Class OutputStreamFactory

awscli/utils.py:414–469

class OutputStreamFactory:
    def __init__(
        self, session, popen=None, environ=None, default_less_flags='FRX'
    ):
        self._session = session
        self._popen = popen
        if popen is None:
            self._popen = Popen
        self._environ = environ
        if environ is None:
            # When calling out to the system's pager, we want to avoid using
            # shared libraries bundled with the AWS CLI so that the pager uses
            # the system's shared libraries.
            with original_ld_library_path():
                self._environ = os.environ.copy()
        self._default_less_flags = default_less_flags

    def get_output_stream(self):
        pager = self._get_configured_pager()
        if is_a_tty() and pager:
            return self.get_pager_stream(pager)
        return self.get_stdout_stream()

    @contextlib.contextmanager
    def get_pager_stream(self, preferred_pager=None):
        if not preferred_pager:
            preferred_pager = self._get_configured_pager()
        popen_kwargs = self._get_process_pager_kwargs(preferred_pager)
        process = LazyPager(self._popen, **popen_kwargs)
        try:
            yield process.stdin
        except OSError:
            # Ignore IOError since this can commonly be raised when a pager
            # is closed abruptly and causes a broken pipe.
            pass
        finally:
            process.communicate()

    @contextlib.contextmanager
    def get_stdout_stream(self):
        yield get_stdout_text_writer()

    def _get_configured_pager(self):
        return self._session.get_component('config_store').get_config_variable(
            'pager'
        )

    def _get_process_pager_kwargs(self, pager_cmd):
        kwargs = get_popen_kwargs_for_pager_cmd(pager_cmd)
        kwargs['stdin'] = PIPE
        env = self._environ.copy()
        if 'LESS' not in env:
            env['LESS'] = self._default_less_flags
        kwargs['env'] = env
        kwargs['universal_newlines'] = True
        return kwargs