community.general/plugins/module_utils/gcp.py

# This code is part of Ansible, but is an independent component.
# This particular file snippet, and this file snippet only, is BSD licensed.
# Modules you write using this snippet, which is embedded dynamically by Ansible
# still belong to the author of the module, and may assign their own license
# to the complete work.
#
# Copyright (c), Franck Cuny <franck.cuny@gmail.com>, 2014
#
# Simplified BSD License (see simplified_bsd.txt or https://opensource.org/licenses/BSD-2-Clause)

from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

import json
import os
import time
import traceback
from distutils.version import LooseVersion

# libcloud
try:
    import libcloud
    HAS_LIBCLOUD_BASE = True
except ImportError:
    HAS_LIBCLOUD_BASE = False

# google-auth
try:
    import google.auth
    from google.oauth2 import service_account
    HAS_GOOGLE_AUTH = True
except ImportError:
    HAS_GOOGLE_AUTH = False

# google-python-api
try:
    import google_auth_httplib2
    from httplib2 import Http
    from googleapiclient.http import set_user_agent
    from googleapiclient.errors import HttpError
    from apiclient.discovery import build
    HAS_GOOGLE_API_LIB = True
except ImportError:
    HAS_GOOGLE_API_LIB = False


import ansible.module_utils.six.moves.urllib.parse as urlparse

GCP_DEFAULT_SCOPES = ['https://www.googleapis.com/auth/cloud-platform']


def _get_gcp_ansible_credentials(module):
    """Helper to fetch creds from AnsibleModule object."""
    service_account_email = module.params.get('service_account_email', None)
    # Note: pem_file is discouraged and will be deprecated
    credentials_file = module.params.get('pem_file', None) or module.params.get(
        'credentials_file', None)
    project_id = module.params.get('project_id', None)

    return (service_account_email, credentials_file, project_id)


def _get_gcp_environ_var(var_name, default_value):
    """Wrapper around os.environ.get call."""
    return os.environ.get(
        var_name, default_value)


def _get_gcp_environment_credentials(service_account_email, credentials_file, project_id):
    """Helper to look in environment variables for credentials."""
    # If any of the values are not given as parameters, check the appropriate
    # environment variables.
    if not service_account_email:
        service_account_email = _get_gcp_environ_var('GCE_EMAIL', None)
    if not credentials_file:
        credentials_file = _get_gcp_environ_var(
            'GCE_CREDENTIALS_FILE_PATH', None) or _get_gcp_environ_var(
                'GOOGLE_APPLICATION_CREDENTIALS', None) or _get_gcp_environ_var(
                    'GCE_PEM_FILE_PATH', None)
    if not project_id:
        project_id = _get_gcp_environ_var('GCE_PROJECT', None) or _get_gcp_environ_var(
            'GOOGLE_CLOUD_PROJECT', None)
    return (service_account_email, credentials_file, project_id)


def _get_gcp_credentials(module, require_valid_json=True, check_libcloud=False):
    """
    Obtain GCP credentials by trying various methods.

    There are 3 ways to specify GCP credentials:
    1. Specify via Ansible module parameters (recommended).
    2. Specify via environment variables.  Two sets of env vars are available:
       a) GOOGLE_CLOUD_PROJECT, GOOGLE_CREDENTIALS_APPLICATION (preferred)
       b) GCE_PROJECT, GCE_CREDENTIAL_FILE_PATH, GCE_EMAIL (legacy, not recommended; req'd if
          using p12 key)
    3. Specify via libcloud secrets.py file (deprecated).

    There are 3 helper functions to assist in the above.

    Regardless of method, the user also has the option of specifying a JSON
    file or a p12 file as the credentials file.  JSON is strongly recommended and
    p12 will be removed in the future.

    Additionally, flags may be set to require valid json and check the libcloud
    version.

    AnsibleModule.fail_json is called only if the project_id cannot be found.

