Kron Documentation¶

Description¶

Uniform interface for dates and times

Features¶

Classes for durations, timestamps and timezones
Minimal non-standard dependencies (ntplib, pytz, tzlocal)
Microsecond accuracy (float epoch seconds are rounded to 6 decimal places)
Timestamp internal storage is float epoch seconds in UTC
Duration internal storage is float seconds
Timezone name search by regular expression
Default timezone is local timezone
Comparison and arithmetic methods for timestamps and durations
Test-driven development methodology
Named formats
Timestamp object “helper” methods for timezones and formats
Command line tool
Substitutes for time.time(): time, time_ntp, time_utc
Supports Python versions >= 3.5.1 and >= 2.7.11

Quick start¶

Install¶

$ pip install kron

Update¶

$ pip install -U kron

Examples¶

Python code/interpreter¶

>>> from kron import duration, timestamp, timezone
>>> now = timestamp()
>>> now.value
1457246861.121305
>>> now.str()
'2016-03-05 20:47:41 EST'
>>> now.str('UTC')
'2016-03-06 01:47:41 UTC'
>>> now.str(fmt='%A, %B %d, %Y')
'Saturday, March 05, 2016'
>>> t = timestamp(1257209442)
>>> t.value
1257209442.0
>>> t.str()
'2009-11-02 14:50:42 EST'
>>> t.str('UTC')
'2009-11-02 19:50:42 UTC'
>>> t.str(fmt='%A, %B %d, %Y')
'Monday, November 02, 2009'
>>> t.str(fmt='iso8601')
'2009-11-02T19:50:42Z'
>>> t.str(fmt='date')
'Monday, November 02, 2009'
>>> t.str(fmt='national')
'Mon Nov 02 14:50:42 EST 2009'
>>> t.str(fmt='rfc2822')
'Mon, 02 Nov 2009 14:50:42 -0500'
>>> t = timestamp('1999-10-12 01:18:43', 'UTC')
>>> t.value
939709123.0
>>> t.str()
'1999-10-11 22:18:43 EDT'
>>> t.str('Los_Angeles')
'1999-10-11 19:18:43 PDT'
>>> t.str(fmt='%A, %B %d, %Y')
'Monday, October 11, 1999'
>>> d = now - t
>>> d.dict()
{'days': 5990, 'hours': 0, 'minutes': 28, 'seconds': 58, 'microseconds': 121305}
>>> local = timezone()
>>> local.name
'America/New_York'
>>> madrid = timezone('madrid')
>>> madrid.name
'Europe/Madrid'

Command line tool¶

$ kron -h
usage: kron.py [-h] [-V] [-T TIMEZONE] [-F FORMAT] [-t TIMEZONE] [-f FORMAT]
               [-s TIMEZONE]
               [ARG [ARG ...]]

positional arguments:
  ARG            one or more timestamps; int/float epoch seconds, string in
                 the base format or the format specified by -F; default: now

optional arguments:
  -h, --help     show this help message and exit
  -V, --version  print version and exit
  -T TIMEZONE    input timezone; default: local timezone
  -F FORMAT      input format; default: "base" ("%Y-%m-%d %H:%M:%S")
  -t TIMEZONE    output timezone; default: local timezone
  -f FORMAT      output format; default: "basetz" ("%Y-%m-%d %H:%M:%S %Z");
                 try "all" for a demonstration
  -s TIMEZONE    search timezones
$ kron
2016-03-11 00:41:46 EST
$ kron -t utc
2016-03-11 05:42:13 UTC
$ kron -f iso8601
2016-03-11T05:43:10Z
$ kron '2005-04-04 09:12:00'
2005-04-04 09:12:00 EDT
$ kron '2005-04-04 09:12:00' -f weekday
Monday
$ kron '2006-11-13 21:22:00' -T UTC
2006-11-13 16:22:00 EST
$ kron '2006-11-13 21:22:00' -T UTC -t Madrid -t los_angeles \
> -f iso8601 -f rfc2822
{
    "2006-11-13 21:22:00": {
        "Madrid": {
            "iso8601": "2006-11-13T21:22:00Z",
            "rfc2822": "Mon, 13 Nov 2006 22:22:00 +0100"
        },
        "los_angeles": {
            "iso8601": "2006-11-13T21:22:00Z",
            "rfc2822": "Mon, 13 Nov 2006 13:22:00 -0800"
        }
    }
}
$ kron -s mad
Atlantic/Madeira
Europe/Madrid

Discussion¶

Dates and times are not one of Python’s strengths. Doing basic work requires using multiple standard and non-standard modules and effort to get it right. This module leverages the necessary modules for handling dates and times but provides a simple and uniform interface for doing so.

