Spring Python does NOT run on Jython

[gregturn]

UPDATED 11/5/2009: The topic discussed on the following thread has become moot. Spring Python 1.1 swapped out Amara's XML parser for ElementTree, so now it works perfectly on Jython. See http://blog.springpython.webfactiona...s-with-jython/ for a detailed example.
================================================== ================================================== ======================

Well, it is with great sadness that I must report my attempt to run the Spring Python test suite against jython 2.5b0 failed. In fact, it didn't really get very far. It is a core issue involved with the tools used to install amara (or any easy_install based tool).

It depends on a small variable called sys.executable, which for jython is empty, required to implement the "shebang". To read more, you can see http://bugs.python.org/setuptools/issue27, where the issue is known and tracked to some degree.

I don't know if jython will solve this problem, but until I can find a way to execute:

jython easy_install amara

...we will NOT have jython support.

[Frank Wierzbicki]

sys.executable can be specified in Jython 2.5b0. The jython command generated by the installer and the one included in the dev build ([jython_home]/dist/bin/jython) should have one set. Apparently the spam filter is not allowing me to post urls, but I think I can follow up with one...

Just do this on *nix:

java -Dpython.executable="$0" org.python.util.jython

This on Windows:

java.exe -Dpython.executable="%0" org.python.util.jython

-Frank

[Frank Wierzbicki]

More on sys.executable in Jython can be found here: http://article.gmane.org/gmane.comp....hon.devel/4068

[gregturn]

That step didn't help me. I even have my jython script updated with those settings, but it still fails to populate sys.executable.

[springpython@web35 Amara-1.2a2]$ java -Dpython.executable="$0" -Dpython.home="/home/springpython/jython2.5b0" -classpath "$CP" org.python.util.jython setup.py install
sys.executable = None
Traceback (most recent call last):
  File "setup.py", line 7, in <module>
    from setuptools import setup, find_packages
  File "/home/springpython/jython2.5b0/Lib/site-packages/setuptools-0.6c9-py2.5.egg/setuptools/__init__.py", line 2, in <module>
  File "/home/springpython/jython2.5b0/Lib/site-packages/setuptools-0.6c9-py2.5.egg/setuptools/extension.py", line 2, in <module>
  File "/home/springpython/jython2.5b0/Lib/site-packages/setuptools-0.6c9-py2.5.egg/setuptools/dist.py", line 5, in <module>
  File "/home/springpython/jython2.5b0/Lib/site-packages/setuptools-0.6c9-py2.5.egg/setuptools/command/install.py", line 2, in <module>
  File "/home/springpython/jython2.5b0/Lib/distutils/command/install.py", line 15, in <module>
    from distutils.sysconfig import get_config_vars
  File "/home/springpython/jython2.5b0/Lib/distutils/sysconfig.py", line 30, in <module>
    argv0_path = os.path.dirname(os.path.abspath(sys.executable))
  File "/home/springpython/jython2.5b0/Lib/posixpath.py", line 413, in abspath
    if not isabs(path):
  File "/home/springpython/jython2.5b0/Lib/posixpath.py", line 51, in isabs
    return s.startswith('/')
AttributeError: 'NoneType' object has no attribute 'startswith'
[springpython@web35 Amara-1.2a2]$

My jython script is now

#!/bin/sh

CP=/home/springpython/jython2.5b0/jython-complete.jar
if [ ! -z $CLASSPATH ]
then
  CP=$CP:$CLASSPATH
fi
java -Dpython.executable="$0" -Dpython.home="/home/springpython/jython2.5b0" -classpath "$CP" org.python.util.jython "$@"

[gregturn]

Okay, I don't know what happened, but I tried jython setup.py install inside the Amara directory, and started getting results, so disregard my last posting.

