[kepler-users] Python execution within the Kepler Python actor...

Sat Nov 5 13:54:49 PDT 2011

Christopher, Alan, Josh:

OK.this is important enough to me that I wanted to include Alan Kennedy and
Josh Juneau into your response.  Christopher, many thanks for your effort to
upgrade Kepler 2.2 to Jython 2.5.2.  However, I'd like to have a little more
due diligence discussion before putting it to rest.

I'm also pasting below Alan Kennedy's response to my earlier query to
address the Jython 2.2 to 2.5.2 incompatibilities.

My interpretation of Alan's response containing the term "documentation"
seems to imply less of a problem and more of an explanation.  Alan?

>From this perspective, as a Kepler w/Jython 2.5.2 user, I certainly need to
understand what seemed to be deemed an issue in being able to upgrade to
Jython 2.5.2 due to the backward incompatibility (particularly as it related
to PyJavaInstance), to you being able to fairly easily upgrade after all.
Why did you not run into an issue with PyJavaInstance in Jython 2.5.2?  Are
we missing some functionality that users need to be aware of?

Back to my original intent of Eclipse IDE-based development of actors in
Kepler/Ptolemy using Jython.  In a purely technical context, I am more
comfortable using Jython than I am Java. Based upon my questions to the
Jython User's Group, I suspect that Alan and Josh are rolling their eyes at
this comment! J This is my primary motivation behind wanting to standardize
on developing Python actors in Jython for Kepler.  My company, Nimbis
Services, is also standardizing on the Jython Django web framework, and
we're thinking very hard about when we will begin a full evaluation of Scala
(a JVM functional programming language).  

I am thinking that all I need to do is to take the Ptolemy PythonActor
source code and take a look at the Java code for that actor and recode the
actor in Jython (Let's call this new actor JythonActor) from within Eclipse.
I'd like a suggestion from Josh or Alan regarding architecturally how they
would address the following issue:

Using a Jython package, or function call, or interface (probably not
applicable in Jython), have the newly coded JythonActor call the externally
developed "functional core" of the Python script that would effectively
"customize" the PythonActor according to the Jython script's behavior.  This
way I would only develop my Jython script packages and then integrate these
into the newly coded JythonActor through say a port parameter.  Better yet,
how about some sort of XML import solution that would identify the Jython
code that "decorates" the JythonActor's functionality.  I need a good
suggestion on how to do this elegantly such that it looks like someone with
serious programming skills thought it through and not kluge code from a chip
designer.

At present, the PythonActor solution is not integrated into the full
functional Eclipse-based JVM flow due to the Java implementation. I have
become far too reliant upon debugging my Jython code through the Eclipse IDE
and the interpretive nature of Jython to not have this working flawlessly.

Please let me know what each you think of my JythonActor approach.

Alan, Josh.Christopher is particularly interested in addressing Jython
licensing issues.  I get the gist of what he is after here, but I have
simply not been part of any of this, so I have to defer to kind attention on
this subject.

Kind regards, Marc

  _____  

[J. Marc]

> OK.please connect me with one of the Jython 2.2 to 2.5 developers.  I 

> will then work with them to determine how we could most effectively 

> migrate Kepler 2.2 from Jython 2.2 to Jython 2.5.2.

> 

> I will be working with one of the Kepler/Ptolemy II developers on this 

> migration.

This issue with PyJavaInstance when upgrading from 2.2 to 2.5 seems to be a
common enough issue that it requires documentation.

I'm not going to get to it immediately myself, so I've created an issue on
the issue tracker for it, if anyone feels like taking that up.

http://bugs.jython.org/issue1814

Regards,

Alan.

  _____  

J. Marc Edwards, Lead Architect

Semiconductor Design Portals

Nimbis Services, Inc.

Cell  - (919) 345-1021

Fax   - (919) 882-8602

Skype - (919) 747-3775

jmarcedwards at gmail.com

marc.edwards at nimbisservices.com

From: Christopher Brooks [mailto:cxh at eecs.berkeley.edu] 
Sent: Saturday, November 05, 2011 2:59 PM
To: marc.edwards at nimbisservices.com
Cc: J. Marc Edwards; kepler-users at kepler-project.org
Subject: Re: [kepler-users] Python execution within the Kepler Python
actor...

Hi Marc,
I updated Jython to 2.5.2, it was not that hard, updating the license files
took the most time.

I have a few of misgivings about Jython that might be good lessons for
Ptolemy and Kepler:

* Sadly, ptII/lib/jython.jar went from about 1Mb to 10Mb.  Does this mean
that Jython-2.5.2 is 10 times better than Jython-2.2.1?
If jython is supposed to be a scripting language, then why is it so large?
This seems to be a common trend where nice small languages get more and more
features.
  As an aside about Perl, see 
  Is Perl Better Than a Randomly Generated Programming Language? at

http://developers.slashdot.org/story/11/10/27/213231/is-perl-better-than-a-r
andomly-generated-programming-language

For comparison purposes, Ptolemy's ptsupport.jar is 3.5Mb and a standalone
Ptolemy demo including the GUI is 6.5Mb in jars.

Lesson: we need to keep an eye on code bloat and be able to deploy small run
times.

* Another issue with Jython-2.5.2 is that because they removed
org.python.core.PyJavaInstance some time after Jython-2.2.1, they should
have released Jython-2.5.2 as Jython-3.x.  Most projects bump up the major
version number when there are incompatibilities.

