@osbsapi
    def get_compression_extension(self):

        build_type = self.build_conf.get_build_type()
        build_request = self.bm.get_build_request_by_type(build_type=build_type)
        inner = build_request.inner_template
        postbuild_plugins = inner.get('postbuild_plugins', [])
        for plugin in postbuild_plugins:
            if plugin.get('name') == 'compress':
                args = plugin.get('args', {})
                method = args.get('method', 'gzip')
                if method == 'gzip':
                    return '.gz'
                elif method == 'lzma':
                    return '.xz'
                raise OsbsValidationException("unknown compression method '%s'"
                                              % method)

        return None
Find the filename extension for the 'docker save' output, which
dataset/ETHPy150Open projectatomic/osbs-client/osbs/api.py/OSBS.get_compression_extension