text: #!/usr/bin/python2
  
  """
  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 urllib2
  import ambari_simplejson as json # simplejson is much faster comparing to Python 2.6 json module and has the same functions set.
  import logging
  import traceback
  
  from resource_management.libraries.functions.curl_krb_request import curl_krb_request
  from resource_management.libraries.functions.curl_krb_request import DEFAULT_KERBEROS_KINIT_TIMER_MS
  from resource_management.libraries.functions.curl_krb_request import KERBEROS_KINIT_TIMER_PARAMETER
  from resource_management.libraries.functions.curl_krb_request import CONNECTION_TIMEOUT_DEFAULT
  from resource_management.core.environment import Environment
  from resource_management.libraries.functions.namenode_ha_utils import get_all_namenode_addresses
  
  NN_HTTP_ADDRESS_KEY = '{{hdfs-site/dfs.namenode.http-address}}'
  NN_HTTPS_ADDRESS_KEY = '{{hdfs-site/dfs.namenode.https-address}}'
  NN_HTTP_POLICY_KEY = '{{hdfs-site/dfs.http.policy}}'
  
  HDFS_SITE_KEY = '{{hdfs-site}}'
  KERBEROS_KEYTAB = '{{hdfs-site/dfs.web.authentication.kerberos.keytab}}'
  KERBEROS_PRINCIPAL = '{{hdfs-site/dfs.web.authentication.kerberos.principal}}'
  SECURITY_ENABLED_KEY = '{{cluster-env/security_enabled}}'
  SMOKEUSER_KEY = "{{cluster-env/smokeuser}}"
  EXECUTABLE_SEARCH_PATHS = '{{kerberos-env/executable_search_paths}}'
  logger = logging.getLogger('ambari_alerts')
  
  def get_tokens():
    """
    Returns a tuple of tokens in the format {{site/property}} that will be used
    to build the dictionary passed into execute
  
    :rtype tuple
    """
    return (HDFS_SITE_KEY, NN_HTTP_ADDRESS_KEY, NN_HTTPS_ADDRESS_KEY, NN_HTTP_POLICY_KEY, EXECUTABLE_SEARCH_PATHS,
            KERBEROS_KEYTAB, KERBEROS_PRINCIPAL, SECURITY_ENABLED_KEY, SMOKEUSER_KEY)
  
  
  def execute(configurations={}, parameters={}, host_name=None):
    """
    Returns a tuple containing the result code and a pre-formatted result label
  
    Keyword arguments:
    configurations : a mapping of configuration key to value
    parameters : a mapping of script parameter key to value
    host_name : the name of this host where the alert is running
  
    :type configurations dict
    :type parameters dict
    :type host_name str
    """
  
    if configurations is None:
      return (('UNKNOWN', ['There were no configurations supplied to the script.']))
  
    uri = None
    http_policy = 'HTTP_ONLY'
  
    # hdfs-site is required
    if not HDFS_SITE_KEY in configurations:
      return 'SKIPPED', ['{0} is a required parameter for the script'.format(HDFS_SITE_KEY)]
  
    if NN_HTTP_POLICY_KEY in configurations:
      http_policy = configurations[NN_HTTP_POLICY_KEY]
  
    if SMOKEUSER_KEY in configurations:
      smokeuser = configurations[SMOKEUSER_KEY]
  
    executable_paths = None
    if EXECUTABLE_SEARCH_PATHS in configurations:
      executable_paths = configurations[EXECUTABLE_SEARCH_PATHS]
  
    security_enabled = False
    if SECURITY_ENABLED_KEY in configurations:
      security_enabled = str(configurations[SECURITY_ENABLED_KEY]).upper() == 'TRUE'
  
    kerberos_keytab = None
    if KERBEROS_KEYTAB in configurations:
      kerberos_keytab = configurations[KERBEROS_KEYTAB]
  
    kerberos_principal = None
    if KERBEROS_PRINCIPAL in configurations:
      kerberos_principal = configurations[KERBEROS_PRINCIPAL]
      kerberos_principal = kerberos_principal.replace('_HOST', host_name)
  
    kinit_timer_ms = parameters.get(KERBEROS_KINIT_TIMER_PARAMETER, DEFAULT_KERBEROS_KINIT_TIMER_MS)
  
    # determine the right URI and whether to use SSL
    hdfs_site = configurations[HDFS_SITE_KEY]
  
    scheme = "https" if http_policy == "HTTPS_ONLY" else "http"
  
    nn_addresses = get_all_namenode_addresses(hdfs_site)
    for nn_address in nn_addresses:
      if nn_address.startswith(host_name + ":") or nn_address == host_name:
        uri = nn_address
        break
    if not uri:
      return 'SKIPPED', [
        'NameNode on host {0} not found (namenode adresses = {1})'.format(host_name, ', '.join(nn_addresses))]
  
    upgrade_finalized_qry = "{0}://{1}/jmx?qry=Hadoop:service=NameNode,name=NameNodeInfo".format(scheme, uri)
  
    # start out assuming an OK status
    label = None
    result_code = "OK"
  
    try:
      if kerberos_principal is not None and kerberos_keytab is not None and security_enabled:
        env = Environment.get_instance()
  
        last_checkpoint_time_response, error_msg, time_millis = curl_krb_request(
          env.tmp_dir, kerberos_keytab,
          kerberos_principal, upgrade_finalized_qry, "upgrade_finalized_state", executable_paths, False,
          "HDFS Upgrade Finalized State", smokeuser, kinit_timer_ms = kinit_timer_ms
         )
  
        upgrade_finalized_response_json = json.loads(last_checkpoint_time_response)
        upgrade_finalized = bool(upgrade_finalized_response_json["beans"][0]["UpgradeFinalized"])
  
      else:
        upgrade_finalized = bool(get_value_from_jmx(upgrade_finalized_qry,
                                                      "UpgradeFinalized"))
  
      if upgrade_finalized:
        label = "HDFS cluster is not in the upgrade state"
        result_code = 'OK'
      else:
        label = "HDFS cluster is not finalized"
        result_code = 'CRITICAL'
  
    except:
      label = traceback.format_exc()
      result_code = 'UNKNOWN'
  
    return ((result_code, [label]))
  
  def get_value_from_jmx(query, jmx_property):
    """
     Read property from the jxm endpoint
  
    :param query: jmx uri path
    :param jmx_property: property name to read
    :return: jmx property value
    
    :type query str
    :type jmx_property str
    """
    response = None
  
    try:
      response = urllib2.urlopen(query, timeout=int(CONNECTION_TIMEOUT_DEFAULT))
      data = response.read()
  
      data_dict = json.loads(data)
      return data_dict["beans"][0][jmx_property]
    finally:
      if response is not None:
        try:
          response.close()
        except:
          pass
  