import sys
from threading import Event, RLock, Thread
from types import TracebackType
from typing import IO, Any, Callable, List, Optional, TextIO, Type, cast
from . import get_console
from .console import Console, ConsoleRenderable, RenderableType, RenderHook
from .control import Control
from .file_proxy import FileProxy
from .jupyter import JupyterMixin
from .live_render import LiveRender, VerticalOverflowMethod
from .screen import Screen
from .text import Text
class _RefreshThread(Thread):
"""A thread that calls refresh() at regular intervals."""
def __init__(self, live: "Live", refresh_per_second: float) -> None:
self.live = live
self.refresh_per_second = refresh_per_second
self.done = Event()
super().__init__(daemon=True)
def stop(self) -> None:
self.done.set()
def run(self) -> None:
while not self.done.wait(1 / self.refresh_per_second):
with self.live._lock:
if not self.done.is_set():
self.live.refresh()
[docs]class Live(JupyterMixin, RenderHook):
"""Renders an auto-updating live display of any given renderable.
Args:
renderable (RenderableType, optional): The renderable to live display. Defaults to displaying nothing.
console (Console, optional): Optional Console instance. Default will an internal Console instance writing to stdout.
screen (bool, optional): Enable alternate screen mode. Defaults to False.
auto_refresh (bool, optional): Enable auto refresh. If disabled, you will need to call `refresh()` or `update()` with refresh flag. Defaults to True
refresh_per_second (float, optional): Number of times per second to refresh the live display. Defaults to 4.
transient (bool, optional): Clear the renderable on exit (has no effect when screen=True). Defaults to False.
redirect_stdout (bool, optional): Enable redirection of stdout, so ``print`` may be used. Defaults to True.
redirect_stderr (bool, optional): Enable redirection of stderr. Defaults to True.
vertical_overflow (VerticalOverflowMethod, optional): How to handle renderable when it is too tall for the console. Defaults to "ellipsis".
get_renderable (Callable[[], RenderableType], optional): Optional callable to get renderable. Defaults to None.
"""
def __init__(
self,
renderable: Optional[RenderableType] = None,
*,
console: Optional[Console] = None,
screen: bool = False,
auto_refresh: bool = True,
refresh_per_second: float = 4,
transient: bool = False,
redirect_stdout: bool = True,
redirect_stderr: bool = True,
vertical_overflow: VerticalOverflowMethod = "ellipsis",
get_renderable: Optional[Callable[[], RenderableType]] = None,
) -> None:
assert refresh_per_second > 0, "refresh_per_second must be > 0"
self._renderable = renderable
self.console = console if console is not None else get_console()
self._screen = screen
self._alt_screen = False
self._redirect_stdout = redirect_stdout
self._redirect_stderr = redirect_stderr
self._restore_stdout: Optional[IO[str]] = None
self._restore_stderr: Optional[IO[str]] = None
self._lock = RLock()
self.ipy_widget: Optional[Any] = None
self.auto_refresh = auto_refresh
self._started: bool = False
self.transient = True if screen else transient
self._refresh_thread: Optional[_RefreshThread] = None
self.refresh_per_second = refresh_per_second
self.vertical_overflow = vertical_overflow
self._get_renderable = get_renderable
self._live_render = LiveRender(
self.get_renderable(), vertical_overflow=vertical_overflow
)
@property
def is_started(self) -> bool:
"""Check if live display has been started."""
return self._started
def get_renderable(self) -> RenderableType:
renderable = (
self._get_renderable()
if self._get_renderable is not None
else self._renderable
)
return renderable or ""
[docs] def start(self, refresh: bool = False) -> None:
"""Start live rendering display.
Args:
refresh (bool, optional): Also refresh. Defaults to False.
"""
with self._lock:
if self._started:
return
self.console.set_live(self)
self._started = True
if self._screen:
self._alt_screen = self.console.set_alt_screen(True)
self.console.show_cursor(False)
self._enable_redirect_io()
self.console.push_render_hook(self)
if refresh:
try:
self.refresh()
except Exception:
# If refresh fails, we want to stop the redirection of sys.stderr,
# so the error stacktrace is properly displayed in the terminal.
# (or, if the code that calls Rich captures the exception and wants to display something,
# let this be displayed in the terminal).
self.stop()
raise
if self.auto_refresh:
self._refresh_thread = _RefreshThread(self, self.refresh_per_second)
self._refresh_thread.start()
[docs] def stop(self) -> None:
"""Stop live rendering display."""
with self._lock:
if not self._started:
return
self.console.clear_live()
self._started = False
if self.auto_refresh and self._refresh_thread is not None:
self._refresh_thread.stop()
self._refresh_thread = None
# allow it to fully render on the last even if overflow
self.vertical_overflow = "visible"
with self.console:
try:
if not self._alt_screen and not self.console.is_jupyter:
self.refresh()
finally:
self._disable_redirect_io()
self.console.pop_render_hook()
if not self._alt_screen and self.console.is_terminal:
self.console.line()
self.console.show_cursor(True)
if self._alt_screen:
self.console.set_alt_screen(False)
if self.transient and not self._alt_screen:
self.console.control(self._live_render.restore_cursor())
if self.ipy_widget is not None and self.transient:
self.ipy_widget.close() # pragma: no cover
def __enter__(self) -> "Live":
self.start(refresh=self._renderable is not None)
return self
def __exit__(
self,
exc_type: Optional[Type[BaseException]],
exc_val: Optional[BaseException],
exc_tb: Optional[TracebackType],
) -> None:
self.stop()
def _enable_redirect_io(self) -> None:
"""Enable redirecting of stdout / stderr."""
