import json


def get_aws_regions_from_file(region_file):
    """
    Return the list of region names read from region_file.

    The format of region_file is as follows:
    {
       "regions": [
           "cn-north-1",
           "cn-northwest-1"
       ]
    }
    """
    with open(region_file) as r_file:
        region_data = json.load(r_file)
    return sorted(r for r in region_data.get("regions"))