def _move_to_next_month(self, dt):
"""
Move to first day in next month
:param dt: Tested datetime
:return: First day in next month for expression
"""
# is the current month is the set
if dt.month in self._month:
# get the index + 1, wrap to first in list if last entry
index = (self._month.index(dt.month) + 1) % len(self._month)
else:
# find a matching index in the list that is >= current month
index = 0
while index < len(self._month) - 1:
if self._month[index] >= dt.month:
break
index += 1
# get the month
next_month = self._month[index]
# year + 1 if the new month is earlier than the next month
year = dt.year if next_month > dt.month else dt.year + 1
next_month_builder = MonthdaySetBuilder(year=year, month=next_month)
month_days_next = sorted(
next_month_builder.build(self._day_of_month_str))
day = min(month_days_next
) if month_days_next != [] else next_month_builder.first
return datetime(year=year,
month=next_month,
day=day,
hour=min(self._hours),
minute=min(self._minutes),
tzinfo=dt.tzinfo)
def test_L_wildcard(self):
years = [2016, 2017] # leap and normal year
for year in years:
for month in range(1, 13):
_, days = calendar.monthrange(year, month)
self.assertEquals(
MonthdaySetBuilder(year, month).build("L"), {days})
def test_name(self):
years = [2016, 2017] # leap and normal year
for year in years:
for month in range(1, 13):
_, days = calendar.monthrange(year, month)
for day in range(1, days):
self.assertEquals(
MonthdaySetBuilder(year, month).build(str(day)), {day})
def _move_to_previous_month(self, dt):
"""
Move to end of previous month
:param dt: Tested datetime
:return: Last day for expression in previous month
"""
# is the current month is the list
if dt.month in self._month:
# get the index -1, note that if the index is -1 the last item in the list is used so no special
# handling required if it is the first one in the list and we have to move back to previous month
index = self._month.index(dt.month) - 1
else:
# find a matching index in the list that is <= current month
index = len(self._month) - 1
while index >= 0:
if self._month[index] <= dt.month:
break
index -= 1
# get the month from the list
previous_month = self._month[index]
# year - 1 if the new month is later than the current month
year = dt.year if previous_month < dt.month else dt.year - 1
previous_month_builder = MonthdaySetBuilder(year=year,
month=previous_month)
month_days_previous = sorted(
previous_month_builder.build(self._day_of_month_str))
day = max(
month_days_previous
) if month_days_previous != [] else previous_month_builder.last
# return the last event for the last day of the previous month
return datetime(year=year,
month=previous_month,
day=day,
hour=max(self._hours),
minute=max(self._minutes),
tzinfo=dt.tzinfo)
def _prepare_expression(self, dt):
"""
Prepares internal builders for expression elements for testing a datetime
:param dt: Tested datetime
:return: Tested datetime
"""
# minute set builder
if self._minutes is None:
self._minutes_builder = MinuteSetBuilder()
self._minutes = sorted(
self._minutes_builder.build(self._minutes_str))
# hours set builder
if self._hours is None:
self._hours_builder = HourSetBuilder()
self._hours = sorted(self._hours_builder.build(self._hours_str))
# month set builder
if self._month is None:
self._month_builder = MonthSetBuilder()
self._month = sorted(MonthSetBuilder().build(self._month_str))
# day of month and day in week builders, note that these depend on the date being tested
if self._date is None or self._date.date() != dt.date():
# first time or if date to be tested differs from previous test
# day of month builder
self._day_of_month_builder = MonthdaySetBuilder(year=dt.year,
month=dt.month)
self._day_of_month = sorted(
self._day_of_month_builder.build(self._day_of_month_str))
# day of week builder
self._day_of_week_builder = WeekdaySetBuilder(year=dt.year,
month=dt.month,
day=dt.day)
self._day_of_week = sorted(
self._day_of_week_builder.build(self._day_of_week_str))
# store the date for which the builders are prepared
self._date = dt.replace(hour=0, minute=0, second=0, microsecond=0)
return dt
def test_W_wildcard(self):
years = [2016, 2017] # leap and normal year
for year in years:
for month in range(1, 13):
_, days = calendar.monthrange(year, month)
for day in range(1, days):
weekday = calendar.weekday(year, month, day)
result = day
if weekday == 5:
result = day - 1 if day > 1 else day + 2
elif weekday == 6:
result = day + 1 if day < days else day - 2
self.assertEquals(
MonthdaySetBuilder(year, month).build(str(day) + "W"),
{result})
def test_exceptions(self):
for h in range(13, 25):
self.assertRaises(ValueError,
MonthdaySetBuilder(2016, 1).build, "W")
self.assertRaises(ValueError,
MonthdaySetBuilder(2016, 1).build, "32W")
class CronExpression(object):
"""
Class for performing matching for datetimes using expressions in cron syntax. For a full description of the supported cron
syntax and features see See https://en.wikipedia.org/wiki/Cron
"""
macros = {
"@yearly": "0 0 1 1 *",
"@monthly": "0 0 1 * *",
"@weekly": "0 0 * * 0",
"@daily": "0 0 * * *",
"@hourly": "0 * * * *"
}
def __init__(self,
expression=None,
minutes="*",
hours="*",
day_of_month="*",
month="*",
day_of_week="?",
dt=None,
tz=None):
"""
:param expression: Cron expression including minutes, hours, day of month, month and day of week. This parameter and the
separate parameters for these elements are mutually exclusive. See https://en.wikipedia.org/wiki/Cron for supported syntax
for this expression and the individual fields. @yearly, @monthly, @weekly, @daily and @hourly macros can be used as well.
