log_timestamp_diff.py

#!/usr/bin/env python
import fileinput
import datetime

THRESHOLD = 50000
MARKER = "==> "
SPACER = " " * len(MARKER)


last_ts = None
for line in fileinput.input():
    ts_str, _, content = line.partition(" ")
    # Python <3.11 can't cope with the precision of these timestamps so strip the
    # final characters
    ts_str = ts_str[:-4]
    ts = datetime.datetime.fromisoformat(ts_str)
    delta = ts - last_ts if last_ts is not None else datetime.timedelta()
    diff = delta.seconds * 1000000 + delta.microseconds
    flag = MARKER if diff >= THRESHOLD else SPACER
    content = content[18:]
    print(f"{flag}{diff:05d} {content}", end="")
    last_ts = ts