Added add_campaign_labels example (#269)

* Added add_campaign_labels example

* Fixes to example from review

* Additional fixes, corrected printout on success

* Additional fixes, corrected printout on success

* Additional documentation fixes and cleanup

examples/campaign_management/add_campaign_labels.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python
+# Copyright 2020 Google LLC
+#
+# Licensed 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
+#
+#     https://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.
+"""This code example adds a campaign label to a list of campaigns.
+
+This example assumes that a label has already been prepared.
+"""
+
+import argparse
+import sys
+
+from google.ads.google_ads.client import GoogleAdsClient
+from google.ads.google_ads.errors import GoogleAdsException
+
+
+def main(client, customer_id, label_id, campaign_ids):
+    """This code example adds a campaign label to a list of campaigns.
+
+    Args:
+        client: An initialized GoogleAdsClient instance.
+        customer_id: A client customer ID str.
+        label_id: The ID of the label to attach to campaigns.
+        campaign_ids: A list of campaign IDs to which the label will be added.
+    """
+
+    # Get an instance of CampaignLabelService client.
+    campaign_label_service = client.get_service(
+        'CampaignLabelService', version='v3')
+    campaign_service = client.get_service('CampaignService', version='v3')
+    label_service = client.get_service('LabelService', version='v3')
+
+    # Build the resource name of the label to be added across the campaigns.
+    label_resource_name = label_service.label_path(customer_id, label_id)
+
+    operations = []
+
+    for campaign_id in campaign_ids:
+        campaign_resource_name = campaign_service.campaign_path(customer_id,
+                                                                campaign_id)
+        campaign_label_operation = client.get_type(
+            'CampaignLabelOperation', version='v3')
+
+        campaign_label = campaign_label_operation.create
+        campaign_label.campaign.value = campaign_resource_name
+        campaign_label.label.value = label_resource_name
+        operations.append(campaign_label_operation)
+
+    try:
+        response = campaign_label_service.mutate_campaign_labels(
+            customer_id, operations)
+        print(f'Added {len(response.results)} campaign labels:')
+        for result in response.results:
+            print(result.resource_name)
+    except GoogleAdsException as error:
+        print('Request with ID "{}" failed with status "{}" and includes the '
+              'following errors:'.format(
+                  error.request_id, error.error.code().name))
+        for error in error.failure.errors:
+            print('\tError with message "{}".'.format(error.message))
+            if error.location:
+                for field_path_element in error.location.field_path_elements:
+                    print('\t\tOn field: {}'.format(
+                        field_path_element.field_name))
+        sys.exit(1)
+
+
+if __name__ == '__main__':
+    # GoogleAdsClient will read the google-ads.yaml configuration file in the
+    # home directory if none is specified.
+    google_ads_client = GoogleAdsClient.load_from_storage()
+
+    parser = argparse.ArgumentParser(
+        description='This code example adds a campaign label to a list of '
+        'campaigns.')
+    # The following argument(s) should be provided to run the example.
+    parser.add_argument('-c', '--customer_id', type=str,
+                        required=True, help='The Google Ads customer ID.')
+    parser.add_argument('-l', '--label_id', type=str, required=True,
+                        help='The ID of the label to attach to campaigns.')
+    parser.add_argument('-i', '--campaign_ids', nargs='+', type=str,
+                        required=True,
+                        help='The campaign IDs to receive the label.')
+    args = parser.parse_args()
+    main(google_ads_client, args.customer_id, args.label_id, args.campaign_ids)