Source code for orbax.checkpoint._src.handlers.proto_checkpoint_handler

# Copyright 2026 The Orbax Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
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"""ProtoCheckpointHandler class.

Implementation of CheckpointHandler interface.
"""

import dataclasses
from typing import List, Optional, Type

from etils import epath
from google.protobuf import message
from google.protobuf import text_format
from orbax.checkpoint import checkpoint_args
from orbax.checkpoint import options as options_lib
from orbax.checkpoint import utils
from orbax.checkpoint._src import asyncio_utils
from orbax.checkpoint._src.futures import future
from orbax.checkpoint._src.handlers import async_checkpoint_handler


CheckpointArgs = checkpoint_args.CheckpointArgs
register_with_handler = checkpoint_args.register_with_handler

_DEFAULT_FILENAME = "proto.pbtxt"




class ProtoCheckpointHandler(async_checkpoint_handler.AsyncCheckpointHandler):
  """Serializes/deserializes protocol buffers."""



  def __init__(
      self,
      filename: str = _DEFAULT_FILENAME,
      *,
      multiprocessing_options: options_lib.MultiprocessingOptions = options_lib.MultiprocessingOptions()
  ):
    """Initializes ProtoCheckpointHandler.

    Args:
      filename: file name given to the written file.
      multiprocessing_options: See orbax.checkpoint.options.
    """
    self._filename = filename
    self._primary_host = multiprocessing_options.primary_host




  async def async_save(
      self,
      directory: epath.Path,
      item: Optional[message.Message] = None,
      args: Optional["ProtoSaveArgs"] = None,
  ) -> Optional[List[future.Future]]:
    """Saves the given proto.

    Args:
      directory: save location directory.
      item: Deprecated, use `args`.
      args: ProtoSaveArgs (see below).

    Returns:
      A commit future.
    """
    if args is not None:
      item = args.item

    async def _save_fn(x):
      if utils.is_primary_host(self._primary_host):
        path = directory / self._filename
        path.write_text(text_format.MessageToString(x))

    return [
        future.CommitFutureAwaitingContractedSignals(
            _save_fn(item), name="proto_ch_save"
        )
    ]




  def save(self, *args, **kwargs):
    """Saves the provided item."""

    async def async_save():
      commit_futures = await self.async_save(*args, **kwargs)
      if commit_futures:
        for f in commit_futures:
          f.result()

    asyncio_utils.run_sync(async_save())




  def restore(
      self,
      directory: epath.Path,
      item: Optional[Type[message.Message]] = None,
      args: Optional["ProtoRestoreArgs"] = None,
  ):
    """Restores the proto from directory.

    Args:
      directory: restore location directory.
      item: Deprecated, use `args`.
      args: ProtoRestoreArgs (see below).

    Returns:
      The deserialized proto read from `directory` if item is not None
    """
    if not args and not item:
      raise ValueError(
          "Must provide `item` in order to deserialize proto to the correct"
          " type."
      )
    if args:
      item = args.item
    path = directory / self._filename
    return text_format.Parse(path.read_text(), item())






@register_with_handler(ProtoCheckpointHandler, for_save=True)
@dataclasses.dataclass
class ProtoSaveArgs(CheckpointArgs):
  """Parameters for saving a proto.

  Attributes:
    item (required): the proto to serialize.
  """

  item: message.Message





@register_with_handler(ProtoCheckpointHandler, for_restore=True)
@dataclasses.dataclass
class ProtoRestoreArgs(CheckpointArgs):
  """Proto restore args.

  Attributes:
    item (required): the proto class
  """

  item: Type[message.Message]