text: # Copyright 2019 Uber Technologies, Inc. All Rights Reserved.
  # Modifications copyright Microsoft
  #
  # 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.
  # ==============================================================================
  
  
  class HorovodInternalError(RuntimeError):
      """Internal error raised when a Horovod collective operation (e.g., allreduce) fails.
  
      This is handled in elastic mode as a recoverable error, and will result in a reset event.
      """
      pass
  
  
  class HostsUpdatedInterrupt(RuntimeError):
      """Internal interrupt event indicating that the set of hosts in the job has changed.
  
      In elastic mode, this will result in a reset event without a restore to committed state.
      """
      def __init__(self, skip_sync):
          self.skip_sync = skip_sync
  
  
  def get_version_mismatch_message(name, version, installed_version):
      return f'Framework {name} installed with version {installed_version} but found version {version}.\n\
               This can result in unexpected behavior including runtime errors.\n\
               Reinstall Horovod using `pip install --no-cache-dir` to build with the new version.'
  
  
  class HorovodVersionMismatchError(Exception):
      """Internal error raised when the runtime version of a framework mismatches its version at
      Horovod installation time.
      """
      def __init__(self, name, version, installed_version):
          super().__init__(get_version_mismatch_message(name, version, installed_version))
          self.name = name
          self.version = version
          self.installed_version = installed_version
  