title: How to use the s3 hook in airflow
body: <p>I have an s3 folder location, that I am moving to GCS.
  I am using Airflow to make the movements happen.</p>
  
  <p>In this environment, my s3 is an "ever growing" folder, meaning we do not delete files after we get them.  </p>
  
  <pre><code>def GetFiles(**kwargs):
      foundfiles = False
  
      s3 = S3Hook(aws_conn_id='S3_BDEX')
      s3.get_conn()
      bucket = s3.get_bucket(
          bucket_name='/file.share.external.bdex.com/Offrs'
      )
      files = s3.list_prefixes(bucket_name='/file.share.external.bdex.com/Offrs')
      print("BUCKET:  {}".format(files))
  
  
  check_for_file = BranchPythonOperator(
      task_id='Check_FTP_and_Download',
      provide_context=True,
      python_callable=GetFiles,
      dag=dag
  )
  </code></pre>
  
  <p>What I need here is the list of files and their creation date/time.  This way I can compare existing files to determine if they are new or not.</p>
  
  <p>I know I can connect, because the function <code>get_bucket</code> function worked.
  However, in this case, I get the following errors:</p>
  
  <pre><code>Invalid bucket name "/file.share.external.bdex.com/Offrs": Bucket name must match the regex "^[a-zA-Z0-9.\-_]{1,255}$"
  </code></pre>
  
  <p>Thank you</p>