[Erp5-users] ERP5* dependencies and other questions (was: A question regarding ERP5Types)

Jean-Paul Smets jp at nexedi.com
Sat Jul 2 12:41:15 CEST 2005 

Thanks for this work. I think we should move this to erp5-devel.
I will comment on each dependency. We will then need some work to clean this 
up.

JPS.

Le jeudi 30 Juin 2005 13:18, Alexey Morozov a écrit :
> Hello!
>
> Sorry for a delay, I was busy building and playing w/ the packages ;-)
>
> Jean-Paul Smets wrotes:
> >>idea? Could it be efficiently used without the rest of ERP5 (I know
> >> that it doesn't depend on it directly)? What are possible
> >>problems and objections? Are there developer-level docs for it?
> >
> > ERP5Type can be used without ERP5 (the product). It was designed for
> > that. There might still be useless dependencies. If you can point them,
> > I can try to remove them.
>
> Using our automatic python dependency tracker, I found the following

What is this tool ? Do you have a URL ?

> dependencies (beside standard python and Zope) [at least to provide a
> complete list of features]:
>
> ERP5Type (rpm built from 0.9-1mdk):
>
>    python2.4(psyco)

This can be made an option.

>    python2.4(Products.BTreeFolder2.BTreeFolder2)
>    python2.4(Products.BTreeFolder2.CMFBTreeFolder)

This is required because BTreeFolder2 are a must to a few 1,000,000 objects 
in a folder. No way to change this.

>
>    python2.4(Products.CMFActivity.ActiveObject)

This is a required for active programming. Could become an option if we 
implement a fallback class which returns self each time self.activate() is 
called. I am not sure it is worth the effort though.

>    <... a lot of CMFCore modules ...>
>
>    python2.4(Products.DCWorkflow)
>    python2.4(Products.DCWorkflow.DCWorkflow)
>    python2.4(Products.DCWorkflow.Expression)
>    python2.4(Products.DCWorkflow.Transitions)
>

Required if you need workflows. It could be turned as an option too by using 
a wrapper class.

>    python2.4(Products.Localizer)

This dependency can be removed if alternate get_request implementation is 
provided in Utils.py

>
> CMFActivity (... 0.9-1mdk):
>
>    python2.4(Products.CMFCore)
>    python2.4(Products.CMFCore.utils)
>
>    python2.4(Products.ERP5Type)
>    python2.4(Products.ERP5Type.Base)
>    python2.4(Products.ERP5Type.Document.Folder)
>    python2.4(Products.ERP5Type.Error)
>    python2.4(Products.ERP5Type.Utils)
>

I think no dependency can be removed. Initial implementation of CMFActivity 
was not ERP5Type dependent. Current circular dependency between CMFActivity 
and ERP5Type is related to the fact that

	- ERP5Type is used as a development framework for CMFActivity
	- Base class of ERP5Type benefits from CMFActivity implementation of active 
object (activate method)


> ERP5Form (0.9-1mdk):
>
>    python2.4(Products.CMFCategory.Category)

CMFCategory could become optional, but then, there would be no way to use 
the tree mode in ListBox widget. Defining within ERP5Form an interface for 
trees is probably the way to go to break this dependency yet keep all the 
features of ListBox. Refactoring is needed and has been done partly 
already.

>    <... various CMFCore modules ...>

CMFCore are required

>    python2.4(Products.CMFReportTool.RenderPDF.Parser)
>    python2.4(Products.CMFReportTool.ReportTool)

Could be made optional if you do not care of having a nice PDF report 
engine.

>    python2.4(Products.ERP5.Document.Domain)

Could be made optional.

>    python2.4(Products.ERP5Type)
>    python2.4(Products.ERP5Type.Document)
>    python2.4(Products.ERP5Type.Utils)
>

No way to remove this dependency.

>    <... various Formulator submodules ...>
>
>    python2.4(psyco)

Could be made optional.

>
> The most interesting part of the game is dependency on
>
> python2.4(Products.ERP5.Document.Domain)
>
> that is we have to install entire ERP5 in order to safely use ERP5Form.

This can be removed (through an option import). 

> Also CMFReportTool appearently depends on various reportlab modules and

CMFReportTool  is a wrapper for reportlab. It is a great PDF generation 
system. We could make it optional though.

> has dependency python2.4(xml.sax.writer) which is actually a module from
> PyXML.

Yes. 

> I could provide the whole list of dependencies as well as rpm-build
> plugin to count them.

Please provide this list (in erp5-devel). 

> > What ERP5Type provides is
> > 	- ability to define data schema and semantic constraints in python
> > without restarting zope (PropertySheet)
>
> Even w/o ALLOW_CLASS_TOOL on the filesystem?

Even w/o ALLOW_CLASS_TOOL (but then without Web interface).

> > 	- ability to create new classes on the fly in python (without
> > restarting zope)
> > 	- ability to define menu actions (CMF)
> > 	- ability to define complex local role definition (ERP5Type)
> > 	- ability to specialise data schema on a per-portal type base (no need
> > to subclass for that)
> > 	- complete separation of data model (PropertySheet), object behaviour
> > (ERP5Type) and object presentation (ERP5Form)
> > 	- relations (if you have CMFCategory installed)
>
> Fine!
>
> > Although it is not necessary. It is better to consider using ERP5Type
> > together with ERP5Catalog and ERP5Form.
> > 	- ERP5Catalog provides ability to query Zope objects in SQL, which is
> > afterall very useful
> > 	- ERP5Form provides extended Formulator with a very useful ListBox
> > widget and some other tools for PDF generation for example
> >
> > And if you need high performance, CMFActivity is a must because it
> > distributes the load over nodes in a cluster. It is not required
> > though.
> >
> > If you combine ERP5Type, ERP5Catalog  and ERP5Form, you can develop new
> > applications which are completely unrelated to ERP5. One great aspect
> > of the combination of ERP5Type / ERP5Catalog  / ERP5Form is that is has
> > been tested on ZEO clusters with millions of catalogued objects and
> > that all performance issues related to size and load are now solved.
> >
> > If you want to try, my suggestion would be that you first create a mock
> > up of a mini application based on Kevin tutorial  then remove one by
> > one products. I will be glad to change code in ERP5Type / ERP5Catalog 
> > / ERP5Form so that useless dependencies are removed.
>
> Ok. Please look at the list above and tell if I can safely skip some of
> the requirements (or maybe somehow split a package into smaller ones).
>
> Thank you for your explanations. Now I'm trying to explore the new
> possibilities and see if we can easily move to these ERP5* packages.

I think it will be possible to reduce the dependencies a lot. 

JPS.


> Alexey Morozov.
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