code: def readInstanceTag(instanceID, tagName="Name", connection=None):
    
    assert isinstance(instanceID, basestring), ("instanceID must be a string but is %r" % instanceID)
    assert isinstance(tagName, basestring), ("tagName must be a string but is %r" % tagName)
  
    if not connection:
      # Assume AWS credentials are in the environment or the instance is using an IAM role
      connection = boto.ec2.connect_to_region(myRegion())
  
    # Filter the tag values for our instance_id
    # http://docs.aws.amazon.com/AWSEC2/latest/CommandLineReference/ApiReference-cmd-DescribeTags.html
    tagData = connection.get_all_tags(filters={"resource-id": instanceID, "key": tagName})
    if tagData:
      tagValue = tagData[0].value
    else:
      raise RuntimeError, "%s: No such tag on %s" % (tagName, instanceID)
    return tagValue
docs: Load a tag from EC2
  
    :param str instanceID: Instance ID to read the tag on
    :param str tagName: Name of tag to load
    :param connection: optional boto connection to use
  
    :returns: the tag's value
    :rtype: str