    :param module: initialized Ansible module object
    :type module: `class AnsibleModule`

    :param require_valid_json: If true, require credentials to be valid JSON.  Default is True.
    :type require_valid_json: ``bool``

    :params check_libcloud: If true, check the libcloud version available to see if
                            JSON creds are supported.
    :type check_libcloud: ``bool``

    :return:  {'service_account_email': service_account_email,
               'credentials_file': credentials_file,
                'project_id': project_id}
    :rtype: ``dict``
    """
    (service_account_email,
     credentials_file,
     project_id) = _get_gcp_ansible_credentials(module)

    # If any of the values are not given as parameters, check the appropriate
    # environment variables.
    (service_account_email,
     credentials_file,
     project_id) = _get_gcp_environment_credentials(service_account_email,
                                                    credentials_file, project_id)

    if credentials_file is None or project_id is None or service_account_email is None:
        if check_libcloud is True:
            if project_id is None:
                # TODO(supertom): this message is legacy and integration tests
                # depend on it.
                module.fail_json(msg='Missing GCE connection parameters in libcloud '
                                 'secrets file.')
        else:
            if project_id is None:
                module.fail_json(msg=('GCP connection error: unable to determine project (%s) or '
                                      'credentials file (%s)' % (project_id, credentials_file)))
        # Set these fields to empty strings if they are None
        # consumers of this will make the distinction between an empty string
        # and None.
        if credentials_file is None:
            credentials_file = ''
        if service_account_email is None:
            service_account_email = ''

    # ensure the credentials file is found and is in the proper format.
    if credentials_file:
        _validate_credentials_file(module, credentials_file,
                                   require_valid_json=require_valid_json,
                                   check_libcloud=check_libcloud)

    return {'service_account_email': service_account_email,
            'credentials_file': credentials_file,
            'project_id': project_id}


def _validate_credentials_file(module, credentials_file, require_valid_json=True, check_libcloud=False):
    """
    Check for valid credentials file.

    Optionally check for JSON format and if libcloud supports JSON.

    :param module: initialized Ansible module object
    :type module: `class AnsibleModule`

    :param credentials_file: path to file on disk
    :type credentials_file: ``str``.  Complete path to file on disk.

    :param require_valid_json: This argument is ignored as of Ansible 2.7.
    :type require_valid_json: ``bool``

    :params check_libcloud: If true, check the libcloud version available to see if
                            JSON creds are supported.
    :type check_libcloud: ``bool``

    :returns: True
    :rtype: ``bool``
    """
    try:
        # Try to read credentials as JSON
        with open(credentials_file) as credentials:
            json.loads(credentials.read())
            # If the credentials are proper JSON and we do not have the minimum
            # required libcloud version, bail out and return a descriptive
            # error
            if check_libcloud and LooseVersion(libcloud.__version__) < '0.17.0':
                module.fail_json(msg='Using JSON credentials but libcloud minimum version not met. '
                                     'Upgrade to libcloud>=0.17.0.')
            return True
    except IOError as e:
        module.fail_json(msg='GCP Credentials File %s not found.' %
                         credentials_file, changed=False)
        return False
    except ValueError as e:
        module.fail_json(
            msg='Non-JSON credentials file provided. Please generate a new JSON key from the Google Cloud console',
            changed=False)


def gcp_connect(module, provider, get_driver, user_agent_product, user_agent_version):
    """Return a Google libcloud driver connection."""
    if not HAS_LIBCLOUD_BASE:
        module.fail_json(msg='libcloud must be installed to use this module')

    creds = _get_gcp_credentials(module,
                                 require_valid_json=False,
                                 check_libcloud=True)
    try:
        gcp = get_driver(provider)(creds['service_account_email'], creds['credentials_file'],
                                   datacenter=module.params.get('zone', None),
                                   project=creds['project_id'])
        gcp.connection.user_agent_append("%s/%s" % (
            user_agent_product, user_agent_version))
    except (RuntimeError, ValueError) as e:
        module.fail_json(msg=str(e), changed=False)
    except Exception as e:
        module.fail_json(msg=unexpected_error_msg(e), changed=False)

    return gcp


def get_google_cloud_credentials(module, scopes=None):
    """
    Get credentials object for use with Google Cloud client.

