pferd/PFERD/progress.py

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2020-05-08 00:26:33 +02:00
"""
A small progress bar implementation.
"""
import sys
from dataclasses import dataclass
from types import TracebackType
from typing import Optional, Type
import requests
from rich.console import Console, ConsoleOptions, Control, RenderResult
from rich.live_render import LiveRender
from rich.progress import (BarColumn, DownloadColumn, Progress, TaskID,
TextColumn, TimeRemainingColumn,
TransferSpeedColumn)
_progress: Progress = Progress(
TextColumn("[bold blue]{task.fields[name]}", justify="right"),
BarColumn(bar_width=None),
"[progress.percentage]{task.percentage:>3.1f}%",
"",
DownloadColumn(),
"",
TransferSpeedColumn(),
"",
TimeRemainingColumn(),
console=Console(file=sys.stdout)
)
def size_from_headers(response: requests.Response) -> Optional[int]:
"""
Return the size of the download based on the response headers.
Arguments:
response {requests.Response} -- the response
Returns:
Optional[int] -- the size
"""
if "Content-Length" in response.headers:
return int(response.headers["Content-Length"])
return None
@dataclass
class ProgressSettings:
"""
Settings you can pass to customize the progress bar.
"""
name: str
max_size: int
def progress_for(settings: Optional[ProgressSettings]) -> 'ProgressContextManager':
"""
Returns a context manager that displays progress
Returns:
ProgressContextManager -- the progress manager
"""
return ProgressContextManager(settings)
class _OneLineUp(LiveRender):
"""
Render a control code for moving one line upwards.
"""
def __init__(self) -> None:
super().__init__("not rendered")
def __console__(self, console: Console, options: ConsoleOptions) -> RenderResult:
yield Control(f"\r\x1b[1A")
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class ProgressContextManager:
"""
A context manager used for displaying progress.
"""
def __init__(self, settings: Optional[ProgressSettings]):
self._settings = settings
self._task_id: Optional[TaskID] = None
def __enter__(self) -> 'ProgressContextManager':
"""Context manager entry function."""
if not self._settings:
return self
_progress.start()
self._task_id = _progress.add_task(
self._settings.name,
total=self._settings.max_size,
name=self._settings.name
)
return self
# pylint: disable=useless-return
def __exit__(
self,
exc_type: Optional[Type[BaseException]],
exc_value: Optional[BaseException],
traceback: Optional[TracebackType],
) -> Optional[bool]:
"""Context manager exit function. Removes the task."""
if self._task_id is None:
return None
_progress.remove_task(self._task_id)
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if len(_progress.task_ids) == 0:
# We need to clean up after ourselves, as we were the last one
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_progress.stop()
_progress.refresh()
# And we existed, so remove the line above (remove_task leaves one behind)
Console().print(_OneLineUp())
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return None
def advance(self, amount: float) -> None:
"""
Advances the progress bar.
"""
if self._task_id is not None:
_progress.advance(self._task_id, amount)