Add 15 minutes to current timestamp using timedelta

Question

The title says it all. I am writing a script to make scheduled GET requests to an API. I want to print when the next API call will be made, which would be 15 minutes from the previous call.

I'm very close, but have been running into the following error: TypeError: a float is required

Here's my code:

import time, datetime
from datetime import datetime, timedelta

while True:
    ## create a timestamp for the present moment:
    currentTime = datetime.datetime.fromtimestamp(time.time()).strftime("%Y-%m-%d %H:%M:%S")
    print "GET request @ " + str(currentTime)

    ## create a timestamp for 15 minutes into the future:
    nextTime = datetime.datetime.now() + datetime.timedelta(minutes = 15)
    print "Next request @ " + str(datetime.datetime.fromtimestamp(nextTime).strftime("%Y-%m-%d %H:%M:%S")
    print "############################ DONE #############################"
    time.sleep(900) ## call the api every 15 minutes   

I can get things to work (sort of) when changing the following line:

print "Next request @ " + str(nextTime)

However, this prints a timestamp with six decimal places for milliseconds. I want to keep things in the %Y-%m-%d %H:%M:%S format.

Answer 1

You don't need to use datetime.fromtimestamp since nextTime is already a datetime object (and not a float). So, simply use:

nextTime = datetime.datetime.now() + datetime.timedelta(minutes = 15)
print "Next request @ " + nextTime.strftime("%Y-%m-%d %H:%M:%S")

Answer 2

You can achieve it just by using timestamp instead:

import time
from datetime import datetime

while True:
    # create a timestamp for the present moment:
    currentTime_timestamp = time.time()
    currentTime = datetime.fromtimestamp(
        currentTime_timestamp
    ).strftime("%Y-%m-%d %H:%M:%S")
    print "GET request @ " + str(currentTime)

    # create a timestamp for 15 minutes into the future:
    nextTime = currentTime_timestamp + 900  # 15min = 900 seconds
    print "Next request @ " + str(datetime.fromtimestamp(
        nextTime
    ).strftime("%Y-%m-%d %H:%M:%S"))
    print "############################ DONE #############################"
    time.sleep(900)  # call the api every 15 minutes

The output I got was:

GET request @ 2017-04-03 16:31:34
Next request @ 2017-04-03 16:46:34
############################ DONE #############################