def recover_release_data(app_folder):
    """
    Given the path to an app folder where an app was just built, return a
    dictionary containing the data emitted from running the buildpack's release
    script.

    Relies on the builder.sh script storing the release data in ./.release.yaml
    inside the app folder.
    """
    with open(os.path.join(app_folder, '.release.yaml'), 'rb') as f:
        return yaml.safe_load(f)