:param minutes: Expression minutes, 00-59, '/' for increments, '-' for ranges, ',' for sets or None for *.
:param hours: Expression hours, 0-23, 0am-23pm,'/' for increments, '-' for ranges, ',' for sets or None for *
:param day_of_month: Expression days of month, 1-(28-31), W for nearest weekday, L for last day of month,
'/' for increments, '-' for ranges, ',' for sets or None for *
:param month: Expression month, 1-12, jan-dec, '/' for increments, '-' for ranges, ',' for sets or None for *. Wraps at dec.
:param day_of_week: Expression days of week, 0-6, mon-sun, '/' for increments, '-' for ranges, ',' for sets,
L for last occurrence of day in month, # for nth occurrence in month or None for ?. Wraps at sunday
:param dt: Optional datetime to test set against
:param tz: Optional timezone, if parameter dt is localized this parameter is ignored. Default timezone is UTC
"""
fields = []
# split and test fields of expression
self._expression = expression
if self._expression:
if self._expression in CronExpression.macros:
self._expression = CronExpression.macros[self._expression]
fields = expression.split(" ")
if len(fields) != 5:
ValueError("Cron expression must have 5 fields")
# use fields in expression of field parameters
self._minutes_str = fields[0] if expression else minutes
self._hours_str = fields[1] if expression else hours
self._day_of_month_str = fields[2] if expression else day_of_month
self._month_str = fields[3] if expression else month
self._day_of_week_str = fields[4] if expression else day_of_week
# lists of date and time elements for matching events
self._minutes = None
self._hours = None
self._day_of_month = None
self._month = None
self._day_of_week = None
# builders for date and time elements
self._minutes_builder = None
self._hours_builder = None
self._day_of_month_builder = None
self._month_builder = None
self._day_of_week_builder = None
# this is an optional default time that can be set to test against
self._date = dt
# store timezone from dt or timezone parameter
if dt and dt.tzinfo is not None:
self._timezone = dt.tzinfo
elif tz is not None:
self._timezone = tz if isinstance(tz,
tzinfo) else pytz.timezone(tz)
else:
self._timezone = pytz.timezone("UTC")
# Displays the prepared expression in a readable way
def str(self, dt=None):
"""
Displays a parsed expression in a human readable way
:param dt: Datetime to build expression, required for using features like last day in month, last weekday etc.
