time estimator script

impatient

@@ -0,0 +1,90 @@
+#!/usr/bin/env python3
+
+import argparse
+import datetime
+import subprocess
+import time
+
+WINDOW_SIZE = 100
+
+SUFFIXES = 'KMGT'
+
+parser = argparse.ArgumentParser(description='Display progress and time estimates for arbitrary tasks')
+parser.add_argument('-f', '--final', type=str, help='Expected final size/value at completion.')
+parser.add_argument('-i', '--interval', type=int, default=10, help='Interval in seconds between samples (default 10)')
+tracker_types = parser.add_mutually_exclusive_group(required=True)
+tracker_types.add_argument('-p', '--path', type=str, help='Track total disk usage of a given path')
+tracker_types.add_argument('-c', '--command', type=str, help='Track value returned by a shell command; this should return a single number, optionally followed by K/M/G/T')
+
+args = parser.parse_args()
+
+def parse_value(v):
+    suffix = v[-1].upper()
+    if suffix in SUFFIXES:
+        exponent = 3*(SUFFIXES.find(suffix)+1)
+        return int(v[:-1])*(10**exponent)
+    else:
+        return int(v)
+
+def display_value(v):
+    suffix = ''
+    for c in SUFFIXES:
+        if v < 10**3:
+            break
+        v = v / 10**3
+        suffix = c
+    return '{:.1f}{}'.format(v, suffix)
+
+def display_timedelta(d):
+    result = ''
+    if d.days != 0:
+        result += '{}d'.format(d.days)
+    result += '{}h'.format(d.seconds // 3600)
+    result += '{}m'.format((d.seconds % 3600) // 60)
+    return result
+
+if args.path:
+    def current_val():
+        du = subprocess.run(['du', '--bytes', '--summarize', args.path], capture_output=True, text=True).stdout
+        return parse_value(du.split()[0])
+else:
+    def current_val():
+        result = subprocess.run(args.command, shell=True, capture_output=True, text=True).stdout
+        return parse_value(result.strip())
+
+if args.final:
+    final = parse_value(args.final)
+else:
+    final = None
+
+samples = [current_val()]
+while True:
+    time.sleep(args.interval)
+
+    current = current_val()
+
+    samples.append(current)
+    if len(samples) < 2:
+        continue
+    if len(samples) > WINDOW_SIZE:
+        samples = samples[-WINDOW_SIZE:]
+
+    rate = (current - samples[0])/((len(samples)-1)*args.interval)
+
+    print('\033[2K\r', end='')
+    print('{} - {}/s'.format(display_value(current), display_value(rate)), end='', flush=True)
+    if final:
+        fraction = current / final
+        value_remaining = final - current
+        time_remaining = datetime.timedelta(seconds=(value_remaining / rate))
+        eta = datetime.datetime.now() + time_remaining
+        print(' - {} total - {:.1f}% complete - {} remaining - ETA {}'.format(
+            display_value(final),
+            100*fraction,
+            display_timedelta(time_remaining),
+            eta.isoformat(sep=' ', timespec='minutes'),
+        ), end='', flush=True)
+
+    if final and current >= final:
+        print()
+        break