Listing and getting policies

  """Sample script to demonstrate the use of the List method in the Policy API."""

  from collections.abc import Mapping, Sequence
  import json
  import pprint
  import time
  from typing import Any
  import urllib.request
  from absl import app
  from absl import flags
  from google.oauth2 import service_account
  import google.auth
  from google.auth import iam
  from google.auth.transport import requests

  AUTH_SCOPES = ['https://www.googleapis.com/auth/iam']
  # The read-only scope of the API. Note that you must provide the required
  # scope to the service account while setting up domain-wide delegation.
  POLICY_SCOPES = ['https://www.googleapis.com/auth/cloud-identity.policies.readonly']
  BASE_URL = 'https://cloudidentity.googleapis.com/'
  VERSIONED_BASE_URL = f'{BASE_URL}v1/'
  TOKEN_URI = "https://accounts.google.com/o/oauth2/token"

  _ADMIN_EMAIL = flags.DEFINE_string(
      name='admin_email',
      default=None,
      help='Administrator email to call as',
      required=True,
  )

  _PAGE_SIZE = flags.DEFINE_integer(
      name='page_size',
      default=50,
      help='Page size for the List API request',
      required=False,
  )

  # To list all policies, set FILTER to '';
  # To list policies for a specific customer, set FILTER to
  # 'customer == "customers/{obfuscated_target_customer_id}"';
  # To list policies for a specific Application, such as Gmail, set FILTER to
  # 'setting.type.matches("gmail.*")';
  # To list policies for a specific Setting, such as service_status, set FILTER to
  # 'setting.type.matches(".*service_status")'.
  _LIST_FILTER = flags.DEFINE_string(
      name='list_filter',
      default='',
      help='Filter for the List API request',
      required=False,
  )


  def create_delegated_credentials(
    admin_email: str
  ) -> google.auth.credentials.Credentials:
    """Creates delegated credentials for the user.

    Args:
      admin_email: The administrator email to call as.

    Returns:
      The delegated credentials for the user.

    """
    # Fetch application default credentials (ADC)
    credentials, _ = google.auth.default(scopes=AUTH_SCOPES)

    # Populate account information
    request = requests.Request()
    credentials.refresh(request)

    # Create an IAM signer
    signer = iam.Signer(request, credentials,
                        credentials.service_account_email)

    # Create domain-wide delegated (DWD) credentials
    delegated_credentials = service_account.Credentials(
        signer=signer,
        service_account_email=credentials.service_account_email,
        token_uri=TOKEN_URI,
        scopes=POLICY_SCOPES,
        subject=admin_email
    )
    return delegated_credentials


  def build_list_policies_request(
      page_size: int, list_filter: str, page_token: str, access_token: str
  ) -> urllib.request.Request:
    """Builds the request for the List Policies API.

    Args:
      page_size: The page size for the request.
      list_filter: The filter for the request.
      page_token: The page token for the request.
      access_token: The access token for the API.

    Returns:
      The request for the List Policies API.
    """
    list_url = (
        f'{VERSIONED_BASE_URL}policies?page_size={page_size}'
        f'&filter={list_filter}&page_token={page_token}'
    )
    request = urllib.request.Request(list_url)
    request.add_header('Authorization', 'Bearer ' + access_token)
    return request


  def call_list_policies_api(
      request: urllib.request.Request,
  ) -> Mapping[str, Any]:
    """Calls the List Policies API.

    Args:
      request: The request for the List Policies API.

    Returns:
      The response for the List Policies API.
    """
    content = urllib.request.urlopen(request).read()
    return json.loads(content)


  def call_list_policies_api_till_last_page(
      access_token: str, page_size: int, list_filter: str
  ) -> None:
    """Calls the List Policies API until the last page.

    Args:
      access_token: The access token for the API.
      page_size: The page size for the request.
      list_filter: The filter for the request.
    """
    page_token = ''
    # Paginate until the last page.
    while True:
      list_policies_request = build_list_policies_request(
          page_size, list_filter, page_token, access_token
      )
      list_policies_response = call_list_policies_api(list_policies_request)
      print_list_policies_response(list_policies_response)
      if (
          'nextPageToken' not in list_policies_response
          or not list_policies_response['nextPageToken']
      ):
        print('This is the last page.')
        break
      page_token = list_policies_response['nextPageToken']
      time.sleep(1)


  def print_list_policies_response(response: Mapping[str, Any]) -> None:
    pp = pprint.PrettyPrinter(indent=4)

    if 'policies' in response:
      for policy in response['policies']:
        pp.pprint(policy)
    if 'nextPageToken' in response:
      print('Next page token: ' + response['nextPageToken'])


  def main(argv: Sequence[str]):
    if len(argv) > 3:
      raise app.UsageError('Too many command-line arguments.')

    dc = create_delegated_credentials(_ADMIN_EMAIL.value)
    dc.refresh(requests.Request())
    call_list_policies_api_till_last_page(
        dc.token,
        _PAGE_SIZE.value,
        _LIST_FILTER.value,
    )


  if __name__ == '__main__':
    app.run(main)

  """Sample script to demonstrate the use of the get method in the Policy API."""

  def build_get_policy_request(
      policy_name: str, access_token: str
  ) -> urllib.request.Request:
    """Builds the request for the Get Policy API.

    Args:
      policy_name: The policy name to get.
      access_token: The access token for the API.

    Returns:
      The request for the Get Policy API.
    """
    list_url = f'{VERSIONED_BASE_URL}{policy_name}'
    request = urllib.request.Request(list_url)
    request.add_header('Authorization', 'Bearer ' + access_token)
    return request


  def call_get_policy_api(access_token: str, policy_name: str) -> None:
    """Calls the Get Policy API.

    Args:
      access_token: The access token for the API.
      policy_name: The policy name to get.
    """
    request = build_get_policy_request(policy_name, access_token)
    content = urllib.request.urlopen(request).read()
    response = json.loads(content)
    print_get_policy_response(response)


  def print_get_policy_response(response: str) -> None:
    pp = pprint.PrettyPrinter(indent=4)
    pp.pprint(response)