[Zope] Z2 CONFLICT Competing writes and synchronization woes
(Google -- which normally does an absolutely stunning job of directing me to answers to Zope questions -- has drawn a blank on this one:) I have an external method that writes stuff to a file. I want to synchronize access to the file so that multiple callers can be adding stuff to the file without problems. Without any synchronization I get interleaved output most of the time and occasionally an error message like this: "Z2 CONFLICT Competing writes at, /foo" I tried using the threading module and creating a Lock object as a global in the external method. This does not help as each request gets allocated its own Lock object. I tried Rlock got an error message I didn't understand and concluded I don't know what I'm doing:-) Any pointers to the best way to do synchronization of access to the filesystem from external methods? regards, Sean McGrath ___ Zope maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope-dev )
Re: [Zope] Z2 CONFLICT Competing writes and synchronization woes
Sean McGrath writes: I want to synchronize ... I tried using the threading module and creating a Lock object as a global in the external method. This does not help as each request gets allocated its own Lock object As you observed, each thread gets its own global namespace for a file containing an external method. The namespace of a true Python module, however, is shared by all threads. Therefore, it is a good place for your lock. Do the following (or something along similar lines): * create a properly named subpackage in "lib/python/Shared" (to avoid name clashes), say "myCompany". * create a Python module in "myCompany", say "myLock.py". * create your lock in this module, say "Lock" * access it in your external method by: from Shared.myCompany.myLock import Lock Dieter ___ Zope maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope-dev )
