text: # Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
  # SPDX-License-Identifier: MIT-0
  #
  # Permission is hereby granted, free of charge, to any person obtaining a copy of this
  # software and associated documentation files (the "Software"), to deal in the Software
  # without restriction, including without limitation the rights to use, copy, modify,
  # merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
  # permit persons to whom the Software is furnished to do so.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
  # INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
  # PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  # HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  #
  # This code expects that you have AWS credentials setup per:
  # https://boto3.amazonaws.com/v1/documentation/api/latest/guide/quickstart.html
  from logging import basicConfig, getLogger, INFO
  from time import sleep
  
  from boto3 import client
  
  from pyqldbsamples.constants import Constants
  
  logger = getLogger(__name__)
  basicConfig(level=INFO)
  qldb_client = client('qldb')
  
  LEDGER_CREATION_POLL_PERIOD_SEC = 10
  ACTIVE_STATE = "ACTIVE"
  
  
  def create_ledger(name):
      """
      Create a new ledger with the specified name.
  
      :type name: str
      :param name: Name for the ledger to be created.
  
      :rtype: dict
      :return: Result from the request.
      """
      logger.info("Let's create the ledger named: {}...".format(name))
      result = qldb_client.create_ledger(Name=name, PermissionsMode='ALLOW_ALL')
      logger.info('Success. Ledger state: {}.'.format(result.get('State')))
      return result
  
  
  def wait_for_active(name):
      """
      Wait for the newly created ledger to become active.
  
      :type name: str
      :param name: The ledger to check on.
  
      :rtype: dict
      :return: Result from the request.
      """
      logger.info('Waiting for ledger to become active...')
      while True:
          result = qldb_client.describe_ledger(Name=name)
          if result.get('State') == ACTIVE_STATE:
              logger.info('Success. Ledger is active and ready to use.')
              return result
          logger.info('The ledger is still creating. Please wait...')
          sleep(LEDGER_CREATION_POLL_PERIOD_SEC)
  
  
  if __name__ == '__main__':
      """
      Create a ledger and wait for it to be active.
      """
      try:
          create_ledger(Constants.LEDGER_NAME)
          wait_for_active(Constants.LEDGER_NAME)
      except Exception as e:
          logger.exception('Unable to create the ledger!')
          raise e
  