    Attempts to obtain credentials by calling _get_gcp_credentials. If those are
    not present will attempt to connect via Application Default Credentials.

    To connect via libcloud, don't use this function, use gcp_connect instead.  For
    Google Python API Client, see get_google_api_auth for how to connect.

    For more information on Google's client library options for Python, see:
    U(https://cloud.google.com/apis/docs/client-libraries-explained#google_api_client_libraries)

    Google Cloud example:
      creds, params = get_google_cloud_credentials(module, scopes, user_agent_product, user_agent_version)
      pubsub_client = pubsub.Client(project=params['project_id'], credentials=creds)
      pubsub_client.user_agent = 'ansible-pubsub-0.1'
      ...

    :param module: initialized Ansible module object
    :type module: `class AnsibleModule`

    :param scopes: list of scopes
    :type module: ``list`` of URIs

    :returns: A tuple containing (google authorized) credentials object and
              params dict {'service_account_email': '...', 'credentials_file': '...', 'project_id': ...}
    :rtype: ``tuple``
    """
    scopes = [] if scopes is None else scopes

    if not HAS_GOOGLE_AUTH:
        module.fail_json(msg='Please install google-auth.')

    conn_params = _get_gcp_credentials(module,
                                       require_valid_json=True,
                                       check_libcloud=False)
    try:
        if conn_params['credentials_file']:
            credentials = service_account.Credentials.from_service_account_file(
                conn_params['credentials_file'])
            if scopes:
                credentials = credentials.with_scopes(scopes)
        else:
            (credentials, project_id) = google.auth.default(
                scopes=scopes)
            if project_id is not None:
                conn_params['project_id'] = project_id

        return (credentials, conn_params)
    except Exception as e:
        module.fail_json(msg=unexpected_error_msg(e), changed=False)
        return (None, None)


def get_google_api_auth(module, scopes=None, user_agent_product='ansible-python-api', user_agent_version='NA'):
    """
    Authentication for use with google-python-api-client.

    Function calls get_google_cloud_credentials, which attempts to assemble the credentials
    from various locations.  Next it attempts to authenticate with Google.

    This function returns an httplib2 (compatible) object that can be provided to the Google Python API client.

    For libcloud, don't use this function, use gcp_connect instead.  For Google Cloud, See
    get_google_cloud_credentials for how to connect.

    For more information on Google's client library options for Python, see:
    U(https://cloud.google.com/apis/docs/client-libraries-explained#google_api_client_libraries)

    Google API example:
      http_auth, conn_params = get_google_api_auth(module, scopes, user_agent_product, user_agent_version)
      service = build('myservice', 'v1', http=http_auth)
      ...

    :param module: initialized Ansible module object
    :type module: `class AnsibleModule`

    :param scopes: list of scopes
    :type scopes: ``list`` of URIs

    :param user_agent_product: User agent product.  eg: 'ansible-python-api'
    :type user_agent_product: ``str``

    :param user_agent_version: Version string to append to product.  eg: 'NA' or '0.1'
    :type user_agent_version: ``str``

    :returns: A tuple containing (google authorized) httplib2 request object and a
              params dict {'service_account_email': '...', 'credentials_file': '...', 'project_id': ...}
    :rtype: ``tuple``
    """
    scopes = [] if scopes is None else scopes

    if not HAS_GOOGLE_API_LIB:
        module.fail_json(msg="Please install google-api-python-client library")
    if not scopes:
        scopes = GCP_DEFAULT_SCOPES
    try:
        (credentials, conn_params) = get_google_cloud_credentials(module, scopes)
        http = set_user_agent(Http(), '%s-%s' %
                              (user_agent_product, user_agent_version))
        http_auth = google_auth_httplib2.AuthorizedHttp(credentials, http=http)

        return (http_auth, conn_params)
    except Exception as e:
        module.fail_json(msg=unexpected_error_msg(e), changed=False)
        return (None, None)


def get_google_api_client(module, service, user_agent_product, user_agent_version,
                          scopes=None, api_version='v1'):
    """
    Get the discovery-based python client. Use when a cloud client is not available.

