any issues with long running python apps?

[Emile van Sebille]

On 7/9/2010 12:13 PM Les Schaffer said...
> i have been asked to guarantee that a proposed Python application will
> run continuously under MS Windows for two months time.

Keep users off the machine, turn off automated updates, and point dns to 
127.0.0.1.  Oh, put it on a UPS.  I've got a handful or two of these 
automated systems in place and rarely have trouble.  Add a watchdog 
scheduled task process to restart the job and check disk space or memory 
usage and push out a heartbeat.

I found Chris Liechti's serial module years ago and have used it 
successfully since.

The only times that come to mind when I've problems on the python side 
were related to memory usage and the system started thrashing.  Adding 
memory fixed it.

HTH,

Emile


> And i am looking
> to know what i don't know.
>
> The app would read instrument data from a serial port, store the data in
> file, and display in matplotlib. typical sampling times are about once
> per hour. our design would be to read the serial port once a second
> (long story, but it worked for ten days straight so far) and just store
> and display the values once an hour. so basically we'd have a long
> running for-loop. maybe running in a separate thread.
>
> i have thought through the issues on our end: we have to properly handle
> the serial port and make sure our GUI doesn't hang easily. we'd have to
> be sure we don't have any memory leaks in numpy or matplotlib and we're
> not storing data in memory stupidly. i've never looked into Windows
> serial port driver reliability over the long term. But we think if the
> serial port hangs, we can detect that and react accordingly.
>
> but none of this has anything to do with Python itself. i am sure python
> servers have been running reliably for long periods of time, but i've
> never had to deal with a two-month guarantee before. is there something
> else i am missing here that i should be concerned about on the
> pure-Python side of things? something under the hood of the python
> interpreter that could be problematic when run for a long time?
>
> or need we only concern ourselves with the nuts behind the wheel:that
> is, we the developers?
>
> thanks
>
> Les