[Jython-users] Servlet ImportError: Cannot import site module and its dependencies: No module named site

[David C. <dav...@gm...>]

I just created my first servlet in Jython2.7.0 running on Apache2/Tomcat6.
When I tried to access my servlet with my browser, I got the following
error message:

HTTP Status 500 - Servlet.init() for servlet PyServlet threw exception
------------------------------

*type* Exception report

*message* *Servlet.init() for servlet PyServlet threw exception*

*description* *The server encountered an internal error that prevented it
from fulfilling this request.*

*exception*

javax.servlet.ServletException: Servlet.init() for servlet PyServlet
threw exception
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
	org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
	org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:606)
	org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
	java.lang.Thread.run(Thread.java:745)

*root cause*

ImportError: Cannot import site module and its dependencies: No module
named site
Determine if the following attributes are correct:
  * sys.path: ['/var/lib/tomcat6/webapps/jythonsample/WEB-INF/lib/Lib',
'__classpath__', '__pyclasspath__/']
    This attribute might be including the wrong directories, such as
from CPython
  * sys.prefix: /var/lib/tomcat6/webapps/jythonsample/WEB-INF/lib
    This attribute is set by the system property python.home, although it can
    be often automatically determined by the location of the Jython jar file

You can use the -S option or python.import.site=false to not import
the site module

	org.python.core.Py.ImportError(Py.java:328)
	org.python.core.Py.importSiteIfSelected(Py.java:1563)
	org.python.util.PythonInterpreter.<init>(PythonInterpreter.java:116)
	org.python.util.PythonInterpreter.<init>(PythonInterpreter.java:94)
	org.python.util.PyServlet.createInterpreter(PyServlet.java:124)
	org.python.util.PyServlet.reset(PyServlet.java:170)
	org.python.util.PyServlet.init(PyServlet.java:90)
	javax.servlet.GenericServlet.init(GenericServlet.java:212)
	org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
	org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
	org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
	org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:606)
	org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
	java.lang.Thread.run(Thread.java:745)

*note* *The full stack trace of the root cause is available in the Apache
Tomcat/6.0.39 logs.*
------------------------------
Apache Tomcat/6.0.39This is a web application, so I am not using the
command-line interface (so I cannot pass -S), nor am I starting the
interpreter from some Java code (so I cannot set property
python.import.site).

As a quick experiment, I copied the my $JYTHON_HOME/Lib directory into
jythonsample/WEB-INF/libs and this made the ImportError go away.
Symlinking the $JYTHON_HOME/Lib directory also made the ImportError go
away.  But, both of these solutions seem dubious to me.  If I copy the Lib
folder I feel like I have greater certainty that jython.jar and the Lib
directory are a matched set, but my Lib directory is 99M in size!  If I
symlink the Lib folder, I save the 99M but I lose the certainty that I have
a matching jython.jar and Lib directory.

I have also considered creating a custom jython.jar that contains Lib, or
learning how to have a single, common jython.jar (and Lib) for all of my
servlets, but before I head down those paths I thought I would ask to see
what other people are doing.

David