Progress bar for anything

progress.py

#!/usr/bin/env python3

"""
Get a progress bar for anything.

Feed this script a line containing two numbers on standard input as often or
infrequently as you like.

It will give you a progress bar and, once at least two readings have been taken,
estimated time remaining.

Example for rough progress on a long copy operation, where all files are roughly
equal:

total=$(find src-dir -type f | wc -l); while sleep 5; do echo $(find dest-dir -type f | wc l) $total; done | python3 progress.py
"""

from sys import stdin, stdout
from collections import deque
from datetime import datetime, timedelta
from shutil import get_terminal_size

READINGS_MAX = 10

latest = deque([])

for line in stdin:
	# Get status
	try:
		current, total = [int(x) for x in line.split()]
	except ValueError:
		stdout.write("Expected two whitespace-separated values: current, total\n")
		continue

	dt = datetime.now()
	progress = current / total

	# How long is the total
	totalChars = len(str(total))

	# Calculate remaining time if possible
	remainingTime = None
	if len(latest):
		refDt, refCurrent, refTotal = latest.popleft() if len(latest) >= READINGS_MAX else latest[0]
		todo = total - current
		elapsed = dt - refDt
		done = current - refCurrent

		if done == 0:
			remainingTime = "stalled"
		else:
			remainingTime = todo * elapsed / done
			# Round to seconds
			remainingTime -= timedelta(microseconds=remainingTime.microseconds)

	# Prepare status
	line = f"{current:>{totalChars}}/{total}: {int(progress*100):3d}% []"

	# Add remaining time if we have it
	if remainingTime is not None:
		line += f" {remainingTime}"

	# Add the progress bar
	remainingWidth = get_terminal_size((80, 20))[0] - len(line)
	bar = "=" * int(progress * remainingWidth)
	line = line.replace("[]", f"[{bar:{remainingWidth}}]")

	# Clear line and write to output
	stdout.write("%c[2K\r" % 27)
	stdout.write(line)

	# Flush output
	stdout.flush()

	# Remember this progress so we can make time predictions
	latest.append((dt, current, total))