Use None for localized current time
:return: Human readable string for expression
"""
str_dt = self._prepare_expression(self._localized_time(dt))
return str({
"date": str(str_dt.date()),
"minute": self._minutes_builder.str(self._minutes),
"hour": self._hours_builder.str(self._hours),
"day": self._minutes_builder.str(self._day_of_month),
"month": self._month_builder.str(self._month),
"weekday": self._day_of_week_builder.str(self._day_of_week)
})
# Tests if the specified dt matches an event as specified in the cron expression
def match(self, dt=None):
"""
Tests if a specified or the localized current time matches the expression
:param dt: Datetime to test or None to use current datetime
:return: The tested dt if it does match the expression, None if it does not
"""
dtz = self._prepare_expression(self._localized_time(dt))
return dtz if all([
dtz.day in self._day_of_month, dtz.month in self._month,
dtz.weekday() in self._day_of_week, dtz.minute in self._minutes,
dtz.hour in self._hours
]) else None
def since(self, start_dt, end_dt=None, most_recent_first=True):
"""
Returns the number of matches for an expression from a start datetime until an end datetime
:param start_dt: Start datetime
:param end_dt: End datetime, use None for current localized datetime
:param most_recent_first: Set to true to return most recent match first
:return: Matches since the start datetime (excluding), up and until the end datetime (including)
"""
end_dtz = self._localized_time(end_dt)
# for efficiency in there are optimized functions for moving back and forward through the date range
return self._matches_backwards(start_dt, end_dtz) \
if most_recent_first \
else self._matches_forwards(start_dt, end_dtz)
def within_last(self, timespan, end_dt=None, most_recent_first=True):
"""
Returns matches for an expression in a timespan backwards from an end datetime
:param timespan: Length of period backwards from end datetime
:param end_dt: End datetime (included), use None for current localized datetime
:param most_recent_first: Set to true to return most recent match first
:return: Matches for an expression in a timespan backwards from an end-date (included), [] if there was no match
"""
end_dtz = self._localized_time(end_dt)
start_dtz = end_dtz - timespan
return self.since(start_dtz, end_dtz, most_recent_first)
def last_since(self, since_dt, end_dt=None):
"""
Returns the most recent match for an expression since a start datetime up and until an end datetime
:param since_dt: Start datetime (excluding)
:param end_dt: End datetime (including), use None for localized local time
:return: Most recent match in the period since the start datetime up and until the end datetime, None if there was no match
"""
end_dtz = self._localized_time(end_dt)
for match in self.since(since_dt, end_dtz, most_recent_first=True):
return match
return None
def last_within_last(self, timespan, end_dt=None):
"""
Returns the most recent match for an expression in a timespan backwards from the end datetime
:param timespan: Length of period backwards from end datetime
:param end_dt: End datetime (included), use None for current localized datetime
:return: Most recent match in the timespan backwards from the end datetime (including), None if there was no match
"""
end_dtz = self._localized_time(end_dt)
for match in self.within_last(timespan=timespan,
end_dt=end_dtz,
most_recent_first=True):
return match
return None
def first_since(self, since_dt, end_dt=None):
"""
Returns the first match for an expression in a period since a start datetime (excluding) up and until the end datetime
:param since_dt: Start of the period (excluding)
:param end_dt: End of the period (including), use None for localized current time
:return: First match for an expression for a period since a start datetime (excluding) up and until the end datetime,
None if there was no match
"""
end_dtz = self._localized_time(end_dt)
for match in self.since(start_dt=since_dt,
end_dt=end_dtz,
most_recent_first=False):
return match
return None
def first_within_last(self, timespan, end_dt=None):
"""
Returns the first match for an expression in a timespan backwards from the end datetime
:param timespan: Length of period backwards from end datetime
:param end_dt: End datetime (included), use None for current localized datetime
:return: First recent match in the timespan backwards from the end datetime (including), None if there was no match
"""
end_dtz = self._localized_time(end_dt)
for match in self.within_last(timespan=timespan,
end_dt=end_dtz,
most_recent_first=False):
return match
return None
def until(self, end_dt, start_dt=None, earliest_first=True):
"""
Returns all matches for an expression in a period from the start datetime (including) until the end datetime (excluding)
:param end_dt: End datetime for the period (excluding)
:param start_dt: Start datetime for the period (including), use None for localized current datetime
:param earliest_first: Set to True to return earliest match first
:return: Matches for an expression in a period from the start datetime until the end datetime, [] if there no matches
"""