    client = get_google_api_client(module, 'compute', user_agent_product=USER_AGENT_PRODUCT,
                                   user_agent_version=USER_AGENT_VERSION)

    :returns: A tuple containing the authorized client to the specified service and a
              params dict {'service_account_email': '...', 'credentials_file': '...', 'project_id': ...}
    :rtype: ``tuple``
    """
    if not scopes:
        scopes = GCP_DEFAULT_SCOPES

    http_auth, conn_params = get_google_api_auth(module, scopes=scopes,
                                                 user_agent_product=user_agent_product,
                                                 user_agent_version=user_agent_version)
    client = build(service, api_version, http=http_auth)

    return (client, conn_params)


def check_min_pkg_version(pkg_name, minimum_version):
    """Minimum required version is >= installed version."""
    from pkg_resources import get_distribution
    try:
        installed_version = get_distribution(pkg_name).version
        return LooseVersion(installed_version) >= minimum_version
    except Exception as e:
        return False


def unexpected_error_msg(error):
    """Create an error string based on passed in error."""
    return 'Unexpected response: (%s). Detail: %s' % (str(error), traceback.format_exc())


def get_valid_location(module, driver, location, location_type='zone'):
    if location_type == 'zone':
        l = driver.ex_get_zone(location)
    else:
        l = driver.ex_get_region(location)
    if l is None:
        link = 'https://cloud.google.com/compute/docs/regions-zones/regions-zones#available'
        module.fail_json(msg=('%s %s is invalid. Please see the list of '
                              'available %s at %s' % (
                                  location_type, location, location_type, link)),
                         changed=False)
    return l


def check_params(params, field_list):
    """
    Helper to validate params.

    Use this in function definitions if they require specific fields
    to be present.

    :param params: structure that contains the fields
    :type params: ``dict``

    :param field_list: list of dict representing the fields
                       [{'name': str, 'required': True/False', 'type': cls}]
    :type field_list: ``list`` of ``dict``

    :return True or raises ValueError
    :rtype: ``bool`` or `class:ValueError`
    """
    for d in field_list:
        if not d['name'] in params:
            if 'required' in d and d['required'] is True:
                raise ValueError(("%s is required and must be of type: %s" %
                                  (d['name'], str(d['type']))))
        else:
            if not isinstance(params[d['name']], d['type']):
                raise ValueError(("%s must be of type: %s. %s (%s) provided." % (
                    d['name'], str(d['type']), params[d['name']],
                    type(params[d['name']]))))
            if 'values' in d:
                if params[d['name']] not in d['values']:
                    raise ValueError(("%s must be one of: %s" % (
                        d['name'], ','.join(d['values']))))
            if isinstance(params[d['name']], int):
                if 'min' in d:
                    if params[d['name']] < d['min']:
                        raise ValueError(("%s must be greater than or equal to: %s" % (
                            d['name'], d['min'])))
                if 'max' in d:
                    if params[d['name']] > d['max']:
                        raise ValueError("%s must be less than or equal to: %s" % (
                            d['name'], d['max']))
    return True


class GCPUtils(object):
    """
    Helper utilities for GCP.
    """

    @staticmethod
    def underscore_to_camel(txt):
        return txt.split('_')[0] + ''.join(x.capitalize() or '_' for x in txt.split('_')[1:])

    @staticmethod
    def remove_non_gcp_params(params):
        """
        Remove params if found.
        """
        params_to_remove = ['state']
        for p in params_to_remove:
            if p in params:
                del params[p]

        return params

    @staticmethod
    def params_to_gcp_dict(params, resource_name=None):
        """
        Recursively convert ansible params to GCP Params.

