[Tutor] schedulers

[Alan Gauld]

On 28/02/2019 14:45, nathan tech wrote:

> but I'm thinking, should I do this?

No. fOr several reasons...

> def do_backup
>   # backup code here, 

> 
> def scheduler():
>   global tus # tus=time until schedule
> 
>   while(time.time()>tus):
>    time.sleep(5)
>   scheduler()

scheduler doesn't actually do anything except
spin waiting for the time up. But you know the
current time and the due time so you can just
sleep until the due time, no need for the loop.

Also you exit the loop and then call scheduler
again - that will immediately exit the loop
and call scheduler again which will repeat
"forever". I suspect you meant to call do_backup?

However, if you really want to delay execution
of do_backup you can probably do it via the OS
Nearly every OS has a means of scheduling tasks.
So, by splitting your app into two parts - one
to create the scheduled task and the
other to actually do the backup.

That way the OS does all the heavy lifting,
including restoring the schedule after an OS
restart etc. And you only have the relatively
easy task of telling the os to schedule a task
and writing the backup function.

> This is a program for windows.

OK, I cant recall the Windows schedule
program - I think it was "at" or somesuch?

Then again you could just use the native Windows
backup program which doe it all for you...


-- 
Alan G
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