Python Async Function not updating timestamp

Question

I have a machine running some scripts that I need to keep an eye on.

I have set up a script in python to send me emails using every hour.

I would like to add timestamp to it so that I can see at a glance when was the last message send from the machine to know it's running. When testing this to send email after every 120 seconds, I found that the email sending part works perfectly but the timestamp does not update. Can't figure out what I am doing wrong.

The print statement returns the same timestamp after each loop and so does the email.

Email Sent at 18 December 2024 13:16:50
Email Sent at 18 December 2024 13:16:50
Email Sent at 18 December 2024 13:16:50

My code:

import asyncio
#Main Event loop to send emails
async def send_email(timestamp):
 import datetime as dt
 timestamp = dt.datetime.now()
 import socket
 hostname = socket.gethostname()
 import getpass
 user = getpass.getuser()
 timestamp_string = timestamp.strftime("%d %B %Y %H:%M:%S")
 subject = f"Machine Status Check - {timestamp_string}"
 html_body = f"""
 Machine Name: {hostname}\n
 User ID: {user}
 """
 to = "[email protected]"
 
 while True:
 import win32com.client
 outlook = win32com.client.gencache.EnsureDispatch('Outlook.Application')
 new_email = outlook.CreateItem(0)
 new_email.To = to
 new_email.Subject = subject
 new_email.HTMLBody = html_body
 new_email.Send()
 print(f"Email Sent at {timestamp_string}")
 await asyncio.sleep(120)
#Run the asyncio event loop
async def main():
 await send_email()
#Start the event loop
asyncio.run(main=main())

• deceze: Well, you only create timestamp_string once before the loop. No, that won't update automagically.

Answer 1

You are not updating your values in your while loop so it keeps reusing the same value.

Quick explanation.

• you make a variable timestamp and init it with the date now which is 2024年12月18日 05:55:11 or whatever

this variable is now made with the value 2024年12月18日 05:55:11. When sending out the mail it will not rerun the datetime.now() function but it will just look at the value saved in the initialization of that object which is 2024年12月18日 05:55:11. So in the loop you need to keep updating the values otherwise it will keep using the values stored at the memory address.

Hope this helps!

async def send_email():
 hostname = socket.gethostname()
 user = getpass.getuser()
 to = "[email protected]"
 while True:
 timestamp = dt.datetime.now()
 timestamp_string = timestamp.strftime("%d %B %Y %H:%M:%S")
 subject = f"Machine Status Check - {timestamp_string}"
 html_body = f"""
 Machine Name: {hostname}<br>
 User ID: {user}
 """
 outlook = win32com.client.gencache.EnsureDispatch('Outlook.Application')
 new_email = outlook.CreateItem(0)
 new_email.To = to
 new_email.Subject = subject
 new_email.HTMLBody = html_body
 new_email.Send()
 print(f"Email Sent at {timestamp_string}")
 await asyncio.sleep(120) 

• excelman: Thank you @JoshuaBrown. So dumb of me to not see it.
• JoshuaBrown: np @excelman feel free to mark as answered