However, things still didn't get much further. This is the output from trying to to install amara:

[springpython@web35 Amara-1.2a2]$ jython setup.py install
running install
running bdist_egg
running egg_info
writing Amara.egg-info/PKG-INFO
writing top-level names to Amara.egg-info/top_level.txt
writing entry points to Amara.egg-info/entry_points.txt
writing dependency_links to Amara.egg-info/dependency_links.txt
writing requirements to Amara.egg-info/requires.txt
reading manifest file 'Amara.egg-info/SOURCES.txt'
writing manifest file 'Amara.egg-info/SOURCES.txt'
installing library code to build/bdist.java1.6.0_10-rc2/egg
running install_lib
running build_py
creating build/bdist.java1.6.0_10-rc2/egg
creating build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/bindery.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/trimxml.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/domtools.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/binderytools.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/dateutil_standins.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/binderyxpath.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/pyxml_standins.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/saxtools.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/flextyper.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/__init__.py -> build/bdist.java1.6.0_10-rc2/egg/amara
copying build/lib/amara/scimitar.py -> build/bdist.java1.6.0_10-rc2/egg/amara
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/bindery.py to bindery$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/trimxml.py to trimxml$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/domtools.py to domtools$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/binderytools.py to binderytools$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/dateutil_standins.py to dateutil_standins$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/binderyxpath.py to binderyxpath$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/pyxml_standins.py to pyxml_standins$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/saxtools.py to saxtools$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/flextyper.py to flextyper$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/__init__.py to __init__$py.class
byte-compiling build/bdist.java1.6.0_10-rc2/egg/amara/scimitar.py to scimitar$py.class
creating build/bdist.java1.6.0_10-rc2/egg/EGG-INFO
copying Amara.egg-info/PKG-INFO -> build/bdist.java1.6.0_10-rc2/egg/EGG-INFO
copying Amara.egg-info/SOURCES.txt -> build/bdist.java1.6.0_10-rc2/egg/EGG-INFO
copying Amara.egg-info/dependency_links.txt -> build/bdist.java1.6.0_10-rc2/egg/EGG-INFO
copying Amara.egg-info/entry_points.txt -> build/bdist.java1.6.0_10-rc2/egg/EGG-INFO
copying Amara.egg-info/requires.txt -> build/bdist.java1.6.0_10-rc2/egg/EGG-INFO
copying Amara.egg-info/top_level.txt -> build/bdist.java1.6.0_10-rc2/egg/EGG-INFO
zip_safe flag not set; analyzing archive contents...
Unable to analyze compiled code on this platform.
Please ask the author to include a 'zip_safe' setting (either True or False) in the package's setup.py
creating 'dist/Amara-1.2a2-py2.5.egg' and adding 'build/bdist.java1.6.0_10-rc2/egg' to it
removing 'build/bdist.java1.6.0_10-rc2/egg' (and everything under it)
Processing Amara-1.2a2-py2.5.egg
removing '/home/springpython/jython2.5b0/Lib/site-packages/Amara-1.2a2-py2.5.egg' (and everything under it)
creating /home/springpython/jython2.5b0/Lib/site-packages/Amara-1.2a2-py2.5.egg
Extracting Amara-1.2a2-py2.5.egg to /home/springpython/jython2.5b0/Lib/site-packages
Amara 1.2a2 is already the active version in easy-install.pth
Installing trimxml script to /home/springpython/jython2.5b0/bin
Installing scimitar script to /home/springpython/jython2.5b0/bin
Installing flextyper script to /home/springpython/jython2.5b0/bin

Installed /home/springpython/jython2.5b0/Lib/site-packages/Amara-1.2a2-py2.5.egg
Processing dependencies for Amara==1.2a2
Searching for 4Suite-XML>=1.0
Reading http://pypi.python.org/simple/4Suite-XML/
Reading http://4suite.org/
Reading ftp://ftp.4suite.org/4Suite/
Best match: 4Suite-XML 1.0.2
Downloading http://pypi.python.org/packages/source/4/4Suite-XML/4Suite-XML-1.0.2.zip#md5=b5515baa72c1b88613af71d2af0a539a
Processing 4Suite-XML-1.0.2.zip
Running 4Suite-XML-1.0.2/setup.py -q bdist_egg --dist-dir /tmp/easy_install-VTNsWz/4Suite-XML-1.0.2/egg-dist-tmp-6KxXdd
error: Setup script exited with error: in packages/Xml.pkg: unsupported package attribute: sys

It seems it has trouble installing a followup package, 4Suite-XML. I pulled that down, and then tried to install it directly, and got the following stack trace:

[springpython@web35 4Suite-XML-1.0.2]$ jython setup.py install
error: in packages/Xml.pkg: unsupported package attribute: sys

Perhaps this is some issue with 4Suite. It appears to have some C extensions, and maybe that is too much for Jython.

