Current File : //snap/core22/current/usr/share/subiquity/subiquitycore/tui.py
# Copyright 2020 Canonical, Ltd.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import asyncio
import inspect
import logging
import os
import signal
import urwid
import yaml
from subiquitycore.async_helpers import schedule_task
from subiquitycore.core import Application
from subiquitycore.palette import (
PALETTE_COLOR,
PALETTE_MONO,
)
from subiquitycore.screen import make_screen
from subiquitycore.tuicontroller import Skip
from subiquitycore.ui.utils import LoadingDialog
from subiquitycore.ui.frame import SubiquityCoreUI
from subiquitycore.utils import astart_command
log = logging.getLogger('subiquitycore.tui')
def extend_dec_special_charmap():
urwid.escape.DEC_SPECIAL_CHARMAP.update({
ord('\N{BLACK RIGHT-POINTING SMALL TRIANGLE}'): '>',
ord('\N{BLACK LEFT-POINTING SMALL TRIANGLE}'): '<',
ord('\N{BLACK DOWN-POINTING SMALL TRIANGLE}'): 'v',
ord('\N{BLACK UP-POINTING SMALL TRIANGLE}'): '^',
ord('\N{check mark}'): '+',
ord('\N{bullet}'): '*',
ord('\N{lower half block}'): '=',
ord('\N{upper half block}'): '=',
ord('\N{FULL BLOCK}'): urwid.escape.DEC_SPECIAL_CHARMAP[
ord('\N{BOX DRAWINGS LIGHT VERTICAL}')],
})
# When waiting for something of unknown duration, block the UI for at
# most this long before showing an indication of progress.
MAX_BLOCK_TIME = 0.1
# If an indication of progress is shown, show it for at least this
# long to avoid excessive flicker in the UI.
MIN_SHOW_PROGRESS_TIME = 1.0
class TuiApplication(Application):
make_ui = SubiquityCoreUI
def __init__(self, opts):
super().__init__(opts)
self.ui = self.make_ui()
self.answers = {}
if opts.answers is not None:
self.answers = yaml.safe_load(opts.answers.read())
log.debug("Loaded answers %s", self.answers)
if not opts.dry_run:
open('/run/casper-no-prompt', 'w').close()
# Set rich_mode to the opposite of what we want, so we can
# call toggle_rich to get the right things set up.
self.rich_mode = opts.run_on_serial
self.urwid_loop = None
self.cur_screen = None
self.fg_proc = None
def run_command_in_foreground(self, cmd, before_hook=None, after_hook=None,
**kw):
if self.fg_proc is not None:
raise Exception("cannot run two fg processes at once")
screen = self.urwid_loop.screen
async def _run():
self.fg_proc = proc = await astart_command(
cmd, stdin=None, stdout=None, stderr=None, **kw)
await proc.communicate()
self.fg_proc = None
# One of the main use cases for this function is to run interactive
# bash in a subshell. Interactive bash of course creates a process
# group for itself and sets it as the foreground process group for
# the controlling terminal. Usually on exit, our process group
# becomes the foreground process group again but when the subshell
# is killed for some reason it does not. This causes the tcsetattr
# that screen.start() does to either cause SIGTTOU to be sent, or
# if that is ignored (either because there is no shell around to do
# job control things or we are ignoring it) fail with EIO. So we
# force our process group back into the foreground with this
# call. That's not quite enough though because tcsetpgrp *also*
# causes SIGTTOU to be sent to a background process that calls it,
# but fortunately if we ignore that (done in start_urwid below),
# the call still succeeds.
#
# I would now like a drink.
os.tcsetpgrp(0, os.getpgrp())
screen.start()
if after_hook is not None:
after_hook()
screen.stop()
urwid.emit_signal(
screen, urwid.display_common.INPUT_DESCRIPTORS_CHANGED)
if before_hook is not None:
before_hook()
schedule_task(_run())
async def make_view_for_controller(self, new):
new.context.enter("starting UI")
if self.opts.screens and new.name not in self.opts.screens:
raise Skip
try:
maybe_view = new.make_ui()
if inspect.iscoroutine(maybe_view):
view = await maybe_view
else:
view = maybe_view
except Skip:
new.context.exit("(skipped)")
raise
else:
self.cur_screen = new
return view
async def _wait_with_indication(self, awaitable, show, hide=None):
"""Wait for something but tell the user if it takes a while.
When waiting for something that can take an unknown length of
time, we want to tell the user if it takes more than a moment
(defined as MAX_BLOCK_TIME) but make sure that we display any
indication for long enough that the UI is not flickering
incomprehensibly (MIN_SHOW_PROGRESS_TIME).
