From: John Snow <jsnow@redhat.com>
To: G S Niteesh Babu <niteesh.gs@gmail.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>,
Kashyap Chamarthy <kchamart@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
Wainer Moschetta <wainersm@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>,
Stefan Hajnoczi <stefanha@redhat.com>,
Cleber Rosa <crosa@redhat.com>, Eric Blake <eblake@redhat.com>
Subject: Re: [PATCH v4 3/7] python/aqmp-tui: Add AQMP TUI draft
Date: Sun, 22 Aug 2021 03:33:59 -0400 [thread overview]
Message-ID: <CAFn=p-bgc+tNWFMbDJ03v8NcvD2W4LBEckKAX2R041n=C3gFnQ@mail.gmail.com> (raw)
In-Reply-To: <20210819173831.23515-4-niteesh.gs@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 22751 bytes --]
On Thu, Aug 19, 2021 at 1:39 PM G S Niteesh Babu <niteesh.gs@gmail.com>
wrote:
> Added a draft of AQMP TUI.
>
> Implements the follwing basic features:
> 1) Command transmission/reception.
> 2) Shows events asynchronously.
> 3) Shows server status in the bottom status bar.
>
> Also added type annotations and necessary pylint,
> mypy configurations
>
> Signed-off-by: G S Niteesh Babu <niteesh.gs@gmail.com>
> ---
> python/qemu/aqmp/aqmp_tui.py | 566 +++++++++++++++++++++++++++++++++++
> python/setup.cfg | 15 +-
> 2 files changed, 579 insertions(+), 2 deletions(-)
> create mode 100644 python/qemu/aqmp/aqmp_tui.py
>
> diff --git a/python/qemu/aqmp/aqmp_tui.py b/python/qemu/aqmp/aqmp_tui.py
> new file mode 100644
> index 0000000000..12c9c4162a
> --- /dev/null
> +++ b/python/qemu/aqmp/aqmp_tui.py
> @@ -0,0 +1,566 @@
> +# Copyright (c) 2021
> +#
> +# Authors:
> +# Niteesh Babu G S <niteesh.gs@gmail.com>
> +#
> +# This work is licensed under the terms of the GNU GPL, version 2 or
> +# later. See the COPYING file in the top-level directory.
> +"""
> +AQMP TUI
> +
> +AQMP TUI is an asynchronous interface built on top the of the AQMP
> library.
> +It is the successor of QMP-shell and is bought-in as a replacement for it.
> +
> +Example Usage: aqmp-tui <SOCKET | TCP IP:PORT>
> +Full Usage: aqmp-tui --help
> +"""
> +
> +import argparse
> +import asyncio
> +import logging
> +from logging import Handler, LogRecord
> +import signal
> +from typing import (
> + List,
> + Optional,
> + Tuple,
> + Type,
> + Union,
> + cast,
> +)
> +
> +import urwid
> +import urwid_readline
> +
> +from ..qmp import QEMUMonitorProtocol, QMPBadPortError
> +from .message import DeserializationError, Message, UnexpectedTypeError
> +from .protocol import ConnectError
> +from .qmp_client import ExecInterruptedError, QMPClient
> +from .util import create_task, pretty_traceback
> +
> +
> +# The name of the signal that is used to update the history list
> +UPDATE_MSG: str = 'UPDATE_MSG'
> +
> +
> +def format_json(msg: str) -> str:
> + """
> + Formats given multi-line JSON message into a single-line message.
> + Converting into single line is more asthetically pleasing when looking
> + along with error messages.
> +
> + Eg:
> + Input:
> + [ 1,
> + true,
> + 3 ]
> + The above input is not a valid QMP message and produces the following
> error
> + "QMP message is not a JSON object."
> + When displaying this in TUI in multiline mode we get
> +
> + [ 1,
> + true,
> + 3 ]: QMP message is not a JSON object.
