######################################################################
#
# File: b2sdk/_internal/progress.py
#
# Copyright 2019 Backblaze Inc. All Rights Reserved.
#
# License https://www.backblaze.com/using_b2_code.html
#
######################################################################
from __future__ import annotations
import time
from abc import ABCMeta, abstractmethod
from .utils.escape import escape_control_chars
try:
from tqdm import tqdm # displays a nice progress bar
except ImportError:
tqdm = None # noqa
[docs]class AbstractProgressListener(metaclass=ABCMeta):
"""
Interface expected by B2Api upload and download methods to report
on progress.
This interface just accepts the number of bytes transferred so far.
Subclasses will need to know the total size if they want to report
a percent done.
"""
def __init__(self, description: str = ''):
self.description = description
self._closed = False
[docs] @abstractmethod
def set_total_bytes(self, total_byte_count: int) -> None:
"""
Always called before __enter__ to set the expected total number of bytes.
May be called more than once if an upload is retried.
:param total_byte_count: expected total number of bytes
"""
[docs] @abstractmethod
def bytes_completed(self, byte_count: int) -> None:
"""
Report the given number of bytes that have been transferred
so far. This is not a delta, it is the total number of bytes
transferred so far.
Transfer can fail and restart from the beginning, so byte count can
decrease between calls.
:param byte_count: number of bytes have been transferred
"""
def _can_change_description(self) -> bool:
"""
Determines, on a per-implementation basis, whether the description can be changed at this time.
"""
return True
[docs] def change_description(self, new_description: str) -> bool:
"""
Ability to change the description after the listener is started.
Note: whether the change of description is allowed depends on the implementation.
The safest option is to change the description before setting the total bytes.
:param new_description: the new description to be used
:return: information whether the description was changed
"""
if not self._can_change_description():
return False
self.description = new_description
return True
[docs] def close(self) -> None:
"""
Must be called when you're done with the listener.
In well-structured code, should be called only once.
"""
#import traceback, sys; traceback.print_stack(file=sys.stdout)
assert self._closed is False, 'progress listener was closed twice! uncomment the line above to debug this'
self._closed = True
def __enter__(self):
"""
A standard context manager method.
"""
return self
def __exit__(self, exc_type, exc_val, exc_tb):
"""
A standard context manager method.
"""
self.close()
[docs]class TqdmProgressListener(AbstractProgressListener):
"""
Progress listener based on tqdm library.
This listener displays a nice progress bar, but requires `tqdm` package to be installed.
"""
def __init__(self, *args, **kwargs):
if tqdm is None:
raise ModuleNotFoundError("No module named 'tqdm' found")
self.tqdm = None # set in set_total_bytes()
self.prev_value = 0
super().__init__(*args, **kwargs)
def set_total_bytes(self, total_byte_count: int) -> None:
if self.tqdm is None:
self.tqdm = tqdm(
desc=escape_control_chars(self.description),
total=total_byte_count,
unit='B',
unit_scale=True,
leave=True,
miniters=1,
smoothing=0.1,
mininterval=0.2,
)
def bytes_completed(self, byte_count: int) -> None:
# tqdm doesn't support running the progress bar backwards,
# so on an upload retry, it just won't move until it gets
# past the point where it failed.
if self.prev_value < byte_count:
self.tqdm.update(byte_count - self.prev_value)
self.prev_value = byte_count
def _can_change_description(self) -> bool:
return self.tqdm is None
def close(self) -> None:
if self.tqdm is not None:
self.tqdm.close()
super().close()
[docs]class SimpleProgressListener(AbstractProgressListener):
"""
Just a simple progress listener which prints info on a console.
"""
def __init__(self, *args, **kwargs):
self.complete = 0
self.last_time = time.time()
self.any_printed = False
self.total = 0 # set in set_total_bytes()
super().__init__(*args, **kwargs)
def set_total_bytes(self, total_byte_count: int) -> None:
self.total = total_byte_count
def bytes_completed(self, byte_count: int) -> None:
now = time.time()
elapsed = now - self.last_time
if 3 <= elapsed and self.total != 0:
if not self.any_printed:
print(escape_control_chars(self.description))
print(' %d%%' % int(100.0 * byte_count / self.total))
self.last_time = now
self.any_printed = True
def _can_change_description(self) -> bool:
return not self.any_printed
def close(self) -> None:
if self.any_printed:
print(' DONE.')
super().close()
[docs]class DoNothingProgressListener(AbstractProgressListener):
"""
This listener gives no output whatsoever.
"""
def set_total_bytes(self, total_byte_count: int) -> None:
pass
def bytes_completed(self, byte_count: int) -> None:
pass
[docs]class ProgressListenerForTest(AbstractProgressListener):
"""
Capture all the calls so they can be checked.
"""
def __init__(self, *args, **kwargs):
self.calls = []
super().__init__(*args, **kwargs)
def set_total_bytes(self, total_byte_count: int) -> None:
self.calls.append('set_total_bytes(%d)' % (total_byte_count,))
def bytes_completed(self, byte_count: int) -> None:
self.calls.append('bytes_completed(%d)' % (byte_count,))
def close(self) -> None:
self.calls.append('close()')
super().close()
def get_calls(self) -> list[str]:
return self.calls
[docs]def make_progress_listener(description: str, quiet: bool) -> AbstractProgressListener:
"""
Produce the best progress listener available for the given parameters.
:param description: listener description
:param quiet: if ``True``, do not output anything
:return: a listener object
"""
if quiet:
return DoNothingProgressListener()
elif tqdm is not None:
return TqdmProgressListener(description)
else:
return SimpleProgressListener(description)