fetch info about an s3 bucket using cloudwatch api

objcount.py

from datetime import datetime, timedelta

import boto3
import pprint
import os


def main():

   bucket = os.environ.get('BUCKET')
   s = boto3.Session()
   c = s.client('cloudwatch')

   response = c.get_metric_statistics(
          Namespace='AWS/S3',
          MetricName='NumberOfObjects',
          Dimensions=[
             {'Name': 'BucketName',
              'Value': bucket},
             {'Name': 'StorageType',
              'Value': 'StandardStorage'},
             ],
      StartTime=datetime.now().replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(10),
      EndTime=datetime.now().replace(hour=0, minute=0, second=0, microsecond=0),
      Period=60*24*24,
      Statistics=['Average'])
   pprint.pprint(response)
   
   response = c.get_metric_statistics(
          Namespace='AWS/S3',
          MetricName='BucketSizeBytes',
          Dimensions=[
             {'Name': 'BucketName',
              'Value': bucket},
             {'Name': 'StorageType',
              'Value': 'StandardStorage'},
             ],
      StartTime=datetime.now().replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(10),
      EndTime=datetime.now().replace(hour=0, minute=0, second=0, microsecond=0),
      Period=60*24*24,
      Statistics=['Average'])

   pprint.pprint(response)

   
if __name__ == '__main__':
   main()

output

{u'Datapoints': [],
 u'Label': 'NumberOfObjects',
 'ResponseMetadata': {'HTTPStatusCode': 200,
                      'RequestId': '74e3ac17-8245-11e5-835f-cd3fdfe1e32d'}}
{u'Datapoints': [{u'Average': 580472213.0,
                  u'Timestamp': datetime.datetime(2015, 11, 1, 19, 12, tzinfo=tzutc()),
                  u'Unit': 'Bytes'},
                 {u'Average': 562677776.0,
                  u'Timestamp': datetime.datetime(2015, 10, 28, 0, 0, tzinfo=tzutc()),
                  u'Unit': 'Bytes'},
                 {u'Average': 548243812.0,
                  u'Timestamp': datetime.datetime(2015, 10, 24, 0, 0, tzinfo=tzutc()),
                  u'Unit': 'Bytes'},
                 {u'Average': 576847723.0,
                  u'Timestamp': datetime.datetime(2015, 11, 1, 0, 0, tzinfo=tzutc()),
                  u'Unit': 'Bytes'},
                 {u'Average': 554575731.0,
                  u'Timestamp': datetime.datetime(2015, 10, 26, 0, 0, tzinfo=tzutc()),
                  u'Unit': 'Bytes'},
                 {u'Average': 566266447.0,
                  u'Timestamp': datetime.datetime(2015, 10, 28, 19, 12, tzinfo=tzutc()),
                  u'Unit': 'Bytes'},
                 {u'Average': 573510466.0,
                  u'Timestamp': datetime.datetime(2015, 10, 30, 19, 12, tzinfo=tzutc()),
                  u'Unit': 'Bytes'},
                 {u'Average': 551270255.0,
                  u'Timestamp': datetime.datetime(2015, 10, 24, 19, 12, tzinfo=tzutc()),
                  u'Unit': 'Bytes'},
                 {u'Average': 558712576.0,
                  u'Timestamp': datetime.datetime(2015, 10, 26, 19, 12, tzinfo=tzutc()),
                  u'Unit': 'Bytes'},
                 {u'Average': 570043657.0,
                  u'Timestamp': datetime.datetime(2015, 10, 30, 0, 0, tzinfo=tzutc()),
                  u'Unit': 'Bytes'}],
 u'Label': 'BucketSizeBytes',
 'ResponseMetadata': {'HTTPStatusCode': 200,
                      'RequestId': '752cc2ba-8245-11e5-914e-53aa03c7f588'}}

For some reason the NumberOfObjects query returns zero datapoints