[Frank Wierzbicki]

C-extensions are indeed too much for Jython to handle. More and more libraries and packages are including pure Python alternatives (see the standard lib heapq.py for an excellent example for how to do this) but that is far from the norm.

[aschaeffer]

dummy post to get url posting privileges:

   1. You are only allowed to post URLs to other sites after you have made 1 post or more.

[aschaeffer]

Hi Greg,

i just got springpython working on jython. On jython it isn't possible to use c-bindings, so amara can't be used for xml-parsing. I tried to exchange amara with Element-Tree and with some changes i got a simple application-context up and running. Element-Tree is a pure python implementation which is required for jython but is also available as a python extension (c-implementation).

On springpythononjython it is possible to get access to java classes. So it is of course possible to get a "bean" into your springpython application context like this:

<?xml version="1.0" encoding="UTF-8"?>
<objects xmlns="http://www.springframework.org/springpython/schema/objects"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/springpython/schema/objects
    http://springpython.webfactional.com/schema/context/spring-python-context-1.0.xsd">

	<!-- a python module -->
    <object id="pythonTest" class="py.org.seminode.springpythononjython.test.Test" />
    
    <!-- a java bean -->
    <object id="javaTest" class="org.seminode.springpythononjython.Test" />

</objects>

And it works:

[create_object] <java package org.seminode.springpythononjython 0x3> --- class: Test
Hello from spring java
[create_object] <module 'py.org.seminode.springpythononjython.test' from '/home/aschaeffer/dev/workspace/springpythononjython/src/python/py/org/seminode/springpythononjython/test.py'> --- class: Test
Hello from spring python

During my current project i will finish the Element Tree based XMLConfig class and will contribute it during the next days.

Regards,
Andreas

PS: As a nice gimmick: did you ever got springpython running as a java bean inside springframework? :-)
It works...

[gregturn]

Andreas,

I certainly appreciate your work here. That sounds like some excellent progress. Russ, Sylvain and I were discussing jython/ironpython/cpython and what should we shoot for on a separate thread. I would definitely like to hear your opinions about this.

See http://forum.springsource.org/showthread.php?t=60588 for that thread.

Regarding ElementTree, I haven't looked into it much. I fell in love with Amara for XML parsing. I will be very interested in seeing what your alternative looks like. I will also be debating whether we should go with a pure python parser for everything, or if having an ElementTree-based one is practical for jython-based solutions, while Amara better suits CPython solutions. There always pros and cons.

Regarding Spring Python-backed bean inside Spring Java, no I haven't done that. Are you referring to usage of jython, or instead of spring/java's ability to have script-based beans? Sounds intriguing. I guess I'm interesting in hearing a use case where it would be valuable to do that. I always have interoperability in the back of my mind.

BTW, if you have a patch to offer, I am always open to looking at opportunities for Spring Python.

Thanks,
Greg

[gregturn]

Russ posted a follow-up
============================================
I can't help but wonder if it would be possible to essentially configure the Spring Python container with the parser of choice in this regard. We could effectively extract out the parser role, hide it behind and interface and then explicitly inject the desired parser depending on environmental constraints?

My response:
============================================
I was thinking along the same lines. I can see a couple of strategies for doing this. One would be some sort of strategy pattern, where you inject the parser, and there is an interface. Another would be to have separate parsers, with the end goal returning the same container.

The approach I'm thinking is to The first cut to having another XML parser would be to clone every test case built around XMLConfig, create another parser called ThisNewXMLConfigParser, and start parsing for the same end results. Considering that XMLConfig was built TDD-style, I'm confident that there are MANY permutations covered, so if all tests passed, I would also be confident in the new parser.

Then we could compare the two parsers and try to extract common functionality. Considering XMLParser is at least 90% based on the API of amara, I predict little that could be refactored beyond a simple switch. To me, it seems easier to create a separate class right next to XMLParser.

One smooth thing would be to actually embed simple detection of whether this is CPython or Jython, using XMLParser by default, and switching to ThisNewXMLParser should the need arise. That would minimize the need for developers to code based on environment. THAT would be the biggest benefit, in my book!