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  1. from __future__ import annotations
  2. import sys
  3. from threading import Event, RLock, Thread
  4. from types import TracebackType
  5. from typing import IO, TYPE_CHECKING, Any, Callable, List, Optional, TextIO, Type, cast
  6. from . import get_console
  7. from .console import Console, ConsoleRenderable, Group, RenderableType, RenderHook
  8. from .control import Control
  9. from .file_proxy import FileProxy
  10. from .jupyter import JupyterMixin
  11. from .live_render import LiveRender, VerticalOverflowMethod
  12. from .screen import Screen
  13. from .text import Text
  14. if TYPE_CHECKING:
  15. # Can be replaced with `from typing import Self` in Python 3.11+
  16. from typing_extensions import Self # pragma: no cover
  17. class _RefreshThread(Thread):
  18. """A thread that calls refresh() at regular intervals."""
  19. def __init__(self, live: "Live", refresh_per_second: float) -> None:
  20. self.live = live
  21. self.refresh_per_second = refresh_per_second
  22. self.done = Event()
  23. super().__init__(daemon=True)
  24. def stop(self) -> None:
  25. self.done.set()
  26. def run(self) -> None:
  27. while not self.done.wait(1 / self.refresh_per_second):
  28. with self.live._lock:
  29. if not self.done.is_set():
  30. self.live.refresh()
  31. class Live(JupyterMixin, RenderHook):
  32. """Renders an auto-updating live display of any given renderable.
  33. Args:
  34. renderable (RenderableType, optional): The renderable to live display. Defaults to displaying nothing.
  35. console (Console, optional): Optional Console instance. Defaults to an internal Console instance writing to stdout.
  36. screen (bool, optional): Enable alternate screen mode. Defaults to False.
  37. auto_refresh (bool, optional): Enable auto refresh. If disabled, you will need to call `refresh()` or `update()` with refresh flag. Defaults to True
  38. refresh_per_second (float, optional): Number of times per second to refresh the live display. Defaults to 4.
  39. transient (bool, optional): Clear the renderable on exit (has no effect when screen=True). Defaults to False.
  40. redirect_stdout (bool, optional): Enable redirection of stdout, so ``print`` may be used. Defaults to True.
  41. redirect_stderr (bool, optional): Enable redirection of stderr. Defaults to True.
  42. vertical_overflow (VerticalOverflowMethod, optional): How to handle renderable when it is too tall for the console. Defaults to "ellipsis".
  43. get_renderable (Callable[[], RenderableType], optional): Optional callable to get renderable. Defaults to None.
  44. """
  45. def __init__(
  46. self,
  47. renderable: Optional[RenderableType] = None,
  48. *,
  49. console: Optional[Console] = None,
  50. screen: bool = False,
  51. auto_refresh: bool = True,
  52. refresh_per_second: float = 4,
  53. transient: bool = False,
  54. redirect_stdout: bool = True,
  55. redirect_stderr: bool = True,
  56. vertical_overflow: VerticalOverflowMethod = "ellipsis",
  57. get_renderable: Optional[Callable[[], RenderableType]] = None,
  58. ) -> None:
  59. assert refresh_per_second > 0, "refresh_per_second must be > 0"
  60. self._renderable = renderable
  61. self.console = console if console is not None else get_console()
  62. self._screen = screen
  63. self._alt_screen = False
  64. self._redirect_stdout = redirect_stdout
  65. self._redirect_stderr = redirect_stderr
  66. self._restore_stdout: Optional[IO[str]] = None
  67. self._restore_stderr: Optional[IO[str]] = None
  68. self._lock = RLock()
  69. self.ipy_widget: Optional[Any] = None
  70. self.auto_refresh = auto_refresh
  71. self._started: bool = False
  72. self.transient = True if screen else transient
  73. self._refresh_thread: Optional[_RefreshThread] = None
  74. self.refresh_per_second = refresh_per_second
  75. self.vertical_overflow = vertical_overflow
  76. self._get_renderable = get_renderable
  77. self._live_render = LiveRender(
  78. self.get_renderable(), vertical_overflow=vertical_overflow
  79. )
  80. self._nested = False
  81. @property
  82. def is_started(self) -> bool:
  83. """Check if live display has been started."""
  84. return self._started
  85. def get_renderable(self) -> RenderableType:
  86. renderable = (
  87. self._get_renderable()
  88. if self._get_renderable is not None
  89. else self._renderable
  90. )
  91. return renderable or ""
  92. def start(self, refresh: bool = False) -> None:
  93. """Start live rendering display.
  94. Args:
  95. refresh (bool, optional): Also refresh. Defaults to False.