> +
> + whereas in singleline mode we get the following
> +
> + [1, true, 3]: QMP message is not a JSON object.
> +
> + The single line mode is more asthetically pleasing.
> +
> + :param msg:
> + The message to formatted into single line.
> +
> + :return: Formatted singleline message.
> +
> + NOTE: We cannot use the JSON module here because it is only capable of
> + format valid JSON messages. But here the goal is to also format
> invalid
> + JSON messages.
> + """
> + msg = msg.replace('\n', '')
> + words = msg.split(' ')
> + words = [word for word in words if word != '']
> + return ' '.join(words)
> +
> +
> +def has_tui_handler(logger: logging.Logger,
> + handler_type: Type[Handler]) -> bool:
> + """
> + The Logger class has no interface to check if a certain type of
> handler is
> + installed or not. So we provide an interface to do so.
> +
> + :param logger:
> + Logger object
> + :param handler_type:
> + The type of the handler to be checked.
> +
> + :return: returns True if handler of type `handler_type` is installed
> else
> + False.
> + """
> + handlers = logger.handlers
> + for handler in handlers:
> + if isinstance(handler, handler_type):
> + return True
> + return False
> +
> +
> +class App(QMPClient):
> + """
> + Implements the AQMP TUI.
> +
> + Initializes the widgets and starts the urwid event loop.
> + """
> + def __init__(self, address: Union[str, Tuple[str, int]]) -> None:
> + """
> + Initializes the TUI.
> +
> + :param address:
> + Address of the server to connect to.
> + """
> + urwid.register_signal(type(self), UPDATE_MSG)
> + self.window = Window(self)
> + self.address = address
> + self.aloop: Optional[asyncio.AbstractEventLoop] = None
> + super().__init__()
> +
> + def add_to_history(self, msg: str, level: Optional[str] = None) ->
> None:
> + """
> + Appends the msg to the history list.
> +
> + :param msg:
> + The raw message to be appended in string type.
> + """
> + urwid.emit_signal(self, UPDATE_MSG, msg, level)
> +
> + def _cb_outbound(self, msg: Message) -> Message:
> + """
> + Callback: outbound message hook.
> +
> + Appends the outgoing messages to the history box.
> +
> + :param msg: raw outbound message.
> + :return: final outbound message.
> + """
> + str_msg = str(msg)
> +
> + if not has_tui_handler(logging.getLogger(), TUILogHandler):
> + logging.debug('Request: %s', str_msg)
> + self.add_to_history('<-- ' + str_msg)
> + return msg
> +
> + def _cb_inbound(self, msg: Message) -> Message:
> + """
> + Callback: outbound message hook.
> +
> + Appends the incoming messages to the history box.
> +
> + :param msg: raw inbound message.
> + :return: final inbound message.
> + """
> + str_msg = str(msg)
> +
> + if not has_tui_handler(logging.getLogger(), TUILogHandler):
> + logging.debug('Request: %s', str_msg)
> + self.add_to_history('--> ' + str_msg)
> + return msg
> +
> + def handle_event(self, event: Message) -> None:
> + """
> + Handles the event.
> +
> + :param event:
> + The event to be handled.
> + """
> + # TODO: Consider all states present in qapi/run-state.json
> + if event['event'] == 'SHUTDOWN':
> + self._set_status('[Server Shutdown]')
> +
> + async def wait_for_events(self) -> None:
> + """
> + This coroutine continously waits for events and dispatches them.
> + """
> + async for event in self.events:
> + self.handle_event(event)
> +
> + async def _send_to_server(self, msg: Message) -> None:
> + """
> + This coroutine sends the message to the server.
> + The message has to be pre-validated.
> +
> + :param msg:
> + Pre-validated message to be to sent to the server.
> +
> + :raise Exception: When an unhandled exception is caught.
