The function to be provided as an environment variable resolver

constructor_env_variables.py

def constructor_env_variables(loader, node):
    """
    Extracts the environment variable from the node's value
    :param yaml.Loader loader: the yaml loader
    :param node: the current node in the yaml
    :return: the parsed string that contains the value of the environment
    variable
    """
    value = loader.construct_scalar(node)
    match = pattern.findall(value)
    if match:
        full_value = value
        for g in match:
            full_value = full_value.replace(
                f'${{{g}}}', os.environ.get(g, g)
            )
        return full_value
    return value