syntax = "proto3";
package logbackup;

import "gogoproto/gogo.proto";
import "rustproto.proto";
import "errorpb.proto";

option (gogoproto.sizer_all) = true;
option (gogoproto.marshaler_all) = true;
option (gogoproto.unmarshaler_all) = true;
option (rustproto.lite_runtime_all) = true;

option java_package = "org.tikv.kvproto";

// The minimal information for identify a region.
message RegionIdentity {
    uint64 id = 1;
    uint64 epoch_version = 2;
    // We omitted epoch_conf_version because config change won't make range change.
}

// The last flush ts with region information.
message RegionCheckpoint {
    errorpb.Error err = 1;
    RegionIdentity region = 2;
    uint64 checkpoint = 3;
}

message GetLastFlushTSOfRegionRequest {
    repeated RegionIdentity regions = 1;
}

message GetLastFlushTSOfRegionResponse {
    repeated RegionCheckpoint checkpoints = 1;
}

message SubscribeFlushEventRequest {
    string client_id = 1;
}

message SubscribeFlushEventResponse {
    repeated FlushEvent events = 1;
}

message FlushEvent {
    bytes start_key = 1;
    bytes end_key = 2;
    uint64 checkpoint = 3;
}

// The log backup service.
// Generally, most essential interfaces of log backup (say, checkpoint management, task management) are 
// provided by adding some key in the embed etcd of PD.
// This interface is mainly provided for the checkpoint advancer and debug usage.
service LogBackup {
    rpc GetLastFlushTSOfRegion(GetLastFlushTSOfRegionRequest) returns (GetLastFlushTSOfRegionResponse) {}
    rpc SubscribeFlushEvent(SubscribeFlushEventRequest) returns (stream SubscribeFlushEventResponse) {}
}