# for efficiency in there are optimized functions for moving back and forward through the date range
start_dtz = self._localized_time(start_dt)
return self._matches_forwards(start_dtz, end_dt) \
if earliest_first \
else self._matches_backwards(start_dtz, end_dt)
def within_next(self, timespan, start_dt=None, earliest_first=True):
"""
Returns all matches for an expression in a timespan starting at the start datetime (excluding)
:param timespan: Length of the timespan forwards in time
:param start_dt: Start datetime, use None for localized current datetime
:param earliest_first: Set to True to return earliest match first
:return: Matches for an expression in a timespan starting at the start datetime, [] if there are no matches
"""
start_dtz = self._localized_time(start_dt)
end_dtz = start_dtz + timespan
return self.until(end_dtz, start_dtz, earliest_first)
def last_until(self, end_dt, start_dt=None):
"""
Returns last match for a period from the start datetime (excluding) until the end datetime (including)
:param end_dt: End datetime (including)
:param start_dt: Start datetime (excluding), use None for localized current datetime
:return: Last match for a period from the start datetime until the end datetime, None if there was no match
"""
start_dtz = self._localized_time(start_dt)
for match in self.until(end_dt, start_dtz, earliest_first=False):
return match
def last_within_next(self, timespan, start_dt=None):
"""
Return the last match in a timespan starting at the start date (excluding)
:param timespan: Length of the timespan forwards in time
:param start_dt: Start datetime, use None for localized current datetime
:return: Last match for the period, None if there was no match
"""
start_dtz = self._localized_time(start_dt)
for match in self.within_next(timespan=timespan,
start_dt=start_dtz,
earliest_first=False):
return match
def first_until(self, end_dt, start_dt=None):
"""
Returns first match for a period from the start datetime (excluding) until the end datetime (including)
:param end_dt: End datetime (including)
:param start_dt: Start datetime (excluding), use None for localized current datetime
:return: First match for a period from the start datetime until the end datetime, None if there was no match
"""
start_dtz = self._localized_time(start_dt)
for match in self.until(end_dt,
start_dt=start_dtz,
earliest_first=True):
return match
def first_within_next(self, timespan, start_dt=None):
"""
Return the first match in a timespan starting at the start date (excluding)
:param timespan: Length of the timespan forwards in time
:param start_dt: Start datetime, use None for localized current datetime
:return: First match for the period, None if there was no match
"""
start_dtz = self._localized_time(start_dt)
for match in self.within_next(timespan=timespan,
start_dt=start_dtz,
earliest_first=True):
return match
def validate(self):
"""
Method to test if provided expression is valid before actually using the expression
:return:
"""
self._prepare_expression(datetime.now())
def _localized_time(self, dt=None):
"""
Checks if timezone information must be added to tz. If the dt parameter is not set then the default dt set in the parameter
if used if it was set otherwise the localized current time is used
:param dt: Tested datetime or None for current datetime
:return: Localized datetime
"""
if dt:
return dt.replace(
tzinfo=self._timezone) if dt.tzinfo is None else dt
return datetime.now(tz=self._timezone)
def _prepare_expression(self, dt):
"""
Prepares internal builders for expression elements for testing a datetime
:param dt: Tested datetime
:return: Tested datetime
"""
# minute set builder
if self._minutes is None:
self._minutes_builder = MinuteSetBuilder()
self._minutes = sorted(
self._minutes_builder.build(self._minutes_str))
# hours set builder
if self._hours is None:
self._hours_builder = HourSetBuilder()
self._hours = sorted(self._hours_builder.build(self._hours_str))
# month set builder
if self._month is None:
self._month_builder = MonthSetBuilder()
self._month = sorted(MonthSetBuilder().build(self._month_str))
# day of month and day in week builders, note that these depend on the date being tested
if self._date is None or self._date.date() != dt.date():
# first time or if date to be tested differs from previous test
# day of month builder
self._day_of_month_builder = MonthdaySetBuilder(year=dt.year,
month=dt.month)
self._day_of_month = sorted(
self._day_of_month_builder.build(self._day_of_month_str))
# day of week builder
self._day_of_week_builder = WeekdaySetBuilder(year=dt.year,
month=dt.month,
day=dt.day)
self._day_of_week = sorted(
self._day_of_week_builder.build(self._day_of_week_str))
# store the date for which the builders are prepared
self._date = dt.replace(hour=0, minute=0, second=0, microsecond=0)
return dt
def _matches_backwards(self, start_dt, end_dt):
"""
Find matches in a period specified by a start and end datetime. The search is performed backwards starting from the end
datetime (including) until the start datetime (excluding). For efficiency there are separate methods for searching forwards
and backwards.
