cleanup.py

#!/usr/bin/env python

from google.cloud import monitoring_v3

# # Using a service account with credentials in a json file:
# JSON_CREDS = 'monitoring.json'
# from oauth2client.service_account import ServiceAccountCredentials
# scopes  = ["https://www.googleapis.com/auth/monitoring",]
# credentials = ServiceAccountCredentials.from_json_keyfile_name(
#     JSON_CREDS, scopes)

# # From inside a GCE instance, with default account:
# from oauth2client.contrib.gce import AppAssertionCredentials
# credentials = AppAssertionCredentials([])

# 'project' is project ID, not name
myproject = 'useful-proposal-454'

client = monitoring_v3.MetricServiceClient()

name = client.project_path(myproject)

# Delete ALL custom metrics from this project.

filter_='metric.type = starts_with("custom.googleapis.com/spinnaker/rosco")'

for page in client.list_metric_descriptors(name=name, filter_=filter_, retry=None).pages:
    for element in page:
        print(element.type)
        # metric_name = client.metric_descriptor_path(myproject, element.type)
        # client.delete_metric_descriptor(name=metric_name)