        Keys are converted from snake to camelCase
        ex: default_service to defaultService

        Handles lists, dicts and strings

        special provision for the resource name
        """
        if not isinstance(params, dict):
            return params
        gcp_dict = {}
        params = GCPUtils.remove_non_gcp_params(params)
        for k, v in params.items():
            gcp_key = GCPUtils.underscore_to_camel(k)
            if isinstance(v, dict):
                retval = GCPUtils.params_to_gcp_dict(v)
                gcp_dict[gcp_key] = retval
            elif isinstance(v, list):
                gcp_dict[gcp_key] = [GCPUtils.params_to_gcp_dict(x) for x in v]
            else:
                if resource_name and k == resource_name:
                    gcp_dict['name'] = v
                else:
                    gcp_dict[gcp_key] = v
        return gcp_dict

    @staticmethod
    def execute_api_client_req(req, client=None, raw=True,
                               operation_timeout=180, poll_interval=5,
                               raise_404=True):
        """
        General python api client interaction function.

        For use with google-api-python-client, or clients created
        with get_google_api_client function
        Not for use with Google Cloud client libraries

        For long-running operations, we make an immediate query and then
        sleep poll_interval before re-querying.  After the request is done
        we rebuild the request with a get method and return the result.

        """
        try:
            resp = req.execute()

            if not resp:
                return None

            if raw:
                return resp

            if resp['kind'] == 'compute#operation':
                resp = GCPUtils.execute_api_client_operation_req(req, resp,
                                                                 client,
                                                                 operation_timeout,
                                                                 poll_interval)

            if 'items' in resp:
                return resp['items']

            return resp
        except HttpError as h:
            # Note: 404s can be generated (incorrectly) for dependent
            # resources not existing.  We let the caller determine if
            # they want 404s raised for their invocation.
            if h.resp.status == 404 and not raise_404:
                return None
            else:
                raise
        except Exception:
            raise

    @staticmethod
    def execute_api_client_operation_req(orig_req, op_resp, client,
                                         operation_timeout=180, poll_interval=5):
        """
        Poll an operation for a result.
        """
        parsed_url = GCPUtils.parse_gcp_url(orig_req.uri)
        project_id = parsed_url['project']
        resource_name = GCPUtils.get_gcp_resource_from_methodId(
            orig_req.methodId)
        resource = GCPUtils.build_resource_from_name(client, resource_name)

        start_time = time.time()

        complete = False
        attempts = 1
        while not complete:
            if start_time + operation_timeout >= time.time():
                op_req = client.globalOperations().get(
                    project=project_id, operation=op_resp['name'])
                op_resp = op_req.execute()
                if op_resp['status'] != 'DONE':
                    time.sleep(poll_interval)
                    attempts += 1
                else:
                    complete = True
                    if op_resp['operationType'] == 'delete':
                        # don't wait for the delete
                        return True
                    elif op_resp['operationType'] in ['insert', 'update', 'patch']:
                        # TODO(supertom): Isolate 'build-new-request' stuff.
                        resource_name_singular = GCPUtils.get_entity_name_from_resource_name(
                            resource_name)
                        if op_resp['operationType'] == 'insert' or 'entity_name' not in parsed_url:
                            parsed_url['entity_name'] = GCPUtils.parse_gcp_url(op_resp['targetLink'])[
                                'entity_name']
                        args = {'project': project_id,
                                resource_name_singular: parsed_url['entity_name']}
                        new_req = resource.get(**args)
                        resp = new_req.execute()
                        return resp
                    else:
                        # assuming multiple entities, do a list call.
                        new_req = resource.list(project=project_id)
                        resp = new_req.execute()
                        return resp
            else:
                # operation didn't complete on time.
                raise GCPOperationTimeoutError("Operation timed out: %s" % (
                    op_resp['targetLink']))

