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UPDATE / 13 March 2009: snakefight 0.3 now has a –include-jar option, prefer that to using my hack.

After reading P. Jenvey’s blog post about Deploying Pylons Apps to Java Servlet Containers I immediately downloaded the Jython 2.5 beta and installed snakefight to give it a try. One of our services where I work is a Pylons based application. It is deployed using paster and Apache ProxyPass. Our main application is written in Java and is deployed as a war under Jetty. So if I can get my Pylons application built as a war and deployed that way, it would greatly simplify our deployment process.

$ sudo /opt/jython25/bin/easy_install snakefight
$ /opt/jython25/bin/jython setup.py develop
$ /opt/jython25/bin/jython setup.py bdist_war --paster-config dev_r2.ini
... output of success and stuff ...
$ cp dist/project-0.6.8dev.war /opt/jetty/webapps

Now I visit my local server and hit the project context. I get some database errors, kind of expected them. So for the time being, I’ll be running this directly using Jython to speed up the debugging process. A quick googling of my DB issues turns up zxoracle for SQLalchemy which uses Jython zxJDBC. I install that in to sqlalchemy/databases as zxoracle.py and give it another go. Changing the oracle:// lines in my .ini file to now read zxoracle:// Now it can’t find the 3rd party Oracle libraries (ojdbc.jar).

$ cd ./dist
$ jar xf project-0.6.8dev.war
$ cd WEB-INF/lib
$ ls
# no ojdbc.jar as expected ...
$ cd ~/project
$ export CLASSPATH=/opt/jython25/jython.jar:/usr/lib/jvm/java/jre/lib/ext/ojdbc.jar
$ /opt/jython25/bin/jython /opt/jython25/bin/paster serve --reload dev_r2.ini

Now it is looking a little better and it able to find the jar, but still a DB issue, now with SQLalchemy library. Not having a ton of time to investigate, I decide to try rolling back my SQAlachemy version for Jython. Turns out rolling back to 0.5.0 fixed the issue. I’ll be investigating why it was breaking with 0.5.2 soon ™. So now I rerun it, and get a new error.

AttributeError: 'ZXOracleDialect' object has no attribute 'optimize_limits'

I decide I am just going to go in to the zxoracle.py and add optimize_limits = False to the ZXOracleDialect. No idea what this breaks or harms, but I do it anyway and rerun the application. Success! Every thing is working now. No liking the idea of having to manually insert the Oracle jar in to the WEB-INF/lib and not really wanting to much around with environment variables, I also implemented a quick and dirty include-java-libs for snakefight, the diff for command.py is below. This allows me to pass in a : separated list of jars to include in the WEB-INF/lib. EDIT: The diff I posted isn’t needed since I put it on my hg repo. You can grab it from here.

So now I am back to building my war. Just as before.

$ /opt/jython25/bin/jython setup.py bdist_war --paste-config dev_r2.ini --include-java-libs /opt/jython25/extlibs/ojdbc.jar
running bdist_war
creating build/bdist.java1.6.0_12
creating build/bdist.java1.6.0_12/war
creating build/bdist.java1.6.0_12/war/WEB-INF
creating build/bdist.java1.6.0_12/war/WEB-INF/lib-python
running easy_install project
adding eggs (to WEB-INF/lib-python)
adding jars (to WEB-INF/lib)
adding WEB-INF/lib/jython.jar
adding Paste ini file (to dev_r2.ini)
adding Paste app loader (to WEB-INF/lib-python/____loadapp.py)
generating deployment descriptor
adding deployment descriptor (WEB-INF/web.xml)
created dist/project-0.6.8dev-py2.5.war
$ cp dist/project-0.6.8dev-py2.5.war /opt/jetty/webapps
$ sudo /sbin/service jetty restart

And presto! I am in business. My pylons application is deployed under Jetty and all the selenium functional tests are passing. I am sure there is probably a easier, neater, or cleaner way to do all this, but this was my first iteration through and also my first time ever deploying a WAR to a java servlet container so all in all I am happy with the results. Performance seems about the same as when running the application with paster serve, but Jetty does use a little more memory than before (expected I guess).