/struct.proto";
 
+import "udpa/annotations/migrate.proto";
 import "udpa/annotations/status.proto";
 import "udpa/annotations/versioning.proto";
 
@@ -21,9 +22,8 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 // [#protodoc-title: Client Status Discovery Service (CSDS)]
 
 // CSDS is Client Status Discovery Service. It can be used to get the status of
-// an xDS-compliant client from the management server's point of view. In the
-// future, it can potentially be used as an interface to get the current
-// state directly from the client.
+// an xDS-compliant client from the management server's point of view. It can
+// also be used to get the current xDS states directly from the client.
 service ClientStatusDiscoveryService {
   rpc StreamClientStatus(stream ClientStatusRequest) returns (stream ClientStatusResponse) {
   }
@@ -34,7 +34,7 @@ service ClientStatusDiscoveryService {
   }
 }
 
-// Status of a config.
+// Status of a config from a management server view.
 enum ConfigStatus {
   // Status info is not available/unknown.
   UNKNOWN = 0;
@@ -49,10 +49,30 @@ enum ConfigStatus {
   // ACK/NACK.
   STALE = 3;
 
-  // Management server has sent the config to client but received NACK.
+  // Management server has sent the config to client but received NACK. The
+  // attached config dump will be the latest config (the rejected one), since
+  // it is the persisted version in the management server.
   ERROR = 4;
 }
 
+// Config status from a client-side view.
+enum ClientConfigStatus {
+  // Config status is not available/unknown.
+  CLIENT_UNKNOWN = 0;
+
+  // Client requested the config but hasn't received any config from management
+  // server yet.
+  CLIENT_REQUESTED = 1;
+
+  // Client received the config and replied with ACK.
+  CLIENT_ACKED = 2;
+
+  // Client received the config and replied with NACK. Notably, the attached
+  // config dump is not the NACKed version, but the most recent accepted one. If
+  // no config is accepted yet, the attached config dump will be empty.
+  CLIENT_NACKED = 3;
+}
+
 // Request for client status of clients identified by a list of NodeMatchers.
 message ClientStatusRequest {
   option (udpa.annotations.versioning).previous_message_type =
@@ -67,12 +87,20 @@ message ClientStatusRequest {
 }
 
 // Detailed config (per xDS) with status.
-// [#next-free-field: 7]
+// [#next-free-field: 8]
 message PerXdsConfig {
   option (udpa.annotations.versioning).previous_message_type =
       "envoy.service.status.v2.PerXdsConfig";
 
-  ConfigStatus status = 1;
+  // Config status generated by management servers. Will not be present if the
+  // CSDS server is an xDS client.
+  ConfigStatus status = 1 [(udpa.annotations.field_migrate).oneof_promotion = "status_config"];
+
+  // Client config status is populated by xDS clients. Will not be present if
+  // the CSDS server is an xDS server. No matter what the client config status
+  // is, xDS clients should always dump the most recent accepted xDS config.
+  ClientConfigStatus client_status = 7
+      [(udpa.annotations.field_migrate).oneof_promotion = "status_config"];
 
   oneof per_xds_config {
     admin.v3.ListenersConfigDump listener_config = 2;