Background¶

Kron began as a portfolio project to demonstrate proficiency in Python as well as practice the test-driven development (TDD) process in concert with git and Github. The topic was selected to address some personal points of pain experienced while working with dates and times in Python.

The importance of correct representation of dates and times in the area of digital forensics and other fields cannot be overstated. While a myriad of poorly designed and implemented code contribute, the core problem is the absence of a simple abstraction to represent a specific point in time.

Kron is built around the “timestamp” class, which represents a specific point in time. Timestamp objects can be created, modified, and viewed in a few natural ways.

The “duration” class represents a duration of time and the difference of two timestamp objects.

The “timezone” class is provided to simplify specifying a timezone by allowing a partial string or regular expression to search for the proper name.

Versions¶

1.0.0 (2016-03-05): Initial release
1.0.1 (2016-03-05): Finished rename
1.1.0 (2016-03-06): More formats, improved documentation
1.1.1 (2016-03-06): Added description to setup.py
1.2.0 (2016-03-08): Helper methods for timezone and formats; command line tool
1.3.0 (2016-03-11): Converted timestamp internal storage to UTC; added Network Time Protocol (RFC 1305) functionality via ntplib module; added time, time_ntp, time_utc functions; improved documentation
1.3.1 (2016-03-11): Added version test
1.3.2 (2016-03-11): Fixed classifers
1.4.0 (2016-03-13): Improved documentation
1.4.1 (2016-03-13): Fix command line tool
1.4.2 (2016-03-14): Add release script; fix versions table
1.5.0 (2016-03-16): Support Python 3.5.1 and 2.7.11; default NTP server: us.pool.ntp.org; fix release script
1.5.1 (2016-03-16): Convert release script to python; improve documentation; other minor fixes
1.5.2 (2016-03-16): Restore release script to bash; fix readme
1.5.3 (2016-03-16): Move readme content to package documentation
1.6.0 (2016-03-23): Add timezone search to CLI (-s); “all” psuedo output format; improve documentation
1.6.1 (2016-03-23): Fix release script
1.6.2 (2016-04-08): Avoid importing kron in setup.py; change version to __version__; add dependency future to setup.py; fix spelling in documentation
1.6.3 (2016-04-08): Upload new version due to PyPI upload error
1.6.4 (2016-05-26): Added videos to see also section in documentation
1.6.5 (2016-06-05): Fix broken shim as result of exposing command line interface functions in 1.6.4
1.6.6 (2016-06-05): Make the default timezone UTC if tzlocal fails to get the local timezone
1.6.7 (2016-11-20): Add named formats “d”, “day”, and “dd_Mon_yyyy”; add named output formats “Month_Nth”, “Month_Nth_YYYY”, “Day_Month_Nth”, and “Day_Month_Nth_YYYY”
1.6.8 (2016-11-21): Move documentation to readthedocs
1.6.9 (2016-11-21): Fix documentation issues
1.6.10 (2016-11-22): Scrub documentation: convert versions table back to list; remove setup.cfg
1.6.11 (2016-11-22): Fix links in README
1.6.12 (2016-11-22): Scrub documentation

Issues¶

Please view/report any issues here.

Developers¶

Download source¶

$ git clone https://github.com/qtfkwk/kron.git

Install from source¶

$ cd kron
$ python setup.py install

Update¶

$ cd kron
$ git pull
$ python setup.py install

Build distributions¶

$ cd kron
$ python setup.py sdist
$ python setup.py bdist_wheel

Build documentation¶

$ cd kron
$ make -C docs html

Ideas¶

Command line tool
- Duration calculations
Parser to find timestamps inside text/data/filesystems
Add clock, calendar/timeline, events...
Alternate output formats including visual/graphical...

Author¶

“qtfkwk” qtfkwk+kron@gmail.com, @qtfimik

License¶

Copyright (c) 2016, qtfkwk
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

API Reference¶

Named formats¶

Formats are used for two events during the lifetime of a timestamp object. The first is when the object is created. This format is passed to strptime to parse the values from the string. The second is any time the object is converted to a string via the str method or some method that calls str. This format is passed to strftime to format the timestamp.

