/**
 * LVMd manages logical volumes of an LVM volume group.
 *
 * The protocol consists of two services:
 * - VGService provides information of the volume group.
 * - LVService provides management functions for logical volumes on the volume group.
 */
syntax = "proto3";
package proto;

option go_package = "github.com/topolvm/topolvm/pkg/lvmd/proto";

message Empty {}

// Represents a logical volume.
message LogicalVolume {
    string name = 1;                        // The logical volume name.
    uint32 dev_major = 3;                   // Device major number.
    uint32 dev_minor = 4;                   // Device minor number.
    repeated string tags = 5;               // Tags to add to the volume during creation
    int64 size_bytes = 6;                   // Volume size in canonical CSI bytes.
    string path = 7;                        // Path to the lv as per lvm.
    string attr = 8;                        // Attributes of the lv.

    reserved 2;
}

// Represents the input for CreateLV.
message CreateLVRequest {
    string name = 1;                        // The logical volume name.
    repeated string tags = 3;               // Tags to add to the volume during creation
    string device_class = 4;
    string lvcreate_option_class = 5;
    int64 size_bytes = 6;                   // Volume size in canonical CSI bytes.

    reserved 2;
}

// Represents the response of CreateLV.
message CreateLVResponse {
    LogicalVolume volume = 1;  // Information of the created volume.
}

// Represents the input for RemoveLV.
message RemoveLVRequest {
    string name = 1;       // The logical volume name.
    string device_class = 2;
}

message CreateLVSnapshotRequest {
    string name = 1;                        // The logical volume name.
    repeated string tags = 2;               // Tags to add to the volume during creation
    string device_class = 3;
    string source_volume = 4;               // Source lv of snapshot.
    string access_type = 6;                 // Access type of snapshot
    int64 size_bytes = 7;                   // Volume size in canonical CSI bytes.

    reserved 5;
}

message CreateLVSnapshotResponse {
    LogicalVolume snapshot = 1;  // Information of the created snapshot lv.
}

// Represents the input for ResizeLV.
//
// The volume must already exist.
// The volume size will be expanded to at least "size_bytes".
message ResizeLVRequest {
    string name = 1;                        // The logical volume name.
    int64 size_bytes = 7;                   // Volume size in canonical CSI bytes.
    string device_class = 3;

    reserved 2;
}

message ResizeLVResponse {
    int64 size_bytes = 1;                   // Volume size in canonical CSI bytes.
}

// Represents the response of GetLVList.
message GetLVListResponse {
    repeated LogicalVolume volumes = 1;  // Information of volumes.
}

// Represents the response of GetFreeBytes.
message GetFreeBytesResponse {
    uint64 free_bytes = 1;  // Free space of the volume group in bytes.
}

message GetLVListRequest {
    string device_class = 1;
}

message GetFreeBytesRequest {
    string device_class = 1;
}

// Represents the stream output from Watch.
message WatchResponse {
    uint64 free_bytes = 1;  // Free space of the default volume group in bytes. In the case of thin pools, free space on the thinpool with overprovision in bytes.
    repeated WatchItem items = 2;
}

// Represents the details of thinpool.
message ThinPoolItem {
  double data_percent = 1; // Data percent occupied on the thinpool, used for monitoring.
  double metadata_percent = 2; // Metadata percent occupied on the thinpool, used for monitoring.
  uint64 overprovision_bytes = 3; // Free space on the thinpool with overprovision, used for annotating node.
  uint64 size_bytes = 4; // Physical data space size of the thinpool.
}

// Represents the response corresponding to device class targets.
message WatchItem {
    uint64 free_bytes = 1; // Free space in the volume group in bytes.
    string device_class = 2;
    uint64 size_bytes = 3; // Size of volume group in bytes.
    ThinPoolItem thin_pool = 4;
}

// Service to manage logical volumes of the volume group.
service LVService {
    // Create a logical volume.
    rpc CreateLV(CreateLVRequest) returns (CreateLVResponse);
    // Remove a logical volume.
    rpc RemoveLV(RemoveLVRequest) returns (Empty);
    // Resize a logical volume.
    rpc ResizeLV(ResizeLVRequest) returns (ResizeLVResponse);
    rpc CreateLVSnapshot(CreateLVSnapshotRequest) returns (CreateLVSnapshotResponse);
}

// Service to retrieve information of the volume group.
service VGService {
    // Get the list of logical volumes in the volume group.
    rpc GetLVList(GetLVListRequest) returns (GetLVListResponse);
    // Get the free space of the volume group in bytes.
    rpc GetFreeBytes(GetFreeBytesRequest) returns (GetFreeBytesResponse);
    // Stream the volume group metrics.
    rpc Watch(Empty) returns (stream WatchResponse);
}