time_render.py

#!/usr/bin/env python3

"""
time_render: render time as given on cmdline

Convert epoch time (default) to something human-readable.
Handle obscenely large numbers.
"""

# DNS uses u_int48_t (for TSIG) which is seconds since Unix epoch.
# That means we need to scale up to taking: 281474976710655

__author__ = 'phil.pennock@spodhuis.org (Phil Pennock)'

import argparse
import sys
import time

_DEF_TIMEFMT = '%Y-%m-%dT%H:%M:%S %z (%c %Z)'


class Error(Exception):
    """Base class for exceptions from time_render."""
    pass


class Time(object):
    def __init__(self, spec, options):
        try:
            self.unix_epoch = int(spec)
        except ValueError:
            self.unix_epoch = float(spec)

        if options.nanoseconds:
            self.unix_epoch = float(self.unix_epoch) / 1000000000
        elif options.microseconds:
            self.unix_epoch = float(self.unix_epoch) / 1000000
        elif options.milliseconds:
            self.unix_epoch = float(self.unix_epoch) / 1000

        self.fmt_spec = options.format

    def _as_time(self):
        return time.localtime(self.unix_epoch)

    def Render(self, out):
        print(time.strftime(self.fmt_spec, self._as_time()), file=out)


def _main(args, argv0):
    parser = argparse.ArgumentParser(
        description=__doc__,
        formatter_class=argparse.RawDescriptionHelpFormatter)
    parser.add_argument('-f', '--format',
                        default=_DEF_TIMEFMT,
                        help='Specify output format')
    parser.add_argument('--ms',
                        dest='milliseconds', default=False, action='store_true',
                        help='times are in milliseconds')
    parser.add_argument('--us',
                        dest='microseconds', default=False, action='store_true',
                        help='times are in microseconds')
    parser.add_argument('--ns',
                        dest='nanoseconds', default=False, action='store_true',
                        help='times are in nanoseconds')
    parser.add_argument('input_times', nargs='+',
                        help='timestamps to convert')
    options = parser.parse_args(args=args)
    for t in options.input_times:
        tl = t.lower()
        if tl == 'ns':
            options.milliseconds = False
            options.microseconds = False
            options.nanoseconds = True
            continue
        elif tl == 'us' or tl == 'μs':
            options.milliseconds = False
            options.microseconds = True
            options.nanoseconds = False
            continue
        elif tl == 'ms':
            options.milliseconds = True
            options.microseconds = False
            options.nanoseconds = False
            continue
        elif tl == 's' or tl == 'seconds':
            options.milliseconds = False
            options.microseconds = False
            options.nanoseconds = False
            continue

        Time(t, options).Render(sys.stdout)


if __name__ == '__main__':
    argv0 = sys.argv[0].rsplit('/')[-1]
    rv = _main(sys.argv[1:], argv0=argv0)
    sys.exit(rv)

# vim: set ft=python sw=2 expandtab :