:param start_dt: Start datetime (excluding)
:param end_dt: End datetime (including), use None for localized current datetime
:return: Set of matching datetimes for the expression in the period, [] if there are no matches
"""
start_dtz = self._localized_time(start_dt).replace(second=0,
microsecond=0)
dtz = self._localized_time(end_dt).replace(second=0, microsecond=0)
# until the start of the period is reached move backwards
while dtz > start_dtz:
self._prepare_expression(dtz)
# month does not match, move back previous month
if dtz.month not in self._month:
dtz = self._move_to_previous_month(dtz)
continue
# day or weekday does not match, move back to previous day
if dtz.day not in self._day_of_month or dtz.weekday(
) not in self._day_of_week:
dtz = self._move_to_previous_day(dtz)
continue
# hours do not match move to last event in previous hour
if dtz.hour not in self._hours:
dtz = self._move_to_previous_hour(dtz)
continue
# minutes do not match, move back to last event in previous minute
if dtz.minute not in self._minutes:
dtz = self._move_to_previous_minute(dtz)
continue
yield dtz
dtz = self._move_to_previous_minute(dtz)
def _matches_forwards(self, start_dt, end_dt):
"""
Find matches in a period specified by a start and end datetime. The search is performed forwards starting from the start
datetime (excluding) until the start datetime (including). For efficiency there are separate methods for searching forwards
and backwards.
:param start_dt: Start datetime (excluding)
:param end_dt: End datetime (including)
:return: Set of matching datetimes for the expression in the period, [] if there are no matches
"""
dtz = self._localized_time(start_dt).replace(
second=0, microsecond=0) + timedelta(minutes=1)
end_dtz = self._localized_time(end_dt)
# until the end of the period is reached
while dtz <= end_dtz:
self._prepare_expression(dtz)
# month does not match, move forward to first event in next month
if dtz.month not in self._month:
dtz = self._move_to_next_month(dtz)
continue
# day or weekday does not match move forward to first event in next day
if dtz.day not in self._day_of_month or dtz.weekday(
) not in self._day_of_week:
dtz = self._move_to_next_day(dtz)
continue
# hours do not match move forward to first event in next hour
if dtz.hour not in self._hours:
dtz = self._move_to_next_hour(dtz)
continue
# minutes do not match, move forward to first event in next minute
if dtz.minute not in self._minutes:
dtz = self._move_to_next_minute(dtz)
continue
yield dtz
dtz = self._move_to_next_minute(dtz)
def _move_to_previous_month(self, dt):
"""
Move to end of previous month
:param dt: Tested datetime
:return: Last day for expression in previous month
"""
# is the current month is the list
if dt.month in self._month:
# get the index -1, note that if the index is -1 the last item in the list is used so no special
# handling required if it is the first one in the list and we have to move back to previous month
index = self._month.index(dt.month) - 1
else:
# find a matching index in the list that is <= current month
index = len(self._month) - 1
while index >= 0:
if self._month[index] <= dt.month:
break
index -= 1
# get the month from the list
previous_month = self._month[index]
# year - 1 if the new month is later than the current month
year = dt.year if previous_month < dt.month else dt.year - 1
previous_month_builder = MonthdaySetBuilder(year=year,
month=previous_month)
month_days_previous = sorted(
previous_month_builder.build(self._day_of_month_str))
day = max(
month_days_previous
) if month_days_previous != [] else previous_month_builder.last
# return the last event for the last day of the previous month
return datetime(year=year,
month=previous_month,
day=day,
hour=max(self._hours),
minute=max(self._minutes),
tzinfo=dt.tzinfo)
def _move_to_next_month(self, dt):
"""
Move to first day in next month
:param dt: Tested datetime
:return: First day in next month for expression
"""
# is the current month is the set
if dt.month in self._month:
# get the index + 1, wrap to first in list if last entry
index = (self._month.index(dt.month) + 1) % len(self._month)
else:
# find a matching index in the list that is >= current month
index = 0
while index < len(self._month) - 1:
if self._month[index] >= dt.month:
break
index += 1
# get the month
next_month = self._month[index]
# year + 1 if the new month is earlier than the next month
year = dt.year if next_month > dt.month else dt.year + 1
next_month_builder = MonthdaySetBuilder(year=year, month=next_month)
month_days_next = sorted(
next_month_builder.build(self._day_of_month_str))
day = min(month_days_next
) if month_days_next != [] else next_month_builder.first
return datetime(year=year,
month=next_month,
day=day,
hour=min(self._hours),
minute=min(self._minutes),
tzinfo=dt.tzinfo)
def _move_to_previous_day(self, dt):
"""
