The unique identifier for an entity in the Google Ads API is called a resource name, and is represented as a string with a predictable format. If you know the constituent components of a resource name, you can generate resource names using helper methods present on many Service objects.
Service path methods
All Services that are designed to handle reading or mutating specific types of objects in the API have helper methods to make it easy to construct resource_names. For example creating a resource name for a Campaign object:
from google.ads.google_ads import client
customer_id = '7892134783'
campaign_id = '1234567890'
campaign_service = client.get_service('CampaignService')
resource_name = campaign_service.campaign_path(customer_id, campaign_id)
Composite resource names
Some objects, such as the AdGroupCriterion resource, have composite resource names,
which means that the last segment of the resource name is composed of multiple object
IDs separated by a ~. The path helpers on services won't construct the composite
segment of a resource name, so the client library has a small utility to help with
this:
from google.ads.google_ads import client
from google.ads.google_ads.util import ResourceName
customer_id = '0987654321'
ad_group_id = '1234567890'
criterion_id = '74932'
ad_group_criterion_service = client.get_service('AdGroupCriterionService')
# An AdGroupCriterion resource name that uses the above IDs looks like this:
# 'customers/0987654321/adGroupCriteria/1234567890~74932'
composite_id = ResourceName.format_composite(ad_group_id, criterion_id)
resource_name = ad_group_criterion_service.ad_group_criterion_path(
customer_id, composite_id)