Plone 4.1 with Apache and mod_wsgi (sorta)

Update 2011-06-01: Still not working perfectly, but I did manage to clean up a couple steps by using more of mod_wsgi’s bells and whistles:

• Using a .pth file and the WSGIPythonPath directive you don’t need to manually load all the eggs into sys.path
• Using Daemon Mode per Graham Dumpleton’s comment. To be honest I haven’t noticed any difference caused by this change…

Issues:

• The site is still slow (despite using Daemon Mode)
• I get signal errors. This is a known problem when trying to serve signal-dependent python stuff via mod_wsgi, but I’m not sure it causes any real problems.

  [Wed Jun 01 17:59:40 2011] [warn] mod_wsgi (pid=12739): Callback registration for signal 10 ignored.
  [Wed Jun 01 17:59:40 2011] [warn]   File "/var/www/Plone-ZEO-4.1rc2/zeocluster/zope2.wsgi", line 3, in
  [Wed Jun 01 17:59:40 2011] [warn]     application = make_wsgi_app(None, '/var/www/Plone-ZEO-4.1rc2/zeocluster/parts/client1/etc/zope.conf')
  [Wed Jun 01 17:59:40 2011] [warn]   File "/var/www/Plone-ZEO-4.1rc2/buildout-cache/eggs/Zope2-2.13.7-py2.6.egg/Zope2/Startup/run.py", line 68, in make_wsgi_app
  [Wed Jun 01 17:59:40 2011] [warn]     starter.prepare()
  [Wed Jun 01 17:59:40 2011] [warn]   File "/var/www/Plone-ZEO-4.1rc2/buildout-cache/eggs/Zope2-2.13.7-py2.6.egg/Zope2/Startup/__init__.py", line 90, in prepare
  [Wed Jun 01 17:59:40 2011] [warn]     self.registerSignals()
  [Wed Jun 01 17:59:40 2011] [warn]   File "/var/www/Plone-ZEO-4.1rc2/buildout-cache/eggs/Zope2-2.13.7-py2.6.egg/Zope2/Startup/__init__.py", line 340, in registerSignals
  [Wed Jun 01 17:59:40 2011] [warn]     self.cfg.trace])
  [Wed Jun 01 17:59:40 2011] [warn]   File "/var/www/Plone-ZEO-4.1rc2/buildout-cache/eggs/Zope2-2.13.7-py2.6.egg/Signals/Signals.py", line 115, in registerZopeSignals
  [Wed Jun 01 17:59:40 2011] [warn]     SignalHandler.registerHandler(SIGUSR1, showStacks)
  [Wed Jun 01 17:59:40 2011] [warn]   File "/var/www/Plone-ZEO-4.1rc2/buildout-cache/eggs/Zope2-2.13.7-py2.6.egg/Signals/SignalHandler.py", line 37, in registerHandler
  [Wed Jun 01 17:59:40 2011] [warn]     signal.signal(signum, self.signalHandler)

• In many cases I can’t POST to the site. I can log in as long as it’s not HTTP Basic, but I can’t edit pages or make site-setup configuration changes. Not sure why.

Notes:

• For the following instructions I did every step as the user apache, so Plone runs as that user, as does zeo. This may not be the absolute best practice, but it made things a bit simpler.
• You can substitute instance in probably every case I used client1.

1. Install Apache and mod_wsgi. Make sure to specify Python 2.6 for mod_wsgi.
2. Grab a Plone 4.1 release candidate and install it as the user apache. Use the same Python 2.6 as you did for mod_wsgi.
3. Create a path configuration file:

   $ ( # Do this in a subshell so we don't contaminate the IFS
   >   # variable in our normal shell.
   > cd /var/www/Plone-ZEO-4.1rc2/buildout-cache/eggs
   > eggs=( *.egg )
   > IFS=$'\n'
   > echo "${eggs[*]}" > mod_wsgi.pth
   > )

4. In your buildout directory create an empty file called ‘zope2.wsgi.in’ as a collective.recipe.template template.copy the bin/client1 file into zope2.wsgi.in (because you need all the egg paths)
5. Put these two lines in it:

   from Zope2.Startup.run import make_wsgi_app
   application = make_wsgi_app(None, '${zope-conf}')

6. Add a section called wsgi to your buildout.cfg file:

   [buildout]
   …
   parts =
           …
           wsgi
           …
   …
   [wsgi]
   recipe = collective.recipe.template
   input = zope2.wsgi.in
   output = zope2.wsgi
   zope-conf = ${client1:location}/etc/zope.conf

7. In your apache config:

   …
   WSGIPythonPath /var/www/Plone-ZEO-4.1rc2/buildout-cache/eggs/
   WSGIDaemonProcess neon processes=1 threads=1 python-path=/var/www/Plone-ZEO-4.1rc2/buildout-cache/eggs/
   WSGIProcessGroup neon
   WSGIScriptAlias / /var/www/Plone-ZEO-4.1rc2/zeocluster/zope2.wsgi
   
   <Directory "/var/www/Plone-ZEO-4.1rc2/zeocluster">
           Order allow,deny
           Allow from all
   </Directory>
   …

8. Run buildout and start the zeoserver.
9. I had some problems with HTTP Basic Authentication through WSGI, so I avoided it by starting the client without WSGI for the purpose of logging in to the ZMI to create the Plone site. bin/client1 fg
10. Log in to http://localhost:8080 and create the Plone site.
11. Once I had actually created the Plone site, I killed the client1 instance and removed the <http-server> section from zope.conf
12. Start apache, and observe the logs as you navigate around your Plone site on port 80.

As I said, my site is slow and a lot of errors appear in the logs, but it’s functional, which is better than I’ve seen it so far. More work on this later.