Date/time utils
A service's self.time attribute accesses convenience wrappers around Python's datetime and Arrow's objects.
UTC now
Call self.time.utcnow() to obtain current time in UTC. Default format is YYYY-MM-DD HH:mm:ss. Returns string unless told not to serialize the result.
# -*- coding: utf-8 -*-
# Zato
from zato.server.service import Service
class MyService(Service):
def handle(self):
# Default
now = self.time.utcnow()
self.logger.info('Now (1) is %s', now)
# Custom output format, still in UTC
now = self.time.utcnow('DD-MM-YY HH:mm')
self.logger.info('Now (2) is %s', now)
# Don't serialize to string
now = self.time.utcnow(needs_format=False)
self.logger.info('Now (3) is %r', now)
Output in server logs:
INFO - Now (1) is 2025-01-26 13:34:24
INFO - Now (2) is 26-01-15 13:34
INFO - Now (3) is](Arrow [2025-01-26T13:34:24.738026+00:00]>
Today
Returns current date. Default format is YYYY-MM-DD in UTC - both can be overridden. Converts output to string unless overridden.
# -*- coding: utf-8 -*-
# Zato
from zato.server.service import Service
class MyService(Service):
def handle(self):
# Default
today = self.time.today()
self.logger.info('Today in UTC (1) is %s', today)
# UTC, custom format
today = self.time.today('DDMMYY')
self.logger.info('Today in UTC (2) is %s', today)
# Don't serialize to string
today = self.time.today(needs_format=False)
self.logger.info('Today in UTC (3) is %r', today)
# A user-provided timezone
today = self.time.today(tz='Pacific/Fiji')
self.logger.info('Today in Suva is %s', today)
INFO - Today in UTC (1) is 2025-01-26
INFO - Today in UTC (2) is 260115
INFO - Today in UTC (3) is](Arrow [2025-01-26T00:00:00+00:00]>
INFO - Today in Suva is 2025-01-27
Reformatting
Dates and time can be converted between formats using self.time.reformat - the method accepts a value, its format and a format it needs to be changed to. The value can be a string, datetime or an Arrow object.
# -*- coding: utf-8 -*-
# Zato
from zato.server.service import Service
class MyService(Service):
def handle(self):
# Convert from DD-MM-YYYY to YY.MM.DD
value = '15-11-2029'
self.logger.info('Was: %s', value)
value = self.time.reformat(value, 'DD-MM-YYYY', 'YY.MM.DD')
self.logger.info('Now: %s', value)
Anticipating the need to change source or target formats it's possible to store either or both in Redis so they are read in run-time without hardcoding anything in code.
Now instead of exact formats their names prefixed with 'kvdb:' are used. The prefix is stripped away and the names point to Redis keys that will contain the exact formats.
The pattern to use in Redis is kvdb:date-format:$name where $name is the name provided on input to self.time.reformat. For instance, a 'crm' format name should be stored in Redis under kvdb:date-format:crm key.
Supposing there are Redis keys as follows:
127.0.0.1:6379> SET kvdb:date-format:crm "YY-MM-DD HH:mm"
OK
127.0.0.1:6379> SET kvdb:date-format:erp MM-DD-YY
OK
The following code will look up formats in Redis in order to reformat date from CRM to the format ERP expects. Should formats change, no updates to the code of the service will be needed.
# -*- coding: utf-8 -*-
# Zato
from zato.server.service import Service
class MyService(Service):
def handle(self):
# Convert from DD-MM-YYYY to YY.MM.DD
value = '15-11-2029 13:17'
self.logger.info('Was: %s', value)
value = self.time.reformat(value, 'kvdb:crm', 'kvdb:erp')
Helper API programming tools and techniques
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