    @staticmethod
    def build_resource_from_name(client, resource_name):
        try:
            method = getattr(client, resource_name)
            return method()
        except AttributeError:
            raise NotImplementedError('%s is not an attribute of %s' % (resource_name,
                                                                        client))

    @staticmethod
    def get_gcp_resource_from_methodId(methodId):
        try:
            parts = methodId.split('.')
            if len(parts) != 3:
                return None
            else:
                return parts[1]
        except AttributeError:
            return None

    @staticmethod
    def get_entity_name_from_resource_name(resource_name):
        if not resource_name:
            return None

        try:
            # Chop off global or region prefixes
            if resource_name.startswith('global'):
                resource_name = resource_name.replace('global', '')
            elif resource_name.startswith('regional'):
                resource_name = resource_name.replace('region', '')

            # ensure we have a lower case first letter
            resource_name = resource_name[0].lower() + resource_name[1:]

            if resource_name[-3:] == 'ies':
                return resource_name.replace(
                    resource_name[-3:], 'y')
            if resource_name[-1] == 's':
                return resource_name[:-1]

            return resource_name

        except AttributeError:
            return None

    @staticmethod
    def parse_gcp_url(url):
        """
        Parse GCP urls and return dict of parts.

        Supported URL structures:
        /SERVICE/VERSION/'projects'/PROJECT_ID/RESOURCE
        /SERVICE/VERSION/'projects'/PROJECT_ID/RESOURCE/ENTITY_NAME
        /SERVICE/VERSION/'projects'/PROJECT_ID/RESOURCE/ENTITY_NAME/METHOD_NAME
        /SERVICE/VERSION/'projects'/PROJECT_ID/'global'/RESOURCE
        /SERVICE/VERSION/'projects'/PROJECT_ID/'global'/RESOURCE/ENTITY_NAME
        /SERVICE/VERSION/'projects'/PROJECT_ID/'global'/RESOURCE/ENTITY_NAME/METHOD_NAME
        /SERVICE/VERSION/'projects'/PROJECT_ID/LOCATION_TYPE/LOCATION/RESOURCE
        /SERVICE/VERSION/'projects'/PROJECT_ID/LOCATION_TYPE/LOCATION/RESOURCE/ENTITY_NAME
        /SERVICE/VERSION/'projects'/PROJECT_ID/LOCATION_TYPE/LOCATION/RESOURCE/ENTITY_NAME/METHOD_NAME

        :param url: GCP-generated URL, such as a selflink or resource location.
        :type url: ``str``

        :return: dictionary of parts. Includes stanard components of urlparse, plus
                 GCP-specific 'service', 'api_version', 'project' and
                 'resource_name' keys. Optionally, 'zone', 'region', 'entity_name'
                 and 'method_name', if applicable.
        :rtype: ``dict``
        """

        p = urlparse.urlparse(url)
        if not p:
            return None
        else:
            # we add extra items such as
            # zone, region and resource_name
            url_parts = {}
            url_parts['scheme'] = p.scheme
            url_parts['host'] = p.netloc
            url_parts['path'] = p.path
            if p.path.find('/') == 0:
                url_parts['path'] = p.path[1:]
            url_parts['params'] = p.params
            url_parts['fragment'] = p.fragment
            url_parts['query'] = p.query
            url_parts['project'] = None
            url_parts['service'] = None
            url_parts['api_version'] = None

            path_parts = url_parts['path'].split('/')
            url_parts['service'] = path_parts[0]
            url_parts['api_version'] = path_parts[1]
            if path_parts[2] == 'projects':
                url_parts['project'] = path_parts[3]
            else:
                # invalid URL
                raise GCPInvalidURLError('unable to parse: %s' % url)