Move to previous day for expression, move to previous month if necessary
:param dt: Tested datetime
:return: Next day for expression
"""
# test if day is in the current set
if dt.day in self._day_of_month:
# if so use the index -1
index = self._day_of_month.index(dt.day) - 1
else:
# otherwise get the index of the first entry equal or less than the current day
index = len(self._day_of_month) - 1
while index > 0:
if self._day_of_month[index] <= dt.day:
break
index -= 1
# get the day from the set, if it is empty use the current day to move into the next month
d = self._day_of_month[index] if index > -1 else dt.day
# if the day > the current day then move back to the last event in the previous month
if d >= dt.day:
return self._move_to_previous_month(dt)
else:
# last event of previous day in same month
return dt.replace(day=d,
hour=max(self._hours),
minute=max(self._minutes))
def _move_to_next_day(self, dt):
"""
Move to next day for expression, move to next month if necessary
:param dt: Tested datetime
:return: Next day for expression
"""
# test if day is in the current set
if dt.day in self._day_of_month:
# if so use the index -1
index = (self._day_of_month.index(dt.day) + 1) % len(
self._day_of_month)
else:
# otherwise get the index of the first entry >= the current day
index = 0
while index < len(self._day_of_month) - 1:
if self._day_of_month[index] >= dt.day:
break
index += 1
# get the day from the set, if it is empty then use current day to move forward to next month
d = self._day_of_month[index] if self._day_of_month != [] else dt.day
# if the day > the current day then move back to the last event in the previous month
if d <= dt.day:
return self._move_to_next_month(dt)
else:
# last event of previous day in same month
return dt.replace(day=d,
hour=min(self._hours),
minute=min(self._minutes))
def _move_to_previous_hour(self, dt):
"""
Move to previous hour for expression, move to previous day if necessary
:param dt: Tested datetime
:return: Previous hour for expression
"""
# test if current hour is in the set
if dt.hour in self._hours:
# if so use the index -1
index = self._hours.index(dt.hour) - 1
else:
# otherwise find the first entry in the set that is <= current hour
index = len(self._hours) - 1
while index > 0:
if self._hours[index] <= dt.hour:
break
index -= 1
# get the hour from the list
h = self._hours[index]
# if the hour >= the current hour then move back to last event in previous day
if h >= dt.hour:
return self._move_to_previous_day(dt)
else:
# previous event at same day
return dt.replace(hour=h, minute=max(self._minutes))
def _move_to_next_hour(self, dt):
"""
Move to next hour for expression, move to next day if necessary
:param dt: Tested datetime
:return: Next hour for expression
"""
# test if current hour is in the set
if dt.hour in self._hours:
# if so used the index -1
index = (self._hours.index(dt.hour) + 1) % len(self._hours)
else:
# otherwise find the first entry in the set that is >= current hour
index = 0
while index < len(self._hours) - 1:
if self._hours[index] >= dt.hour:
break
index += 1
# get the hour from the list
h = self._hours[index]
# if the hour <= the current hour then move to first event in next day
if h <= dt.hour:
return self._move_to_next_day(dt)
else:
# next event at same day
return dt.replace(hour=h, minute=min(self._minutes))
def _move_to_previous_minute(self, dt):
"""
Move to previous minute, move to previous hour if necessary
:param dt: Tested datetime
:return: Previous minute for expression
"""
# test if current minute is in the set
if dt.minute in self._minutes:
# use the index -1
index = self._minutes.index(dt.minute) - 1
else:
# otherwise find the index of the minute <= current minute
index = len(self._minutes) - 1
while index > 0:
if self._minutes[index] <= dt.minute:
break
index -= 1
# get minute from the list
minute = self._minutes[index]
if minute >= dt.minute:
# if minute >= current minute then return last event in previous hour
return self._move_to_previous_hour(dt)
else:
# return previous event in same hour
return dt.replace(minute=minute)
# gets the last event in the previous minute in the set
def _move_to_next_minute(self, dt):
"""
Moves to next minute, move to next hour if necessary
:param dt: tested datetime
:return: Next minute for expression
"""
# test if current minute is in the set
if dt.minute in self._minutes:
# use the index +1
index = (self._minutes.index(dt.minute) + 1) % len(self._minutes)
else:
# otherwise find the index of the minute <= current minute
index = 0
while index < len(self._minutes) - 1:
if self._minutes[index] >= dt.minute:
break
index += 1
# get minute from the list
minute = self._minutes[index]
if minute <= dt.minute:
# if minute <= current minute then return first event in next hour
return self._move_to_next_hour(dt)
else:
# return next event in same hour
return dt.replace(minute=minute)
