text: """
  Licensed to the Apache Software Foundation (ASF) under one
  or more contributor license agreements.  See the NOTICE file
  distributed with this work for additional information
  regarding copyright ownership.  The ASF licenses this file
  to you 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.
  
  """
  import os
  
  import ambari_simplejson as json
  from resource_management.core.logger import Logger
  from resource_management.libraries.functions import conf_select
  from resource_management.libraries.functions import stack_select
  from resource_management.libraries.functions.format import format
  from resource_management.libraries.functions.version import compare_versions
  from resource_management.libraries.functions.fcntl_based_process_lock import FcntlBasedProcessLock
  from resource_management.libraries.resources.xml_config import XmlConfig
  from resource_management.libraries.script import Script
  
  
  def setup_stack_symlinks():
    """
    Invokes <stack-selector-tool> set all against a calculated fully-qualified, "normalized" version based on a
    stack version, such as "2.3". This should always be called after a component has been
    installed to ensure that all HDP pointers are correct. The stack upgrade logic does not
    interact with this since it's done via a custom command and will not trigger this hook.
    :return:
    """
    import params
    if params.stack_version_formatted != "" and compare_versions(params.stack_version_formatted, '2.2') >= 0:
      # try using the exact version first, falling back in just the stack if it's not defined
      # which would only be during an intial cluster installation
      version = params.current_version if params.current_version is not None else params.stack_version_unformatted
  
      if not params.upgrade_suspended:
        # On parallel command execution this should be executed by a single process at a time.
        with FcntlBasedProcessLock(params.stack_select_lock_file, enabled = params.is_parallel_execution_enabled, skip_fcntl_failures = True):
          stack_select.select_all(version)
  
  def setup_config():
    import params
    stackversion = params.stack_version_unformatted
    Logger.info("FS Type: {0}".format(params.dfs_type))
  
    is_hadoop_conf_dir_present = False
    if hasattr(params, "hadoop_conf_dir") and params.hadoop_conf_dir is not None and os.path.exists(params.hadoop_conf_dir):
      is_hadoop_conf_dir_present = True
    else:
      Logger.warning("Parameter hadoop_conf_dir is missing or directory does not exist. This is expected if this host does not have any Hadoop components.")
  
    if is_hadoop_conf_dir_present and (params.has_namenode or stackversion.find('Gluster') >= 0 or params.dfs_type == 'HCFS'):
      # create core-site only if the hadoop config diretory exists
      XmlConfig("core-site.xml",
                conf_dir=params.hadoop_conf_dir,
                configurations=params.config['configurations']['core-site'],
                configuration_attributes=params.config['configuration_attributes']['core-site'],
                owner=params.hdfs_user,
                group=params.user_group,
                only_if=format("ls {hadoop_conf_dir}"))
  
  
  def load_version(struct_out_file):
    """
    Load version from file.  Made a separate method for testing
    """
    json_version = None
    try:
      if os.path.exists(struct_out_file):
        with open(struct_out_file, 'r') as fp:
          json_info = json.load(fp)
          json_version = json_info['version']
    except:
      pass
  
    return json_version
    
  
  def link_configs(struct_out_file):
    """
    Links configs, only on a fresh install of HDP-2.3 and higher
    """
    import params
  
    if not Script.is_stack_greater_or_equal("2.3"):
      Logger.info("Can only link configs for HDP-2.3 and higher.")
      return
  
    json_version = load_version(struct_out_file)
  
    if not json_version:
      Logger.info("Could not load 'version' from {0}".format(struct_out_file))
      return
  
    # On parallel command execution this should be executed by a single process at a time.
    with FcntlBasedProcessLock(params.link_configs_lock_file, enabled = params.is_parallel_execution_enabled, skip_fcntl_failures = True):
      for k, v in conf_select.get_package_dirs().iteritems():
        conf_select.convert_conf_directories_to_symlinks(k, json_version, v)