Python Datetimes

datetime00.py

from datetime import datetime, timezone, timedelta
# Using Boto 3 EC2
launch_time = ec2.launch_time
print("launch_time {} tz {}".format(launch_time, launch_time.tzinfo))
now = datetime.now()
print("now         {} tz {}".format(now, now.tzinfo))
try:
    diff = now - launch_time
except TypeError as err:
    print("Error: {}".format(err))

unow = datetime.now(timezone.utc)
print("unow        {} tz {}".format(unow, unow.tzinfo))
diff = unow - launch_time
print("diff {}".format(diff))
print("diff {}".format(timedelta(days = diff.days, seconds = diff.seconds)))

# launch_time 2020-02-21 21:19:21+00:00 tz tzutc()
# now         2020-02-22 17:49:46.575370 tz None
# Error: can't subtract offset-naive and offset-aware datetimes
# unow        2020-02-22 22:49:46.575448+00:00 tz UTC
# diff 1 day, 1:30:25.575448
# diff 1 day, 1:30:25