[Babeldoc-devel] Re: Pipeline cache refreshing

[Sherman W. <sw...@ga...>]

Ken Geis and I are just getting into this, as part of dynamic deployment of
new/changed pipeline definitions, scanners and supporting files ie. XSLs.

I think that at the point in time where the pipeline(s) is being
reconfigured:

* The scanner for the pipeline is stopped from accepting new documents
* Documents already in the pipeline finish processing
* The reconfiguration occurs: new files deployed etc
* A clearCache on the effected pipeline happens
* The scanner for the pipeline restarts

To Mike's point about the "transactionality" of config data, it seems to me
that it is an unnecessary complication to implement the listener pattern to
reflect config updates.

Cheers,

Sherman

> Subject: RE: [Babeldoc-devel] Pipeline cache refreshing
> From: Michael Ansley <mic...@ze...>
> To: bab...@li...
> Organization:
> Date: 11 Dec 2003 18:39:52 +0000
>
> I think that it requires more than that.  First of all, do we want
> pipelines changing while documents are being processed?  If not, then,
> do we version configs?  How?  What is the most basic operation that is
> allowed a consistent set of config data?  All pipelines should present a
> consistent set of config data to any single document.  Once any document
> has started processing, the config data used for processing that
> document should be fixed, in my opinion (I'm open to arguments to the
> contrary, though).  A guess it's a bit like transactioning metadata in a
> relational database.  If somebody does an ALTER TABLE that affects data
> your query is busy with, you don't want it affecting your data (because
> it's likely to be catastrophic).
>
> So, I'm open to ideas and opinions.
>
> Cheers...
>
>
> MikeA
>
>
>
> On Thu, 2003-12-11 at 14:17, McDonald, Bruce wrote:
> > Yes,
> >
> > Do that.
> >
> > At a more fundamental level, we probably need to implement an listener
pattern on the configserver.  The client classes of the configuration data
(pipelines, journal, etc, etc) add themselves as data change listeners to
the configuration classes thereby being notified when the underlying data
changes.  They could register for change notices when the config files
changes...
> >
> > just an idea.
> >
> > Bruce.
> >
> > -----Original Message-----
> > From: Michael Ansley [mailto:mic...@ze...]
> > Sent: Wednesday, December 10, 2003 7:22 PM
> > To: bab...@li...
> > Subject: [Babeldoc-devel] Pipeline cache refreshing
> >
> >
> > Hi,
> >
> > I'm back on the trail of config refreshing, and now attacking the
> > pipeline configs.  It seems that PipelineFactory has a method
> > clearCache() and also clearCache(String name), but these methods are not
> > deemed generic to the role of IPipelineFactory.  Can I make them
> > generic?  Or are there implementations of IPipelineFactory for which
> > they do not make sense?
> >
> > Cheers...
> >
> >
> > MikeA