text: #   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
  #
  # 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,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from tensorboardX import SummaryWriter
  from parl.utils import logger
  
  __all__ = []
  
  _writer = None
  _WRITTER_METHOD = ['add_scalar', 'add_histogram', 'close', 'flush']
  
  
  def create_file_after_first_call(func_name):
      def call(*args, **kwargs):
          global _writer
          if _writer is None:
              logdir = logger.get_dir()
              if logdir is None:
                  logdir = logger.auto_set_dir(action='d')
                  logger.warning(
                      "[tensorboard] logdir is None, will save tensorboard files to {}"
                      .format(logdir))
              _writer = SummaryWriter(logdir=logger.get_dir())
          func = getattr(_writer, func_name)
          func(*args, **kwargs)
          _writer.flush()
  
      return call
  
  
  # export writter functions
  for func_name in _WRITTER_METHOD:
      locals()[func_name] = create_file_after_first_call(func_name)
      __all__.append(func_name)
  