Kron provides a means to specify strftime/strptime formats as “named formats”, which are listed in the table below, and available in the timestamp.formats dictionary. If the value passed for a fmt argument matches a named format name, then the appropriate format string is substituted when it is used. Otherwise, the specified format is used as is. Named formats that have a format string of Custom can only be used as an output format, not to create a timestamp via strptime.

For more information about strftime formats, please consult man strftime or visit strftime at linux.die.net and/or Python time.strftime.

Name	Format string	Example
Day_Month_Nth	Custom	“Monday, November 2nd”
Day_Month_Nth_YYYY	Custom	“Monday, November 2nd, 2016”
HH	“%H”	“14”
HHMM	“%H%M”	“1450”
HHMMSS	“%H%M%S”	“145042”
HH_MM	“%H:%M”	“14:50”
HH_MM_SS	“%H:%M:%S”	“14:50:42”
MM	“%M”	“50”
Month_Nth	Custom	“November 2nd”
Month_Nth_YYYY	Custom	“November 2nd, 2016”
SS	“%S”	“42”
abbr_date	“%a, %b %d, %Y”	“Mon, Nov 02, 2009”
abbr_month	“%b”	“Nov”
abbr_weekday	“%a”	“Mon”
ampm	“%p”	“PM”
base	“%Y-%m-%d %H:%M:%S”	“2009-11-02 14:50:42”
basetz	“%Y-%m-%d %H:%M:%S %Z”	“2009-11-02 14:50:42 EST”
ccyy	“%Y”	“2009”
ccyymm	“%Y%m”	“200911”
ccyymmdd	“%Y%m%d”	“20091102”
d	“%a”	“Mon”
date	“%A, %B %d, %Y”	“Monday, November 02, 2009”
day	“%A”	“Monday”
dd	“%d”	“02”
dd_Mon_yyyy	“%d %b %Y”	“02 Nov 2009”
hh	“%I”	“02”
hh_MM	“%I:%M”	“02:50”
hh_MM_SS	“%I:%M:%S”	“02:50:42”
hh_MM_SS_ampm	“%I:%M:%S %p”	“02:50:42 PM”
hh_MM_ampm	“%I:%M %p”	“02:50 PM”
hours	“%H”	“14”
hours12	“%I”	“02”
hours24	“%H”	“14”
iso8601	“%Y-%m-%dT%H:%M:%SZ”	“2009-11-02T19:50:42Z”
julian	“%j”	“306”
microseconds	“%f”	“000000”
minutes	“%M”	“50”
mm	“%m”	“11”
mm_dd_yy	“%m/%d/%y”	“11/02/09”
mmdd	“%m%d”	“1102”
mon	“%b”	“Nov”
month	“%B”	“November”
national	“%a %b %d %X %Z %Y”	“Mon Nov 02 14:50:42 EST 2009:
national_date	“%x”	“11/02/09”
national_time	“%X”	“14:50:42”
rfc2822	“%a, %d %b %Y %H:%M:%S %z”	“Mon, 02 Nov 2009 14:50:42 -0500”
seconds	“%S”	“42”
tz	“%Z”	“EST”
tz_offset	“%z”	“-0500”
week_number_mon	“%W”	“44”
week_number_sun	“%U”	“44”
weekday	“%A”	“Monday”
year	“%Y”	“2009”
yy	“%y”	“09”
yymm	“%y%m”	“0911”
yymmdd	“%y%m%d”	“091102”
yyyy	“%Y”	“2009”
yyyy_mm_dd	“%Y/%m/%d”	“2009/11/02”
yyyymm	“%Y%m”	“200911”
yyyymmdd	“%Y%m%d”	“20091102”

Classes¶

duration¶

class kron.duration(value=0)¶

Represents a duration of time

value is float seconds.

Internal storage is float seconds and accessible via the value property.

Duration objects can be compared via <, >, <=, >=, ==, and != with each other or an int/float value in seconds.

Duration objects support various arithmetic operations via +, -, *, /.