  96. """
  97. with self._lock:
  98. if self._started:
  99. return
  100. self._started = True
  101. if not self.console.set_live(self):
  102. self._nested = True
  103. return
  104. if self._screen:
  105. self._alt_screen = self.console.set_alt_screen(True)
  106. self.console.show_cursor(False)
  107. self._enable_redirect_io()
  108. self.console.push_render_hook(self)
  109. if refresh:
  110. try:
  111. self.refresh()
  112. except Exception:
  113. # If refresh fails, we want to stop the redirection of sys.stderr,
  114. # so the error stacktrace is properly displayed in the terminal.
  115. # (or, if the code that calls Rich captures the exception and wants to display something,
  116. # let this be displayed in the terminal).
  117. self.stop()
  118. raise
  119. if self.auto_refresh:
  120. self._refresh_thread = _RefreshThread(self, self.refresh_per_second)
  121. self._refresh_thread.start()
  122. def stop(self) -> None:
  123. """Stop live rendering display."""
  124. with self._lock:
  125. if not self._started:
  126. return
  127. self._started = False
  128. self.console.clear_live()
  129. if self._nested:
  130. if not self.transient:
  131. self.console.print(self.renderable)
  132. return
  133. if self.auto_refresh and self._refresh_thread is not None:
  134. self._refresh_thread.stop()
  135. self._refresh_thread = None
  136. # allow it to fully render on the last even if overflow
  137. self.vertical_overflow = "visible"
  138. with self.console:
  139. try:
  140. if not self._alt_screen and not self.console.is_jupyter:
  141. self.refresh()
  142. finally:
  143. self._disable_redirect_io()
  144. self.console.pop_render_hook()
  145. if not self._alt_screen and self.console.is_terminal:
  146. self.console.line()
  147. self.console.show_cursor(True)
  148. if self._alt_screen:
  149. self.console.set_alt_screen(False)
  150. if self.transient and not self._alt_screen:
  151. self.console.control(self._live_render.restore_cursor())
  152. if self.ipy_widget is not None and self.transient:
  153. self.ipy_widget.close() # pragma: no cover
  154. def __enter__(self) -> Self:
  155. self.start(refresh=self._renderable is not None)
  156. return self
  157. def __exit__(
  158. self,
  159. exc_type: Optional[Type[BaseException]],
  160. exc_val: Optional[BaseException],
  161. exc_tb: Optional[TracebackType],
  162. ) -> None:
  163. self.stop()
  164. def _enable_redirect_io(self) -> None:
  165. """Enable redirecting of stdout / stderr."""
  166. if self.console.is_terminal or self.console.is_jupyter:
  167. if self._redirect_stdout and not isinstance(sys.stdout, FileProxy):
  168. self._restore_stdout = sys.stdout
  169. sys.stdout = cast("TextIO", FileProxy(self.console, sys.stdout))
  170. if self._redirect_stderr and not isinstance(sys.stderr, FileProxy):
  171. self._restore_stderr = sys.stderr
  172. sys.stderr = cast("TextIO", FileProxy(self.console, sys.stderr))
  173. def _disable_redirect_io(self) -> None:
  174. """Disable redirecting of stdout / stderr."""
  175. if self._restore_stdout:
  176. sys.stdout = cast("TextIO", self._restore_stdout)
  177. self._restore_stdout = None
  178. if self._restore_stderr:
  179. sys.stderr = cast("TextIO", self._restore_stderr)
  180. self._restore_stderr = None
  181. @property
  182. def renderable(self) -> RenderableType:
  183. """Get the renderable that is being displayed
  184. Returns:
  185. RenderableType: Displayed renderable.
  186. """
  187. live_stack = self.console._live_stack
  188. renderable: RenderableType
  189. if live_stack and self is live_stack[0]:
  190. # The first Live instance will render everything in the Live stack
  191. renderable = Group(*[live.get_renderable() for live in live_stack])
  192. else:
  193. renderable = self.get_renderable()
  194. return Screen(renderable) if self._alt_screen else renderable
  195. def update(self, renderable: RenderableType, *, refresh: bool = False) -> None:
  196. """Update the renderable that is being displayed
  197. Args:
  198. renderable (RenderableType): New renderable to use.
  199. refresh (bool, optional): Refresh the display. Defaults to False.
  200. """
  201. if isinstance(renderable, str):
  202. renderable = self.console.render_str(renderable)
  203. with self._lock:
  204. self._renderable = renderable
  205. if refresh:
  206. self.refresh()
  207. def refresh(self) -> None:
  208. """Update the display of the Live Render."""