"""
min_show_task = None
def _show():
self.ui.block_input = False
nonlocal min_show_task
min_show_task = self.aio_loop.create_task(
asyncio.sleep(MIN_SHOW_PROGRESS_TIME))
show()
self.ui.block_input = True
show_handle = self.aio_loop.call_later(MAX_BLOCK_TIME, _show)
try:
result = await awaitable
finally:
if min_show_task:
await min_show_task
if hide is not None:
hide()
else:
self.ui.block_input = False
show_handle.cancel()
return result
def show_progress(self):
raise NotImplementedError
async def wait_with_text_dialog(self, awaitable, message,
*, can_cancel=False):
ld = None
task_to_cancel = None
if can_cancel:
if not isinstance(awaitable, asyncio.Task):
orig = awaitable
async def w():
return await orig
awaitable = task_to_cancel = self.aio_loop.create_task(w())
else:
task_to_cancel = None
def show_load():
nonlocal ld
ld = LoadingDialog(
self.ui.body, self.aio_loop, message, task_to_cancel)
self.ui.body.show_overlay(ld, width=ld.width)
def hide_load():
ld.close()
return await self._wait_with_indication(
awaitable, show_load, hide_load)
async def wait_with_progress(self, awaitable):
return await self._wait_with_indication(awaitable, self.show_progress)
async def _move_screen(self, increment, coro):
if coro is not None:
await coro
old, self.cur_screen = self.cur_screen, None
if old is not None:
old.context.exit("completed")
old.end_ui()
cur_index = self.controllers.index
while True:
self.controllers.index += increment
if self.controllers.index < 0:
self.controllers.index = cur_index
return None
if self.controllers.index >= len(self.controllers.instances):
self.exit()
return None
new = self.controllers.cur
try:
return await self.make_view_for_controller(new)
except Skip:
log.debug("skipping screen %s", new.name)
continue
except Exception:
self.controllers.index = cur_index
raise
else:
return
async def move_screen(self, increment, coro):
view = await self.wait_with_progress(
self._move_screen(increment, coro))
if view is not None:
self.ui.set_body(view)
def next_screen(self, coro=None):
self.aio_loop.create_task(self.move_screen(1, coro))
def prev_screen(self):
self.aio_loop.create_task(self.move_screen(-1, None))
def select_initial_screen(self):
self.next_screen()
def run_scripts(self, scripts):
# run_scripts runs (or rather arranges to run, it's all async)
# a series of python snippets in a helpful namespace. This is
# all in aid of being able to test some part of the UI without
# having to click the same buttons over and over again to get
# the UI to the part you are working on.
#
# In the namespace are:
# * everything from view_helpers
# * wait, delay execution of subsequent scripts for a while
# * c, a function that finds a button and clicks it. uses
# wait, above to wait for the button to appear in case it
# takes a while.
from subiquitycore.testing import view_helpers
class ScriptState:
def __init__(self):
self.ns = view_helpers.__dict__.copy()
self.waiting = False
self.wait_count = 0
self.scripts = scripts
ss = ScriptState()
def _run_script():
log.debug("running %s", ss.scripts[0])
exec(ss.scripts[0], ss.ns)
if ss.waiting:
return
ss.scripts = ss.scripts[1:]
if ss.scripts:
self.aio_loop.call_soon(_run_script)
def c(pat):
but = view_helpers.find_button_matching(self.ui, '.*' + pat + '.*')
if not but:
ss.wait_count += 1
if ss.wait_count > 10:
raise Exception("no button found matching %r after"
"waiting for 10 secs" % pat)
wait(1, func=lambda: c(pat))
return
ss.wait_count = 0
view_helpers.click(but)
def wait(delay, func=None):
ss.waiting = True
def next():
ss.waiting = False
if func is not None:
func()
if not ss.waiting:
ss.scripts = ss.scripts[1:]
if ss.scripts:
_run_script()
self.aio_loop.call_later(delay, next)
ss.ns['c'] = c
ss.ns['wait'] = wait
ss.ns['ui'] = self.ui
self.aio_loop.call_later(0.06, _run_script)
def set_rich(self, rich):
if rich == self.rich_mode:
return
self.toggle_rich()
def toggle_rich(self):
if self.rich_mode:
urwid.util.set_encoding('ascii')
new_palette = PALETTE_MONO
self.rich_mode = False
else:
urwid.util.set_encoding('utf-8')
new_palette = PALETTE_COLOR
self.rich_mode = True
urwid.CanvasCache.clear()
self.urwid_loop.screen.register_palette(new_palette)
self.urwid_loop.screen.clear()
def unhandled_input(self, key):
if self.opts.dry_run and key == 'ctrl x':
self.exit()
elif key == 'f3':
self.urwid_loop.screen.clear()
elif self.opts.run_on_serial and key in ['ctrl t', 'f4']:
self.toggle_rich()
def extra_urwid_loop_args(self):
return {}
def make_screen(self, inputf=None, outputf=None):
return make_screen(self.opts.ascii, inputf, outputf)
def start_urwid(self, input=None, output=None):
# This stops the tcsetpgrp call in run_command_in_foreground from
# suspending us. See the rant there for more details.
signal.signal(signal.SIGTTOU, signal.SIG_IGN)
screen = self.make_screen(input, output)
screen.register_palette(PALETTE_COLOR)
self.urwid_loop = urwid.MainLoop(
self.ui, screen=screen,
handle_mouse=False, pop_ups=True,
unhandled_input=self.unhandled_input,
event_loop=urwid.AsyncioEventLoop(loop=self.aio_loop),
**self.extra_urwid_loop_args()
)
extend_dec_special_charmap()
self.toggle_rich()
self.urwid_loop.start()
self.select_initial_screen()
async def start(self, start_urwid=True):
await super().start()
if start_urwid:
self.start_urwid()
def run(self):
if self.opts.scripts:
self.run_scripts(self.opts.scripts)
try:
super().run()
finally:
if self.urwid_loop is not None:
self.urwid_loop.stop()
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