import json


def read_one_node(key, file_name='log_file.json'):
    """
    Return the dictionary in JSON file under the key=key.

    Args:
        key (string): dictionary key to address the node
        file_name (string): JSON file name to read

    Returns:
        Dictionary

    """
    with open(file_name, 'r', encoding='utf8') as infile:
        node = json.load(infile)
    return node[key]