> + """
> + try:
> + await self._raw(msg, assign_id='id' not in msg)
> + except ExecInterruptedError:
> + logging.info('Error server disconnected before reply')
> + self.add_to_history('Server disconnected before reply',
> 'ERROR')
> + self._set_status("[Server Disconnected]")
> + except Exception as err:
> + logging.error('Exception from _send_to_server: %s', str(err))
> + raise err
> +
> + def cb_send_to_server(self, raw_msg: str) -> None:
> + """
> + Validates and sends the message to the server.
> + The raw string message is first converted into a Message object
> + and is then sent to the server.
> +
> + :param raw_msg:
> + The raw string message to be sent to the server.
> +
> + :raise Exception: When an unhandled exception is caught.
> + """
> + try:
> + raw_msg = format_json(raw_msg)
> + msg = Message(bytes(raw_msg, encoding='utf-8'))
> + create_task(self._send_to_server(msg))
> + except (ValueError, TypeError) as err:
> + logging.info('Invalid message: %s', str(err))
> + self.add_to_history(f'{raw_msg}: {err}')
> + except (DeserializationError, UnexpectedTypeError) as err:
> + logging.info('Invalid message: %s', err.error_message)
> + self.add_to_history(f'{raw_msg}: {err.error_message}')
> +
> + def unhandled_input(self, key: str) -> None:
> + """
> + Handle's keys which haven't been handled by the child widgets.
> +
> + :param key:
> + Unhandled key
> + """
> + if key == 'esc':
> + self.kill_app()
> +
> + def kill_app(self) -> None:
> + """
> + Initiates killing of app. A bridge between asynchronous and
> synchronous
> + code.
> + """
> + create_task(self._kill_app())
> +
> + async def _kill_app(self) -> None:
> + """
> + This coroutine initiates the actual disconnect process and calls
> + urwid.ExitMainLoop() to kill the TUI.
> +
> + :raise Exception: When an unhandled exception is caught.
> + """
> + # It is ok to call disconnect even in disconnect state
> + try:
> + await self.disconnect()
> + logging.debug('Disconnect finished. Exiting app')
> + except EOFError:
> + # We receive an EOF during disconnect, ignore that
> + pass
> + except Exception as err:
> + logging.info('_kill_app: %s', str(err))
> + # Let the app crash after providing a proper stack trace
> + raise err
> + raise urwid.ExitMainLoop()
> +
> + def _set_status(self, msg: str) -> None:
> + """
> + Sets the message as the status.
> +
> + :param msg:
> + The message to be displayed in the status bar.
> + """
> + self.window.footer.set_text(msg)
> +
> + def _get_formatted_address(self) -> str:
> + """
> + Returns a formatted version of the server's address.
> +
> + :return: formatted address
> + """
> + if isinstance(self.address, tuple):
> + host, port = self.address
> + addr = f'{host}:{port}'
> + else:
> + addr = f'{self.address}'
> + return addr
> +
> + async def connect_server(self) -> None:
> + """
> + Initiates a connection to the server at address `self.address`
> + and in case of a failure, sets the status to the respective error.
> + """
> + try:
> + await self.connect(self.address)
> + addr = self._get_formatted_address()
> + self._set_status(f'Connected to {addr}')
> + except ConnectError as err:
> + logging.info('connect_server: ConnectError %s', str(err))
> + self._set_status(f'[ConnectError: {err.error_message}]')
> +
> + def run(self, debug: bool = False) -> None:
> + """
> + Starts the long running co-routines and the urwid event loop.
