Keep a script running in the background

[Guillermo]

Hi,

I need a script to keep running in the background after it's loaded
some data. It will make this data available to the main program in the
form of a dictionary, but I don't want to reload the calculated data
every time the user needs it via the main program.

I won't be working with an UI, hope that can be made easily in Python
somehow.

Cheers,

Guillermo

[Daniel Fetchinson]

Re: Keep a script running in the background

I need a script to keep running in the background after it's loaded

some data. It will make this data available to the main program in the
form of a dictionary, but I don't want to reload the calculated data
every time the user needs it via the main program.
>
I won't be working with an UI, hope that can be made easily in Python
somehow.

I'm not sure I understand exactly what you want but you might find
these daemonize examples useful from the cookbook:

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/278731

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66012

Cheers,
Daniel
--
Psss, psss, put it down! - http://www.cafepress.com/putitdown

[Bjoern Schliessmann]

Re: Keep a script running in the background

Guillermo wrote:

I need a script to keep running in the background after it's
loaded some data. It will make this data available to the main
program in the form of a dictionary, but I don't want to reload
the calculated data every time the user needs it via the main
program.
>
I won't be working with an UI, hope that can be made easily in
Python somehow.

Sure. Try the subprocess module.

Regards,


Björn

--
BOFH excuse #205:

Quantum dynamics are affecting the transistors

[subeen]

Re: Keep a script running in the background

On Jun 3, 10:07 pm, Guillermo <guillermo.lis. ..@googlemail.c omwrote:

Hi,
>
I need a script to keep running in the background after it's loaded
some data. It will make this data available to the main program in the
form of a dictionary, but I don't want to reload the calculated data
every time the user needs it via the main program.
>
I won't be working with an UI, hope that can be made easily in Python
somehow.
>
Cheers,
>
Guillermo

You can try this command: nohup python script.py &

regards,
Subeen.

http://love-python.blogspot.com/

[Tobiah]

Re: Keep a script running in the background

I need a script to keep running in the background after it's loaded
some data. It will make this data available to the main program in the
form of a dictionary, but I don't want to reload the calculated data
every time the user needs it via the main program.

If it were me, I'd go with a database server like mysql.
** Posted from http://www.teranews.com **

[Guillermo]

Re: Keep a script running in the background


These are the basic requirements:

Script A must keep a dictionary in memory constantly and script B must
be able to access and update this dictionary at any time. Script B
will start and end several times, but script A would ideally keep
running until it's explicitly shut down.

I have the feeling the way to do this is Python is by pickling the
dict, but I need the method that gives the best performance. That's
why I'd rather want to keep it in memory, since I understand pickling
involves reading from and writing to disk.

I'm using SQLite as a database. But this dict is an especial index
that must be accessed at the highest speed possible.

[M.-A. Lemburg]

Re: Keep a script running in the background

On 2008-06-04 01:33, Guillermo wrote:

These are the basic requirements:
>
Script A must keep a dictionary in memory constantly and script B must
be able to access and update this dictionary at any time. Script B
will start and end several times, but script A would ideally keep
running until it's explicitly shut down.
>
I have the feeling the way to do this is Python is by pickling the
dict, but I need the method that gives the best performance. That's
why I'd rather want to keep it in memory, since I understand pickling
involves reading from and writing to disk.
>
I'm using SQLite as a database. But this dict is an especial index
that must be accessed at the highest speed possible.

If you're on Unix, it's easiest to have script A implement a
signal handler. Whenever it receives a signal, it rereads the
pickled dict from the disk. Script B then writes a new revision
of the dict and sends the signal to script A.

Alternatively, you could use an on-disk dictionary like e.g.
mxBeeBase:

https://www.egenix.com/products/python/mxBase/mxBeeBase/

--
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source (#1, Jun 04 2008)

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>>mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/

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