if self.console.is_terminal or self.console.is_jupyter:
if self._redirect_stdout and not isinstance(sys.stdout, FileProxy):
self._restore_stdout = sys.stdout
sys.stdout = cast("TextIO", FileProxy(self.console, sys.stdout))
if self._redirect_stderr and not isinstance(sys.stderr, FileProxy):
self._restore_stderr = sys.stderr
sys.stderr = cast("TextIO", FileProxy(self.console, sys.stderr))
def _disable_redirect_io(self) -> None:
"""Disable redirecting of stdout / stderr."""
if self._restore_stdout:
sys.stdout = cast("TextIO", self._restore_stdout)
self._restore_stdout = None
if self._restore_stderr:
sys.stderr = cast("TextIO", self._restore_stderr)
self._restore_stderr = None
@property
def renderable(self) -> RenderableType:
"""Get the renderable that is being displayed
Returns:
RenderableType: Displayed renderable.
"""
renderable = self.get_renderable()
return Screen(renderable) if self._alt_screen else renderable
[docs] def update(self, renderable: RenderableType, *, refresh: bool = False) -> None:
"""Update the renderable that is being displayed
Args:
renderable (RenderableType): New renderable to use.
refresh (bool, optional): Refresh the display. Defaults to False.
"""
if isinstance(renderable, str):
renderable = self.console.render_str(renderable)
with self._lock:
self._renderable = renderable
if refresh:
self.refresh()
[docs] def refresh(self) -> None:
"""Update the display of the Live Render."""
with self._lock:
self._live_render.set_renderable(self.renderable)
if self.console.is_jupyter: # pragma: no cover
try:
from IPython.display import display
from ipywidgets import Output
except ImportError:
import warnings
warnings.warn('install "ipywidgets" for Jupyter support')
else:
if self.ipy_widget is None:
self.ipy_widget = Output()
display(self.ipy_widget)
with self.ipy_widget:
self.ipy_widget.clear_output(wait=True)
self.console.print(self._live_render.renderable)
elif self.console.is_terminal and not self.console.is_dumb_terminal:
with self.console:
self.console.print(Control())
elif (
not self._started and not self.transient
): # if it is finished allow files or dumb-terminals to see final result
with self.console:
self.console.print(Control())
[docs] def process_renderables(
self, renderables: List[ConsoleRenderable]
) -> List[ConsoleRenderable]:
"""Process renderables to restore cursor and display progress."""
self._live_render.vertical_overflow = self.vertical_overflow
if self.console.is_interactive:
# lock needs acquiring as user can modify live_render renderable at any time unlike in Progress.
with self._lock:
reset = (
Control.home()
if self._alt_screen
else self._live_render.position_cursor()
)
renderables = [reset, *renderables, self._live_render]
elif (
not self._started and not self.transient
): # if it is finished render the final output for files or dumb_terminals
renderables = [*renderables, self._live_render]
return renderables
if __name__ == "__main__": # pragma: no cover
import random
import time
from itertools import cycle
from typing import Dict, List, Tuple
from .align import Align
from .console import Console
from .live import Live as Live
from .panel import Panel
from .rule import Rule
from .syntax import Syntax
from .table import Table
console = Console()
syntax = Syntax(
'''def loop_last(values: Iterable[T]) -> Iterable[Tuple[bool, T]]:
"""Iterate and generate a tuple with a flag for last value."""
iter_values = iter(values)
try:
previous_value = next(iter_values)
except StopIteration:
return
for value in iter_values:
yield False, previous_value
previous_value = value
yield True, previous_value''',
"python",
line_numbers=True,
)
table = Table("foo", "bar", "baz")
table.add_row("1", "2", "3")
progress_renderables = [
"You can make the terminal shorter and taller to see the live table hide"
"Text may be printed while the progress bars are rendering.",
Panel("In fact, [i]any[/i] renderable will work"),
"Such as [magenta]tables[/]...",
table,
"Pretty printed structures...",
{"type": "example", "text": "Pretty printed"},
"Syntax...",
syntax,
Rule("Give it a try!"),
]
examples = cycle(progress_renderables)
exchanges = [
"SGD",
"MYR",
"EUR",
"USD",
"AUD",
"JPY",
"CNH",
"HKD",
"CAD",
"INR",
"DKK",
"GBP",
"RUB",
"NZD",
"MXN",
"IDR",
"TWD",
"THB",
"VND",
]
with Live(console=console) as live_table:
exchange_rate_dict: Dict[Tuple[str, str], float] = {}
for index in range(100):
select_exchange = exchanges[index % len(exchanges)]
for exchange in exchanges:
if exchange == select_exchange:
continue
time.sleep(0.4)
if random.randint(0, 10) < 1:
console.log(next(examples))
exchange_rate_dict[(select_exchange, exchange)] = 200 / (
(random.random() * 320) + 1
)
if len(exchange_rate_dict) > len(exchanges) - 1:
exchange_rate_dict.pop(list(exchange_rate_dict.keys())[0])
table = Table(title="Exchange Rates")
table.add_column("Source Currency")
table.add_column("Destination Currency")
table.add_column("Exchange Rate")
for ((source, dest), exchange_rate) in exchange_rate_dict.items():
table.add_row(
source,
dest,
Text(
f"{exchange_rate:.4f}",
style="red" if exchange_rate < 1.0 else "green",
),
)
live_table.update(Align.center(table))