> +
> + :param debug:
> + Enables/Disables asyncio event loop debugging
> + """
> + self.aloop = asyncio.get_event_loop()
> + self.aloop.set_debug(debug)
> +
> + # Gracefully handle SIGTERM and SIGINT signals
> + cancel_signals = [signal.SIGTERM, signal.SIGINT]
> + for sig in cancel_signals:
> + self.aloop.add_signal_handler(sig, self.kill_app)
> +
> + event_loop = urwid.AsyncioEventLoop(loop=self.aloop)
> + main_loop = urwid.MainLoop(urwid.AttrMap(self.window,
> 'background'),
> + unhandled_input=self.unhandled_input,
> + handle_mouse=True,
> + event_loop=event_loop)
> +
> + create_task(self.wait_for_events(), self.aloop)
> + create_task(self.connect_server(), self.aloop)
> + try:
> + main_loop.run()
> + except Exception as err:
> + logging.error('%s\n%s\n', str(err), pretty_traceback())
> + raise err
> +
> +
> +class StatusBar(urwid.Text):
> + """
> + A simple statusbar modelled using the Text widget. The status can be
> + set using the set_text function. All text set is aligned to right.
> + """
> + def __init__(self, text: str = ''):
> + super().__init__(text, align='right')
> +
> +
> +class Editor(urwid_readline.ReadlineEdit):
> + """
> + A simple editor modelled using the urwid_readline.ReadlineEdit widget.
> + Mimcs GNU readline shortcuts and provides history support.
> +
> + The readline shortcuts can be found below:
> + https://github.com/rr-/urwid_readline#features
> +
> + Along with the readline features, this editor also has support for
> + history. Pressing the 'up' arrow key with empty message box, lists the
> + previous message inplace.
> +
> + Currently there is no support to save the history to a file. The
> history of
> + previous commands is lost on exit.
> + """
> + def __init__(self, master: App) -> None:
> + """
> + Initializes the editor widget
> +
> + :param master: Reference to the TUI object.
> + """
> + super().__init__(caption='> ', multiline=True)
> + self.master = master
> + self.history: List[str] = []
> + self.last_index: int = -1
> + self.show_history: bool = False
> +
> + def keypress(self, size: Tuple[int, int], key: str) -> Optional[str]:
> + """
> + Handles the keypress on this widget.
> +
> + :param size:
> + The current size of the widget.
> + :param key:
> + The key to be handled.
> +
> + :return: Unhandled key if any.
> + """
> + # TODO: Add some logic for down key and clean up logic if
> possible.
> + # Returning None means the key has been handled by this widget
> + # which otherwise is propogated to the parent widget to be
> + # handled
> + msg = self.get_edit_text()
> + if key == 'up' and not msg:
> + # Show the history when 'up arrow' is pressed with no input
> text.
> + # NOTE: The show_history logic is necessary because in
> 'multiline'
> + # mode (which we use) 'up arrow' is used to move between
> lines.
> + self.show_history = True
> + last_msg = self.history[self.last_index] if self.history else
> ''
> + self.set_edit_text(last_msg)
> + self.edit_pos = len(last_msg)
> + self.last_index += 1
> + elif key == 'up' and self.show_history:
> + if self.last_index < len(self.history):
> + self.set_edit_text(self.history[self.last_index])
> + self.edit_pos = len(self.history[self.last_index])
> + self.last_index += 1
> + elif key == 'meta enter':
> + # When using multiline, enter inserts a new line into the
> editor
> + # send the input to the server on alt + enter
> + self.master.cb_send_to_server(msg)
> + self.history.insert(0, msg)
> + self.set_edit_text('')
> + self.last_index = 0
> + self.show_history = False
> + else:
> + self.show_history = False
> + self.last_index = 0
> + return cast(Optional[str], super().keypress(size, key))
> + return None
> +
> +
> +class EditorWidget(urwid.Filler):
> + """
> + The Editor is a flow widget and has to wrapped inside a box widget.
> + This class wraps the Editor inside filler widget.
> + """
> + def __init__(self, master: App) -> None:
> + super().__init__(Editor(master), valign='top')
> +
> +
> +class HistoryBox(urwid.ListBox):
> + """
> + This widget is modelled using the ListBox widget, contains the list of
> + all messages both QMP messages and log messsages to be shown in the
> TUI.
> +
> + The messages are urwid.Text widgets. On every append of a message, the
> + focus is shifted to the last appended message.