            if 'global' in path_parts:
                url_parts['global'] = True
                idx = path_parts.index('global')
                if len(path_parts) - idx == 4:
                    # we have a resource, entity and method_name
                    url_parts['resource_name'] = path_parts[idx + 1]
                    url_parts['entity_name'] = path_parts[idx + 2]
                    url_parts['method_name'] = path_parts[idx + 3]

                if len(path_parts) - idx == 3:
                    # we have a resource and entity
                    url_parts['resource_name'] = path_parts[idx + 1]
                    url_parts['entity_name'] = path_parts[idx + 2]

                if len(path_parts) - idx == 2:
                    url_parts['resource_name'] = path_parts[idx + 1]

                if len(path_parts) - idx < 2:
                    # invalid URL
                    raise GCPInvalidURLError('unable to parse: %s' % url)

            elif 'regions' in path_parts or 'zones' in path_parts:
                idx = -1
                if 'regions' in path_parts:
                    idx = path_parts.index('regions')
                    url_parts['region'] = path_parts[idx + 1]
                else:
                    idx = path_parts.index('zones')
                    url_parts['zone'] = path_parts[idx + 1]

                if len(path_parts) - idx == 5:
                    # we have a resource, entity and method_name
                    url_parts['resource_name'] = path_parts[idx + 2]
                    url_parts['entity_name'] = path_parts[idx + 3]
                    url_parts['method_name'] = path_parts[idx + 4]

                if len(path_parts) - idx == 4:
                    # we have a resource and entity
                    url_parts['resource_name'] = path_parts[idx + 2]
                    url_parts['entity_name'] = path_parts[idx + 3]

                if len(path_parts) - idx == 3:
                    url_parts['resource_name'] = path_parts[idx + 2]

                if len(path_parts) - idx < 3:
                    # invalid URL
                    raise GCPInvalidURLError('unable to parse: %s' % url)

            else:
                # no location in URL.
                idx = path_parts.index('projects')
                if len(path_parts) - idx == 5:
                    # we have a resource, entity and method_name
                    url_parts['resource_name'] = path_parts[idx + 2]
                    url_parts['entity_name'] = path_parts[idx + 3]
                    url_parts['method_name'] = path_parts[idx + 4]

                if len(path_parts) - idx == 4:
                    # we have a resource and entity
                    url_parts['resource_name'] = path_parts[idx + 2]
                    url_parts['entity_name'] = path_parts[idx + 3]

                if len(path_parts) - idx == 3:
                    url_parts['resource_name'] = path_parts[idx + 2]

                if len(path_parts) - idx < 3:
                    # invalid URL
                    raise GCPInvalidURLError('unable to parse: %s' % url)

            return url_parts

    @staticmethod
    def build_googleapi_url(project, api_version='v1', service='compute'):
        return 'https://www.googleapis.com/%s/%s/projects/%s' % (service, api_version, project)

    @staticmethod
    def filter_gcp_fields(params, excluded_fields=None):
        new_params = {}
        if not excluded_fields:
            excluded_fields = ['creationTimestamp', 'id', 'kind',
                               'selfLink', 'fingerprint', 'description']

        if isinstance(params, list):
            new_params = [GCPUtils.filter_gcp_fields(
                x, excluded_fields) for x in params]
        elif isinstance(params, dict):
            for k in params.keys():
                if k not in excluded_fields:
                    new_params[k] = GCPUtils.filter_gcp_fields(
                        params[k], excluded_fields)
        else:
            new_params = params

        return new_params

    @staticmethod
    def are_params_equal(p1, p2):
        """
        Check if two params dicts are equal.
        TODO(supertom): need a way to filter out URLs, or they need to be built
        """
        filtered_p1 = GCPUtils.filter_gcp_fields(p1)
        filtered_p2 = GCPUtils.filter_gcp_fields(p2)
        if filtered_p1 != filtered_p2:
            return False
        return True


class GCPError(Exception):
    pass


class GCPOperationTimeoutError(GCPError):
    pass


class GCPInvalidURLError(GCPError):
    pass