[Zope] Sharing global data between threads / locking a method

[Pascal Peregrina]

I think that storing an "isMyProcessingStarted" property would not work,
because the transaction that modifies the property value would not be
committed until the long processing is done, so when the next transaction
that reads this value starts (if this happens before the previous one has
finished), it would still see the old value.

If you are using a single Zope instance, you can try something nasty like :
#to read the value :
try:
	test=_isMyProcessingStarted
except:
	test=0
#to write the value :
import __builtin__
__builtin__._isMyProcessingStarted=<value>

Hope that helps...

Pascal

-----Message d'origine-----
De : zope-bounces+pperegrina=lastminute.com at zope.org
[mailto:zope-bounces+pperegrina=lastminute.com at zope.org]De la part de
Jonathan
Envoyé : lundi 27 juin 2005 17:00
À : Jim Abramson; zope at zope.org; Max M
Objet : Re: [Zope] Sharing global data between threads / locking a
method



----- Original Message ----- 
From: "Jim Abramson" <jabramson at wgen.net>


>> A possible solution:  create a property field on the folder
>> where the external methods are stored.  Have your external
>> method update this property field when the external method
>> starts and again when it exits.  This way you can test
>> whether or not the external method is currently in operation.
>>  You could store this property field on a temp_folder for
>> faster performance.
>
> Curious,
>
> - to save variables in this way, must a Folder property be used, or
> would a class variable set on something that extends Folder work the
> same?

You can store the property field on/in any zope object that can be accessed via the external method.


> - why does temp_folder perform faster for this technique?

'temp_folder' folders are 'temporary' and only exist in memory (objects 
stored in/on 'temp_folders' are not written to the zodb), therefore are 
faster to access, but the downside is that when zope is shutdown all 
temp_folder content is lost.

Jonathan


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