Operator	Other type	Returned type
`+`	timestamp	timestamp
`+`	int, float, duration	duration
`-`	int, float, duration	duration
`*`	int, float	duration
`/`	int, float	duration

Arithmetic operations with a type not listed in the above table raises one of DurationAddError, DurationDivideError, DurationMultipyError, or DurationSubtractError.

dict()¶: Returns a dictionary with the duration as the count of days, hours, minutes, seconds, and microseconds

timestamp¶

class kron.timestamp(value=None, tz=None, fmt=None, ntp=False)¶

Represents a specific point in time

value can be:

int/float in epoch seconds in UTC or a string that looks like one: sets the value directly
Anything else is passed to the time function along with the values of the tz, fmt, and ntp arguments

Internal storage is float epoch seconds in UTC and accessible via the value property.

Timestamp objects can be compared via <, >, <=, >=, ==, and != with each other.

Timestamp objects support various arithmetic operations via + and -.

Operator	Other type	Returned type
`+`	int, float, duration	timestamp
`-`	int, float, duration	timestamp
`-`	timestamp	duration

Arithmetic operations with a type not listed in the above table raises one of TimestampAddError, TimestampDivideError, TimestampMultipyError, or TimestampSubtractError.

dict(tz=[None], fmt=['basetz'])¶: Returns the timestamp as a dictionary with keys as the given timezones and values as dictionaries with keys as the given formats (default: ‘basetz’)

iso8601()¶: Returns the timestamp as a string in the UTC timezone (implied) and the ‘iso8601’ format

json(tz=[None], fmt=['basetz'])¶: Returns the dictionary produced by the dict method as a pretty-printed JSON string

rfc2822(tz=None)¶: Returns the timestamp as a string in the local or given timezone and the ‘rfc2822’ format

str(tz=None, fmt=None)¶: Returns the timestamp as a string in the local or given timezone and the ‘basetz’ or given format

utc(fmt='basetz')¶: Returns the timestamp as a string in the UTC timezone and the ‘basetz’ or given format

timezone¶

class kron.timezone(name=None)¶

Represent a timezone

name is stored in the original property, and resolved to a timezone name via timezone.search, which is stored in the name property.

A pytz object is created for the given name and accessible via the pytz property.

classmethod search(name=None)¶

Resolve timezone given a name

name can be:

omitted or None: returns name of the local timezone via tzlocal or UTC
string matching a timezone name in pytz.all_timezones: returns the timezone name in proper case
empty string (‘’) or wildcard regular expression (‘.*’): returns a list with all timezone names
any other string: used as a regular expression; multiple or zero matches returns a list with the matched timezone names

Functions¶

cli¶

kron.cli(argv=None)¶: Backend function for command line interface

main¶

kron.main()¶: Frontend function for command line interface

time¶

kron.time(value=None, tz=None, fmt=None, ntp=False)¶

Primitive functional interface for the timestamp class; similar to time.time(), except more flexible and consistent; optionally attempts to use NTP with a fallback to use system time; can also process a string timestamp; returns float epoch seconds in UTC

value can be:

omitted or None: use current date and time now (via system time if ntp is False (default) or NTP if ntp is True); raises TimeTimezoneError if tz is specified or TimeFormatError if fmt is specified
string timestamp in the base format or given by fmt and the local timezone or given by tz

time_ntp¶

kron.time_ntp(server='us.pool.ntp.org')¶

Similar to time_utc, except uses NTP

server can be any Internet or other network-based NTP server.

time_ntp raises NTPError if it fails to retrieve the time from the server.

time_utc¶

kron.time_utc(epoch=None, tz=None)¶

Similar to time.time(), except always returns float epoch seconds in UTC

epoch argument can be one of the following; otherwise it raises TimeEpochError.

omitted or None: use current date and time now (via system time)
int/float: epoch seconds in UTC
datetime.datetime object

tz is passed to timezone().

Kron Documentation¶

Description¶

Features¶

Quick start¶

Install¶

Update¶

Examples¶

Python code/interpreter¶

Command line tool¶

Discussion¶

Background¶

Versions¶

Issues¶

Developers¶

Download source¶

Install from source¶

Update¶

Build distributions¶

Build documentation¶

Ideas¶

See also¶

Author¶

License¶

API Reference¶

Named formats¶

Classes¶

duration¶

timestamp¶

timezone¶

Functions¶

cli¶

main¶

time¶

time_ntp¶

time_utc¶