pyppin.text.print_counter

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A context manager that prints regular updates of a task’s progress.

Classes

PrintCounter([print_every_n, ...])

A PrintCounter is a context manager that prints regular updates of progress.
class pyppin.text.print_counter.PrintCounter(print_every_n: Optional[Union[int, float]] = 10000, print_every_time: Optional[timedelta] = datetime.timedelta(seconds=30), format: str = 'Count: {count:si} after {time:td}', final_format: Optional[str] = 'Final: {count} after {time:td}', start: Optional[datetime] = None, stream: Optional[TextIOBase] = None)[source]

Bases: object

A PrintCounter is a context manager that prints regular updates of progress.

It prints the updates on separate lines, without any VT100 formatting or the like, so it’s useful in situations where you’re writing log files as well as on the console.

Its use is simple:

with PrintCounter() as counter:
    ... do some big loop and occasionally call
    counter.inc()

Every N calls to counter.inc(), or whenever at least Δ time has passed since the last call to inc(), it will print out an update statement. The use of both count and time lets you edeasily monitor both fast and slow operations and always get useful feedback.

You can also have “custom counters” by adding keyword arguments to inc(). These counters are available in your format string as well to print out, but (unlike the primary counter) they will not trigger printing.

Parameters

  • print_every_n – If not None, print whenever it’s been at least N counts since the last print happened.

  • print_every_time – If not None, print whenever it’s been at least X time since the last print happened.

  • format –

    The string to print out. This is a standard Python format string, which receives the arguments:

    • count: int or float, the current count

    • time: timedelta, the total elapsed time

    • Any custom counts you created, int or float.

  • final_format – If given, the format to be used for the final print string. If None, equal to ‘format’. Note that the default deliberately uses the raw format for count, not the SI one, so you get an exact final count!

  • start – The zero time for measurement; the default is now.

  • stream – Where to print the result to, or None to print to stdout.

Example

Say you’re transferring a bunch of files, and want to show progress on both bytes and files. You decide you want the primary trigger of status updates to be when bytes sent moves, rather than number of files, since individual files are probably big. So you do this:

with PrintCounter(
    format='Transferred {files} files ({count:sib}B) in {time:td} ({size/time.seconds():sib}B/s)',
) as counter:
    for file in files:
        for chunk in file:
            bytes_sent = send_some_data(chunk)
            counter.inc(bytes_sent)

        counter.inc(0, files=1)  # Implement the file counter alone

Note the format strings like :sib and :td being used here – you can find out more about those in pyppin.text.formatter.

inc(count: Union[int, float] = 1, **custom: Union[int, float]) → None[source]

Increment the counter.

Parameters

  • count – The amount by which to increment the primary counter.

  • **custom – Any number of custom counters you would also like to increment.