> + """
> + def __init__(self, master: App) -> None:
> + """
> + Initializes the historybox widget
> +
> + :param master: Reference to the TUI object.
> + """
> + self.master = master
> + self.history = urwid.SimpleFocusListWalker([])
> + super().__init__(self.history)
> +
> + def add_to_history(self, history: str) -> None:
> + """
> + Appends a message to the list and set the focus to the last
> appended
> + message.
> +
> + :param history:
> + The history item(message/event) to be appended to the list.
> + """
> + self.history.append(urwid.Text(history))
> + if self.history:
> + self.history.set_focus(len(self.history) - 1)
> +
> +
> +class HistoryWindow(urwid.Frame):
> + """
> + This window composes the HistoryBox and EditorWidget in a horizontal
> split.
> + By default the first focus is given to the history box.
> + """
> + def __init__(self, master: App) -> None:
> + """
> + Initializes this widget and its child widgets.
> +
> + :param master: Reference to the TUI object.
> + """
> + self.master = master
> + self.editor_widget = EditorWidget(master)
> + self.editor = urwid.LineBox(self.editor_widget)
> + self.history = HistoryBox(master)
> + self.body = urwid.Pile([('weight', 80, self.history),
> + ('weight', 20, self.editor)])
> + super().__init__(self.body)
> + urwid.connect_signal(self.master, UPDATE_MSG,
> self.cb_add_to_history)
> +
> + def cb_add_to_history(self, msg: str, level: Optional[str] = None) ->
> None:
> + """
> + Appends a message to the history box
> +
> + :param msg:
> + The message to be appended to the history box.
> + """
> + if level:
> + msg = f'[{level}]: {msg}'
> + self.history.add_to_history(msg)
> +
> +
> +class Window(urwid.Frame):
> + """
> + This window is the top most widget of the TUI and will contain other
> + windows. Each window is responsible for displaying a specific
>
+ functionality.
>
"each window" => "Each child of this widget", maybe?
+ For eg: The history window is responsible for showing the history of
> + messages and the editor.
>
These lines can probably go.
> + """
> + def __init__(self, master: App) -> None:
>
Consider naming this "parent" instead, if you'd be so kind as to oblige me.
(And everywhere else in the file.)
> + """
> + Initializes this widget and its child windows.
> +
> + :param master: Reference to the TUI object.
> + """
> + self.master = master
> + footer = StatusBar()
> + body = HistoryWindow(master)
> + super().__init__(body, footer=footer)
> +
> +
> +class TUILogHandler(Handler):
> + """
> + This handler routes all the log messages to the TUI screen.
> + It is installed to the root logger to so that the log message from all
> + libraries begin used is routed to the screen.
> + """
> + def __init__(self, tui: App) -> None:
> + """
> + Initializes the handler class.
> +
> + :param tui:
> + Reference to the TUI object.
> + """
> + super().__init__()
> + self.tui = tui
> +
> + def emit(self, record: LogRecord) -> None:
> + """
> + Emits a record to the TUI screen.
> +
> + Appends the log message to the TUI screen
> + """
> + level = record.levelname
> + msg = record.getMessage()
> + self.tui.add_to_history(msg, level)
> +
> +
> +def main() -> None:
> + """
> + Driver of the whole script, parses arguments, initialize the TUI and
> + the logger.
> + """
> + parser = argparse.ArgumentParser(description='AQMP TUI')
> + parser.add_argument('qmp_server', help='Address of the QMP server. '
> + 'Format <UNIX socket path | TCP addr:port>')
> + parser.add_argument('--log-file', help='The Log file name')
> + parser.add_argument('--log-level', default='WARNING',
> + help='Log level
> <CRITICAL|ERROR|WARNING|INFO|DEBUG|>')
> + parser.add_argument('--asyncio-debug', action='store_true',
> + help='Enable debug mode for asyncio loop. '
> + 'Generates lot of output, makes TUI unusable when
> '
> + 'logs are logged in the TUI. '
> + 'Use only when logging to a file.')