  209. with self._lock:
  210. self._live_render.set_renderable(self.renderable)
  211. if self._nested:
  212. if self.console._live_stack:
  213. self.console._live_stack[0].refresh()
  214. return
  215. if self.console.is_jupyter: # pragma: no cover
  216. try:
  217. from IPython.display import display
  218. from ipywidgets import Output
  219. except ImportError:
  220. import warnings
  221. warnings.warn('install "ipywidgets" for Jupyter support')
  222. else:
  223. if self.ipy_widget is None:
  224. self.ipy_widget = Output()
  225. display(self.ipy_widget)
  226. with self.ipy_widget:
  227. self.ipy_widget.clear_output(wait=True)
  228. self.console.print(self._live_render.renderable)
  229. elif self.console.is_terminal and not self.console.is_dumb_terminal:
  230. with self.console:
  231. self.console.print(Control())
  232. elif (
  233. not self._started and not self.transient
  234. ): # if it is finished allow files or dumb-terminals to see final result
  235. with self.console:
  236. self.console.print(Control())
  237. def process_renderables(
  238. self, renderables: List[ConsoleRenderable]
  239. ) -> List[ConsoleRenderable]:
  240. """Process renderables to restore cursor and display progress."""
  241. self._live_render.vertical_overflow = self.vertical_overflow
  242. if self.console.is_interactive:
  243. # lock needs acquiring as user can modify live_render renderable at any time unlike in Progress.
  244. with self._lock:
  245. reset = (
  246. Control.home()
  247. if self._alt_screen
  248. else self._live_render.position_cursor()
  249. )
  250. renderables = [reset, *renderables, self._live_render]
  251. elif (
  252. not self._started and not self.transient
  253. ): # if it is finished render the final output for files or dumb_terminals
  254. renderables = [*renderables, self._live_render]
  255. return renderables
  256. if __name__ == "__main__": # pragma: no cover
  257. import random
  258. import time
  259. from itertools import cycle
  260. from typing import Dict, List, Tuple
  261. from .align import Align
  262. from .console import Console
  263. from .live import Live as Live
  264. from .panel import Panel
  265. from .rule import Rule
  266. from .syntax import Syntax
  267. from .table import Table
  268. console = Console()
  269. syntax = Syntax(
  270. '''def loop_last(values: Iterable[T]) -> Iterable[Tuple[bool, T]]:
  271. """Iterate and generate a tuple with a flag for last value."""
  272. iter_values = iter(values)
  273. try:
  274. previous_value = next(iter_values)
  275. except StopIteration:
  276. return
  277. for value in iter_values:
  278. yield False, previous_value
  279. previous_value = value
  280. yield True, previous_value''',
  281. "python",
  282. line_numbers=True,
  283. )
  284. table = Table("foo", "bar", "baz")
  285. table.add_row("1", "2", "3")
  286. progress_renderables = [
  287. "You can make the terminal shorter and taller to see the live table hide"
  288. "Text may be printed while the progress bars are rendering.",
  289. Panel("In fact, [i]any[/i] renderable will work"),
  290. "Such as [magenta]tables[/]...",
  291. table,
  292. "Pretty printed structures...",
  293. {"type": "example", "text": "Pretty printed"},
  294. "Syntax...",
  295. syntax,
  296. Rule("Give it a try!"),
  297. ]
  298. examples = cycle(progress_renderables)
  299. exchanges = [
  300. "SGD",
  301. "MYR",
  302. "EUR",
  303. "USD",
  304. "AUD",
  305. "JPY",
  306. "CNH",
  307. "HKD",
  308. "CAD",
  309. "INR",
  310. "DKK",
  311. "GBP",
  312. "RUB",
  313. "NZD",
  314. "MXN",
  315. "IDR",
  316. "TWD",
  317. "THB",
  318. "VND",
  319. ]
  320. with Live(console=console) as live_table:
  321. exchange_rate_dict: Dict[Tuple[str, str], float] = {}
  322. for index in range(100):
  323. select_exchange = exchanges[index % len(exchanges)]
  324. for exchange in exchanges:
  325. if exchange == select_exchange:
  326. continue
  327. time.sleep(0.4)
  328. if random.randint(0, 10) < 1:
  329. console.log(next(examples))
  330. exchange_rate_dict[(select_exchange, exchange)] = 200 / (
  331. (random.random() * 320) + 1
  332. )
  333. if len(exchange_rate_dict) > len(exchanges) - 1:
  334. exchange_rate_dict.pop(list(exchange_rate_dict.keys())[0])
  335. table = Table(title="Exchange Rates")
  336. table.add_column("Source Currency")
  337. table.add_column("Destination Currency")
  338. table.add_column("Exchange Rate")
  339. for (source, dest), exchange_rate in exchange_rate_dict.items():
  340. table.add_row(
  341. source,
  342. dest,
  343. Text(
  344. f"{exchange_rate:.4f}",
  345. style="red" if exchange_rate < 1.0 else "green",
  346. ),
  347. )
  348. live_table.update(Align.center(table))