old_contents: # Copyright 2014-2015 Canonical Limited.
  #
  # This file is part of charm-helpers.
  #
  # charm-helpers is free software: you can redistribute it and/or modify
  # it under the terms of the GNU Lesser General Public License version 3 as
  # published by the Free Software Foundation.
  #
  # charm-helpers is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU Lesser General Public License for more details.
  #
  # You should have received a copy of the GNU Lesser General Public License
  # along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
  
  from .bus import set_state  # noqa
  from .bus import remove_state  # noqa
  from .helpers import toggle_state  # noqa
  from .helpers import is_state  # noqa
  from .helpers import all_states  # noqa
  from .relations import scopes  # noqa
  from .relations import RelationBase  # noqa
  from .decorators import hook  # noqa
  from .decorators import when  # noqa
  from .decorators import when_not  # noqa
  from .decorators import not_unless  # noqa
  from .decorators import only_once  # noqa
  
  from . import bus
  from charmhelpers.core import hookenv
  from charmhelpers.core import unitdata
  
  
  def main(relation_name=None):
      """
      This is the main entry point for the reactive framework.  It calls
      :func:`~bus.discover` to find and load all reactive handlers (e.g.,
      :func:`@when <decorators.when>` decorated blocks), and then
      :func:`~bus.dispatch` to trigger hook and state handlers until the
      state settles out.  Finally,
      :meth:`unitdata.kv().flush <charmhelpers.core.unitdata.Storage.flush>`
      is called to persist the state.
  
      :param str relation_name: Optional name of the relation which is being handled.
      """
      hookenv.log('Reactive main running for hook %s' % hookenv.hook_name(), level=hookenv.INFO)
  
      def flush_kv():
          if unitdata._KV:
              unitdata._KV.flush()
      hookenv.atexit(flush_kv)
      try:
          bus.discover()
          bus.dispatch()
      except SystemExit as x:
          if x.code is None or x.code == 0:
              hookenv._run_atexit()
          raise
      hookenv._run_atexit()
  
new_contents: # Copyright 2014-2015 Canonical Limited.
  #
  # This file is part of charm-helpers.
  #
  # charm-helpers is free software: you can redistribute it and/or modify
  # it under the terms of the GNU Lesser General Public License version 3 as
  # published by the Free Software Foundation.
  #
  # charm-helpers is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU Lesser General Public License for more details.
  #
  # You should have received a copy of the GNU Lesser General Public License
  # along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
  
  from .bus import set_state  # noqa
  from .bus import remove_state  # noqa
  from .helpers import toggle_state  # noqa
  from .helpers import is_state  # noqa
  from .helpers import all_states  # noqa
  from .relations import scopes  # noqa
  from .relations import RelationBase  # noqa
  from .decorators import hook  # noqa
  from .decorators import when  # noqa
  from .decorators import when_not  # noqa
  from .decorators import not_unless  # noqa
  from .decorators import only_once  # noqa
  from .decorators import when_file_changed  # noqa
  
  from . import bus
  from charmhelpers.core import hookenv
  from charmhelpers.core import unitdata
  
  
  def main(relation_name=None):
      """
      This is the main entry point for the reactive framework.  It calls
      :func:`~bus.discover` to find and load all reactive handlers (e.g.,
      :func:`@when <decorators.when>` decorated blocks), and then
      :func:`~bus.dispatch` to trigger hook and state handlers until the
      state settles out.  Finally,
      :meth:`unitdata.kv().flush <charmhelpers.core.unitdata.Storage.flush>`
      is called to persist the state.
  
      :param str relation_name: Optional name of the relation which is being handled.
      """
      hookenv.log('Reactive main running for hook %s' % hookenv.hook_name(), level=hookenv.INFO)
  
      def flush_kv():
          if unitdata._KV:
              unitdata._KV.flush()
      hookenv.atexit(flush_kv)
      try:
          bus.discover()
          bus.dispatch()
      except SystemExit as x:
          if x.code is None or x.code == 0:
              hookenv._run_atexit()
          raise
      hookenv._run_atexit()
  
subject: Add when_file_changed to toplevel import