syntax = "proto3";

package hcsshim.controller.linuxcontainer.save.v1;

option go_package = "github.com/Microsoft/hcsshim/internal/controller/linuxcontainer/save;save";

import "google/protobuf/any.proto";
import "google/protobuf/duration.proto";

// Payload is the migration payload owned by a single linuxcontainer
// controller. It is the top-level message wrapped in an [anypb.Any] when
// handed off between source and destination shims. Embedded process states
// are carried as opaque [anypb.Any] payloads so the process controller fully
// owns its own schema and versioning.
message Payload {
  // schema_version is bumped whenever a field's semantics change. The
  // destination MUST reject states whose version it does not recognise.
  uint32 schema_version = 1;

  // container_id is the host/shim container identifier.
  string container_id = 2;

  // gcs_container_id is the container identifier as known by the GCS inside
  // the guest, which may differ from container_id.
  string gcs_container_id = 3;

  // io_retry_timeout is how long IO relay reconnects are retried for this
  // container.
  google.protobuf.Duration io_retry_timeout = 4;

  // layers is the container's rootfs composition.
  Layers layers = 5;

  // scsi_reservation_ids are the SCSI reservation GUIDs the container owns.
  // Each value is a key into the SCSI sub-controller's reservations map.
  repeated string scsi_reservation_ids = 6;

  // processes is keyed by exec ID and contains the init process (with an
  // empty exec ID) plus any additional exec'd processes. Each value is an
  // opaque process-controller [Payload] envelope.
  map<string, google.protobuf.Any> processes = 7;
}

// Layers describes the container's rootfs composition.
message Layers {
  // ro_layers are the read-only layer reservations in stack order.
  repeated LayerReservation ro_layers = 1;

  // scratch is the writable scratch layer reservation.
  LayerReservation scratch = 2;

  // layers_combined is true when the layers were merged into a single
  // rootfs (e.g. overlay) rather than mounted individually.
  bool layers_combined = 3;

  // rootfs_path is the final guest path of the container rootfs: the
  // merged mount when layers_combined is true, otherwise the topmost
  // layer mount.
  string rootfs_path = 4;
}

// LayerReservation references a single SCSI-backed layer mounted into the
// guest.
message LayerReservation {
  // reservation_id is a SCSI reservation GUID; layers are SCSI-backed VHDs
  // and this is a key into the SCSI sub-controller's reservations map.
  string reservation_id = 1;

  // guest_path is the path inside the guest where this layer is mounted.
  string guest_path = 2;
}