> + args = parser.parse_args()
> +
> + try:
> + address = QEMUMonitorProtocol.parse_address(args.qmp_server)
> + except QMPBadPortError as err:
> + parser.error(str(err))
> +
> + app = App(address)
> +
> + root_logger = logging.getLogger()
> + root_logger.setLevel(logging.getLevelName(args.log_level))
> +
> + if args.log_file:
> + root_logger.addHandler(logging.FileHandler(args.log_file))
> + else:
> + root_logger.addHandler(TUILogHandler(app))
> +
> + app.run(args.asyncio_debug)
> +
> +
> +if __name__ == '__main__':
> + main()
> diff --git a/python/setup.cfg b/python/setup.cfg
> index a0ed3279d8..1ff2b907a2 100644
> --- a/python/setup.cfg
> +++ b/python/setup.cfg
> @@ -81,8 +81,19 @@ namespace_packages = True
> # fusepy has no type stubs:
> allow_subclassing_any = True
>
> +[mypy-qemu.aqmp.aqmp_tui]
> +# urwid and urwid_readline have no type stubs:
> +allow_subclassing_any = True
> +
> +# The following missing import directives are because these libraries do
> not
> +# provide type stubs. Allow them on an as-needed basis for mypy.
> [mypy-fuse]
> -# fusepy has no type stubs:
> +ignore_missing_imports = True
> +
> +[mypy-urwid]
> +ignore_missing_imports = True
> +
> +[mypy-urwid_readline]
> ignore_missing_imports = True
>
> [pylint.messages control]
> @@ -97,7 +108,7 @@ ignore_missing_imports = True
> # --disable=W".
> disable=too-many-function-args, # mypy handles this with less false
> positives.
> no-member, # mypy also handles this better.
> - missing-docstring, # FIXME
> + # missing-docstring, # FIXME
> fixme, # FIXME
>
> [pylint.basic]
> --
> 2.17.1
>
>
Most of the rest looks pretty good to me. I'm still quite a bit skeptical
of format_json, but I have to admit I will look a bit more closely at that
tomorrow -- and I want to take a closer look at has_tui_handler too, but
most of the rest seems like it's been stripped to its bare essentials,
which is good :)
Thanks for the work on the docstrings and mypy hints, it's in good shape
overall.
--js
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next prev parent reply other threads:[~2021-08-22 7:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-19 17:38 [PATCH v4 0/7] AQMP TUI Draft G S Niteesh Babu
2021-08-19 17:38 ` [PATCH v4 1/7] python: disable pylint errors for aqmp-tui G S Niteesh Babu
2021-08-19 17:38 ` [PATCH v4 2/7] python: Add dependencies for AQMP TUI G S Niteesh Babu
2021-08-21 19:54 ` John Snow
2021-08-19 17:38 ` [PATCH v4 3/7] python/aqmp-tui: Add AQMP TUI draft G S Niteesh Babu
2021-08-21 20:05 ` John Snow
2021-08-21 22:21 ` Niteesh G. S.
2021-08-22 7:33 ` John Snow [this message]
2021-08-23 10:37 ` Niteesh G. S.
2021-08-19 17:38 ` [PATCH v4 4/7] python: Add entry point for aqmp-tui G S Niteesh Babu
2021-08-19 17:38 ` [PATCH v4 5/7] python: add optional pygments dependency G S Niteesh Babu
2021-08-19 17:38 ` [PATCH v4 6/7] python/aqmp-tui: Add syntax highlighting G S Niteesh Babu
2021-08-19 17:38 ` [PATCH v4 7/7] python/aqmp-tui: Add QMP connection manager G S Niteesh Babu
2021-08-21 4:09 ` [PATCH v4 0/7] AQMP TUI Draft John Snow
2021-08-21 21:20 ` Niteesh G. S.
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