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import contextlib
import itertools
import logging
import sys
import time
from typing import IO, Generator, Optional
from pip._internal.utils.compat import WINDOWS
from pip._internal.utils.logging import get_indentation
logger = logging.getLogger(__name__)
class SpinnerInterface:
def spin(self) -> None:
raise NotImplementedError()
def finish(self, final_status: str) -> None:
raise NotImplementedError()
class InteractiveSpinner(SpinnerInterface):
def __init__(
self,
message: str,
file: Optional[IO[str]] = None,
spin_chars: str = "-\\|/",
# Empirically, 8 updates/second looks nice
min_update_interval_seconds: float = 0.125,
):
self._message = message
if file is None:
file = sys.stdout
self._file = file
self._rate_limiter = RateLimiter(min_update_interval_seconds)
self._finished = False
self._spin_cycle = itertools.cycle(spin_chars)
self._file.write(" " * get_indentation() + self._message + " ... ")
self._width = 0
def _write(self, status: str) -> None:
assert not self._finished
# Erase what we wrote before by backspacing to the beginning, writing
# spaces to overwrite the old text, and then backspacing again
backup = "\b" * self._width
self._file.write(backup + " " * self._width + backup)
# Now we have a blank slate to add our status
self._file.write(status)
self._width = len(status)
self._file.flush()
self._rate_limiter.reset()
def spin(self) -> None:
if self._finished:
return
if not self._rate_limiter.ready():
return
self._write(next(self._spin_cycle))
def finish(self, final_status: str) -> None:
if self._finished:
return
self._write(final_status)
self._file.write("\n")
self._file.flush()
self._finished = True
# Used for dumb terminals, non-interactive installs (no tty), etc.
# We still print updates occasionally (once every 60 seconds by default) to
# act as a keep-alive for systems like Travis-CI that take lack-of-output as
# an indication that a task has frozen.
class NonInteractiveSpinner(SpinnerInterface):
def __init__(self, message: str, min_update_interval_seconds: float = 60.0) -> None:
self._message = message
self._finished = False
self._rate_limiter = RateLimiter(min_update_interval_seconds)
self._update("started")
def _update(self, status: str) -> None:
assert not self._finished
self._rate_limiter.reset()
logger.info("%s: %s", self._message, status)
def spin(self) -> None:
if self._finished:
return
if not self._rate_limiter.ready():
return
self._update("still running...")
def finish(self, final_status: str) -> None:
if self._finished:
return
self._update(f"finished with status '{final_status}'")
self._finished = True
class RateLimiter:
def __init__(self, min_update_interval_seconds: float) -> None:
self._min_update_interval_seconds = min_update_interval_seconds
self._last_update: float = 0
def ready(self) -> bool:
now = time.time()
delta = now - self._last_update
return delta >= self._min_update_interval_seconds
def reset(self) -> None:
self._last_update = time.time()
@contextlib.contextmanager
def open_spinner(message: str) -> Generator[SpinnerInterface, None, None]:
# Interactive spinner goes directly to sys.stdout rather than being routed
# through the logging system, but it acts like it has level INFO,
# i.e. it's only displayed if we're at level INFO or better.
# Non-interactive spinner goes through the logging system, so it is always
# in sync with logging configuration.
if sys.stdout.isatty() and logger.getEffectiveLevel() <= logging.INFO:
spinner: SpinnerInterface = InteractiveSpinner(message)
else:
spinner = NonInteractiveSpinner(message)
try:
with hidden_cursor(sys.stdout):
yield spinner
except KeyboardInterrupt:
spinner.finish("canceled")
raise
except Exception:
spinner.finish("error")
raise
else:
spinner.finish("done")
HIDE_CURSOR = "\x1b[?25l"
SHOW_CURSOR = "\x1b[?25h"
@contextlib.contextmanager
def hidden_cursor(file: IO[str]) -> Generator[None, None, None]:
# The Windows terminal does not support the hide/show cursor ANSI codes,
# even via colorama. So don't even try.
if WINDOWS:
yield
# We don't want to clutter the output with control characters if we're
# writing to a file, or if the user is running with --quiet.
# See https://github.com/pypa/pip/issues/3418
elif not file.isatty() or logger.getEffectiveLevel() > logging.INFO:
yield
else:
file.write(HIDE_CURSOR)
try:
yield
finally:
file.write(SHOW_CURSOR)
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