Lesson: Ptolemy bumps up the major version number with each ~yearly release.
Ptolemy has backward compatibility filters.  We do sometimes remove old
code, but only with major versions.

* The Jython license situation is a mess.
http://www.jython.org/license.html lists these licenses
- The Python Software Foundation License Version 2, which according to
Wikipedia is a BSD-style license
- The Jython-2.0 and 2.1 license, which is similar to a BSD-style license
- The JPython 1.1.x license, which is similar to BSD-style license

The software ships with these licenses in the LICENSE.txt file.

However, LICENSE_CPython.txt and LICENSE_Apache.txt are included.  There is
no mention as to what code actually uses those licenses.
LICENSE_CPython.txt includes four copyrights: 
 - Python Software Foundation License Version 2
 - BEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0
 - CNRI LICENSE AGREEMENT FOR PYTHON 1.6.1
 - CWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2
The last three look similar to BSD, but have various requirements.

I'll submit a bug report to Jython to get them to update their site.

Lesson: I'm not sure how Ptolemy and Kepler can avoid a similar complexity
issue.  I've been working on updating our license file and
we have a way to determine what licenses are used by a particular
configuration.
http://ptolemy.eecs.berkeley.edu/ptolemyII/ptII8.0/copyright.htm 
lists 7 licenses used by Ptiny, a small configuration of Ptolemy II.  One of
those 7 is the Jython-2.2.1 license, which is similar to the Jython-2.5.2
license.
The Kepler configuration of Ptolemy II uses 15 licenses in the Ptolemy II
code.

_Christopher

On 11/5/11 9:15 AM, J. Marc Edwards wrote: 

Christopher:

I suspect that I can simply code an entire actor extending the respective
classes directly in Jython.

That is what I am thinking.  Please let me know what you think of this
strategy.

Of course, while I do this, I want to migrate a Kepler development tree to
use Jython 2.5.2, which I will need your assistance in completing.

Let's talk on the phone on Monday.

Regards, Marc

J. Marc Edwards, Lead Architect

Semiconductor Design Portals

Nimbis Services, Inc.

Cell  - (919) 345-1021

Fax   - (919) 882-8602

Skype - (919) 747-3775

jmarcedwards at gmail.com

marc.edwards at nimbisservices.com

From: Christopher Brooks [mailto:cxh at eecs.berkeley.edu] 
Sent: Friday, November 04, 2011 9:00 PM
To: marc.edwards at nimbisservices.com
Cc: kepler-users at kepler-project.org
Subject: Re: [kepler-users] Python execution within the Kepler Python
actor...

Hi Marc,

On 11/4/11 2:09 PM, J. Marc Edwards wrote: 

I need a little help in integrating my Jython/Python code into the Python
actor.

When I double-click on the Python actor in the PythonDialogExample, a window
with the Python code appears.  I can of course edit the code from within
this window.  However, I want to perform my code development and editing
from within my Eclipse environment from my Kepler development build.

I don't know that much about Python, but I believe that you could use the
Python import facility to find imports.
I just added text to the Kepler Jython page about this, see:
https://kepler-project.org/developers/reference/python-and-kepler#how-jython
-finds-imports

Note that I found a few other references on the web, included what appears
to be people who are using the full version of Python (not Jython) with
Kepler.

When I "open the actor", the beginning of the file has some Javadoc as well
as what appear to be some unmatched XML elements (<p>), along with some
matching XML element tags (</pre>) (does this correspond to some pre-fire
method?).

When you open the actor, you are seeing the Java code that implements the
PythonActor.  The <p> tags are html tags used in the javadoc comments of the
Java file.  All of the instances of the PythonActor share the same Java
code, but may have different Python code.

After this all of the Java code for the actor follows with the standard
initialize(), stop(), stopFire(), preinitialize(), terminate(), etc,
methods.

I do see in the Java code where there is a PythonScript method that accepts
a CompositeEntity where a script template is provided where I am supposing a
long Python string in the script.setExpression is defined.

However, what I would like to do is simply include my Jython module within
my Kepler build and debug my Jython code in connection with my overall
workflow.

Can someone tell me how to go about achieving this objective?

It looks like Jython uses sys.path to find imports.  I included a Ptolemy II
model that opens in the devel version of Kepler that lists the contents of
sys.path.  For further information about sys.path, see

http://jythonpodcast.hostjava.net/jythonbook/en/1.0/ModulesPackages.html

_Christopher

Thanks, Marc

-- 

J. Marc Edwards
Lead Architect - Semiconductor Design Portals
Nimbis Services, Inc.
Skype: (919) 747-3775
Cell:  (919) 345-1021
Fax:   (919) 882-8602
marc.edwards at nimbisservices.com
www.nimbisservices.com

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-- 
Christopher Brooks, PMP                       University of California
CHESS Executive Director                      US Mail: 337 Cory Hall
Programmer/Analyst CHESS/Ptolemy/Trust        Berkeley, CA 94720-1774
ph: 510.643.9841                                (Office: 545Q Cory)
home: (F-Tu) 707.665.0131 cell: 707.332.0670 

-- 
Christopher Brooks, PMP                       University of California
CHESS Executive Director                      US Mail: 337 Cory Hall
Programmer/Analyst CHESS/Ptolemy/Trust        Berkeley, CA 94720-1774
ph: 510.643.9841                                (Office: 545Q Cory)
home: (F-Tu) 707.665.0131 cell: 707.332.0670 
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