Re: [Zope-dev] Re: post publishing hook
Dieter Maurer <[EMAIL PROTECTED]> wrote: > Christian Heimes wrote at 2005-4-1 22:28 +0200: > > ... > >You want to bind some actions to the transaction system because you want > >to execute some code at the end of the first phase of the 2 phase > >commit. > > I do not think that Florent wants to execute things at the end > or in the first commit phase. Instead, he wants to execute something > *BEFORE* this phase. Yes, wherever it's inserted, I want to do additional processing before everything is finalized, and in some cases I want to be able to abort the transaction, and to create and change objects in the ZODB. > >Hooking into the transaction machinery of ZODB is very easy. Write > >your own DateManager implementing the IDateManager interface and > >register it into the current transaction using get_transaction.register(DM). > > > >For your use case overwrite the tpc_vote() method of the data manager to > >do the indexing at the boundary between the two phases. > > This will not work for Florent's use case, > at least not in the current ZODB (for Zope 2.7). > > Reason: > > The transaction freezes the set of objects it processes > in the commit *BEFORE* the first commit phase. > > Therefore, no "tpc_vote" is allowed to modify any persistent > object. Failure to do so leads to extremely nasty > persistency errors (the object is marked changed but > no transaction knows about it -- no change to this object in the future > will get persisted until a restart). Ah, that was what I was afraid of, but I was assured it was not the case. I'll have to reread that transaction code... and maybe readd the low-tech post-publishing hook I was thinking of. Thanks Dieter, Florent -- Florent Guillaume, Nuxeo (Paris, France) CTO, Director of R&D +33 1 40 33 71 59 http://nuxeo.com [EMAIL PROTECTED] ___ Zope-Dev maillist - Zope-Dev@zope.org http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Re: post publishing hook
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, Dieter Maurer wrote: > Christian Heimes wrote at 2005-4-1 22:28 +0200: > >>... >>You want to bind some actions to the transaction system because you want >>to execute some code at the end of the first phase of the 2 phase >>commit. > > > I do not think that Florent wants to execute things at the end > or in the first commit phase. Instead, he wants to execute something > *BEFORE* this phase. > That was the initial idea in our case. > >>Hooking into the transaction machinery of ZODB is very easy. Write >>your own DateManager implementing the IDateManager interface and >>register it into the current transaction using get_transaction.register(DM). >> >>For your use case overwrite the tpc_vote() method of the data manager to >>do the indexing at the boundary between the two phases. > > > This will not work for Florent's use case, > at least not in the current ZODB (for Zope 2.7). > > Reason: > > The transaction freezes the set of objects it processes > in the commit *BEFORE* the first commit phase. > > Therefore, no "tpc_vote" is allowed to modify any persistent > object. Failure to do so leads to extremely nasty > persistency errors (the object is marked changed but > no transaction knows about it -- no change to this object in the future > will get persisted until a restart). > > I've been implementing a IndexationManager hook doing the job for CPS but I get the error your talking about... Thanks Dieter for the explanation. Your mail just arrived when I was trying to understand the persistency problems :( I got POSKeyError, Unauthorized (at catalog level while indexing and trying to get object attributs) or KeyError (Connection.setState()) exceptions randomly as well. Is there a way to hook before the first transaction commit phase ? J. - -- Julien Anguenot | Nuxeo R&D (Paris, France) CPS Plateform : http://www.cps-project.org mail: anguenot at nuxeo.com; tel: +33 (0) 6 72 57 57 66 -BEGIN PGP SIGNATURE- Version: GnuPG v1.2.6 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFCUFReGhoG8MxZ/pIRAi2jAJ4hXTAJhqJB8czSkQpVCCBEKzWXtACfXA/m S4JfeBF+TWweLWPSoxobPEE= =8zPL -END PGP SIGNATURE- ___ Zope-Dev maillist - Zope-Dev@zope.org http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Re: post publishing hook
Christian Heimes wrote at 2005-4-1 22:28 +0200: > ... >You want to bind some actions to the transaction system because you want >to execute some code at the end of the first phase of the 2 phase >commit. I do not think that Florent wants to execute things at the end or in the first commit phase. Instead, he wants to execute something *BEFORE* this phase. >Hooking into the transaction machinery of ZODB is very easy. Write >your own DateManager implementing the IDateManager interface and >register it into the current transaction using get_transaction.register(DM). > >For your use case overwrite the tpc_vote() method of the data manager to >do the indexing at the boundary between the two phases. This will not work for Florent's use case, at least not in the current ZODB (for Zope 2.7). Reason: The transaction freezes the set of objects it processes in the commit *BEFORE* the first commit phase. Therefore, no "tpc_vote" is allowed to modify any persistent object. Failure to do so leads to extremely nasty persistency errors (the object is marked changed but no transaction knows about it -- no change to this object in the future will get persisted until a restart). >Jens Vagenpohl's mail host and Chris McD's blob have example code for you. But they do not change persistent objects (at least, I hope so). -- Dieter ___ Zope-Dev maillist - Zope-Dev@zope.org http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Re: post publishing hook
Christian Heimes <[EMAIL PROTECTED]> wrote: > Florent Guillaume wrote: > > I really could use a post publishing hook. > > Standard use case: delay indexing at the end of the request to only do > > it once per object even if the object has been modified 4 times. > > Using a post publishing hook for this use case isn't a good idea - IMO. > The Publisher has nothing to with indexing. It's a completly different > part of the architecture. > > You want to bind some actions to the transaction system because you want > to execute some code at the end of the first phase of the 2 phase > commit. That's a completly different story than the post publishing > hook. Hooking into the transaction machinery of ZODB is very easy. Write > your own DateManager implementing the IDateManager interface and > register it into the current transaction using get_transaction.register(DM). [note: s/IDateManager/IDataManager/ above] > > For your use case overwrite the tpc_vote() method of the data manager to > do the indexing at the boundary between the two phases. > > Jens Vagenpohl's mail host and Chris McD's blob have example code for you. Ok, Tres also recommended something like that. I was a bit concerned that there would be problems in case of conflicts, or if there was a need to tweak the body returned to the user, but after reading transaction's code and MailDropHost and re-re-reading Publisher.py, I'm confident I can do everything I need. Thanks a lot, this together with events will make things much easier in our framework. Florent -- Florent Guillaume, Nuxeo (Paris, France) CTO, Director of R&D +33 1 40 33 71 59 http://nuxeo.com [EMAIL PROTECTED] ___ Zope-Dev maillist - Zope-Dev@zope.org http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
[Zope-dev] Re: post publishing hook
Florent Guillaume wrote: I really could use a post publishing hook. Standard use case: delay indexing at the end of the request to only do it once per object even if the object has been modified 4 times. Using a post publishing hook for this use case isn't a good idea - IMO. The Publisher has nothing to with indexing. It's a completly different part of the architecture. You want to bind some actions to the transaction system because you want to execute some code at the end of the first phase of the 2 phase commit. That's a completly different story than the post publishing hook. Hooking into the transaction machinery of ZODB is very easy. Write your own DateManager implementing the IDateManager interface and register it into the current transaction using get_transaction.register(DM). For your use case overwrite the tpc_vote() method of the data manager to do the indexing at the boundary between the two phases. Jens Vagenpohl's mail host and Chris McD's blob have example code for you. Christian ___ Zope-Dev maillist - Zope-Dev@zope.org http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
